Expert DD MSK

M
o 0
KELETAL
S.J.Manaster, MO, PhO, FACR

Professor of Radiology
University of Utah School of Medicine
Salt Lake City, Utah
Carollo Andrews, MO
Musculoskeletal Radiology
Mink Radiologic Imaging
Beverly Hills, California
Cheryl A. Petersilge, MD
Chair, Department of RadIOlogy
Vice Chair, Regional Radiology
Marymount Hospital, Cleveland Clinic Ilealth System
Cleveland, Ohio
Catherine C. Roberts, MD
Associate Dean, Mayo School of Health Sciences
Associate Professor of Radiology
Consultant Radiologist
Mayo Clinic
Scottsdale, Arizona
AMIRSYS8
Names you know. Content you trust.8
iii
AMIRSYS
Names you know. Content you trust.'"
First Edition
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Printed in Canada by Friesens, Altona, Manitoba, Canada
ISBN: 978-1-9318-8403-7
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Library of Congress Cataloging-ill-Publication Data
Manaster, B. J.
Expertddx. Musculoskeletal / B.j. Manaster. n 1st ed.
p.; em.
title: Musculoskeletal
Includes index.
ISBN 978-1-931884-03-7
I. Musculoskeletal systemnDiseases--Diagnosis--Atlases. 2. Diagnosis, DifferentialnAtiases. I. Title. II. Title: Musculoskeletal.
IDNLM: I. Musculoskeletal Diseases--diagnosis--Atlases. 2. Musculoskeletal SystemnAtiases. 3. Diagnosis, Differential--i\tlases. WE
17 M267e 20081
RC925.7.M3482008
612.7022'2ndc22
2008039950
iv
The authors wish to dedicate this book to our fellow musculoskeletal radiologists, past and present.
ft was not so many decades ago that osseous neoplasms were not recognized as distinguishable entities,
and arthritides were treated radiographically as a sil/gle process, Dedicated l1IusCliloskeletalradiologists
were few and far betweel/; howeve/; these few individuals began to make important observations and
sllClrethem with one another, This sharing process grew into two major societies, the Society of Skeletal
Radiology al/d the International Skeletal Society, both of which continue to serve as excellent sounding
boards and learning opportunities for I/lusCliloskeletal radiologists. Many of these individuals se/ved
as our mentors. As we conducted research for this book, we came to realize how significant their
contributions were; we are tmly standing on the shoulders of giants. We authors have also reinforced our
affection for one aI/other; throughout the process of producing this book, we have continued to learn fi'O/lI
ol/e al/otlm; enjoy one another's support, and feel inspired toward continued growth.
v
Once the appropriate technical protocols have been delineated, the best quality images obtained,
and the cases queued up on PACS, the diagnostic responsibility reaches the radiology reading room. The
radiologist must do more than simply "lay words on" but reach a real conclusion. If we cannot reach a
definitive diagnosis, we must offer a reasonable differential diagnosis. A list that's too long is useless; a list
that's too short may be misleading. To be useful, a differential must be more than a rote recitation from
some dusty book or a mnemonic from a lecture way back when. Instead, we must take into account key
imaging findings and relevant clinical information.
With these considerations in mind, we at Amirsys designed our Expert Differential Diagnoses series-
EXPERTddx for short. Leading experts in every subspecialty of radiology identified the top differential
diagnoses in their respective fields, encompassing specific anatomic locations, generic imaging findings,
modality-specific findings, and clinically based indications. Our experts gathered multiple images, both
typical and variant, for each EXPERTddx. Each features at least eight beautiful images that iUustrate the
possible diagnoses, accompanied by captions that highlight the pertinent imaging findings. Hundreds
more are available in the eBook feature that accompanies every book. In classic Amirsys fashion, each
EXPERTddx includes bulleted text that distills the available information to the essentials. You'll find
helpful clues for diagnoses, ranked by prevalence as Common, Less Common, and Rare but Important.
Our EXPERTddx series is designed to help radiologists reach reliable-indeed, expert-conclusions.

Whether you are a practicing radiologist or a resident/fellow in training, we think the EXPERTddx series
wiIJ quickly become your practical "go_to" reference.
Anne G. Osborn, MD
Executive Vice President and Editor-in-Chief, Amirsys lne.
Paula]. Woodward, MD
Executive Vice President and Medical Director, Amirsys Ine.
vii
PREFACE
The world of musculoskeletal radiology is becoming daunting, with a huge knowledge base required as
we confront an exponentially expanding number of diagnoses and their associated imaging characteristics.
We all continually attack the steep learning curve required to stay "on top" of the subspecialty, and we
welcome reference material that can quickly address specific questions regarding an imaging finding or
clinical presentation. Ex ert Differential Dia nosis: Musculoskeletal is a unique collection addressing
this need; it offers over 200 expert differential diagnoses that cover a broad spectrum of musculoskeletal
diseases, including trauma, arthritis, tumor, congenital, and metabolic disease. The lists are those our
authors feel are most useful in our daily work. They are organized according to likelihood of occurrence,
and there is both text and imaging provided to further differentiate among the differential possibilities.
The book has three major sections. The "Clinically Based" differentials will serve you best when you
are given a general directive to determine the source of pain (for example, "lateral hip pain", "nerve
entrapment of the lower extremity") or clinically observed abnormality (for example, "cavus foot
deformity", "arthritis in a teenager", "hemihypertrophy"). The "Image Based" differentials will serve you
best when you have a unique imaging appearance that has a relatively short differential (for example,
"target lesions of bone", "nodular calcification", "lesion with bright Tl signal", "enlarged peripheral
nerves"). The" Anatomy Based" differential list is necessarily long in this musculoskeletal text. Anatomic
location of abnormalities is crucially important in the musculoskeletal system. Thus, there are lists of
abnormalities involving some specific bone or joint locations (for example, "solitary rib lesion", "tibial
bowing", "fluid collections about the knee"). There are also anatomic differential lists with more generic
locations (for example, "flat bone, bubbly lesion", "long bone, undertubulation", "MCP-predominant
arthritis"). ote that, among the long bone differential lists, there is a differentiation according to
location along the length of the bone (epiphyseal/subchondral, metaphyseal, diaphyseal) as well as
transversely across the bone (central, eccentric, cortically based, surface location).
Take a few moments to look at the table of contents and familiarize yourself with the layout of the
book. You will then recognize that an abnormality you are seeking to define may be found in several lists.
For example, an abnormality consisting of multiple aggressive lesions in the pelvic girdle of a child would
be included in the "flat bones, permeative lesion" list in the anatomy based section, but also would be
discussed in the "polyostotic lesions, child" list in the image based section. Another example might be of
a hand radiograph showing acroosteolysis and DIP erosions. This would be included in the anatomically
based list "acroosteolysis" found listed under "fingers and toes" as well as in the anatomically based list
"IP-predominant arthritis" found under "joints". Perusal of the table of contents will be valuable in
making best use of this reference.
We hope that you find this book useful in your daily practice of radiology and as a study guide if you
are just entering our specialty. It should be useful to orthopedic surgeons, physiatrists, rheumatologists,
and other practitioners as well. It is, of course, inevitable that we have neglected to discuss some
differentials (remember, though, that most spine discussions are found in the Brain and Spine text). It is
just as inevitable that we have left out some entities that belong in some of the lists or that the order we
have chosen in a list is debatable. We would be happy to hear your comments and suggestions. The eBook
companion allows us to add, alter, and update our lists. Email me at bjmanaster@amirsys.com and we will
consider your suggestions.
B.j. Manaster, MD, PhD, FACR

Professor of Radiology
University of Utah School of Medicine
Salt Lake City, UT
ix
ACKNOWLEDGMENTS
Text Editing
Douglas Grant Jackson
Ashley R. Renlund, MA
KellieJ. Heap
Image Editing
Jeffrey J. Marmorstone
Mitch D. Curinga
Medical Text Editing

Jay Johnson, MD
Art Direction and Design

Lane R. Bennion, M5
Richard Coombs, M5
Production Lead
Melissa A. Hoopes
50me images were previously published in Manaster BJ, May DA, Disler DG. Musculoskeletal Imaging: The Requisites. 2nd ed.
Philadelphia, PA: Mosby, Elsevier; 2002. Each of these images is Identified by "M5K Req" in the caption.
These images appear as follows: part.page.image; 1.5.1; 1.10.1; 1.14.2; 1.25.1; 1.25.3; 1.36.5; 1.37.1; 1.37.5; 1.39.5; 1.39.6; 1.42.5; 1.46.1;
1.47.6; 1.49.2; 1.50.2; 1.53.2; 1.54.2; 1.55.2; 1.55.5; 1.55.6; 1.57.5; 1.61.1; 1.61.2; 1.62.6; 1.65.3; 1.65.4; 1.77.6; 1.82.5; 1.82.6; 1.86.5; 1.87.1;
1.87.5; 1.87.6; 1.94.1; 1.95.1; 1.95.3; 1.95.4; 1.104.3; 1.106.2; 1.118.5; 1.121.3; 1.123.1; 1.124.1; 1.127.2; 1.129.1; 1.150.4; 1.156.1; 1.156.3;
1.157.4; 1.163.6; 1.182.5; 1.184.1; 1.189.5; 1.191.3; 1.191.4; 1.239.6; 1.249.2; 1.253.1; 1.253.2; 1.254.6; 1.257.3; 1.266.1; 1.278.1; 1.333.5;
1.339.1; 1.355.3; 1.355.4; 1.371.2; 1.371.6; 11.7.6; 11.8.2; 11.13.2; 11.15.2; 11.16.3; 11.17.4; 11.18.1; 11.19.2; 11.22.6; 11.23.3; 11.27.1; 11.31.4;
11.31.6; 11.35.6; 11.41.1; 11.41.2; 11.42.2; 11.43.2; 11.46.4; 11.47.3; 11.48.2; 11.49.3; [1.51.1; 11.57.1; 11.58.1; 11.86.3; 11.87.4; 11.91.1; 11.102.1;
11.102.2; 11.114.3; 11.114.5; 11.115.2; 11.118.4; 11.119.3; 11.120.1; 11.120. 5; [1.121.5; 11.123.2; 11.129.6; 11.142.5; 11.144.1; 11.145.1; 11.145.4;
11.158.1; 11.188.6; 111.17.1; 111.75.1; 111.112.4; 111.137.6; 111.1 51.5; 111.159.6; 111.177.3; 111.181.2; and 111.183.3.
xi
SECTIONS
PART I
Anatomy Based
Flat Bones
Long Bone, Epiphyseal
Long Bone, Metaphyseal
Long Bone, Meta-Diaphyseal
Long Bone, Growth Plate
Periosteum
Joint Based
Shoulder Girdle and Upper Arm
Elbow and Forearm
Wrist and Hand
Fingers and Toes
Intervertebral Disc
Paraspinal Abnormalities
Vertebral Shape
Vertebral Lesions
Ribs
Pelvis
Hip and Thigh
Knee and Lower Leg
Foot and Ankle
PART II
Image Based
Radiograph/CT, Osseous
Radiograph/CT, Soft Tissue
MR, Osseous
MR, Soft Tissue
MR, Joint
Ultrasound
Nuclear Medicine
PART III
Clinically Based
Elbow and Forearm
Wrist and Hand
Pelvis, Hip, and Thigh
Knee and Leg
Ankle and Foot
Spine
Systemic Disease
xiii
TABLE OF CONTENTS
Long Bone, Surface Ouxtacortical) Lesion 1-60
PART I BI Manaster, MD, 1'hD, FACR
Anatomy Based
Long Bone, Meta-Diaphyseal
Flat Bones Long Bone, Central Diaphyseal Lesion, 1-66
Flat Bones, Focally Expanded or Bubbly Lesion 1-2 Non-aggressive
B.f. Manaster, MD, PIID, FACR B.f. Manaster, MD, 1'IID, FACR
Flat Bones, Permeative Lesion 1-6 Long Bone, Diaphyseal Lesion, Aggressive: Adult 1-70
B./. Manaster, MD, PIID, FACR B.f. Manaster, MO, PhD, FACR
Long Bone, Diaphyseal Lesion, Aggressive: Child 1-74
B.f. Manaster, MO, I'hD, FACR
Long Bone, Epiphyseal
Long Bone, Aggressive Diaphyseal Lesion with 1-78
Long Bone, Epiphyseal: Irregular or Stippled 1-12 Endosteal Thickening
B.f. Manaster, MD, PIID, FACR B.f. Manaster, MD, PhD, FACR
Long Bone, Epiphyseal, Overgrowth/Ballooning 1-16 Long Bone, Cortically Based Diaphyseal Lesion, 1-80
BI Manaster, MD, PhD, FACR Sclerotic
Long Bone, Epiphysis, Sclerosis/Ivory 1-18 BI Manaster, MD, 1'hD, FA R
BI Manaster, MD, 1'110, FACR Long Bone, Cortically Based Diaphyseal Lesion, 1-84
Long Bone, Epiphyseal/Apophyseal/Subchondral 1-22 Lytic
Lytic Lesion BI Manaster, MD, PhD, FACII
BI Mallaster, MO, 1'110, FACR Long Bone, Diffuse Cortical/Endosteal 1-90
Thickening
Long Bone, Metaphyseal
Tibial Metadiaphyseal Cortically Based Lesion 1-94
Long Bone, Metaphyseal Bands & Lines 1-26 BI Mallaster, MD, PhO, FACR
Cheryt A. Petersilge, MD
Long Bone, Undertubulation 1-96
Long Bone, Metaphyseal Cupping 1-30 B./. Mal7I1ster, MD, I'hD, FACR
Cheryl A. l'etersilge, MO
Long Bone, Overtubulation 1-102
Long Bone, Metaphyseal Fraying 1-32 BI Manaster, MD, PhD, FACR
Cheryl A. Petersilge, MO
Long Bone, Central Metaphyseal Lesion, 1-34
Non-aggressive
Long Bone, Growth Plate
BI Manaster, MO, PhD, FACR Growth Plate, Premature Physeal Closure 1-106
Long Bone, Central Metaphyseal Lesion, 1-40 B.f. Manaster, MD, PhD, FACR
Aggressive Growth Plate, Widened Physis 1-108
BI Manaster, MD, PhD, FACR B.f. Manaster, MO, PhD, FACR
Long Bone, Metaphyseal Lesion, Bubbly 1-44
B.f. Manaster, MO, 1'IID, FACR
Periosteum
Long Bone, Eccentric Metaphyseal Lesion, 1-48
Periosteum: Aggressive Periostitis 1-1]2
Non-aggressive
Cat/JerilJe C. Roberts, MD
B.f. Manaster, MD, 1'hO, FACR
Long Bone, Eccentric Metaphyseal Lesion, I-S2 Periosteum: Solid Periostitis 1-116
Aggressive
B./. Manaster, MD, 1'hO, FACR Periosteum: Bizarre Horizontal Periosteal 1-]22
Long Bone, Cortically Based Metaphyseal Lesion I-56 Reaction
BI Manaster, MD, PI'D, FACR B.f. Manaster, MD, PhD, FACR
XIV
Periosteum: Periostitis Multiple 1-126 Anterosuperior Labral Variations/Pathology 1-218
Bones/Acropachy, Adult Catl1er;l1e C. Roberts, MO
E./. Mal/aster, MO, 1'110, FACR Fluid Collections about the Shoulder 1-222
Periosteum: Periostitis Multiple Bones, Child 1-130 Carol L. AI/drews, MO
EI Mal/asler, MO, 1'110, FACR
Elbow and Forearm

Joint Based Radial Dysplasias/ Aplasia 1-226
Arthritis with Normal Bone Density 1-134 Catl1er;l1e C. Roberts, MO
B.J. Mal1asler, MO, 1'110, FACR Forearm Deformity 1-228
Arthritis with Osteopenia 1-138 Catl1er;l1e C. Roberts, MO
B.J. Mal/aster, MO, 1'110,FACR
Arthritis with Productive Changes 1-142 Wrist and Hand
BI Mal1aster, MO, 1'110, FACR
Carpal Cystic/Lytic Lesions 1-232
Erosive Arthritis 1-146
Cl1eryl A. Petersilge, MO
R./. MalJaster, MO, 1'110, FACR
Abnormal Radiocarpal Angle 1-234
Mixed Erosive/Productive Arthritis 1-152
Catl1er;l1e C. Roberts, MO
B.J. Mal/aster, MO, 1'110, FACR
Arthritis with Large Subchondral Cysts 1-154
E.J. Mal/aster, MO, 1'110, FACR Fingers and Toes
Atrophic joint Destruction 1-158 Arachnodactyly 1-238
Cat/7eril1e C. Roberts, MO B./. MalJasler, MO, 1'110, FACR
Arthritis Mutilans 1-162 Soft Tissue Mass in a Finger 1-240
Catheril1e C. Roberts, MO Cather;l1e C. Roberts, MO
Neuropathic Osteoarthropathy 1-164 Acroosteolysis 1-246
B.J. Mcmaster, MO, 1'110, FACR B.J. Mal1aster, MO, 1'110, FACR
Arthritis with Preserved Cartilage Space 1-166 Acroosteosclerosis 1-250
EI Mallaster, MO, 1'110, FACR Catl1er;l1e C. Roberts, MO
Widened joint Space 1-170 Phalangeal Cystic/Lytic Lesions 1-252
Catl1er;l1e C. Roberts, MO HI Mal/asler, MO, 1'110, FACR
Ankylosis 1-176 Sesamoiditis 1-258
HI Mal/aster, MO, 1'110, FACR Carol L. AI/drews, MO
Calcified Intraarticular Body/Bodies 1-180 Short Metacarpal/Metatarsal 1-260
B.j. Ma'laster, MO, 1'110, FACR BI Mal/asler, MO, 1'110, FACR
Chondrocalcinosis 1-184 Ulnar Deviation (MCP joints) 1-264
B.J. Mallasler, MO, PhO, FACR Cat/lerirle C. Roberts, MO
Periarticular Calcification 1-186 Swelling & Periostitis of Digit (Dactylitis) 1-266
HI Mal1aster, MO, PhO, FACR H.j. Mal1aster, MO, 1'110, FACI?
MCP-Predominant Arthritis 1-192
BI Mal/aster, MO, 1'110, FACR
Intervertebral Disc
IP-Predominant Arthritis 1-194
H.J. Mal/aster, MO, 1'110, FACR Lesions Crossing a Disc Space 1-268
Monoarthritis 1-198
BI Mal1aster, MO, 1'110, FACR Discal Mineralization 1-270
lntraarticular Mass 1-202
BI Mal1aster, MO, 1'110, FACR
Arthroplasty with Lytic/Cystic Lesions 1-206 Paraspinal Abnormalities
HI Mal/aster, MO, 1'110, FACR Ossification/Calcification Anterior to Cl 1-274
Cl1eryl A. Pelers;lge, MO
Shoulder Girdle and Upper Arm Paravertebral Ossification and Calcification 1-276
Clavicle Lesions, Nonarticular 1-208
Cl1eryl A. Pelersilge, MO Linear Ossification Along Anterior Spine 1-280
Distal Clavicular Resorption 1-212
Proximal Humerus, Erosion Medial Metaphysis 1-214 Vertebral Shape

Catheril/e C. Roberts, MO Bullet Shaped Vertebra/ Anterior Vertebral Body 1-282
Glenohumeral Malalignment 1-216 Beaking
CI7eryl A. Petersilge, MO Cheryl A. Petersilge, MO
xv
Congenital & Acquired Childhood 1-284 Fluid Collections about the Knee 1-356
Platyspondyly BI Monaster, MO, PhO, FACR
Popliteal Mass, Extraarticular 1-362
Fish (Biconcave) or H-Shaped Vertebra 1-288 BI MClllaster, MO, PhO, FACll
Cheryl A. Petersilge, MO Alterations in Meniscal Size 1-366
Squaring of One or More Vertebra 1-290 B./. Mal/aster, MO, PhO, FACR
Cheryl A. Petersilge, MO Genu Valgum (Knock Knees) 1-370
B./. Monaster, MO, PhO, FACR
Vertebral Lesions Genu Varum (Bow Leg Deformity) 1-372
B./. Mal/osler, MO, 1'110,FACR
Vertebral Body Sclerosis 1-292
Spinal Osteophytes 1-298 Foot and Ankle

Cheryl A. Petersilge, MO Achilles Tendon Thickening/Enlargement 1-374
Lesions Originating in Vertebral Body 1-300 Carol L. Andrews, MO
Cheryl A. Petersilge, MD Calcaneal Erosions, Posterior Tubercle 1-376
Lesions Originating in Posterior Elements 1-306 BI Mal/osler, MO, PhO, FACR
Clleryl A. Petersilge, MD Retrocalcaneal Bursitis 1-380
Carol L. Andrews, MO
Ribs Soft Tissue Mass in the Foot 1-382

Rib otching, Inferior 1-308
Catlleril/e C. Roberls, MO Talar Beak 1-388
Catherine C. Roberts, MO
Rib Notching, Superior 1-310
Catherine C. Roberts, MO Tarsal Cystic/Lytic Lesions 1-390
Solitary Rib Lesion 1-3]2
B.j. Mal/aster, MO, PhO, FACR
PART II
Pelvis Image Based
Sacroiliitis, Bilateral Symmetric 1-3]6
BI Mal/aster, MO, PhO, FACR Radiograph/CT, Osseous
Sacroiliitis, Bilateral Asymmetric 1-320
11-2
Polyostotic Lesions, Adult
B./. MOIlOster, MO, PlIO, FACR
HI Manasler, MO, PhO, FACR
Sacroiliitis, Unilateral 1-322
Polyostotic Lesions, Child 11-8
BI Mal/aster, MO, PhO, FACR
B./. Mal/osler, MO, 1'110,FACR
Symphysis Pubis with Productive 1-324
11-14
Solitary Geographic Lytic Lesions
Changes/Fusion Catheril/e C. Roberts, MO
Catheril/e C. Roberts, MO
Sclerotic Bone Lesion, Solitary 11-20
Symphysis Pubis, Widening 1-326
B./. MOIlOslel~ MO, 1'110, FACR
Sclerotic Bone Lesions, Multiple 11-26
Supra-acetabular Jliac Destruction 1-330
B./. MOIlOster, MO, 1'110, FACR
Sclerotic Lesion with Central Lucency 11-32
Catheril/e C. Roberts, MO
Hip and Thigh Sequestration 11-36
Protrusio Acetabuli 1-334 Catherine . /lober/s, MO
Carol L. AI/drews, MO Target Lesions of Bone 11-40
Coxa Magna Deformity 1-338 Catllerine C. Roberts, MO
BI Monaster, MD, 1'110,FACR Matrix-Containing Bone Lesions 11-44
Hip Labral Tears, Etiology 1-340 B./. Monaster, MO, 1'110, FACR
B./. Monaster, MO, PhO, FACR Benign Osseous Lesions that Can Appear II-SO
Aggressive
Knee and Lower Leg HI Monaster, MO, PhO, FACR
Metastases to Bone II-56

Enlargement of Intercondylar Notch Distal 1-346 Catllerille C. /loberts, MO
Femur
Carol L. AI/drews, MO Generalized Increased Bone Density, Adult 11-60
Carol L. AI/drews, MO
Patellar Lytic Lesions 1-348
BI Monaster, MD, PhO, FACR Generalized Increased Bone Density, Child 11-64
Carol 1. Andrews, MO
Tibial Bowing 1-352
B./. Monaster, MO, PhO, FACR
XVI
Sclerosing Dysplasias 11-68 Target Lesion of Soft Tissues 11-158
BI Mallaster, MD, PIID, FACR Catller;lIe C. Roberts, MD
Hypertrophic Callus Formation 11-74 Cystic Masses 11-160

Clleryl A. Petersi/ge, MD Cat/lerille C. Iloberls, MD
Bone within Bone Appearance 11-76 Subcutaneous Mass 11-166

Catllerille C. Roberts, MD Catller;ne C. Roberts, MD
Osteopen ia 11-80 Enlarged Muscle 11-172

Clleryl A. Peters;lge, MD Clleryl A. Peters;lge, MD
Osteoporosis, Generalized 11-82 Muscle Atrophy 11-176

Clleryl A. Peters;lge, MD Calilerine C. Roberts, MD
Regional Osteoporosis 11-88 Intermuscular Edema 11-]80

Clleryl A. Pelersilge, MD Calilerille C. Roberts, MV
Cortical Tunneling 11-92 Tenosynovitis/Tenosynovial Fluid 11-184
Clleryl A. Pelersilge, MD Carol L. Alldrews, MD
Pseudoarthrosis 11-94 Enlarged Peripheral Nerves 11-]86

Clleryl A. Pelersilge, MD B./. Mallaster, MD, PIIV, FACR
Enthesopathy 11-96
Clleryl A. Petersi/ge, M D MR, Joint
Tendon & Ligamentous Ossification 11-100
Intraarticular Low Signal Material, All Sequences 11-]90
Clleryl A. Pelersilge, MD
BI Mallaster, MD, PIID, FACR
Bone Age, Advanced 11-]02
Catllerille C. Roberts, MD
Bone Age, Delayed 11-104

Ultrasound
Catllerille C. Roberts, MD Anechoic Mass 11-194
Carol L. Alldrews, MIJ
Radiograph/eT, Soft Tissue

Soft Tissue Ossification 11-106
Nuclear Medicine
Call1erille C. Roberls, MD Photopenic Lesions & False Negative Scans 11-196
Nodular Calcification 11-110 Clleryl A. Petersilge, MD
Catller;ne C. Roberts, MD Soft Tissue Uptake on Bone Scan 11-198
Linear and Curvilinear Calcification 11-1]6 Clleryl A. Petef5;lge, MD
Catllerille C. Roberts, MD Superscan 11-204
Soft Tissue Neoplasm Containing Calcification 11-122 Cllel)'1 A. Pelers;lge, MV
B.j. Mallasler, MD, PIID, FACR
PART III
MR, Osseous Clinically Based
Bone Marrow Edema Syndromes (Proximal 11-126
Femur)
Carol L. Alldrews, MD
Subchondral Edematous-like Signal 11-130 Painful or Enlarged Sternoclavicular Joint 11I-2
Carol L. Alldrews, MD Clleryl A. Petersilge, MD
Abnormal Epiphyseal Marrow Signal 11-132 Rotator Cuff Symptoms 11I-4

Carol L. Alldrews, MD BI Mallaster, MD, PIIV, FACR
Increased Marrow Fat 11-136 Shoulder Instability 11I-8

Carol L. Andrews, MD III Mallaster, MD, PIIV, FACR
Marrow Hyperplasia 11-140 Anteroinferior Labral/Capsule Injury 11I-12

Carol L. Alldrews, MD Carol L. Amlrews, MD
Bone Lesions with Fluid/Fluid Levels 11-]44 Nerve Entrapment, Shoulder 11I-I 4
Call1er;lIe C. Roberts, MD Carol L. Alldrews, MD
MR, Soft Tissue Elbow and Forearm

Lesion with Bright T] Signal 11-146 Elbow Deformities in Children and Young Adults 11I-16
Catllerine C. Roberts, MD C1leryl A. Petersi/ge, MD
Soft Tissue Lesions with Predominately Low Tl 11-150 Lateral Elbow Pain 11I-]8
& T2 Signal Catller;lIe C. Roberts, MD
Catller;lIe C. Roberts, MD Medial Elbow Pain 11I-22
Soft Tissue Lesions with Fluid/Fluid Levels 11-154 Clleryl A. Petersilge, MV
Catllerine C. Roberts, MD
XVll
Olecranon Bursi tis 11I-26 Diabetic Foot Complications 11I-142
Clleryl A. Petersilge, MD B.f. Monaster, MO, PlIO, FACR
Nerve Entrapment, Elbow & Wrist 11I-28
Spine
Painful Scoliosis 11I-144
Wrist and Hand Cheryl A. Petersilse, MD
Wrist Clicking/Clunking/Instability 11I-32
Systemic Disease
Ulnar Sided Wrist Pain 11I-36
Carol L. Andrews, MD
Arthritis in a Teenager 11I-148
B.f. Mal1Oster, MO, PhD, FACR
Radial Sided Wrist Pain 111-42
Anemia with Musculoskeletal Manifestations 11I-152
Avascular Necrosis 11I-156

Pelvis, Hip, and Thigh B.f. Monaster, MD, 1'110,FACR
Groin/Hip Pain 11I-48 Heterotopic Ossification 11I-162
Carol L. Andrews, MO Catherine C. Roberts, MO
Lateral Hip Pain III-54 Rickets & Osteomalacia 11I-166

Carol L. Andrews, MO Cheryl A. Petersi/se, MO
Snapping Hip III-58 Soft Tissue Contractures 11I-170
Carol L. Alldrews, MO Catherille C. Roberts, MO
Thigh Pain 11I-60 Short Limb, Unilateral 11I-172
Carol L. Andrews, MD R.I. Malmster, MO, PhO, FACR
Nerve Entrapment, Lower Extremity 11I-64 Hemihypertrophy 11I-178
Carol L. Andrews, MO Cheryl A. Petersi/ge, MO
Hip Pain, Elderly Patient 11I-68 Focal Gigantism/Macrodactyly 11I-180

Carol L. Alldrews, MD C/leryl A. Petersi/ge, MO
Painful Hip Replacement 11I-74 Dwarfism with Major Spine Involvement 11I-184
B.f. Mallaster, MO, PhO, FACR Catllerine C. Roberts, MO
Dwarfism with Short Extremities 11I-186

Knee and Leg Catherille C. Roberts, MD
Dwarfism with Short Ribs 11I-188

Anterior Knee Pain 11I-80 Catherine C. Roberts, MO
Dwarfism with Horizontal Acetabular Roof 11I-190
Medial Knee Pain 11I-86 Catherille C. Roberts, MO
Calf Pain 11I-92
CaroIL.Alldwws,MD
Painful Knee Replacement 11I-98

B.f. Monaster, MO, PhO, FACR
Ankle and Foot

Anterior Ankle Pain/Impingement 11I-104
C1leryl A. Petersilge, MO
Medial Ankle Pain 11I-108
Lateral Ankle Pain 11I-114
Cheryl A. Petersilse, MO
Heel Pain 11I-120
Pain in the Ball of the Foot 11I-126

Pes Plano Valgus (Flatfoot) 11I-132
B.f. Monaster, MO, PhO, FACR
CavusFootDeformity 11I-136
Congenital Foot Deformity 11I-138

B.f. Monaster, MD, PI1D, FACR
XVlll
xxi
PART I
Anatomy Based
Flat Bones
long Bone, Epiphyseal
long Bone, Metaphyseal
long Bone, Meta-Diaphyseal
long Bone, Growth Plate
Periosteum
Joint Based
Elbow and Forearm
Wrist and Hand
Fingers and Toes
Intervertebral Disc
Paraspinal Abnormalities
Vertebral Shape
Vertebral lesions
Ribs
Pelvis
Hip and Thigh
Knee and lower leg
Foot and Ankle
en
<ll FLATBONES, FOCAllY EXPANDED OR BUBBLYlESION
c
o
[])
ro DIFFERENTIAL DIAGNOSIS • Plasmacytoma

u::
o Pelvis & spine are most frequent locations
'0
Q)
Common • Though it develops into multiple
en
III • Giant Cell Tumor (GCT) myeloma, the lesion itself often appears
[])
>-
• Plasmacytoma relatively non-aggressive
-
E
o
III
c:
«
• Fibrous Dysplasia (FD), Pelvis
• Metastases: Thyroid, Kidney
less Common
o Lytic & bubbly in pelvis; occasionally more
aggressive with cortical breakthrough
o Requires MR survey to determine whether
• Aneurysmal Bone Cyst (ABC) it has advanced to more diffuse myeloma
• Chondrosarcoma, Conventional • Fibrous Dysplasia (FD), Pelvis
• Unicameral Bone Cyst (UBC) o FD has different manifestations in
• Hemophilia different types of bones
• Hyperparathyroidism, Brown Tumor o Pelvic FD is usually lytic & bubbly
• Expanded lesion may be quite large
Rare but Important
• Occasionally, more mild expansion with
• Chondromyxoid Fibroma ground-glass matrix, similar to lesion in
• Chondroblastoma long bone
• Osteoblastoma o Nonaggressive appearance
• Langerhans Cell Histiocytosis (LCH) o Often polyostotic, which suggests
• Cystic Angiomatosis diagnosis
• Metastases: Thyroid, Kidney
ESSENTIAL INFORMATION o Flat bones & axial skeleton most common
sites for metastatic osseous lesions
Key Differential Diagnosis Issues
• Most metastases are focal or permeative,
• Bubbly lesion in pelvis is usually a benign and multiple
process o Solitary expanded metastases less common
o Exceptions: Metastatic, plasmacytoma,
• Tend to have either renal cell or thyroid
chondrosarcoma may appear relatively as primary lesion
nonaggressive & should be considered o Note: Renal cell metastases may be
• Hint: Patient age can be a helpful extremely vascular
differentia tor among these lesions, though • When renal cell metastasis is suspected &
not always reliable axial imaging is performed, include a
• Hint: Cartilage tumors are common in look at kidneys
pelvis & scapula; remember to consider both • If kidney shows suspicious lesion,
benign & malignant varieties consider embolization of metastatic
• Note that list order is not the likelihood of lesion prior to biopsy
the individual lesion occurring, but its • Bleeding from biopsy can be excessive &
occurring with this specific appearance even life-threatening if it is at a site
o For example, LCH is common in pelvis,
which cannot be compressed
but only rarely appears bubbly, so is listed
as "rare" Helpful Clues for Less Common Diagnoses
• Aneurysmal Bone Cyst (ABC)
Helpful Clues for Common Diagnoses o ABC is common lesion in patients < 30
• Giant Cell Tumor (GCT) years of age
o Lytic lesion which is usually only
o More common in long than flat bones
moderately expanded in long bones o When present in flat bones, has typical
o Often large, highly expanded & even lytic bubbly expanded appearance
bubbly in pelvis o MR shows fluid levels except in small
o Prime age range: 30-60 years minority which are solid
o MR usually contains some low signal
• Chondrosarcoma, Conventional
within predominant high signal on T2; o Common lesion in adults (30-60 years age
may have fluid levels range most frequent), rare in teenagers
I
2
FLAT BONES, FOCALLY EXPANDED OR BUBBLY LESION »
o Flat bones & metaphyses of long bones are o HPTH is common (along with Brown
-
~
Cll
o
3
'<
most frequent locations tumors) in pelvis OJ
Cll
o Generally low grade at presentation, so o Expanded bubbly appearance much less CIl
(1)
may be mildly expanded, without cortical common for Brown tumor than lytic, c.
breakthrough focal, well-marginated destruction ::!!
~
o Rarely will present as expanded or bubbly Helpful Clues for Rare Diagnoses OJ
o Chondroid matrix (but not invariably)
o
• Chondromyxoid Fibroma ~
CD
o Hint: Consider chondrosarcoma for any o Rare lesions, but when in pelvis or scapula
CIl
lesion in flat bone in patient in 30-60 year may be bubbly

age range • Chondroblastoma
• Chondrosarcoma often underdiagnosed o Relatively common lesion in epiphyses
as a benign lesion o Pelvic presentation is rare
• Inadequate resection at initial treatment • Osteoblastoma
is devastating; inevitable recurrence o Rare lesion in non-axial location
• Unicameral Bone Cyst (UBe) • Langerhans Cell Histiocytosis (LCH)
o UBC most frequent in metaphyses of
o Common childhood lesion; pelvis is
children (especially proximal humerus) frequent location
o When UBC occurs in adult, tends to be in
o Presentation most commonly is minimally
unusual location, particularly pelvis expanded; bubbly appearance is rare
o Shows mild expansion of lytic lesion
• Cystic Angiomatosis
o No reactive change
o Rare vascular lesion
o MR confirms fluid centrally
o Location in pelvis is relatively common for
• Hemophilia all intraosseous vascular tumors, including
o Pelvis is frequent location for pseudotumor
this one
o Expanded lytic "lesion" arises from
o Slowly expanding lytic lesion which may
subperiosteal or intraosseous bleed become quite large
• Focal destruction of bone due to pressure o Other vascular tumors tend to be less
erosion expansile and more likely to be aggressive
• Development of large mass containing
pools of blood
• Though lesion may appear alarmingly
aggressive, borders of osseous destruction
oft;en are well-marginated
• Hyperparathyroidism, Brown Tumor
Giant Cell Tumor (GCT) Plasmacytoma
AP radiograph shows a hugely expanded lytic lesion

arising from the inferior pubic ramus, extending to the
AP radiograph
occupying
shows an
the superior pubic
expanded
ramus _
lytic lesion
It is
I
acetabulum •. It appears non-aggressive, despite its moderately aggressive, without cortical breakthrough;
size. GeT may be highly expansile in the pelvis. plasmacytoma commonly presents in this way.
3
en
Q) FLAT BONES, FOCALLY EXPANDED OR BUBBLY LESION
c:
o
CO
~
ro
u::
"t:l
Q)
en
Fibrous Dysplasia (FD), Pelvis Metastases: Thyroid, Kidney
III (Left) AP ,adiograph shows a
CO bubbly, wildly expanded
>. lesion arising from the iliac
-
E
o
III
c:
<l:
wing" Despite its size, the
lesion is non·aggressive.
Fibrous dysplasia is bubbly
when it arises in the pelvis;
this is an exlreme case.
(Right) AP radiograph shows
a highly expanded lytic
lesion of the distal clavicle
•• with destruction of the
acromion by contiguous
extent Ell This was a solitary
expansile renal cell
metastasis; a thin layer of
bone actually encased the
lesion.
Aneurysmal Bone Cyst (ABC) Chondrosarcoma, Conventional

(Left) Anteroposterior
radiograph shows an
expanded lytic lesion
occupying the iliac wing ••
in a 2 year old. ABC is more
frequently seen in long
bones, but may be found in
flat bones occasionally.
(Right) Anteroposterior
radiograph shows a
pathologic fracture into a
lytic expanded acetabular
lesion" in a 60 year old.
The lesion is
well-circumscribed.
Although it most resembles
GCT, biopsy proved low
grade chondrosarcoma.
Unicameral Bone Cyst (UBC) Unicameral Bone Cyst (UBC)

radiograph shows a subtle
lytic lesion in the Wac wing
which contains
pseudotrabeculations ••
The lesion is not aggressive.
This is a middle aged patient;
UBC should be considered.
(Right) Axial bone CT in the
same patient as previous
image shows mild expansion
of the lesion" proved to
be UBC. When this lesion
arises in an adult; the
location is frequently the
pelvis.
I
4
flAT BONES, FOCALLY EXPANDED OR BUBBLY LESION
(Leh) AP radiograph shows

an expanded lytic lesion of
the pelvis with a sclerotic
margin. It appears
moderately aggressive. In a
patient with hemophilia,
pseudotumor of the iliac
wing can be highly
destructive, yet maintain a
sclerotic margin. (tMSK
Req). (Right) Axial CfCT in
the same patient shows the
expansion of the iliac wing
from intraosseous bleeds.
as well as a sharp cut-offEil
providing a sclerotic margin.
The iliacus is distended by
hematoma.
(Left) AP radiograph shows

an expanded bubbly lesion
_ The bones show
generalized osteopenia, but
in this case there are no
other clues that this is a
Brown tumor in a patient
with hyperparathyroidism.
radiograph shows a lytic
lesion of the iliac wing,
expanded but with a densely
sclerotic border. Cartilage
lesions should be considered
in cases of non-aggressive
pelvic tumors; this proved to
be chondromyxoid fibroma.
Chondroblastoma
(Leh) AP radiograph shows a
lytic bubbly lesion in the iliac
wing in this child •. Axial
imaging proved mild
expansion. This is a rare
presentation of
chondroblastoma in the
pelvis; it ;s usually an
epiphyseal lesion. (RighI) AP
radiograph shows highly
expanded lytic lesions
involving both pubic rami ••
as well as the iliac wing _.
They are large but
non-aggressive; growth was
documented over at leas! 10
years. This is a vascular
tumor, cystic angiomatosis.
I
5
C/)
Q) FLAT BONES, PERMEATIVE LESION
c
o
[!J
ro
u:: DIFFERENTIAL DIAGNOSIS • Radiograph often normal; MR diagnosis
• Ewing Sarcoma
"'C
ell
Common o Wider age range (5-30 years) than
C/)
<0 • Metastases, Bone Marrow osteosarcoma
III
;., • Osteomyelitis o Location tends to be different with age
E • Ewing Sarcoma
-
«
o
<0
c:
• Osteosarcoma, Conventional
• Chondrosarcoma
• Younger patients: Long bones
• Teenagers & young adults: Flat bones
o Highly aggressive permeative lesion
• Malignant Fibrous Histiocytoma, Bone o Large soft tissue mass
• Langerhans Cell Histiocytosis (LCH) • Osteosarcoma, Conventional
• Lymphoma o Common location: Long bones,
• Multiple Myeloma (MM) metaphyseal
• Leukemia o Flat bones, especially pelvis, are less
• Hyperparathyroidism/Renal Osteodystrophy, frequently involved
Brown Tumor • However, osteosarcoma is such a
• Fibrosarcoma common lesion that pelvic
• Plasmacytoma osteosarcomas are seen not infrequently
Less Common o Usually produce tumor osteoid:
• Angiosarcoma, Osseous Amorphous, osseous density
• Radiation Osteonecrosis o Highly aggressive, with soft tissue mass
• Chondrosarcoma
Rare but Important
o Pelvis is common location of
• Radiation-Induced Sarcoma chondrosarcoma; scapula less so
• Paget Sarcoma o May appear permeative & aggressive
• Chronic Recurrent Multifocal Osteomyelitis • Often is lower in grade than the other
sarcomas listed above, which accounts
ESSENTIAL INFORMATION for its lower position on this list
o Chondroid matrix usually present
Key Differential Diagnosis Issues o Because lesion often undetected for long
• Wide range of aggressive lesions arise in flat period of time, may be large, with huge
bones soft tissue mass extending intrapelvically
• Hint: Watch for evidence of polyostotic o Watch for multiple hereditary exostosis,
lesions, which may narrow the differential which predisposes to degeneration
Helpful Clues for Common Diagnoses • Proximal sites in body are most likely to
• Metastases, Bone Marrow degenerate to chondrosarcoma
o Metastases most commonly involve axial • Malignant Fibrous Histiocytoma, Bone
skeleton & flat bones o Flat bones are less common site of
o Diagnosis may be difficult in pelvis & involvement than long bones
scapula o Nonspecific appearance: Lytic, permeative,
• Thin bones, often in osteoporotic cortical breakthrough with soft tissue mass
patients o Fibrosarcoma: Similar appearance
• Overlying soft tissues • Langerhans Cell Histiocytosis (LCH)
• Osteomyelitis o Pelvis & scapula are common sites
o Either from hematogenous seeding or o Watch for polyostotic lesions in a child
direct trauma o Lesions are lytic; range of appearance from
o Watch for air in sinus tract non-aggressive to highly aggressive
o Watch for dense reactive bone formation o Aggressive lesions may show more rapid
o Chronic recurrent multifocal osteomyelitis destruction than sarcomas
• Occurs in children with several months o Aggressive lesions may have cortical
of vague pain breakthrough with soft tissue mass
• Often no systemic symptoms • Lymphoma
I
6
FLAT BONES, PERMEATIVE lESION »
:J
..•o
III
o Adults: Generally solitary bone lesion 3

Helpful Clues for less Common Diagnoses '<
• Pelvis & scapula are common locations • Angiosarcoma, Osseous OJ
III
• Destructive lytic lesion with cortical o Rare tumor, but pelvic involvement
VI
en
breakthrough frequent
Co
TI
• Soft tissue mass often enormous, o Often polyostotic; especially lower §I
showing a more infiltrative character extremities OJ
than sarcoma o
:J
• Radiation Osteonecrosis <t>
o Children: 50% present as polyostotic VI
o Common in sites frequently treated with
• Aggressive lesion with cortical radiation: Pelvis & scapula
breakthrough and soft tissue mass o May become less common with more
• Multiple Myeloma (MM) modern radiation treatment
o Both MM and plasmacytoma generally
• Old cases will persist for many years
have well-defined lytic lesions o Appearance: Mixed lytic & sclerotic; may
o Aggressive or permeative pattern is
be somewhat permeative; no mass
uncommon o Watch for distribution in a radiation port
o Exception for MM is a presentation
without focality but with diffuse Helpful Clues for Rare Diagnoses
infiltration • Radiation-Induced Sarcoma
• Permeative pattern is so subtle that o Common locations same as those for
lesions not detected on radiograph; radiation osteonecrosis: Pelvic, scapula
presents with osteoporosis o Destructive change superimposed on
• Diagnosis made on MR survey radiation osteonecrosis; soft tissue mass
• Leukemia o Generally occurs 7-10 years following RT
o Often presents with such a subtle • Paget Sarcoma
infiltrative pattern that only osteoporosis o Rare degeneration of Paget bone lesion
is detected by radiograph o Only with extensive & long term disease
o MR shows extent of lesions, which often o Degeneration more frequently seen in
include flat bones axial & flat bones than long bones
• Hyperparathyroidism/Renal o Acquires appearance of lesion it
Osteodystrophy, Brown Tumor degenerates into
o Brown tumor is usually well-defined, but • Osteosarcoma: Amorphous osteoid
surrounding bone is so osteoporotic that • Chondrosarcoma: Chondroid matrix
overall appearance may be aggressive • May be mixed types of sarcomas
o Watch for other signs of bone resorption
Metastases, Bone Marrow Metastases, Bone Marrow
AP radiograph shows a diffuse permeative Iylic lesion

involving the entire scapula, destroying all osseous
Coronal T1WI MR of the same patient shows the
expanded lesion arising from the body of the scapula
I
integrity of the bone. The padent had undergone ••. The patient was discovered 10 have renal cell
arthroscopy J months earlierfor shoulder pain. carcinoma, which often results in solitary metastases.
7
l/J
Q) FLAT BONES, PERMEATIVE LESION
c
o
CD
CO
u::
"0
Ql
VI
Osteomyelitis Osteomyelitis
III (Left) Axial bone CT shows
CD "multiple lytic lesions". in
>. the scapula of a patient who
-E
o
III
r::
<l:
has just arrived from
Ethiopia. With this history &
appearance, infection must
be considered. (Right) Axial
T1 C+ FS MR of the same
patient shows multiple
abscesses in the 50ft tissues
on either side of the scapula
Ell they communicated
through an osseous defect.
This was a Staphylococcus
osteomyelitis.
Ewing Sarcoma Ewing Sarcoma

(Leh) Lateral radiograph
shows a highly aggressive
lesion with destruction of the
body of the scapula III in a
young adult. Axial imaging
showed a very large
associated soft tissue mass.
In a patient of this age,
Ewing sarcoma must be
considered and was proven.
(Right) Lateral bone scan of
the same patient shows
multiple osseous metastases
at the time of diagnosis. Of
all bone sarcomas, Ewing
sarcoma is the most likely to
present with osseous
metastases.
Osteosarcoma, Conventional Osteosarcoma, Conventional

(Left) AP radiograph shows a
sclerotic lesion of the
posterior iliac wing _
overlapping the sacral ala, in
a teenager. The sclerosis is
typical of dense osteoid
matrix, and the lesion must
be presumed to be
osteosarcoma. (Right) Axial
T2WI F5 MR of the same
patient confirms the highly
destructive iliac wing lesion,
with a 50ft tissue mass
extending both anteriorly
and posteriorly _ This was
a high grade osteosarcoma,
requiring an internal
hemipelvectomy.
I
8
FLAT BONES, PERMEATIVE LESION »
..o
::::l
III
3
'<
OJ
III
Chondrosarcoma Chondrosarcoma
'"
lD
Co
lytic lesion in the iliac wing
:!!
• of a 35 year old. It ~
contains a dense chondroid OJ
matrix; the diagnosis must be o
::::l
chondrosarcoma. Note, (!)
however, tha t the lesion

does not appear particularly
'"
permeative;
chondrosarcoma often
presents with a lower grade
than other sarcomas. (Right)
Axial bone CT in a different
patient shows destruction of
the iliac wing •. There is a
huge soft tissue mass arising
from the bone that contains
a chondroid matrix.

"naked 51joint" on the right
Note how lucent the right 51
join! appears. compared
with the left, where there is
normal overlap of the
posterior ifiac wing & sacral
ala. The naked 51join!
indicates a lesion involving
the right posterior iliac wing.
(Right) Axial bone CT of the
same patient shows the lytic
lesion of the posterior iliac
wing. with cortical
breakthrough. Biopsy proved
MFH.
Langerhans Cell Histiocytosis (LCH) Langerhans Cell Histiocytosis (LCH)

lytic permeative lesion
involving the acetabulum of
this child •. Concern for
Ewing sarcoma should be
raised, but it should also be
remembered that LCH is
frequently found in the flat
bones and occasionally
appears highly aggressive.
(Right) Axial PO F5E MR of
osseous destruction and
confirms a large soft tissue
mass. deviating the
rectum. At biopsy this
proved to be a highly
aggressive LCH.
I
9
en flAT BONES, PERMEATIVE lESION
Q)
c
o
CO
CO
u:::
"0
Ql
VI
lymphoma lymphoma
III (Left) Anteroposterior
CO radiograph shows a highly
>- permeative lesion in the
E pelvis of a young woman _.
•...oIII It could represent several
r::
« malignant processes; this is
lymphoma, with a large soft
tissue mass. (t MSK Req).
radiograph shows
permeative lytic lesions
iliac wings =
involving both right & left
as well as a
femoral neck lesion E!IIII in an
African American child. 50%
of lymphomas present as a
polyostotic process in
children.
Multiple Myeloma (MM) Multiple Myeloma (MM)

diffuse osteoporosis, which is
abnormal for a 50 year old
man. This appearance is
suspicious for a permeative
infiltrative process; at this
age, multiple myeloma or
leukemia should be
considered. (Right) Coronal
STIR MR in the same patient,
part of a myeloma survey,
shows abnormal signal
the pelvis =
throughout the majority of
confirming
infiltration. There is also a
focal femoral neck lesion 11III.
Biopsy showed multiple
myeloma.
Hyperparathyroidism/Renal
leukemia Osteodystrophy, Brown Tumor
(Left) Axial STIR MR shows a
diffuse infiltrative process
involving the entire pelvis as
well as sacrum. The]O year
old patient had diffuse bone
pain but no focal
abnormalities on radiograph
(not shown), typical of
leukemia. (Right) AP
radiograph shows a poorly
marginated, mildly
aggressive lesion within the
acetabulum III. There is also
a well-circumscribed lesion
in the femoral neck EiIl as
well as osteopenia. This
makes the diagnosis of
Brown tumor.
I
10
FLAT BONES, PERMEATIVE LESION
Fibrosarcoma Plasmacytoma
permeative lesion in the
pubic bones" with cortical
breakthrough and a soft
tissue mass. This is a
nonspecific appearance;
biopsy showed
fibrosarcoma. (Right) AP
radiograph shows a highly
aggressive lytic lesion
destroying the left iliac wing
_ extending to the sacrum.
Though plasmacytoma most
frequently has a less
aggressive appearance; that
proved to be the diagnosis in
this case.
Angiosarcoma, Osseous Radiation Osteonecrosis

destroying the iliac wing in a
young adult. The patient had
other lesions in the lower
extremity; the diagnosis is
angiosarcoma. (Right) AP
radiograph shows a mixed
lytic and sclerotic lesion
involving the scapula,
clavicle, ribs, and proximal
humerus. Though it appears
somewhat aggressive, the
port-like configuration of the
abnormality helps make the
diagnosis of radiation
osteonecrosis.
Radiation-Induced Sarcoma Pagel Sarcoma

(Leh) Lateralradiograph
shows destructive change in
the scapula, with osteoid
formation within a farge soft
tissue mass'" Thepatient
had radiation to the scapula
7 years earlier, and this is a
radiation-induced
osteosarcoma. (RighI) AP
radiograph shows an
enlarged iliac wing with
amorphous osteoid
production" replacing the
underlying bone.
Additionally, there is an
enlarged, disordered,
vertebral body HI. Findings
are of Paget osteosarcoma.
I
11
co
Q)
LONG BONE, EPIPHYSEAL: IRREGULAR OR STIPPLED
l/J
>-
.J::
Cl.
Cl. DIFFERENTIAL DIAGNOSIS • Warfarin embryopathy
W • Chondrodysplasia punctata
Q)
c
Common
o Helpful Clues for Common Diagnoses
CO • Normal Variant in Child (Mimic)
• Normal Variant in Child (Mimic)
Ol • Osteonecrosis
C
o o Seen in adolescents
--' • Legg-Calve-Perthes (LCP)
o Located on posterior aspect of femoral
"'C • Juvenile Idiopathic Arthritis OIA)
Ql
l/J
condyles
ltl Less Common • Seen best on AP notch view which
CO
>. • Rickets profiles posterior femoral condylar
E • Hypothyroidism surface
•...o
ltl
C
• Osteomyelitis • Generally not visible on regular AP view
<l: • Complications of Warfarin (Coumadin) • May be seen on lateral
• Chondrodysplasia Punctata o MR shows overlying cartilage to be normal
• Trevor Fairbank (Dysplasia Epiphysealis o Do not confuse with pathologic process
Hemimelica) such as osteochondral injury or JIA
• Spondyloepiphyseal Dysplasia • Osteonecrosis
• Nail Patella Disease (Fong) o Prior to significant flattening, may see
Rare but Important punctate fragments in bed of site of
• Thermal Injury, Frostbite necrosis
• Complications of Dilantin • Legg-Calve-Perthes (LCP)
o Femoral head osteonecrosis in child (usual
• Hypoparathyroidism
• Hyperparathyroidism age range 4-8 years)
• Hypopituitarism o Capital epiphyseal flattening, increased
• Acromegaly density, fragmentation
o Results in coxa magna deformity
• Trisomy 18
• Down Syndrome (Trisomy 21) • Juvenile Idiopathic Arthritis OIA)
• Fetal Alcohol Syndrome o "Crenulated" irregularity of carpal bones
• Mucopolysaccharidoses o Irregularity on femoral condylar articular
• Multiple Epiphyseal Dysplasia surface
• Pseudoachondroplasia Helpful Clues for Less Common Diagnoses
• Homocystinuria • Rickets
• Oilier Disease/Maffucci (Mimic) o True abnormality is metaphyseal/physeal
widening & fraying
o With weakened physis, epiphysis may slip,
ESSENTIAL INFORMATION
resulting in irregularity & fragmentation
Key Differential Diagnosis Issues • Hypothyroidism
• May be able to separate into irregular versus o Infant: Stippled epiphyses
stippled epiphyses o Toddler: Severe delay in skeletal
o Common diagnoses for "irregular" maturation
epiphyses • Fragmentation of femoral capital
• Normal variant, knee epiphysis
• Osteonecrosis • Osteomyelitis
• Legg-Calve-Perthes o Prenatal or childhood infections may cross
• Juvenile idiopathic arthritis from metaphysis to involve epiphysis
• Rickets • Epiphysis may slip
• Osteomyelitis • Destructive change results in irregularity,
• Trevor Fairbank fragmentation
• Spondyloepiphyseal dysplasia • Complications of Warfarin (Coumadin)
o Common diagnoses for "stippled" o Maternal ingestion during early pregnancy
epiphyses o Stippled epiphyses
• Hypothyroidism
I
12
LONG BONE, EPIPHYSEAL: IRREGULAR OR STIPPLED »
o Hypoplastic nose, eye malformations, o a.k.a., Fong disease, osteo-onychodysplasia

-
::l
III
o
3
'<
mental retardation o Absent or small patellae OJ
III
• Chondrodysplasia Punctata o Posterior iliac "horns" 1Il
CD
o Stippled epiphyses o Nail dysplasia Co
o Non-rhizomelic type: Conradi o Radial head hypoplasia, subluxation r

o
::J
Hunermann; nonlethal & autosomal o Irregularity & flattening of epiphyses; less CO
dominant constant finding than nail & patella OJ

o
::J
o Rhizomelic type: Lethal autosomal abnormalities CD
recessive; multiple other abnormalities Helpful Clues for Rare Diagnoses m
1:l
• Trevor Fairbank (Dysplasia Epiphysealis 1:l
• Thermal Injury, Frostbite ::J"
Hemimelica) o Epiphyses at risk for vascular injury with
'<
1Il
CD
o Cartilaginous proliferation at epiphysis OJ
vasoconstriction from cold temperature
• Considered analogous to epiphyseal o May become dense, fragmented
osteochondroma o Early fusion results in short phalanges
o Irregular lobulations superimposed on
o Thumb generally not involved (folded into
epiphyses palm in cold temperatures)
o Lower limb (knee, ankle, hip) most
• Multiple Epiphyseal Dysplasia
frequently affected o Hereditary disease, usually autosomal
o May be polyarticular
dominant
o Monomelic
o Delayed & irregular mineralization of
• Spondyloepiphyseal Dysplasia epiphyses
o Group of disorders resulting in short trunk
o Results in coxa vara & genu vara or valgum
dwarfism o Early osteoarthritis
o Congenita & tarda forms, with spectrum of
o Vertebral involvement variable & generally
abnormalities mild
o Platyspondyly
• Pseudoachondroplasia
o Generalized delay in epiphyseal
o Heterogeneous inherited skeletal dysplasia
ossification with dwarfism
o Once epiphysis forms, it is flattened &
o Malformations not apparent until early
irregular childhood
o May have metaphyseal flaring
o Shortening of tubular bones
o Develops coxa vara, genu valgum
• Flaring of metaphyses
o Early osteoarthritis
• Variable irregularity of epiphyses
• Nail Patella Disease (Fong)
Normal Variant in Child (Mimic) Normal Variant in Child (Mimic)
AP nOlch view shows irregularity of the medial & lateral

femoral condyles" in a child. The notch view profiles
AP radiograph of the same knee shows smoolh normal
femoral condyles. This, in combinaUon of the notch
I
the posterior portions of the femoral condyles, the view, localizes the epiphyseal irregulariUes to the
expected locaUonof this normal variant. posterior condyles.
13
ro LONG BONE, EPIPHYSEAL: IRREGULAR OR STIPPLED
Q)
(/)
>,
.c
C-
.0.
w
Q)
c Osteonecrosis legg-Calve-Perthes (lCP)
o
[lJ (Left) Anteroposterior
Ol radiograph shows
C
o fragmentation of the humeral
-l head" This is in the
"tl weight-bearing portion and is
Q)
III typical of both the location
I'll and appearance of
aI osteonecrosis. (Right)
>-
-
E Anteroposterior radiograph
o shows irregularity, flattening,
I'll and increased density in the
c:
<l: femoral capital epiphysis •.
This child has typical
Legg-Calve-Perthes. (t MSK
Req).
Juvenile Idiopathic Arthritis (JIA) Rickets

shows irregularity involving
the entire surface of the
femoral condyles" in this
patient with JIA. Such
"crenulation" may be seen
involving carpal bones as
well. (Righi) AP radiograph
shows irregularity of the
femoral capital epiphysis •.
along with fraying of the
metaphysis Elll widened
zone of provisional
calcification, and slipped
epiphysis. These are typical
changes of rickets in a
patient with renal
osteodystrophy.
Hypothyroidism Hypothyroidism
radiograph shows
fragmentation of the femoral
capital epiphysis •.. This
patient also had severely
delayed skeletal maturation.
This appearance suggests
LCp, but it is also seen in
hypothyroidism. (Right)
Anteroposterior radiograph
in an infant shows stippled
epiphyses" at the femoral
head/greater trochanter.
Hypothyroidism is one of
several entities that may
present with stippled
epiphyses.
I
14
LONG BONE, EPIPHYSEAL: IRREGULAR OR STIPPLED »
:J
..•o
III
3
'<
[D
III
VI
Osteomyelitis Complications of Warfarin (Coumadin) <tl
(Left) Lateral radiograph a.
shows irregularity & r
fragmentation of the o
:J
calcaneal apophysis m This <0
patient has osteomyelitis, III
o
with the associated :J
<tl
destruction. (Right) AP
radiographs show stippling m
"2.
of the epiphyses and "0
apophyses" of the ::r
'<
VI
acetabulum and femoral
CD
head. This infant's mother OJ
had been given Warfarin
during pregnancy; stippled
epiphyses are one
manifestation of Warfarin
embryopathy.
Trevor Fairbank (Dysplasia Epiphysealis

Chondrodysplasia Punctata Hemimelica)
fLeft) Anteroposterior
radiograph shows stippled
epiphyses at the sacrum.
and femoral heads ElII. This
finding is nonspecific, but
this patient had other
maniFestations of
chondrodysplasia punctata.
radiograph shows irregularity
of the epiphyses of the
tibiotalar joint •. This is
actually an epiphyseal
osteochondroma, termed
Trevor Fairbank dysplasia.
The irregular bone results in
joint damage.
(Left) Lilteral radiograph

shows irregularity of the
femoral condyles _ This is
the appearance of a
relatively mild form of
spondyloepiphyseal
dysplasia. (Right)
shows irregularity and
flattening of the femoral
condyles of the left knee.
There is also hypoplasia of
the patellae. Both findings
are seen in nail patella
(Fang) disease.
I
15
ro
Q)
LONG BONE, EPIPHYSEAL,OVERGROWTH/BALLOONING
(/)
>-
.r:
a.
a.
W
DIFFERENTIAL DIAGNOSIS Helpful Clues for Common Diagnoses
Q)
Common • Juvenile Idiopathic Arthritis alA)
c
o o Hemophilia: Similar to JIA
en • Juvenile Idiopathic Arthritis alA)
o Chronic hyperemia from synovitis alA) or
OJ
c • Hemophilia: MSK Complications
o recurrent intraarticular bleed (hemophilia)
-l Less Common o Knee> elbow> ankle
"tl
Ql • Septic Joint o Erosion of intercondylar or trochlear notch
III
III
en • Epiphyseal Fracture, Pediatric o Erosions, cartilage loss in both
>. • Epiphyseal Dysplasia • JIA may be distinguished by carpal fusion
•..Eo
III
• Hyperemia, Other Causes
• Turner Syndrome (Mimic)
• Hemophilia may be distinguished by
dense effusion (hemosiderin deposition)
C
« • Blount Disease (Mimic)
Helpful Clues for Less Common Diagnoses
Rare but Important • Septic Joint
• Meningococcemia (Mimic) o Effusion, cartilage loss, erosions
o Tuberculosis or fungal etiologies more
ESSENTIAL INFORMATION likely to result in overgrowth than
bacterial
Key Differential Diagnosis Issues • Slower joint destruction, so occurs over a
• Hyperemia is the fundamental cause of longer period of time, allowing chronic
overgrowth in several cases hyperemia
o In skeletally immature patient • Less likely to have reactive osseous
• Prolonged hyperemia adjacent to joint ...• change than bacterial etiology
overgrowth (ballooning) of epiphysis • Epiphyseal Fracture, Pediatric
• In addition to enlarged epiphysis, o Hyperemia with fracture healing results in
hyperemia ...•early physeal fusion ...•short overgrowth
limb o Watch for malunion
o Etiologies of overgrowth secondary to • Epiphyseal Dysplasia
hyperemia include o May be fragmented in severe cases or
• Hemophilia overgrown if less severe
• Juvenile idiopathic arthritis • Turner & Blount Disease (Mimics)
• Septic joint, particularly tuberculosis or o Underdevelopment or collapse of medial
fungal etiology tibial condyle results in relative
• Epiphyseal or metaphyseal fracture overgrowth of medial femoral condyle
Juvenile Idiopathic Arthritis (JIA) Hemophilia: MSK Complications
I AP radiograph shows significant enlargement

(overgrowth) of the femoral epiphyses. relativeto the
Lateral radiograph shows no erosions but a huge
effusion. in a hemophilic. There is a widened notch
diaphyses. There are severe erosions & widening of the (displacement of Blumensaatline HIJ. The epiphyses &
inte,condylar notch HI in this patient with /fA. patella are overgrown relative to the diaphyses.
16
LONG BONE, EPIPHYSEAL, OVERGROWTH/BALLOONING :>
-
:::l
Ql
o
3
'<
01
Ql
VI
Septic Joint Epiphyseal Fracture, Pediatric (1)
(Left) AP ,adiograph shows C.
an enlarged left femoral head
& neck =.This /2 year old
had a septic joint treated 9
r
o
:::l
(Q
months earlier. The OJ

o
hyperemia from the process :::l
(l)
resulted in overgrowth in this
child. (Right) AP radiograph m
"2.
demonstrates relalive
overgrowth of the left patella ":::r
'<
VI
and epiphyses" (compare (l)
to normal right side EilI). The OJ
patient had a patellar
fracture as a child, resulting
in hyperemia, enough to
result in overgrowth of the
patella and adjacent femoral
epiphyses.
Turner Syndrome (Mimic)

symmetric enlarged femoral
epiphyses, giving a
II ballooned" appearance.
Note also the morphologic
flattening of the tibial
plateaus. The patient is
short; the diagnosis is
spondyloepiphyseal
dysplasia. (Right) AP
radiograph shows relative
flattening/underdevelopment
of the medial tibial condyle
_ which results in an
overgrowth of the medial
femoral condyle EilI. This
appears as focal ballooning
of the femoral epiphysis.
Meningococcemia (Mimic)
collapse of the medial tibial
metaphysis .:I in Blount
disease. There may be
compensatory overgrowth of
the medial femoral condyle
Ell but rarely enough to
prevent a significant varus
deformity. (Right) AP
radiograph shows
fragmentation & dysmorphic
changes in the femoral
capital epiphysis EilI typical
of meningococcemia. This
mimics a ballooned
epiphysis, but is due to
ischemia from thrombotic
episodes.
I
17
C'O
Q)
LONG BONE, EPIPHYSIS, SCLEROSIS/IVORY
VI
>-
.s:::
C-
on. DIFFERENTIAL DIAGNOSIS Helpful Clues for Common Diagnoses
w
Q)
Common • Osteonecrosis (AVN)
c
o o Sclerosis is 1st radiographic sign of AVN,
al • Osteonecrosis (AVN)
OJ • Renal Osteodystrophy secondary to surrounding osteopenia
c
o (relative sclerosis)
.-J Less Common • Classic appearance is central sclerosis in
"'C
ell • Cement & Bone Fillers, Normal femoral head
VI
<ll
al
• Neoplasm o Later, sclerosis is secondary to osseous
>- o Chondroblastoma impaction from collapse
E
-
«
o
<ll
C
o Ewing Sarcoma
o Osteosarcoma, Conventional
• Legg-Calve-Perthes (LCP)
o Even later, sclerosis is from reparative bone
formation
• Renal Osteodystrophy
• Osteopoikilosis o Diffuse sclerosis, including epiphyses
• Osteopetrosis • May be part of primary disease, due to
• Pycnodysostosis activation of osteoblasts
Rare but Important • More prominent, as neostosis, when
• Down Syndrome (Trisomy 21) undergoing effective treatment
• Hypopituitarism o Indistinct trabeculae
• Hypothyroidism o Other signs of renal osteodystrophy
• Turner Syndrome • Rickets: Widened zone of provisional

• Morquio Syndrome calcification, frayed metaphyses
• Thiemann Disease • Hyperparathyroidism: Resorption
• Deprivation Dwarfism patterns (subperiosteal, endosteal,
• Multiple Epiphyseal Dysplasia subchondral, subligamentous)
• Trichorhinophalangeal Dysplasia • Soft tissue calcification
• Seckel Syndrome Helpful Clues for Less Common Diagnoses
• Lesch-Nyhan • Cement & Bone Fillers, Normal
• Idiopathic Hypercalcemia o Commonly used to fill lesion sites
• Homocystinuria following curettage
• Complications of Fluoride • Most common lesion in epiphyseal
region treated this way is giant cell
ESSENTIAL INFORMATION tumor
o Cement: Homogeneous, more dense than
Key Differential Diagnosis Issues cortical bone
• Differentiate between extent of sclerosis o Non-structural bone graft: Round or square
o Focal, isolated to epiphysis pieces, same density as cortical bone
• Osteonecrosis • As it incorporates, approaches normal
• Chondroblastoma bone density
• Legg-Calve-Perthes o Rare use of coral as structure with
o Epiphyseal/metaphyseal haversian canal-like morphology to allow
• Ewing sarcoma substitution by normal bone
• Chondrosarcoma • Neoplasm
• Osteopoikilosis o Chondroblastoma
o Diffuse • Most common epiphyseal neoplasm
• Renal osteodystrophy • Generally arise in skeletally immature
• Osteopetrosis (teenage, young adult) patients
• Pycnodysostosis • Margin generally sclerotic
• All diagnoses listed as "rare but • May contain chondroid matrix, resulting
important" in greater sclerosis
• Often elicits dense periosteal reaction
o Ewing Sarcoma
I
18
lONG BONE, EPIPHYSIS, SCLEROSIS/IVORY »
::l
• Generally meta diaphyseal lesion, but o Round, regular, generally subcentimeter

-
III
o
3
'<
may cross into epiphysis (physis is only a sclerotic lesions to
III
relative barrier) • Bone islands (hamartoma) III
CD
• Age range: 5-30 years o Epiphyseal & metaphyseal C.
o Generally bilaterally symmetric r

• Lesion generally is highly aggressive, o
:J
with permeative destruction, cortical o One of the sclerosing dysplasias <C
OJ
breakthrough, & soft tissue mass o Incidental finding o
:J
• Rarely may be more indolent, remaining • Osteopetrosis <1l
contained for a variable amount of time o Severe sclerosing dysplasia, involving m

• Elicits significant osseous reaction, in the entire skeleton (axial & appendicular) "
"
::T
form of new bone formation; this is the o Homogeneously dense bones '<
(fJ
<1l
source of sclerosis o Undertubulation of long bones Q)
o Osteosarcoma, Conventional • Due to poor function of osteoclasts;

• Generally metaphyseal in location, but inhibiting remodeling
may cross into epiphysis • May also be manifest as "bone-in-bone"
• Highly aggressive lesion, with permeative appearance
bone destruction, cortical breakthrough, • Pycnodysostosis
soft tissue mass o Severe sclerosing dysplasia, involving
• Tumor osteoid results in amorphous entire skeleton (axial & appendicular)
sclerosis, both in the bone and in the o Homogeneously dense bones
soft tissue mass o Undertubulation of long bones
• Legg-Calve-Perthes (LCP) o Similar in appearance to osteopetrosis
o Osteonecrosis of femoral head in child o Morphologic differentiating factors
• Age 4-8 most common • Wormian bones
o Early sign: Sclerosis of femoral head • Acroosteolysis
o Later signs • Small angle of jaw
• Fragmentation of femoral head Helpful Clues for Rare Diagnoses
• Flattening of femoral head • Those listed under "rare but important" are
o Late appearance
extraordinarily uncommon
• Coxa magna deformity (short, broad o Disease process itself is rare
femoral head and neck) o Manifestation of sclerotic epiphyses in
• Early development of osteoarthritis these diagnoses is even more rare
• Osteopoikilosis
AP radiograph shows sclerosis in the femoral head.

an early indication of osteonecrosis. An outline of a
Anteroposterior radiograph shows sclerosis, flattening,
and irregularity of the femoral head. in a young adult.
I
renal transplant is seen in the iliac fossa III indicating There are linear densities in the neck HI. indicating pin
steroids as the etiology of the osteonecrosis. tracks; the patient had SeFE resulting in AVN.
19
l\l
Q)
LONG BONE, EPIPHYSIS, SCLEROSIS/IVORY
rJ)
>-
.r:
C>-
C>-
W
Q)
c:: Renal Osteodystrophy Renal Osteodystrophy
o
[]:J (Left) AntefOposterior
OJ radiograph shows diffuse
c::
o increased density, including
--l the humeral epiphysis. There
"0 is also subperiosteal
Q)
rJ) resorption" and a Brown
ra tumor _ the patient has
[]:J
>. renalosteodys/fophy. (Right)
E Posteroanterior radiograph
-o
ra
r::
<l:
shows sclerosis in the radial
epiphysis _ but there is
also generalized increased
density as well as
indistinctness of the
/fabeculae. Endosteal
resorptive pal/ern adds 10
the Findings of renal
osteodystfOphy.
Cement & Bone Fillers, Normal

(Left) Lateral radiograph
shows sclerosis of the ring
apophyses and endplates III
in a patient with renal
osteodystrophy, termed
"rugger jersey" sign. (Right)
Posteroanterior radiograph
shows an expanded lytic
lesion of the distal radius
which has been treated by
curel/age and bone graFting
III. Non-structural bone
graFt may have fOunded or
square pieces & should be
diFFerentiated FfOm
chondroid or osteoid matrix.
Cement & Bone Fillers, Normal Chondroblastoma

(Left) AntefOposterior
radiograph shows dense
material placed at the MTP
joint" Following resection
of a Failed arthfOplasty"
The material has canals the
width of Haversian canals; it
is a coral graFt. (Right) FfOg
lateral radiograph shows an
epiphyseal lesion with a
dense sclefOtic margin _
containing a small amount of
chondroid ma/fix. The
appearance is typical of
chondfOblaslOma.
I
20
LONG BONE, EPIPHYSIS, SCLEROSIS/IVORY :r>
~
..•
~
o
3
'<
OJ
~
III
Chondroblastoma <Il
(Left) Late,al radiograph a.
shows a lytic lesion with r
surrounding dense sclerosis o
::J
Ell There is thick, dense <0
periosteal reaction" The OJ
o
lesion is typical of ::J
<ll
chondroblastoma. (Right)
Lateral radiograph shows m
"0
uniform sclerosis of the "0
epiphysis _ without ::r
'<
III
destructive changes. This
<ll
patient had Ewing sarcoma OJ
that originated in the
metaphysis & extended to
involve the epiphysis; the
density is due to reactive
change.
Osteosarcoma, Conventional
radiograph shows a densely
sclerotic metaphysis,
extending to the epiphysis,
with periosteal reaction and
soft tissue mass" all
typical of osteosarcoma.
There is an ossified lymph
node metastasis III (Right)
shows flattened and sclerotic
femoral capital epiphysis _.
This is typical of advanced
Legg-Calve-Perthes disease
and will develop into a coxa
magna deformity.
Osteopoikilosis Osteopetrosis
(Left) Axial NECT shows
multiple small round
sclerotic densities in both
femoral epiphyses and both
acetabulae. The appearance
is typical of osteopoikilosis, a
sclerosing dysplasia. (Right)
shows uniform density of the
epiphyses _ as well as the
remainder of the bones in
this child. Note also the
undertubulation of the
femora Ell indicating poor
remodeling with growth. This
is typical osteopetrosis.
I
21
m
(I)
lONG BONE, EPIPHYSEALIAPOPHYSEALISUBCHONDRAllYTIC lESION
en
>-
.r:
Cl.
'0. DIFFERENTIAL DIAGNOSIS o Lytic lesion arising eccentrically within the
w epiphysis
(I)
c:: Common • May extend into the metaphysis as the
o
CD • Giant Cell Tumor physis fuses, but origin is clearly
OJ
c:: • Chondroblastoma epiphysis
o • Pyrophosphate Arthropathy
--l • Location of origin may be confusing at
"0 • Osteomyelitis, Pediatric irregular physis in proximal humerus
Cl>
en • Lymphoma o Narrow zone of transition, but margin
m
CD • Langerhans Cell Histiocytosis usually sclerotic; this helps to distinguish
>.
E • Pigmented Villonodular Synovitis (PVNS) from GCT
-
m
o
c::
<l:
• Metastases, Bone Marrow
• Osteoarthritis
o May contain subtle chondroid matrix, but
may be entirely lytic
less Common • Subchondral Cyst: May become large,
• Gout simulating a lytic subchondral lesion
• Giant Cell Tumor Tendon Sheath o Pyrophosphate Arthropathy
• Osteomyelitis, Adult • May develop particularly large
subchondral cysts
Rare but Important • Hint: Watch for subtle chondrocalcinosis
• Amyloid Deposition to consider the diagnosis
• Soft Tissue Mass Erosion (Mimic) • Most frequent locations: Knee, wrist, hip
• Chondrosarcoma, Clear Cell o Pigmented Villonodular Synovitis
(PVNS)
ESSENTIAL INFORMATION • May develop large subchondral
cysts/erosions
• Monoarticular
• Hint: Consider patient age; only a limited • Associated nodular or lining synovitis
number of lesions are epiphyseal/apophyseal which contains mixed low & high MR
in children signal on T2 and enhances
• Hint: In older adult, look for reasons to o Osteoarthritis
suspect an arthritic etiology, with • Associated subchondral cysts are
subchondral cyst creating the "lytic lesion" particularly large in acetabulum (termed
Helpful Clues for Common Diagnoses "Egger cysts"); this is the site most likely
• Giant Cell Tumor to be confused with lytic lesion
o GCT: Lytic lesion arising eccentrically in • In long bones, watch for associated
metaphysis; location is highly specific osteophytes & cartilage loss
• By time of discovery, has usually o Gout
extended to subchondral bone; this • Occasionally develops large subchondral
makes GCT fall into the subchondral cysts without other signs of arthritis,
bone lesion category which may be confusing
• Hint: Narrow zone of transition but • Watch for other sites of arthritis, may
margin generally not sclerotic; this have more typical appearance of gout
character is often a distinguishing feature o Amyloid Deposition
• Occasionally may appear & behave • Deposition in bone appears as
aggressi vely subchondral lesion containing low signal
• Most frequent age range: 30-60 material
o Rarely arises in skeletally immature patient • Usually associated prominent thickening
• Begins in metaphysis & crosses into of tendons &/or capsule which remains
epiphysis as physis fuses low signal intensity on MR
• Will not show the sclerotic margin of • Osteomyelitis, Pediatric
chondroblastoma
• Chondroblastoma
I
22
lONG BONE, EPIPHYSEAl/APOPHYSEAl/SUBCHONDRAllYTIC lESION »
..
:J
III
o
o Metaphyseal location is most common site 3
Helpful Clues for Rare Diagnoses '<
of osteomyelitis in child, due to terminal • Soft Tissue Mass Erosion (Mimic) OJ
III
vascular configuration o Erosion from adjacent soft tissue mass
VI
C1>
o Young children have vessels crossing Co
usually is only focal scalloping r
physis; they may develop osteomyelitis in o Larger erosion may, if imaged en face, give o
:J
epiphysis or both locations the appearance of a lytic lesion
CO
CD
• Lymphoma • Chondrosarcoma, Clear Cell o
:J
o In children, 50% of cases present as CD
o Rare chondrosarcoma arising in the
multifocallesion m
epiphysis or subchondral region "2.
o Most lesions are metadiaphyseal & are o Generally does not appear aggressive
-0
::::r
highly aggressive '<
o Hint: Often misdiagnosed as VI
CD
o When in epiphysis, lesions are aggressive OJ
chondroblastoma; if pathology not in
• Langerhans Cell Histiocytosis agreement, consider this lesion
o Often polyostotic; most frequent location
is fiat bones and diaphyses Alternative Differential Approaches
o May also appear in epiphyses & apophyses • True epiphyseal lesions (prior to skeletal
o Range of appearance & behavior from maturation)
non-aggressive to highly aggressive o Chondroblastoma
• Metastases, Bone Marrow o Osteomyelitis, pediatric

o May occur in long bones, subchondral or o Langerhans cell histiocytosis
epiphyseal location: Femur and humerus o Lymphoma
o Age and history should be suggestive o GCT (extending from metaphysis)
• Subchondral cysts/lytic lesions (following
Helpful Clues for less Common Diagnoses skeletal maturation)
• Giant Cell Tumor Tendon Sheath o Subchondral cysts, arthritis-related:
o Not infrequently causes focal erosion of
Osteoarthritis, pyrophosphate arthropathy,
underlying bone, simulating a lytic lesion gout
o Associated soft tissue swelling in path of a
o Giant cell tumor
tendon; hands & feet are primary locations o Osteomyelitis, adult
• Osteomyelitis, Adult o Metastases, bone marrow
o More frequently diaphyseal, but may arise
o Pigmented villonodular synovitis (PVNS)
in subchondral region o Soft tissue mass erosion (mimic)
o Serpiginous pattern & reactive sclerosis
o Amyloid deposition
o Chondrosarcoma, clear cell
Giant Cell Tumor Chondroblastoma
AP radiograph shows
non-sclerotic margin •.
a lytic geographic lesion with
It arises in the metaphysis but
AP radiograph shows a lytic lesion arising in the
epiphysis of the humerus • in a teenager (note the
I
extends to the subchondral cortex. The constellation of nearly fused physis 1IlJ. The margin is more sclerouc
findings in this young adult is typical of GCT. than in most GCTs but typical of chondroblastoma.
23
C'O
Q)
LONG BONEr EPIPHYSEAL/APOPHYSEAL/SUBCHONDRAL LYTIC LESION
'"
>.
.r:
Q.
Q.
W
Q)
c Pyrophosphate Arthropathy Osteomyelitis, Pediatric
o
CO (Leh) Sagittal T2WI MR
OJ shows multiple subchondral
c
o cysts •• along with
--l osteophytes in an older
"C patient. The radiograph
Gl
IJ) showed chondrocalcinosis.
nl The diagnosis is
aJ
pyrophosphate arthropathy,
>-
E which may develop huge
•..
o
nl
subchondral cysts. (RighI)
Sagittal T1WI MR shows low
c:
« signal replacing Hoffa fat
pad, extending inlO the tibial
epiphysis EilI in a 4 year old.
This is typical of epiphyseal
osteomyelitis, which may be
seen in children. The
radiograph was normal.
langerhans Cell Histiocytosis

(Lefl) AP radiograph shows a
lytic lesion occupying the
epiphysis III with reactive
bone sclerosis 11II. This 7
year old had multiple other
permeative lesions, which
proved 10 be lymphoma.
This tumor presents as a
POlyoslOtic lesion SO% of the
time in children. (RighI) AP
lesion within the greater
trochanteric apophysis'" in
a teenager. LCH most
frequently is found in the
diaphysis or flat bones but
may be epiphyseal or
apophyseal.
Pigmented Villonodular Synovitis (PVNS) Metastases, Bone Marrow

(Leh) Sagittal T1WI MR
shows a lesion containing
low signal material which
has replaced Hoffa fat pad
III. The lesion has also
eroded into the tibial
epiphysis Bl PVNS
frequently is found in the
knee and may cause
erosions, presenting as a lytic
lesion on radiograph. (RighI)
AP radiograph shows a
subtle lytic lesion occupying
the trochlea •. This was
painful & showed cortical
breakthrough on MR; it
proved 10 be a renal cell
metastasis.
I
24
LONG BONE, EPIPHYSEAL/APOPHYSEAL/SUBCHONDRAL LYTIC LESION :>
::l
..•.
III
o
3
'<
[l:J
III
III
Giant Cell Tumor Tendon Sheath Cl>
(Left) AP ,adiograph shows a Co
Iylic well-circumscribed r
lesion" in a 45 year old o
:J
woman. There was no other <C
finding of knee arlhropathy. OJ

o
However, there were classic :J
C1l
findings of gout involving Ihe
1st MTP; sodium urale m
-0
crystals were seen on knee -0
aspirate. It MSK Req). :::r
'<
(Right) Lateral radiograph (J)
C1l
shows lytic lesions involving Dl
Ihe epiphysis & head of
adjacent phalanges" Volar
sofl tissue mass helps make
Ihe diagnosis of GCT tendon
sheath, which may erode
underlying bone.
Osteomyelitis, Adult
(Left) Axial bone CT shows a
serpiginous lytic lesion •.
wilhin the femoral
subchondral region. There is
surrounding sclerotic osseous
reaction. The pattern is
typical of osteomyelitis.
Subchondral location is
unusual in absence of septic
joint (t MSK Req). (Right)
Sagittal T2WI MR shows a
subchondral erosion
containing low signal
malerial ElIl along with low
signal thickening of Ihe
rolator cuff tendons" BOlh
findings are Iypical of
amyloid deposilion.
Soft Tissue Mass Erosion (Mimic) Soft Tissue Mass Erosion (Mimic)
radiograph shows a Iylic
lesion within the lateral
humeral condyle" The
lesion appears
well-marginated, though
there are regions that appear
slighlly more aggressive •.
(Right) Sagiltal STIR MR of
the same patient shows a
large softlissue lesion •.
which proved 10 be
schwannoma, with local
invasion into the distal
humerus" It is unusualto
have such extensive local
osseous invasion.
I
25
LONG BONE, METAPHYSEAL BANDS & LINES
DIFFERENTIAL DIAGNOSIS • Isolated physeal involvement: Trauma,

radiation, metastatic disease, disuse
(l)
Common osteoporosis, hyperemia
c • Growth Arrest Lines
a Helpful Clues for Common Diagnoses
co • Chronic Illness
Ol
c • Growth Arrest Lines
a • Trauma
o DB, VB: Sharply defined, thin dense lines
--' • Normal Variant
"0 o Variable distance from metaphysis
CI> • Disuse Osteoporosis
VI
III • Chemotherapy depending on age of insult
CO o Underlying insult may not be identifiable
>. • Malnutrition or Prolonged
E Hyperalimentation • Chronic Illness
•...o o LB, VB: Any illness including sickle cell
III
c:
• Hyperemia
<C • Heavy Metal or Chemical Ingestion anemia, rickets, osteogenesis imperfecta,
neoplasm
• Rickets
o LB: Nonspecific manifestation of illness
• Radiation
o May develop DB during healing
Less Common • Trauma
• Leukemia o LB: Acute injury, early healing
• Juvenile Idiopathic Arthritis OIA) o DB, VB: Healing Salter fractures, chronic
• Ankylosing Spondylitis injury, stress fracture
• Complications of High Dose Drug Therapy • ± Metaphyseal cupping/fraying
(Non -Ch emothera peu tic) • Normal Variant
• Metastases o DB, LB: Otherwise normal skeleton
• Osteoporosis o Normal fibula helps differentiate from
Rare but Important other conditions such as lead poisoning
• Complications of Vitamin 0 • Disuse Osteoporosis
• Osteopetrosis o LB: Regional distribution
• Hypothyroidism, Treated • Chemotherapy
• Complications of Fluoride o LB, VB
• Hypoparathyroidism • Malnutrition or Prolonged
• Pseudohypoparathyroidism Hyperalimentation
• Idiopathic Hypercalcemia o LB
• Scurvy • Hyperemia
• Congenital Infection o LB: Bone resorption leads to osteoporosis
• Aminopterin Fetopathy o Arthritis, infection
• Hypophosphatasia • Heavy Metal or Chemical Ingestion
• Erythroblastosis Fetalis o DB, AB: Lead most common; lines are late
• Osteopathia Striata manifestation
• Primary Oxalosis • Rickets
o LB, VB (healing): Manifestation of bone
resorption of hyperparathyroidism
ESSENTIAL INFORMATION • Radiation
Key Differential Diagnosis Issues o VB, LB, DB; ± physeal widening, fraying
• Manifestations include: Dense horizontal o DB, AB during healing
bands (DB), lucent bands (LB), alternating Helpful Clues for Less Common Diagnoses
dense & lucent bands (AB), vertical dense • Leukemia
bands (VB) o LB: May also see osteolytic lesions,
o AB indicate multiple insults separated in periostitis
time o DB, during healing
• Most are systemic, involve multiple physes o 2-5 years old
o Especially at knee, wrist (sites of greatest • Juvenile Idiopathic Arthritis OIA)
growth) o LB due to hyperemia & chronic illness
I
26
LONG BONE, METAPHYSEAL BANDS & LINES :l>
:J
...•
III
o
o Monoarticular to symmetric polyarticular o DB: Ligament & tendon ossification, axial 3
'<
o Uniform joint space narrowing, marginal & appendicular III
III
erosions, periostitis o Osteosclerosis, abnormal dentition, VI
CD
• Ankylosing Spondylitis subcutaneous calcification Q.
r
o LB due to osteoporosis, hyperemia • Pseudohypoparathyroidism o
:J
o Anterior & posterior spinal fusion o DB: Same as hypoparathyroidism CO
CO
o Symmetric sacroiliitis o Differentiating features o
:J
o Hip, shoulder arthritis; enthesopathy • Short stature, developmental delay <1>
• Complications of High Dose Drug • Short metacarpals, especially 4 & 5 ~

<1>
Therapy (Non-Chemotherapeutic) • Subcutaneous calcification, ossification Oi
"D
o DB • Idiopathic Hypercalcemia ::r
'<
en
• Metastases o DB: Diffuse bone sclerosis <1>
Q)
o LB, DB (during healing), especially • Scurvy
neuroblastoma, lymphoma o DB, LB: Orientation of growth plate:lucent
• Osteolytic lesions & periostitis from line (scurvy line):dense line
direct tumor invasion o Metaphyseal beaks, periostitis
• Osteoporosis • Congenital Infection
o LB:Juvenile idiopathic, Cushing disease o DB, VB, celery stalk
o Includes rubella, CMV, syphilis, herpes
Helpful Clues for Rare Diagnoses
simplex, toxoplasmosis
• Complications of Vitamin D
o DB, AB: Variable manifestations;
• Aminopterin Fetopathy
o DB
osteoporosis, osteosclerosis, cortical
thickening, soft tissue calcification • Hypophosphatasia
o LB, VB: Physis mimics rickets
• Osteopetrosis
o DB, LB, AB: Generalized osteosclerosis
• Erythroblastosis Fetalis
o LB: Diffuse soft tissue edema
o Metaphyseal expansion
• Hypothyroidism, Treated • Osteopathia Striata
o VB: Mild metaphyseal expansion
o DB: Abnormal epiphyses
o Asymptomatic
• Complications of Fluoride
o DB: t Bone density, osteophytes, ligament
• Primary Oxalosis
o DB, AB ± renal osteodystrophy
calcification
o Drumstick metacarpals
o Axial changes dominate
o Renal calculi, parenchymal calcification
• Hypoparathyroidism
o Vascular calcification
Growth Arrest Lines Growth Arrest Lines
Lateral radiograph shows a single growth recovery line

in the distal tibia ••. In many cases an underlying
Anteroposterior radiograph shows diffuse osteopenia
from osteogenesis imperfecta. Multiple metaphyseal
I
contributing cause is not known. lines • are present, corresponding to growth lines
associaled with bisphosphonate therapy.
27
m
<l>
lONG BONE, METAPHYSEAL BANDS & LINES
(/)
>.
.r::
e>-
a;m
~
<l> Trauma Trauma
c (Left) Anteroposterior
o
CO radiograph shows irregularity
Ol of the physis with sclerosis
c
o along the metaphyseal
--l margin __ in this Little
"C
Q)
League pitcher with a
(/) chronic repetitive injury.
ltl
CO (Right) Anteroposterior
>. radiograph shows a typical
-E
o
ltl
c:
<l:
slress fracture with ill-defined
sclerotic line E!II and
adjacent periosteal new
bone formation __
Normal Variant Disuse Osteoporosis

radiograph shows the
appearance of normal
physes __ mimicking dense
metaphyseal bands.
Differentiation from other
entities such as lead
poisoning can be difficult.
fRight) Anteroposterior
radiograph shows lucent
metaphyseal band __
caused by disuse
osteoporosis following
immobilization after open
reduction. internal fixation
fORIF) of a tibial diaphyseal
fracture.
Heavy Metal or Chemical Ingestion Rickets

radiograph shows the classic
dense metaphyseal lines __
seen with lead poisoning.
Involvement of the fibula
helps distinguish this
appearance from a normal
variant. (Right)
shows markedly abnormal
physis in this patient with
renal rickets. The physes are
cupped and frayed with
lucent and sclerotic
metaphyseal bands __
I
28
LONG BONE, METAPHYSEAL BANDS & LINES :I>
~
..•.
III
o
3
'<
tll
III
II>
leukemia leukemia (1)
(Leh) Anteroposterior 0-
radiograph shows diffuse r
osteopenia and subtle lucent o
::>
metaphyseal bands. in co
this patient with leukemia. IJJ
o
(Right) Oblique radiograph ::>
CD
shows lypical appearance of
leukemic metaphyseal lucent 5:
CD
lines. at the ankle. 1ii
-0
::r
'<
II>
CD
OJ
Ankylosing Spondylitis Scurvy

(Leh) Anteroposterior
radiograph shows lucent
bands at the metaphyses ••
as an early manifestation of
osteoporosis in a patient with
hyperemia from ankylosing
spondylosis. (Right)
shows classic signs of scurvy
including diffuse osteopenia
and dense lines at the
metaphyses and epiphyses.
The dense metaphyseal line
IIIis known as the white
line of Frankel.
radiograph shows typical
appearance of syphilis on
radiographs. The tibias show
Wimberger signs Ell and
generalized metaphyseal
osteiti5~which appears as
lucent bands •. (Right)
shows a typical appearance
of congenital syphilis with
generalized metaphyseal
osteitis manifesting as
metaphyseal lucencies _
I
29
ro lONG BONE, METAPHYSEAL CUPPING
<ll
VI
>.
.r:
Q.
May be isolated or involve random sites
a;ro DIFFERENTIAL DIAGNOSIS o
~ Helpful Clues for Common Diagnoses
Common
<ll
C
• Normal Variant • Child Abuse, Metaphyseal Fx (Mimic)
o
0)
• Child Abuse, Metaphyseal Fx (Mimic) o Horizontal shear through growth plate;
OJ
C periostitis during healing
o less Common
--' • Renal Osteodystrophy Helpful Clues for less Common Diagnoses
"0
CIl
VI • Rickets • Renal Osteodystrophy
o Combination of rickets &
'"
III • Pediatric Fracture
>- • Prolonged Immobilization hyperparathyroidism (HPTH)
-E
o
«'"
c:
• Sickle Cell Anemia
Rare but Important
• Pediatric Fracture
o Delayed complication
• Prolonged Immobilization
• Post Infection o Associated disuse osteoporosis
• Radiation-Induced • Sickle Cell Anemia
• Scurvy o Metacarpals, metatarsals; AVN, infarcts,
• Hypophosphatasia coarse trabecula, dactylitis, osteomyelitis
• Achondroplasia
• Metaphyseal Dysplasias Helpful Clues for Rare Diagnoses
• Polio (Prolonged Immobilization) • Radiation-Induced
o Regional mixed t & • bone density
• Hypervitaminosis A
• Scurvy
o Subperiosteal hemorrhage, osteopenia
ESSENTIAL INFORMATION • Hypophosphatasia
o Coarse trabecula, osteopenia
• Rickets, renal osteodystrophy & • Achondroplasia
o Short femora & humeri; spine & pelvic
hypophosphatasia: Overgrowth of
disorganized chondrocytes anomalies
o Hint: Involves sites of rapid growth: Distal
• Metaphyseal Dysplasias
o Short stature, bowing of long bones
radius/ulna, distal femur, proximal tibia,
costochondral articulations • Polio (Prolonged Immobilization)
o Especially knees, metatarsals; muscle
• Other entities: Oligemia, thrombosis create
central metaphyseal depression; causative wasting, thin gracile osteoporotic bones
insult need not be at growth plate • Hypervitaminosis A
o Hyperostosis, premature physeal fusion
I Anteroposterior radiograph shows 2 metaphyseal corner Posteroanterior radiograph shows a widened zone or
30
fractures E!II of the upper humerus in this vicUm of child
abuse. The fractures mimic the appearance of a
widened and cupped metaphysis.
metaphyses of the radius and ulna
chronic renal disease.
=
provisional calcification and cupping/fraying of the
in this child with
:t>
LONG BONEr METAPHYSEAL CUPPING :J
...•
Dl
o
3
'<
to
Dl
VI
(1)
(Left) AntelOposteriOl 0-
radiograph shows changes of r
nutritional deficiency rickets o
:J
including metaphyseal <0
cupping and fraying of the OJ
o
distal radius and ulna •• :J
(!)
radiograph shows changes of ;s::
(!)
rickets. The glOwth plate
OJ
-0
changes are due to an
::T
increase ;n the number of '<
chondlOcytes with 1055of the
en
(!)
Q)
normal columnar
organization, leading to
widening and cupping of the
glOwth plate.
radiograph shows classic
signs of scurvy including
osteopenia and dense lines
at the metaphyses and
epiphyses. Mild cupping is
present at the proximal and
distal metaphyses of both
tibia and fibula ••. (Right)
AntelOposterior radiograph
of a patient with
hypophosphatasia shows
oSleopenia and a widened
zone of provisional
ossification of the growth
plates •• with mild cupping
of the distal femur EiII.
radiograph shows flaring
(cupping) of the metaphyses
of the distal femora" in
this patient with
achondlOplasia. (Right)
Lateral radiograph shows
widening of the distal radial
metaphysis" with mild
irregularity of the growth
plate in this patient with
metaphyseal dysplasia.
I
31
lONG BONE, METAPHYSEAL FRAYING
DIFFERENTIAL DIAGNOSIS • Osteomyelitis, Pediatric

o Focal metaphyseal osteopenia &
Q)
Common destruction
c • Chronic Repetitive Trauma
o
CD
• Physeal Fractures, Pediatric
OJ
• Osteomyelitis, Pediatric o Any healing fracture or avulsion
C
o • Physeal Fractures, Pediatric • Child Abuse, Metaphyseal Fracture
-l
• Child Abuse, Metaphyseal Fracture o Corner fractures, cupping late
"tl
Q)
VI less Common Helpful Clues for less Common Diagnoses
III
al • Rickets • Rickets
>. • Thermal Injury
E o Metaphyseal osteolysis & cupping, coarse
•..o
III
• Neuropathic Disease ill-defined trabecula, rachitic rosary,
«
C
Rare but Important enlarged knees, ankles, & wrists
• Radiation o Generalized osteopenia, delayed skeletal
• Hypophosphatasia maturation, bowing
• Copper Deficiency, Infantile • Thermal Injury
• Metaphyseal Chondrodysplasias o Soft tissues changes including calcification
• Neuropathic Disease
o Exaggerated changes including extensive
ESSENTIAL INFORMATION fragmentation
Key Differential Diagnosis Issues Helpful Clues for Rare Diagnoses
• Hint: Differentiate isolated/multisite from • Radiation
systemic involvement o Regional osteopenia
o Systemic: Sites of rapid growth = proximal • Hypophosphatasia
& distal tibia/fibula, distal radius/ulna o Hint: Distinct finger-like lucent extension
o Isolated/multisite: Chronic repetitive into metaphysis from growth plate
trauma, osteomyelitis, fracture, thermal o Osteopenia, cranial synostosis, bowing,
injury, neuropathic disease, radiation fractures, metaphyseal spurs
• Metaphyseal sclerosis common • Copper Deficiency, Infantile
• Periosteal new bone with fractures, trauma, o Metaphyseal cupping & spurs, hypotonia,
osteomyelitis, neuropathic disease seizures, mental retardation
Helpful Clues for Common Diagnoses • Metaphyseal Chondrodysplasia
• Chronic Repetitive Trauma o Metaphyseal cupping, short stature,
o Sport/situation & site specific bowing
Chronic Repetitive Trauma Chronic Repetitive Trauma
I Anteroposterior radiograph shows osteolysis of the distal

radius _ in a skeletally immature patient. This is a form
Coronal oblique Tl WI MR shows widening and
irregularity of the physis _ in this Little League pitcher
of chronic Salter f injury that is seen particularly in with chronic injury from throwing curve balls.
young gymnasts.
32
LONG BONE, METAPHYSEAL FRAYING »
:J
..•o
Cl
3
'<
OJ
Cl
VI
(\)
(Left) Late,al ,adio8faph 0-
shows demineralization of r
the posterior calcaneus with o
::J
(Q
i"egula,ity of the central
portion of the metaphyseal OJ
o
side of the growth plate. ::J
co
in this patient with biopsy &
culture-proven osteomyelitis. ~
co
5i
radiograph shows changes of "0
::T
a healing ischial tuberosity '<
VI
avulsion. The growth plate is co
widened and i"egular. OJ
when compared to the

opposite normal physis.
Child Abuse, Metaphyseal Fracture

radiograph shows 2
metaphyseal corner fractures
Ell of the upper humerus.
Periosteal reaction is
occu"ing along the shaft _.
The metaphyseal margin of
the growth plate has lost its
normal sharp margin _
indicating injury throughout
the physis. (Right)
shows typical bone changes
in nutritional rickets. The
metaphyses are widened
(cupping) _ and the
margins of the growth plate
are i"egular (fraying) _
radiograph shows a widened
zone of provisional
calcification at all the physes
of the knee. in this patient
with nutritional rickets. The
weakened physes have
allowed a valgus deformity
to develop. (Right)
shows a widened zone of
provisional ossification at the
physes • as well as diffuse
osteopenia. Serological
studies proved
hypophosphatasia.
I
33
ro
Q)
lONG BONE, CENTRAL METAPHYSEAL lESION, NON-AGGRESSIVE
l/J
>.
.c
0-
ro DIFFERENTIAL DIAGNOSIS o May have small focal regions of endosteal
Q)
~ scalloping; no periosteal reaction
Q)
Common • Enostosis (Bone Island)
c • Enchondroma
o o Dense, regular hamartomatous cortical
en • Enostosis (Bone Island) bone formation in marrow
Ol
c • Paget Disease
o o Fades into normal bone at edges
-.J
• Chronic Osteomyelitis o May be large and continue to enlarge
"0
CIl
l/J
• Bone Infarct o Elicits no reaction; low signal on all MR
en'" • Hyperparathyroidism sequences; does not enhance
>. • Chondrosarcoma, Conventional • Paget Disease
•..oE • Desmoplastic Fibroma
• Intraosseous Lipoma
o Usually originates at subchondral bone
and progresses through metaphysis
~
'c" • Plasmacytoma towards diaphysis
• Langerhans Cell Histiocytosis o Variably lytic, mixed lytic and sclerotic,
• Fibrous Dysplasia depending on stage
• Unicameral Bone Cyst o Enlarges the involved bone
• Metastases, Bone Marrow o Sharp sclerotic margin ("blade of grass")
• Fibroxanthoma (NOF) (Thin Bone) • Chronic Osteomyelitis
• Giant Cell Tumor (Large) o Applies to any variety (e.g., bacterial,
• Aneurysmal Bone Cyst (Thin Bone) tuberculosis, fungal)
less Common o Lytic, oval, well-marginated, metaphyseal
• Liposclerosing Myxofibrous Tumor (LSMFT) lesion; not as permeative as acute bacterial
• Tuberculosis osteomyelitis
• Fungal o Elicits surrounding reactive bone
• Osteoblastoma formation in marrow and thick
periosteal/endosteal reaction
Rare but Important • TB and fungal osteomyelitis generally
• Vascular Tumor elicit less prominent osseous reaction
• Chondrosarcoma, Clear Cell o MR may show chronic intraosseous abscess
• Sarcoidosis • Bone Infarct
• Ollier Disease o Central, metaphyseal, geographic, lytic
• Maffucci Syndrome lesion; often noted only after dystrophic
calcification forms
ESSENTIAL INFORMATION • Dystrophic calcification often
serpiginous in pattern
o When diffuse (as in sickle cell disease),
may appear as a generalized t density
• Hyperparathyroidism
o Brown tumor is lytic and geographic, with
subtle sclerotic margin
o Often central metaphyseal, but not
restricted to this location
o Should see other signs of osseous
resorption: Mixed increased & decreased
bone density & various resorption patterns
o Brown tumor often hyperossifies once
treated, mimicking a sclerotic lesion
o Location: Central metaphysis, particularly
for chondrosarcoma arising in
enchondroma
I
34
LONG BONE, CENTRAL METAPHYSEAL LESION, NON-AGGRESSIVE »
..
;:,
Ql
o
o Chondroid matrix usually present, though o Initial plasma cell lesion, prior to 3
'<
it may be sparse or even absent dissemination as multiple myeloma III
Ql
o Most metaphyseal chondrosarcomas are o Generally non-aggressive to minimally VI
(t)
low grade, appearing geographic & aggressive in appearance 0-
o Pelvic, axial, or central metaphyseal r

non-aggressive o
:J
• Watch for change in character of lytic o Lytic, geographic lesion, generally without to
cortical breakthrough or osseous reaction OJ
lesion or chondroid matrix to suggest o
:J
degeneration of enchondroma to • Narrow zone of transition, but usually (l)
chondrosarcoma non-sclerotic margin

• Extensive endosteal scalloping suggests • Langerhans Cell Histiocytosis
degeneration to chondrosarcoma, but is o Common childhood lesion, ranges from
infrequently seen non-aggressive to highly aggressive
• Watch for thickening of endosteum: o Lytic, metaphyseal or diaphyseal; long
Good clue for degeneration to bones, skull, axial skeleton
chondrosarcoma • Fibrous Dysplasia
o This lesion is often underdiagnosed as a o Ground-glass matrix in long bones; mildly
benign tumor expansile
• Curettage yields poor results, with almost o Central, but located anywhere along
inevitable recurrence, often with higher length of bone, including metaphyses
grade lesion o Frequent bowing deformities
• Suggest diagnosis of chondrosarcoma • Unicameral Bone Cyst
despite non-aggressive appearance o Lytic, expanded, cystic (may have "fallen
• Desmoplastic Fibroma fragment" sign)
o Lytic non-aggressive osseous lesion o As it matures, "grows away" from
o Metadiaphyseal metaphysis
o Predominantly low signal on T2 weighted • Metastases, Bone Marrow
MR images; enhances o May be solitary & appear relatively
• Analogous to soft tissue fibromatosis non-aggressive
• Intraosseous Lipoma • Fibroxanthoma (NOF) (Thin Bone) &
o Central metaphyseal lytic lesion Aneurysmal Bone Cyst (Thin Bone)
o May contain dystrophic calcification o In thin bone, these normally eccentric
o Follows fat signal on all MR sequences lesions appear central
• Plasmacytoma • Giant Cell Tumor (Large)
o Usually eccentric; if large, appears central
Enchondroma Enostosis (Bone Island)
Anteroposterior radiograph shows a geographic

metaphyseal lesion without sclerotk margin which
central Anteroposterior radiograph shows a uniformly dense
central metaphyseal sclerotic lesion. The edges "(adell
I
into normal bone and may appear almost spiculated
contains punctate chondroid matrix. This is the most
common location and appearance {or enchondroma. =. This appearance is typical of a giant bone island
35
ro
Ql
LONG BONE, CENTRAL METAPHYSEAL LESION, NON-AGGRESSIVE
en
>-
.s:::
a.
ro
Q)
~
Ql Paget Disease Chronic Osteomyelitis
C
o (Left) Anteroposterior
aJ radiograph shows focal
CJl enlargement of the distal
c
o metaphysis of the humerus.
-' The lesion occupies the bone
"'C from the subchondral cortex,
CIl
VI moving proximally, with a
ltl
aJ sharp border with normal
>- bone. It is mixed lytic &
E sclerotic and entirely typical
•...o
ltl
of Paget disease. (Right)
c: Anteroposterior radiograph
<I: shows mild expansion of the
distal radius, containing a
Iyac, weJ/-marginated lesion
=. Prominent surrounding
osseous reaction Ell is seen,
typical of chronic infection.
Bone Infarct Hyperparathyroidism

central metaphyseal lesion
containing dense dystrophic
calcification which follows a
somewhat serpiginous
pal/ern III The appearance
is typical of bone infarct.
a nonspecific, geographic,
central, metaphyseal lesion
III However, the patient
has generalized increased
bone density, coarsened
trabeculae, and
subperiosteal resorption III
all typical of HPTH. The
lesion is a Brown tumor.
Chondrosarcoma, Conventional Desmoplastic Fibroma

lytic central metaphyseal
lesion, which causes minimal
endosteal scalloping _
Note the endosteal
thickening _ Despite the
non-aggressive appearance,
chondrosarcoma must be
considered; it was proven at
biopsy. rtMSK Req). (Right)
Lateral radiograph shows a
non-aggressive central
metadiaphyseal lesion with
distal pathologic fracture. In
an adult, desmoplastic
fibroma should be
considered; it was proven at
biopsy.
I
36
lONG BONE, CENTRAL METAPHYSEAL lESION, NON-AGGRESSIVE >::l
...•
III
o
3
'<
OJ
III
Ul
Intraosseous lipoma Plasmacytoma (l)
(Leh) AP radiograph shows a a.
faint lytic lesion in the central r
metaphysis. which has no o
::l
other defining features on to
radiograph. It has elicited no aJ
o
host reaction. MR proved fat ::l
(1)
signal within the entire lesion
on all sequences. (t MSK
Req). (Right) Anteroposterior
radiograph shows a large
central metaphyseal lytic
lesion. It appears geographic,
but with non·sc/erotic
margins •. This description
applies to giant cell tumor as
well as plasmacytoma; the
latter was proven at biopsy.
langerhans Cell Histiocytosis

geographic lytic lesion in the
central metadiaphysis of a
child _ It has elicited
dense periosteal thickening
Ell but itself does not
appear aggressive. This is I
typical appearance that may
be seen in the range of LCH
appearance. (Right) AP
radiograph shows a central
metaphyseal lesion which
contains ground-glass density
all. This is a typical
appearance and location for
fibrous dysplasia. The lesion
has not yet caused bowing
or thinning of the cortex.
Unicameral Bone Cyst Metastases, Bone Marrow

typical UBC in the central
metaphysis of the radius of a
child. The lytic geographic
lesion has a pathologic
fracture. as well as a
"fallen fragment" sign"
demonstrating its cystic
nature. (tMSK Req). (Right)
solitary lytic lesion in a
metaphyseal equivalent all.
The lesion appears
geographic and relatively
non-aggressive, but proved
to be metastatic breast
carcinoma. Metastases may
appear relatively benign.
I
37
C1l
OJ
LONG BONE, CENTRAL METAPHYSEAL LESION, NON-AGGRESSIVE
II)
>-
.r:
Cl.
C1l
Q)
:2
OJ Fibroxanthoma (NOF) (Thin Bone) Fibroxanthoma (NOF) (Thin Bone)
C
o (Leh) AP radiograph in this
CO young child shows a large
Ol bubbly lesion occupying the
C
o central metadiaphysis. The
.....J
humerus is thin at this age,
"0
Q)
and fibroxanthoma may
I/) occupy the entire width of
01
CO the bone, rather than having
>- its usual cortically based
E appearance. (Right) AP
•...o
01
radiograph in a child shows
C a lytic lesion occupying the
<t: entire metaphysis of the
fibula .:II. Normally
eccentric lesions like NOF
may appear central in thin
bones. Note the more typical
lesion in the tibia BI.
Giant Cell Tumor (Large) Giant Cell Tumor (Large)

(Left)Sagittal CT reformat
shows a lytic central
metaphyseal lesion causing
endosteal scalloping. It is
geographic but has a
non-sclerotic margin. GCT,
when this large, may occupy
the entire width of the
metaphysis and appear
central rather than eccentric.
lesion occupying the entire
metaphysis of the fibula,
extending to the subchondral
cortex. It proved to be GCT,
appearing central in a small
bone.
Liposclerosing Myxofibrous Tumor

Aneurysmal Bone Cyst (Thin Bone) (LSMFT)
highly expanded but
geographic lytic lesion of the
proximal fibular metaphysis
=::I in ateenager. The cortex
is thin but intact. This is an
ABC; though this lesion is
usually eccentric, it occupies
the entire width of a small
bone. (Right) AP radiograph
shows a well-defined central
metaphyseal lesion •• which
has mixed lytic and sclerotic
regions. This is typical of
LSMFT;this lesion is found
almost exclusively in this
proximal femora/location.
I
38
~
lONG BONE, CENTRAL METAPHYSEAL lESION, NON-AGGRESSIVE
.•
::J
Ql
o
3
'<
III
Ql
III
Tuberculosis Osteoblastoma (1)
(Left) PA radiog,aph shows a a.
multiloculated central r
metaphyseal lytic lesion III. o
:::J
/I has elicited a small amount <C
of periosteal reaction Ell but OJ

o
no osseous sclerosis. This is :::J
<tl
typical of TB or fungal
osteomyelitis. The distal s:
<tl
osteoporosis suggests the 1ii
lesion has been present for a 1:l
:r
long period of time. (RighI) '<
III
AP radiograph shows a <tl
centra/lytic lesion in a t\l
metaphyseal equivalent III.

ft is non-aggressive.
Osteoblastoma rarely occurs
outside the axial skeleton,
bullhis is one such case.
Sarcoidosis
(Lefl) Anteroposterior
radiograph shows a
longstanding lytic lesion
within the central metaphysis
of the femur. It has elicited
very regular periosteal and
endosteal reaction. This was
a case of Iymphangiomalosis,
present {or> 10 years.
(RighI) Oblique radiograph
shows central metaphyseal
lytic lesions containing lacy
trabeculae _ typical of
phalangeal sarcoidosis.
allier Disease Maffucci Syndrome

(Left) PA radiograph shows
multiple central metaphyseal
lytic lesions III. Chondroid
matrix is seen in one lesion
Ell. though it is not required
for the diagnosis of Oilier
disease. This patient also had
the typical unilateral
metaphyseal long bone
lesions. (tMSK Req). (RighI)
PA radiograph shows central
metaphyseal lytic lesions
similar to the previous case.
In addition there is a soft
tissue hemangioma showing
phleboliths _ securing the
diagnosis of Maffucci
syndrome. (tMSK Req).
I
39
LONG BONE, CENTRAL METAPHYSEAL LESION, AGGRESSIVE
DIFFERENTIAL DIAGNOSIS • Osteosarcoma, Conventional

o Common sarcoma; metaphyseal location is
Q)
Common most typical
c • Metastases, Bone Marrow
o o Though location is more frequently
lJ]
OJ
• Multiple Myeloma eccentric within metaphysis, once lesion
C
o • Osteosarcoma, Conventional becomes large, it occupies entire
-.J
• Osteomyelitis, Adult metaphysis and appears central
"tl
Q) • Osteomyelitis, Pediatric o May be lytic, but more frequently contains
Ul
nl
lJ]
• Chondrosarcoma immature amorphous osteoid
>. • Malignant Fibrous Histiocytoma (MFH), o Highly aggressive, with cortical
E
-
<
o
nl
C
Bone
• Fibrosarcoma
• Plasmacytoma
breakthrough, periosteal reaction, soft
tissue mass
• Osteomyelitis, Adult
• Ewing Sarcoma o Central metaphysis is a frequent location
• Leukemia o Appearance may be highly permeative and
• Langerhans Cell Histiocytosis aggressive, with periosteal reaction and
Less Common soft tissue mass
• Giant Cell Tumor, Aggressive o Radiograph/CT may show typical
• Angiosarcoma, Osseous serpiginous pattern of bone destruction
• Chronic Recurrent Multifocal Osteomyelitis o MR demonstrates abscesses
• Osteomyelitis, Pediatric
o Central metaphysis is most frequent
ESSENTIAL INFORMATION location of childhood osteomyelitis,
Key Differential Diagnosis Issues through hematogenous spread
• Majority of osseous lesions occur o May appear highly aggressive, with
predominantly in metaphysis, so list of permeative change, periosteal reaction,
metaphyseal lesions is lengthy; this and abscesses
differential deals with those that appear • Chondrosarcoma
aggressive o Central proximal metaphysis is most
• Lesions tend to preferentially occur frequent location of chondrosarcoma
centrally, eccentrically, cortically, or at o Mirrors the most frequent location of
osseous surface; this list covers those that are enchondroma, a common precursor of
located centrally chondrosarcoma
o Often contains punctate chondroid
Helpful Clues for Common Diagnoses
matrix, but may be entirely lytic
• Metastases, Bone Marrow o Lesion often appears moderately aggressive
o Metastases are most common aggressive
or non-aggressive; may be geographic or
osseous lesion may have only subtle regions which
o Aside from axial lesions, central
appear aggressive
metaphysis is a common location of o May have endosteal scalloping; however,
metastases frequently has endosteal thickening
o Generally proximal to knees and elbows
o Cortical breakthrough and soft tissue mass
o Solitary metastasis is most likely renal or
are uncommon in low grade lesions
thyroid carcinoma • Malignant Fibrous Histiocytoma (MFH),
• Multiple Myeloma Bone
o Myeloma is a relatively common
o Central metaphyseal location is most
aggressive bone lesion common
o Generally presents with polyostotic lesions
o Aggressive permeative lesion with
o May present with single axial or
periosteal reaction, cortical breakthrough,
metaphyseal lesion, plus others that are and soft tissue mass
not apparent (too small, or diffuse o Fibrosarcoma appears similar to MFH
infiltration seen only as osteoporosis)
I
40
LONG BONE, CENTRAL METAPHYSEAL LESION, AGGRESSIVE »
:l
...•
III
o
o MFH may arise secondary to bone infarct • May be geographic, with sclerotic margin 3
'<
• Central metaphysis is most frequent • May be highly permeative, eliciting [Jl
III
location of bone infarct periosteal reaction, cortical VI
CD
• Lesions may contain central dystrophic breakthrough, and soft tissue mass C-
o
calcification, residua of infarct Helpful Clues for Less Common Diagnoses o
:J
• Plasmacytoma • Giant Cell Tumor, Aggressive
(Q
OJ
o Most frequent location is pelvis, in a o
o GCT arises in the metaphysis, extending :J
metaphyseal equivalent towards the subchondral bone
(t)
o May also arise in the central metaphysis o GCT generally is eccentric within the
s::
(t)
o Characteristically appears fairly geographic 0;

metaphysis, but as it grows to occupy the "0
• Narrow zone of transition entire metaphysis it may appear central
::T
'<
VI
• Non-sclerotic margin o Most GCT cases are geographic (t)
OJ
• Generally only moderately aggressive • Narrow zone of transition, but
• Ewing Sarcoma non-sclerotic margin
o Central aggressive lesion, with periosteal o GCT may occasionally develop a more
reaction, cortical breakthrough, and soft aggressive appearance and behavior, with
tissue mass rare malignant behavior
o Most frequently diaphyseal, but not
• Angiosarcoma, Osseous
uncommonly is metadiaphyseal o Discussion includes other aggressive
o May have prominent reactive bone vascular lesions (hemangioendothelioma,
formation within the osseous portion of hemangiopericytoma)
the lesion o Located preferentially in lower extremities
• Leukemia (including pelvis)
o Generally presents as diffuse osteopenia o Lesions in long bones tend to be located
o Focal lytic metaphyseal lesion may rarely centrally in metaphysis
be seen o May be solitary, but often polyostotic
o MR usually shows extensive metaphyseal o Range of aggressiveness from geographic to
lesions throughout skeleton highly permeative
• Langerhans Cell Histiocytosis • Chronic Recurrent Multifocal
o Most frequent location is axial skeleton or
Osteomyelitis
central metadiaphyseal portion of long o Long term pain, but X-rays often normal
bone o Metaphyseal & axial lesions seen optimally
o Lytic lesion with wide range of on MR, appearing aggressive & multifocal
appearances
AP radiograph shows an aggressive permeative lesion

located centrally in the meliJphysis Ell with pathologic
PA bone scan in the same patient shows the expected
lesion ~ & demonstrates it to be solitary. Note the
I
fracture. The patient is 38 years old; despite the morphologic abnormality of the left kidney ~ this
young age, metastasis must be strongly considered. leads to the diagnosis of metastatic renal cell carcinoma.
41
LONG BONE, CENTRAL METAPHYSEAL LESION, AGGRESSIVE
Q) Multiple Myeloma Osteosarcoma, Conventional

c fLeft) AntefOposterior
o
CO radiograph shows a lytic,
OJ slightly geographic lesion in
C
o the central metaphysis •.
---l
Careful observation suggests
"t:l a similar lesion in the left
Cl)
IJ) femoral neck and another in
C1l
[Xl the left inferior pubic ramus.
>- Non-marginated multiple
E lesions suggest myeloma.
•..
o
C1l
(Right) Lateral radiograph
c: shows a dense permeative
« lesion within the metaphysis,
with large osteoid-producing
soft tissue mass =.
aggressive periosteal
There is
reaction; this is classic

osteosarcoma.
Osteomyelitis, Adult Osteomyelitis, Pediatric

permeative lytic lesion III
occupying the central
metaphysis of the tibia.
There is periosteal reaction
HI. This appearance could
be an aggressive tumor, but
in this case is osteomyelitis.
(Right) AntefOposterior
radiograph in a 13 year old
lytic meta diaphyseal lesion
•. The diagnosis could
easily be Ewing sarcoma, but
biopsy pfOved
staphylococcal osteomyelitis.
Malignant Fibrous Histiocytoma (MFH),

Chondrosarcoma Bone
lytic, moderately aggressive
lesion in the central
metaphysis" The lesion
changes character distally,
where chondroid matrix is
seen Ei!l indicating
enchondroma degenerating
to chondfOsarcoma. ft MSK
Req). (Right) AP radiograph
shows central metaphyseal
bone infarct Ei!l There is a
highly permeative lesion
extending ffOm the infarct
•. MFH may arise
secondary to bone infarct;
central metaphyseal location
is typical.
I
42
LONG BONE, CENTRAL METAPHYSEAL LESION, AGGRESSIVE »
::J
..•o
Ql
3
'<
OJ
Ql
Plasmacytoma Ewing Sarcoma t/I
=
(1)
(Left) AP radiograph shows a a.
lytic expanded lesion that r
has no sclerotic margin and o
::J
(Q
has cortical breakthrough,
located in a metaphyseal CD
o
equivalent. This moderately ::J
CD
aggressive appearance and
location is typical of
plasmacytoma. (Right) AP
radiograph in an 8 year old
lesion =.
central metadiaphyseal
Though Ewing
sarcoma ;s thought of as a
diaphyseal lesion, it is not
uncommon for it to arise in
the metadiaphysis.
leukemia
(Left) Coronal STIR MR
shows a prominent
meta diaphyseal lesion
this ]0 year old, which
in =
proved to be acute leukemia.
The radiograph was normal.
Thispermeative lesion was
not solitary; note lesions
throughout the pelvis and
left femur. (Right) AP
radiograph shows an
aggressive permeative lesion
in the femoral neck =This
is a nonspecific appearance,
but it should be remembered
that LCH may appear highly
aggressive, imitating Ewing
sarcoma and osteomyelitis.
Giant Cell Tumor, Aggressive Angiosarcoma, Osseous

moderately aggressive lesion
•. occupying the proximal
femoral metaphysis. GCT
can be quite aggressive in
appearance & behavior.
Though usually eccentric, a
large GCT may appear
central, as in this case.
a moderately aggressive
lesion in the central femoral
neck metaphysis" There
are other subtle lesions in the
femoral neck and ischium
lID.Angiosarcoma is often
polyostotic.
I
43
lONG BONE, METAPHYSEAL LESION, BUBBLY
DIFFERENTIAL DIAGNOSIS • Hint: Enchondroma, Oilier disease, Maffucci

syndrome usually bubbly only when located
Common in small bones of hand & foot
ill
C
o • Fibroxanthoma (Non-Ossifying Fibroma)
ell Helpful Clues for Common Diagnoses
• Giant Cell Tumor (GCT)
0>
C • Aneurysmal Bone Cyst (ABC) • Fibroxanthoma (Non-Ossifying Fibroma)
o o Common lesion in children
-' • Metastases: Thyroid, Kidney
o Eccentric (cortically based), metaphyseal is
"0
Q) • Chondrosarcoma, Conventional
VI
III
most common location
r:c less Common • In thin bone, may occupy entire width
>- • Chondromyxoid Fibroma (CMF) o Generally has bubbly appearance;
E
-o
III
C
<l:
• Chondroblastoma (CB)
• Unicameral Bone Cyst (UBC)
occasionally quite large
o Sclerotic rim; natural history is to heal,
• Enchondroma, Phalanx increasing peripheral sclerosis & replacing
• Oilier Disease with normal bone
• Maffucci Syndrome. • Giant Cell Tumor (GCT)
• Osteosarcoma, Telangiectatic o Common lesion in adults (30-60 most
• Osteoblastoma (OB) frequent age range)
Rare but Important o Originates eccentrically in metaphysis
• Plasmacytoma • Usually extends to subchondral bone by

time of discovery
o As lesion increases in size, it expands &
ESSENTIAL INFORMATION progresses towards bubbly appearance
Key Differential Diagnosis Issues o Lesion is lytic; may acquire
• Hint: Age is an important parameter in this pseudotrabeculations in wall
differential • Pseudotrabeculations add to "bubbly"
o Bubbly metaphyseal lesion in child appearance
• Fibroxanthoma o Important differentiating feature is narrow
• Aneurysmal bone cyst zone of transition but non-sclerotic margin
• Less common: CMF, CB, UBC, o Most frequent locations: Around knee,
telangiectatic osteosarcoma, OB distal forearm bones, proximal femur

o Bubbly metaphyseal lesion in teenager or • Aneurysmal Bone Cyst (ABC)
young adult o Common lesion in children & up to age 30
o Most common location: Eccentric
• Fibroxanthoma
• Giant cell tumor metaphyseal
• Aneurysmal bone cyst • In thin bone, may occupy entire width
• Less common: CMF, CB, UBC, o Expansion may be tremendous, but
telangiectatic osteosarcoma, OB generally retains a thin rim of calcification
o Bubbly metaphyseal lesion in adult> 30 (best seen on CT)
years o MR usually shows lesion full of fluid levels;
• Giant cell tumor rarely may be solid
• Metastases (thyroid, kidney) • Metastases: Thyroid, Kidney
• Chondrosarcoma o Metaphyses are common location for
• Plasmacytoma metastatic deposits
• Hint: In older patient, be certain to consider o Most metastases cause only mild
chondrosarcoma expansion
o Common lesion in metaphysis that usually • Exception: Thyroid & kidney metastases
appears relatively non-aggressive, though often are solitary & highly expanded
not often truly bubbly o If kidney metastasis is suspected, consider
o Underdiagnosis & undertreatment have embolization prior to biopsy

serious consequences • Highly vascular lesion may bleed
significantly
I
44
LONG BONE, METAPHYSEALLESION, BUBBLY »
• Chondrosarcoma, Conventional • Chondroblastoma (CB)
-
::l
Ql
o
3
'<
o Most common location: Central o Eccentric lesion originating in epiphysis, llJ
Ql
metaphysis generally in teenager
• Proximal long bones> distal • As patient becomes skeletally mature, '"
CD
a.
o Potentially dangerous lesion since it may lesion often extends into metaphysis r
o
::l
appear quite non-aggressive • However, "bubbly metaphyseal" is an (Q
• Generally low grade (though may be unusual appearance for the lesion OJ
o
::l
large) when first discovered o If adjacent to cortex, expansion may lead CO
• May cause mild expansion, with to a mild bubbly appearance s:
CO
pseudotrabeculation, appearing bubbly o Lytic or small amount of chondroid fii
-0
• Adjacent cortex generally thinned, but • Unicameral Bone Cyst (UBC) ::T
'<
may cause endosteal thickening, o Common lesion of childhood (j)
CO
Q)
especially immediately distal to lesion o Central metaphyseal (especially proximal
• Chondroid matrix, but may be lytic humerus) is most frequent location
o Danger lies in underdiagnosis, leading to o Most common appearance is of central
potentially catastrophic undertreatment lucency with mild expansion of bone &
• If treated as benign with curettage & thinning of endosteal cortex
bone grafting, lesion will recur, often • With time, may develop
with spread to local soft tissues pseudotrabeculations in wall, giving a
o Hint: Always consider chondrosarcoma in "bubbly" appearance
following circumstances • Generally not truly significantly
• Proximal femoral or humeral expanded or bubbly
metaphyseal, PLUS • Enchondroma, Phalanx
• "Non-aggressive bubbly" lesion, PLUS o Enchondroma in long bone is generally
• Patient falls in 30-60 year age range! not expansile, except for mild focal
Helpful Clues for Less Common Diagnoses scalloping of endosteal cortex
o Exception: Small bones of hands & feet
• Chondromyxoid Fibroma (CMF)
o Most frequent location is eccentric in
• Enchondroma may show significantly
proximal tibial metaphysis bubbly expansion
o Uncommon lesion seen mostly in children
• Appears more aggressive than it behaves
and young adults • Often has punctate chondroid matrix,
o Sclerotic margination & bubbly appearance
but may be entirely lytic
o allier disease & Maffucci syndrome have
o Usually lytic, though may have chondroid
similar bubbly appearance of phalangeals
Fibroxanthoma (Non-Ossifying Fibroma)
Lateral radiograph shows well-marginated bubbly lesion

in the metadiaphysis 11II. The lesion is cortically based
Oblique radiograph shows bubbly lesion occupying
entire width of the metadiaphysis 11II. When a
I
and is typical of fibroxanlhoma. The natural history is to fibroxanthoma becomes large in a thin bone (fibula, or
heal in with normal bone. humerus in a child), it may appea, central in localion.
45
LONG BONE, METAPHYSEAL LESION, BUBBLY
ClJ Giant Cell Tumor (GCT)

C
o (Leh) PA radiograph shows a
OJ bubbly lesion in distal radial
OJ metaphysis, a common
C
o location for GCT. Though
-l
these lesions are usually less
"0 bubbly in appearance than
Ql
III in this case, GCT may
III
al contain
>- pseudotrabeculations that
-
E
o
III
C
«
give such an appearance.
!tMSK Req). (RighI) AP
radiograph shows a
longstanding GCT that has
expanded with a somewhat
bubbly appearance. There
are pseudotrabeculations;
the location & appearance is
typical of GO:
Aneurysmal Bone Cyst (ABC) Aneurysmal Bone Cyst (ABC)

shows an extremely
expanded bubbly lesion
arising eccentrically from the
metaphysis of the ulna ••.
The location and appearance
is typical of ABC. (RighI)
bubbly expanded lesion
occupying the entire width
of the fibula" with a thin
conical rim, in a teenager.
The age and appearance are
typical for ABC; when ABC
arises in a thin bone such as
the fibula, it may appear to
be central in location.
Metastases: Thyroid, Kidney Chondrosarcoma, Conventional

an expanded lesion of the
metaphysis ElIlI with thin rim
of lesser trochanter
remaining III The patient is
middle-aged; though the
lesion could be a giant cell
tumor, solitary metastasis
must be considered (thyroid
in this case). (RighI) Lateral
radiograph in a middle-aged
patient shows a somewhat
bubbly metaphyseal lesion.
Few other bubbly
metaphyseal lesions occur in
this location or age.
Chondrosarcoma must be
suspected & was proven.
I
46
LONG BONE, METAPHYSEAL LESION, BUBBLY »
::l
...•
ell
o
3
'<
Dl
ell
Chondromyxoid Fibroma (CMF) Chondroblastoma (CB) III
ll>
(Left) Anteroposterior a.
radiograph shows a mildly r
expanded and bubbly lesion o
::l
located eccentrically in the to
tibial metaphysis Ia. The OJ
o
tibia is the most frequent :J
CD
location, and this is a typical
appearance of CMF. (Right) s:
CD
Axial bone CT shows a small
1ii
bubbly eccentric lesion. at TI
::r
the junction of epiphysis & '<
VI
metaphysis in a young adult. CD
There is a small focus of Ol
chondroid matrix IIID; this is
chondroblas/oma.
Enchondroma, Phalanx
(Left) AI' radiograph in a
child shows a mildly
expanded metaphyseal
lesion. Pseudotrabeculations
may occasionally be seen in
UBC" particularly in the
healing phase, making them
appear bubbly. UBC more
normally is more bland in
appearance. (Right) I'A
radiograph shows a bubbly,
highly expanded phalangeal
lesion. Enchondroma in
other locations does not
appear bubbly but often
does when located in the
phalanx. Note the subtle
chondroid matrix.
Oilier Disease Maffucci Syndrome

(Left) Sagittal bone CT
reformat shows bubbly
lesions in several small bones
of the foot" with a normal
adjacent me/atarsal ElIl all
typical of Oilier disease.
Note the absence of
chondroid matrix; it need
not be present in
enchondromas. (Right) I'A
radiograph shows multiple
bubbly lesions in the small
bones of the hand, along
with phleboliths in a soft
tissue hemangioma Ia. The
constellation is typical of
Maffucci syndrome. (t MSK
Req).
I
47
lONG BONE, ECCENTRIC METAPHYSEAL lESION, NON-AGGRESSIVE
DIFFERENTIAL DIAGNOSIS o Dense sclerotic border around a lytic,

sometimes bubbly, lesion
Q)
Common o Natural history is to heal, with sclerosis
c • Enostosis (Bone Island)
o first, then remodeling to normal bone
OJ • Fibroxanthoma (Non-Ossifying Fibroma) • Stress Fracture, Adult
OJ
C
o • Stress Fracture, Adult o Typical location in long bones
--' • Giant Cell Tumor (GCT) • Medial subcapital femur
"C
ell • Aneurysmal Bone Cyst (ABC) • Medial basicervical femur
III
III
OJ
• Bone Infarct • Medial proximal tibial metaphysis
:>. • Metaphyseal Extension of Subchondral Cyst • Distal tibial metaphysis
E
-
o
III
C
«
• Arthroplasty Component Wear/Particle
Disease
• Chronic Osteomyelitis •
o Linear sclerosis is diagnostic
o If uncertain, MR is diagnostic
Giant Cell Tumor (GCT)
• Hyperparathyroidism, Brown Tumor o Eccentric metaphysis is most frequent
• Langerhans Cell Histiocytosis (LCH) location
less Common • Though it usually reaches subchondral
• Liposclerosing Myxofibrous Tumor (LSMFT) bone, origin is metaphyseal, NOT
• Chondromyxoid Fibroma (CMF) epiphyseal
• Chondroblastoma (Mimic) o Most common age range: 30-60 years
• Osteosarcoma, Telangiectatic o Distinct radiographic appearance: Narrow
zone of transition but non-sclerotic margin
Rare but Important o Usually non-aggressive, but may have
• Tuberculosis aggressive or even malignant features
• Fungal o MR usually has some central low T2 signal
• Vascular Tumors • Aneurysmal Bone Cyst (ABC)
• Osteoblastoma o Generally highly eccentric & metaphyseal
o May be highly expanded, but generally
ESSENTIAL INFORMATION retains thin cortical rim
• Rim may not be visible on radiograph
Key Differential Diagnosis Issues but seen on CT
• Wide variety of lesions arise in an eccentric • Completely lytic
location in the metaphysis o MR shows fluid levels in the vast majority
• Most can be distinguished from one another • Remember that many other lesions may
with a high degree of confidence contain fluid levels
o Hint: Pay attention to details of lesion
• Remember that rarely ABC may be solid,
Helpful Clues for Common Diagnoses without fluid levels
• Enostosis (Bone Island) o Age: Generally < 30 years
o Normal hamartomatous bone formation • Bone Infarct
within medullary space; metaphysis is o Metaphysic most frequent location
most common location • When extensive, as in sickle cell, extends
o Dense sclerotic bone with edges that "fade" to diaphysis
into normal bone o When lytic, unlikely to be visible on
o Only significant differential is a sclerotic radiograph
metastasis o Visible with dystrophic calcification
• MR or PET/CT helps to differentiate • May be globular or serpiginous
• Fibroxanthoma (Non-Ossifying Fibroma) • Calcification may enlarge over time
o Lesion of childhood and teenagers • Beware of changing character of lesion; .
o Metaphysis is most common location (may new permeative change suggests
become metadiaphyseal) degeneration to malignant fibrous
o When eccentric (or cortically based, histiocytoma
appearing eccentric), diagnosis is secure
I
48
lONG BONE, ECCENTRIC METAPHYSEAL lESION, NON-AGGRESSIVE :l>
:J
..•o
III
• Metaphyseal Extension of Subchondral o Location not specific: May be metaphyseal, 3

'<
Cyst diaphyseal, or epiphyseal OJ
III
o Some arthritic processes may develop • May be central or eccentric 11l
(1)
particularly large subchondral cysts o Degree of aggressiveness unreliable; has C,
• May mimic metaphyseal tumor wide range of appearance r

o
:J
• Most frequent mimics: Pyrophosphate Helpful Clues for less Common Diagnoses (Q
OJ
arthropathy, gout, pigmented • Liposclerosing Myxofibrous Tumor o
:J
villonodular synovitis (LSMFf) CD
o Watch for chondrocalcinosis, other o Highly location-specific: Eccentric

evidence of arthritis proximal femoral metaphysis
• Arthroplasty Component Wear/Particle o Generally contains some degree of
Disease sclerosis; may have lipomatous portions
o Lytic lesions around prosthesis should
• Chondromyxoid Fibroma (CMF)
stimulate search for source of particles o Rare tumor which has high degree of
producing osteolysis location specificity: Eccentric metaphyseal
• Polyethylene, cement, metallic beads, in tibia
bone o Sclerotic margin, may be bubbly
• Patients generally also of age typical for o Either chondroid matrix or lytic
metastatic disease/myeloma • Chondroblastoma (Mimic)
• Chronic Osteomyelitis o Generally not confusing; if lesion extends
o Metaphysis is most frequent location of
from epiphysis into metaphysis following
osteomyelitis physeal fusion, may appear metaphyseal
o If chronic, lytic lesion is well-marginated
• Most common potential site of
o Sclerotic reactive bone surrounds lesion;
confusion: Proximal humerus
also endosteal sclerosis • Osteosarcoma, Telangiectatic
• Hyperparathyroidism, Brown Tumor o Most frequent site: Eccentric metaphyseal
o Brown tumor is lytic & generally
o Dangerous lesion: Much of lesion appears
geographic but without sclerotic margin non-aggressive (narrow sclerotic margin)
o Location not specific to either metaphysis
• Lytic; no osteoid produced
or diaphysis • Contains fluid levels; easily
o Diffusely abnormal bone density & other
misdiagnosed as ABC
resorptive patterns should suggest HPTH o Despite appearance, behavior & prognosis
• Langerhans Cell Histiocytosis (LCH) same as conventional osteosarcoma
Enostosis (Bone Island) Fibroxanthoma (Non-Ossifying Fibroma)
Anteroposterior radiograph shows a slightly eccentric

densely sclerotic giant bone island. Note the dense
AP radiograph shows a well-marginated lytic lesion
located eccentrically in the metaphysis _ Though
I
regular matrix fading off into normal bone, an expected NOr is usually cortically based, it may appear eccentric.
finding in enostosis. This lesion is beginning to heal, with peripheral sclerosis.
49
lONG BONEr ECCENTRIC METAPHYSEAlLESIONr NON-AGGRESSIVE
ill Stress Fracture, Adult Giant Cell Tumor (GCT)

c:: (leh) AP radiograph shows a
o
cc slighlly linear sclerotic
0)
c:: "lesion" • located
o eccentrically in the medial
--' metaphysis 01 the lemur. This
"'C
<1l is a stress (racture, located in
III the typical medial
III
cc basicervicallocation. (Right)
>- AP radiograph shows a lytic
E
-
«
o
III
c::
lesion located eccentrically
within the metaphysis _
The lesion has a narrow zone
of transition but no sclerotic
margin and reaches the
subchondral cortex; this is
the classic location and
appearance 01 a giant cell
tumor. (tMSK Req).
Aneurysmal Bone Cyst (ABC) Bone Infarct

(left) Anteroposterior
eccentric lesion in the
metaphysis 01 the great toe
1m. lesion is geographic.
Appearance is typical,
though not pathognomonic,
01 ABC. Multiple I'uid levels
were shown on MR. (Right)
sclerotic, angularly shaped
locus, located eccentrically
in the metaphysis 1m. The
shape & character 01 the
dystrophic calcilication is
typical 01 bone inlarct;
location may be either
central or eccentric.
Metaphyseal Extension of Subchondral Arthroplasty Component Wear/Particle

Cyst Disease
(leh) AP radiograph shows
an eccentric, subchondral,
metaphyseal lesion • that
appears non-aggressive.
Note that there is
chondrocalcinosis present as
well 1m. This is a large
subchondral cyst in a patient
with pyrophosphate
arthropathy. (Right)
shows an eccentric
metaphyseal lytic lesion
surrounding a screw. in a
knee arthroplasty. This is
osteolysis resulting Irom
particle disease secondary to
wear 01 the polyethylene.
I
50
lONG BONE, ECCENTRIC METAPHYSEAL LESION, NON-AGGRESSIVE :t>
::l
..•o
III
3
'<
III
III
VI
Chronic Osteomyelitis ltl
(Left) AP radiograph shows Q.
an eccentric, lytic, r
geographic lesion within the o
:J
metaphysis". There is a <C
fairly dense surrounding OJ

a
osseous reaction. The :J
CD
chronic osteomyelitis, or s:
CD
Brodie abscess. (Right) Qi
Lateral radiograph shows a "0
::r
lytic lesion located '<
VI
eccentrically in metaphysis CD
EiIl There is generalized III
abnormal bone density with

abnormal trabeculae; this is
a brown tumor in a patient
with hyperparathyroidism &
renal osteodystrophy.

Langerhans Cell Histiocytosis (LCH) (LSMFT)
lytic, fairly geographic lesion
located eccentrically in the
metaphysis" of an infant. It
does not appear aggressive,
though there is a small
amount of periosteal reaction
•. LCH may be eccentric,
as in this case, but is more
frequentfy central. (Right) AP
radiograph shows an
eccentric metaphyseal, lytic
lesion containing a sclerotic
focus" LSMFT is highly
location-specific, being
found almost exclusively in
the proximal femoral
metaphysis.
Chondroblastoma (Mimic)
slightly bubbly lytic lesion
with a sclerotic border
located eccenlricalfy within
the tibial metaphysis. The
appearance & location are
typical for a CMF. (Right)
Lateral radiograph shows an
eccentric lytic lesion in the
humerus arising in the
epiphysis of a teenager".
Though the majority of the
lesion is within the epiphysis,
it extends slightly into the
metaphysis III once the
physis fuses, possibly
misleading one as to its
origin.
I
51
LONG BONE, ECCENTRIC METAPHYSEALLESION, AGGRESSIVE
DIFFERENTIAL DIAGNOSIS o Most common aggressive metaphyseal

tumor in children & teenagers
Q)
Common • Uncommon in adults 25-70 years of age
c • Osteosarcoma, Conventional
o • Second peak of cases in patients> 70
CO • Osteomyelitis
Ol years of age 2° to radiation, Paget
C
o • Giant Cell Tumor degeneration, chondrosarcoma
-.J
• Metastases, Bone Marrow dedifferentiation
'tl
Q)
III Less Common o Almost invariably highly aggressive
III
CO • Langerhans Cell Histiocytosis o Tumor osteoid in majority of cases
>- • Aneurysmal Bone Cyst • Amorphous; may be extremely subtle in
E
•...oIII • Malignant Fibrous Histiocytoma, Bone soft tissue mass
c • Lymphoma • Disorganized, less dense than bone
« • Osteosarcoma, Telangiectatic • When tumor osteoid is in bone, may
• Fibrosarcoma appear densely sclerotic
• Radiation-Induced Sarcoma • Matrix may be absent altogether
o MR shows variable regions of low signal
Rare but Important
relating to osteoid
• Angiosarcoma, Osseous
• Osteomyelitis
• Hemangioendothelioma, Osseous o Metaphyseal site is common 2° to blood
• Hemangiopericytoma, Osseous supply to that site, especially in children
o May be central or eccentric
ESSENTIAL INFORMATION o Permeative with periosteal reaction
• May follow a serpiginous pattern
o With bacterial infections (the most
• Differential includes a variety of malignant common), often have adjacent sclerotic
& benign lesions
bone reaction
o Malignant lesions which appear aggressive
o Cortical breakthrough with soft tissue
• Osteosarcoma, conventional mass (abscess), fascial fluid
• Metastases • On radiograph, fat planes obliterated
• Malignant fibrous histiocytoma rather than distorted (as with tumors)
• Lymphoma o Watch for sequestrum (dense isolated
• Fibrosarcoma devascularized bone fragment)
• Radiation-induced sarcoma • Giant Cell Tumor
• Vascular sarcomas o Eccentric site within metaphysis is most
o Outlier: Benign lesions appearing
common location
aggressive o Most frequent appearance is geographic,
• Osteomyelitis but without sclerotic margin
• Giant cell tumor o Not rarely, appearance & behavior is more
• Langerhans cell histiocytosis aggressive or even metastatic
• Aneurysmal bone cyst • Wide zone of transition
o Outlier: Malignant lesions which may have
• Cortical breakthrough, soft tissue mass
only subtle signs of aggressiveness o MR usually has areas of low T2 signal
• Metastases within mass, though majority are high Sl
• Osteosarcoma, telangiectatic • Metastases, Bone Marrow
• Vascular sarcomas o Metastases frequent in long bones,
• Hint: Remember to keep the outliers in especially metaphyseal locations
mind for this differential o Metastases may be only subtly aggressive
Helpful Clues for Common Diagnoses • Usually do not have large soft tissue mass
• Osteosarcoma, Conventional Helpful Clues for Less Common Diagnoses
o Eccentric metaphyseal is most common
• Langerhans Cell Histiocytosis
location o Common lesion in children
I
52
LONG BONE, ECCENTRIC METAPHYSEAL LESION, AGGRESSIVE »
..o
:l
III
o Lesions may be metaphyseal, diaphyseal, o May occur eccentrically in metaphysis 3

'<
or epiphyseal o Early lesions may not appear aggressive; [ll
III
o Most lesions are central, but metaphyseal watch for any signs pointing towards VI
ll>
lesions may be eccentric (especially in aggressiveness Co
o Advanced lesion is highly permeative, r

proximal humerus) o
::J
o Range of appearances from nonaggressive often with large soft tissue mass <0
[ll
to highly aggressive o Rapidly advancing tumor may contain a o
::J
o Frequently polyostotic sequestrum CD
• Aneurysmal Bone Cyst • Osteosarcoma, Telangiectatic s:

CD
o Benign lesion that may appear highly o Uncommon variety of osteosarcoma OJ
"0
aggressive o Most frequently eccentric in metaphysis or
'<
• Aggressive expansion with ballooning of o Generally is lytic, without tumor osteoid VI
CD
III
cortex o Dangerous lesion since majority of lesion
• May be aggressive within metaphysis,· may appear non-aggressive on radiograph
with less sclerotic margin than usual • Much of lesion may be geographic, even
o Most frequent location is eccentric in with sclerotic margin
metaphysis • Watch for any red flag suggesting a
o Usually has very thin surrounding cortex, permeative portion or any small sign of
even with aggressive lesion cortical breakthrough
o MR shows fluid levels in vast majority, o Also dangerous on MR since the majority
though solid ABC does occur of lesion is filled with fluid levels
• Malignant Fibrous Histiocytoma, Bone • Watch for nodularity in periphery of
o Aggressive lesion that may be metaphyseal lesion which enhances
or diaphyseal o Hint: This is a lesion one must watch for
o Cortical breakthrough, soft tissue mass carefully
o Often central, but may be eccentric • Undertreatment as "ABC" is devastating
o Generally adult, but rarely seen in children • Small tumor nodules may be missed by
o Usually not specific in appearance pathologist
• Exception is MFH arising in bone infarct, • Same metastatic potential & poor
where dystrophic calcification of infarct prognosis as conventional osteosarcoma
may be distinguishing factor • Radiation-Induced Sarcoma
• Fibrosarcoma appears similar to MFH o Watch for radiation osteonecrosis with
• Lymphoma changing (aggressive) behavior
o Generally central diaphyseal lesion
AP radiograph shows an aggressive permeative AP radiograph shows an eccentric lesion with a sclerotic I
metaphyseal lesion •• that has tumor osteoid formation
both within the bone and within the soft tissue mass Ell
This is a classic osteosarcoma.
=
margin. about much of the circumference. However,
there is subtle cortical breakthrough an indication of
aggressiveness in this osteosarcoma. (tMSK Req).
53
LONG BONE, ECCENTRIC METAPHYSEAL LESION, AGGRESSIVE
Q) Osteosarcoma, Conventional Osteomyelitis

c (Leh) Anteroposterior
o
[IJ radiograph shows a highly
Cl aggressive eccentric lesion in
C
o
....J
the metaphysis of a child III.
Even though there is no
"III
III
III
osteoid matrix, osteosarcoma
is the most likely diagnosis
[IJ and was subsequently
>- proven. (Right)
E Anteroposterior radiograph
.•..o
III
shows an eccentric, rather
c: permeative lesion. within
< the metaphysis of a child.
Osteomyelitis most
frequently arises in the
metaphysis in this age group
due to hematogenous
spread. (t MSK Req).
Giant Cell Tumor Giant Cell Tumor

(Leh) Lateral radiograph of
the hip shows a large, lytic,
metaphyseal lesion that is
eccentrically located, with
absent cortex anteriorly _
The remainder of the lesion
shows a non-sclerotic but
geographic margin, typical of
giant cell tumor (GCT).
(Right) Axial bone CT of the
same case shows the
destruction of the anterior
cortex III and suggests that
the remaining borders are
irregular. This is a typical
appearance and location for
an aggressive GCT.
Metastases, Bone Marrow Langerhans Cell Histiocytosis

an aggressive-appearing
eccentric lytic lesion in the
metaphysis of the femur Ell
with avulsion fracture of the
lesser trochanter _. This is a
typical expanded solitary
metastasis; the primary was
thyroid. (Right) AP
permeative & aggressive
lesion '-Iocated
eccentrically in the
metaphysis of an infant. This
could represent osteomyelitis
or a neuroblastoma
metastasis, but LCH must be
considered & was proven.
I
54
LONG BONE, ECCENTRIC METAPHYSEAL LESION, AGGRESSIVE »
-
:>
Ql
o
3
'<
lD
Ql
II>
Aneurysmal Bone Cyst Aneurysmal Bone Cyst t1>
(Left) AP radiograph shows a a.
lytic eccentric lesion in the r
metaphysis" It is so o
:>
permeative that it almost to
cannot be seen, bUllhere is aJ
o
a subtle margin present. :>
Cll
Though osteosarcoma is the
most likely lesion to present
in this way, other lesions
might be considered. (Right)
Axial T2WI MR of the same
case shows fluid levels
throughout the lesion
ABC was proven after a
=-
careful pathologic search
proved no evidence or
telangiectatic osteosarcoma.
(tMsK Req).
Malignant Fibrous Histiocytoma, Bone Lymphoma

aggressive eccentric
metaphyseal lesion, with
permeative change & cortical
breakthrough. This
appearance is best for a
diagnosis of osteosarcoma in
this teenager, but biopsy
proved MFH. (Right)
shows an eccentric lytic
lesion in the femoral neck III
that appears of intermediate
aggressiveness, with a
moderately narrow zone of
transition. This proved to be
lymphoma.
Osteosarcoma, Telangiectatic Osteosarcoma, Telangiectatic

lytic, eccentric, metaphyseal
lesion that, in places,
appears geographic Ell
Other regions show a wider
zone of transition" and
there is cortical breakthrough
III. Concern for
telangiectatic osteosarcoma
must be raised. (t MsK Req).
(Right) Axial T2WI MR in the
same patient shows the
osseous les;on • with a
large soft tissue mass •. A
few fluid levels are present
E!Il along with solid tumor in
as.
this telangiectatic
(tMSK Req).
I
\ 55
(ij LONG BONE, CORTICALLY BASED METAPHYSEAL LESION
Ql
III
>-
..c:
-
~
0-
ra
Ql
Common
DIFFERENTIAL DIAGNOSIS
o
• Edema may obscure fracture line
Have a high degree of suspicion for these
fractures in elderly or osteoporotic patients
ai
c: • Insufficiency Fractures, Appendicular
o • Stress Fracture, Adult
CO • Stress Fracture, Adult
01 o Stress fractures of long bones often occur
c: • Osteoid Osteoma
o
...J
in metaphyseal region
• Osteochondroma • Femoral neck {basicervical)
'0
QI • Fibrous Dysplasia • Medial proximal tibia
III
IV • Fibroxanthoma (Non-Ossifying Fibroma) o On radiograph, watch for subtle
al
>- • Aneurysmal Bone Cyst abnormalities
-E
o
IV
c:
«
Less Common
• Adamantinoma
• Soft Tissue Tumor Excavation (Mimic)
• Focal linear sclerosis
• Periosteal reaction
o If suspected, MR should be performed
• May show only stress reaction (high
Rare but Important
signal in cortex on fluid sequences, low
• Langerhans Cell Histiocytosis on Tl, with surrounding edema but no
• Osteofibrous Dysplasia fracture line)
• If fractured, linear low signal fracture line
ESSENTIAL INFORMATION with surrounding edema
• Edema rarely may obscure fracture line
• Osteoid Osteoma
• Cortically based metaphyseal lesions require o Most osteoid osteoma (00) are cortically
special attention based in the diaphysis
o May put patient at risk for fracture
o Next most frequent location is
o May actually be a fracture
intraarticular, particularly at femoral neck
o In either case, patient needs protection
o Femoral neck 00 generally are in the
against completion of fracture mid-cervical region
o Hint: Include insufficiency or stress
• 00 itself is cortically based; on axial
fractures of the metaphyses in your search imaging, either anterior, medial, or
pattern posterior cortex
• Hint: In child or teenager with hip pain, • Axial imaging used to localize lesion,
search femoral neck for osteoid osteoma generally for radiofrequency ablation
o Relatively common location
o Femoral neck 00 is within hip joint
o May result in morphologic changes which • Elicits long-term joint effusion
obscure the actual diagnosis • Large effusion may result in long-term
Helpful Clues for Common Diagnoses lateral subluxation of femoral head
• Insufficiency Fractures, Appendicular o Lateral subluxation of femoral head, over
o In ufficiency fractur of long bon often several months, results in morphologic
occur in metaphyseal region changes
• 'urgical neck humerus • Calcar bultre sing
• Femoral n ck ( ubcapital, • steophyte formation, femoral head
in tertrochanteric) • F moral n ck valgus
• Medial proximal tibia • idening of radiographic teardrop
o On radiograph, watch for subtl han res ( vergrowth of medial acetabular wall)
• ortical buckle o Morphologic hang s may div rt attention
• Focallin ar clerosis at expected site to ard a dyspla ia or arthritis
o If insuffici ncy fracture is u p ted o Intraarticular 0 elicits densely sclerotic
clinically or radiographically, MR should reactive osseous formation
be performed • Unlike diaphy eal 00, reactiv bon
• Linear low signal fracture line seen on may not surround 00; generally i distal
either Tl or fluid sensitive sequence tOO, in subtrochanteric region
I
LONG BONE, CORTICALLY BASED METAPHYSEAL LESION l>
:l
...•
III
o
o Reactive bone may divert attention away • Fibrous Dysplasia 3
'<
from the 00 nidus o Generally central, but may arise in cortex al
III
o Between the morphologic changes & o Common lesion, so a cortical location l/I
CD
reactive sclerosis, lesion itself may be should not be surprising Co
difficult to visualize o Ground-glass matrix is helpful in the r

o
:l
• Hint: In correct age group, search for this diagnosis, but not always present <0
OJ
lesion in femoral neck o Generally polyostotic o
:>
• Osteochondroma • Fibroxanthoma (Non-Ossifying Fibroma) CD
o Usually metaphyseal in location, arising o Usually more metadiaphyseal than purely ~
CD
from cortex metaphyseal Oi
"0
o Exophytic (cauliflower) variety o Cortically based, but may become large ::r
'<
• Normal cortex and marrow from enough that the cortical origin is obscured '"CD
III
underlying metaphysis seen extending o Lytic, with sclerotic margin in children
into stalk of lesion o Natural history is to heal, with sclerosis,
• Periphery of lesion may have less well then remodeling to normal bone
organized bone • Aneurysmal Bone Cyst
• Cartilage cap should not be greater than o ABC generally arises eccentrically within
1.S cm in thickness metaphysis; true cortical origin
o Sessile variety uncommon
• Seen frequently in multiple hereditary Helpful Clues for Less Common Diagnoses
exostosis (MHE) • Adamantinoma
• Broad base extending along the o Cortical, generally anterior tibia
metaphysis metadiaphysis
• Normal marrow and cortex in this base • Soft Tissue Tumor Excavation (Mimic)
• Results in a morphologic change at the o Cortical invasion by soft tissue mass may
metaphyses which is often symmetric mimic lytic cortical lesion on radiograph
• Morphologic change gives the
appearance of broadened metaphyses & Helpful Clues for Rare Diagnoses
undertubulation • Langerhans Cell Histiocytosis
• Often mistakenly called a dysplasia o Common lesion; cortical origin is rare
• Hint: MHE is far more frequent than • Osteofibrous Dysplasia
metaphyseal dysplasias; with broad o Rare cortical lesion; generally proximal
metaphyses, look for a way to diagnose anterior tibial metadiaphysis rather than
sessile exostoses metaphysis
Insufficiency Fractures, Appendicular
AP radiograph shows a faint linear sclerosis at the

cortical metaphysis •. There is significant
aspect of the
Coronal T2WI MR of the same patient shows the
fracture, with impacted fragments • and fluid at
I
osteoporosis in this patient with rheumatoid arthritis; the fracture site III. Proximal tibia, along with proximal
radiograph is diagnostic of insufficiency fracture. femur, is a Frequent site (or an insufficiency fracture.
57
ro
Q)
LONG BONE, CORTICALLY BASED METAPHYSEAL LESION
'">-
.<:
a.
ro
Q;
~
Q) Stress Fracture. Adult Stress Fracture. Adult
c (Left) Coronal T1 WI MR
o
CD shows a basicervical stress
OJ fracture in a runner •. This
C
o is the cfassic localion of a
-..J
stress fracture, as opposed to
"0
Ql
an insufficiency fracture at
the subcapital or
'"ro
CD intertrochanteric locations.
>- (Right) AP radiograph shows
E scferosis at the medial
-«
o
.C"
basicervical site expected for
a stress fracture •. This
patient is a marathon runner
who ignored advice to rest
and "ran through the pain I'.
This led to complelion of the
fracture_
Osteoid Osteoma Osteoid Osteoma

small round lytic lesion in the
femoral neck metaphysis _.
There is reactive sclerosis
extending distal to the lesion
E!lI. The appearance is
typical of inlraarticular
osteoid osteoma. (Right)
Axial CT obtained during
ablalive procedure shows
the needle entering the
osteoid osteoma, which is
localized at the cortex Ill.
Localization of intraarlicular
osteoid osteoma ;s virtually
always at the cortex. Note
the adjacent thick cortical
reaction.
Osteochondroma Osteochondroma
shows normal bone
extending from the
metaphysis as a stalk III into
the exostosis. More
peripherally the bone is not
as organized into regular
trabeculae. This continuation
of marrow and cortex into
the mass is the hallmark of
osteochondroma. (tMSK
shows a palient with mulliple
hereditary exostoses, with
the typical exophytic type
• as well as the sessile
forms" broadly based at
the cortex.
I
58
LONG BONE, CORTICALLY BASED METAPHYSEAL LESION >
::l
..•o
III
3
'<
DJ
III
Fibroxanthoma (Non-Ossifying Fibroma) f/l
(l)
(Left) Axial NECT shows a Co
cortically based metaphyseal r
lesion which has a o
:J
ground-glass matrix ElII. The <0
appearance of the matrix is DJ
o
typical of fibrous dysplasia. :J
Ctl
Although the lesion is usually
located centrally, it may arise ;;::
Ctl
eccentrically or cortically.
1ii
(Right) Lateralradiograph "0
shows a large lytic lesion
~
'<
f/l
with sclerotic margins, Ctl
located in the cortex of the OJ
meta diaphysis lEI. The lesion
is beginning to heal, with
peripheralscferosis. Despite
the size, the appearance &
location are typical of NOF.
Aneurysmal Bone Cyst

cortically based metaphyseal
lytic lesion that is expanded
but retains a thin cortical rim
B. This is an ABC; these
lesions usually arise
eccentrically within the
marrow but occasionally
may arise within the cortex.
a lytic lesion arising from the
cortex of the distal tibial
metaphysis 11II. Though the
lesion appears
well-marginated, it enlarged
rapidly & behaved
aggressively. This is an
adamantinoma.
Soft Tissue Tumor Excavation (Mimic)

(Left) Axial T7 C+ MR shows
a 50ft tissue lesion 11IIII (MFH)
that is adjacent to the distal
femoral metaphysis, resulting
in local invasion HI. This
cortical excavation results in
an apparent, cortically
based, lytic lesion on the
radiograph. (Right) Lateral
radiograph shows a lytic,
cortically based lesion in the
distal tibial metaphysis 11IIII.
Although by location this
lesion is most likely
adamantinoma, at biopsy it
proved to be LCH with an
unusual presentation.
I
59
roill LONG BONE, SURFACE (JUXTACORTICAL) LESION
en
>-
.r:
0-
ro DIFFERENTIAL DIAGNOSIS o Hint: Most extend to intramedullary
1il space; must include this observation to
~
Common ensure adequate resection
ill
c • Osteosarcoma, Parosteal
o o Location: Distal femur> proximal tibia>
CO • Periosteal Chondroma
OJ proximal femur> proximal humerus
C
o • Myositis Ossificans (Mimic) • Periosteal Chondroma
--l
Less Common o a.k.a., juxtacortical chondroma
"tl
Q)
en • Osteochondroma (Mimic) o Matrix arising at surface of bone,
III
CO • Aneurysmal Bone Cyst (Mimic) extending into soft tissues; often difficult
:>. • Osteosarcoma, Periosteal to differentiate between chondroid &
E
-«
o
III
C
• Tug Lesion (Mimic)
• Avulsion Fractures (Mimic)
osteoid
o Scallops underlying cortex but does not
• Florid Reactive Periostitis & Bizarre involve medullary space
Osteochondromatous Proliferation o May be impossible to differentiate from
• High Grade Surface Osteosarcoma periosteal osteosarcoma by imaging
• Subperiosteal Ganglion • Hint: Periosteal chondroma is much
• Subperiosteal Abscess more common than periosteal
osteosarcoma
Rare but Important
• Myositis Ossificans (Mimic)
• Parosteal Lipoma o Mature myositis ossificans (MO) not
• Osteoma difficult to diagnose
• Osteoid Osteoma, Periosteal o Immature myositis forms amorphous
• Parosteal Chondrosarcoma osteoid (6-8 weeks following trauma) .
• If it is adjacent to bone, may mimic
ESSENTIAL INFORMATION periosteal or surface osteosarcoma
• May elicit periosteal reaction & even
abnormal marrow signal on MR
• Hint: Limited number of true surface lesions
• Watch for zoning of more mature bone
o Mimics may be cortically based or highly
peripherally, which is the opposite of the
expanded eccentric lesions
growing pattern of osteosarcoma
o Mimics may relate to local trauma
• Hint: Be careful not to confuse early Helpful Clues for Less Common Diagnoses
myositis ossificans with periosteal • Osteochondroma (Mimic)
osteosarcoma o Usually not difficult to differentiate, but a
o Both radiograph and biopsy may be small exostosis may mimic parosteal
confusing, depending on stage of lesion osteosarcoma
o Axial imaging & attention to zoning of o Continuation of cortex and marrow into
ossification helps to differentiate stalk-like lesion makes the diagnosis
o Hint: Myositis is much more frequently • Aneurysmal Bone Cyst (Mimic)
seen than periosteal osteosarcoma o Arises from cortex or highly eccentrically
in bone, so is not a true surface lesion
o May balloon so extensively that it has an
• Osteosarcoma, Parosteal appearance of arising from the surface
o Most common surface lesion of bone
o Watch for thin rim of cortex continuing
o Mature bone formation at surface
around lesion & fluid levels
• When it is large, appears to "wrap
• Osteosarcoma, Periosteal
around" the cortex, often with a cleft
o Rare form of surface osteosarcoma, with
between most of the mass & the low grade appearance & behavior
underlying bone
o Generally produces matrix (though may
• Zoning: More mature centrally than not) at surface of cortex, extending into
peripherally soft tissues
I
60
lONG BONE, SURFACE (JUXTACORTICAl) lESION »
::l
...•
III
o
o Often scallops underlying cortex, but o May scallop underlying cortex but is not 3
'<
generally does not invade marrow invasive III
III
• Tug Lesion (Mimic) o Mass follows fluid signal on all sequences VI
<ll
o Tendinous insertion may "tug" its • Subperiosteal Abscess Co
attachment, resulting in mimic of surface o Raises the periosteum, soft tissue abscess r
o
:J
mass o Obliterates soft tissue fat planes (Q
o Initially adjacent cortex becomes less III

• Underlying cortex may resorb o
::l
• Reactive soft tissue forms "mass", distinct; eventually may extend into CD
sometimes with reactive calcification medullary space as osteomyelitis s::

CD
• "Cortical desmoid" at posteromedial Helpful Clues for Rare Diagnoses Qi
"'D
corner of distal femoral metaphysis is ::r
• Parosteal Lipoma '<
best known site o Rare appearance of deep soft tissue lipoma '"
CD
OJ
• Avulsion fracture may mimic surface o Lipoma is classic in appearance but arises
lesion of bone in same way immediately adjacent to surface of bone
• Florid Reactive Periostitis & Bizarre o Elicits a prominent periosteal reaction,
Osteochondromatous Proliferation often horizontal in relation to cortex
o Very similar appearing to mature myositis
• Osteoma
or parosteal osteosarcoma o Rarely occurs in long bones; generally part
o Involves small bones of hands> feet
of a polyposis syndrome (Gardner)
o Likely related to trauma
o Sclerotic "bumps" of dense bone arising
• High Grade Surface Osteosarcoma from cortex: Hamartomatous bone
o Tumor osteoid formation surface lesion
• Osteoid Osteoma, Periosteal
o Osteoid is amorphous & disordered; no
o Least common site of osteoid osteoma
strong zoning to periphery is seen o Soft tissue mass adjacent to & scalloping
o Soft tissue mass, evaluated on MR, is more
bone
extensive than osteoid o Little host reactive bone formation
o Histology: Same as conventional
• Parosteal Chondrosarcoma
osteosarcoma; higher grade & degree of o Identical to conventional
aggressiveness than parosteal or periosteal chondrosarcoma, but arising on surface of
osteosarcoma bone with fibrous pseudocapsule
• Subperiosteal Ganglion connecting to periosteum
o Rare location of ganglion
o May cause scalloping of cortex, but
o Lifts the periosteum, may result in
generally no medullary invasion
horizontal periosteal reaction formation
Late,al radiograph shows posterior cor/icalthickening

• without other features. Ltxation & appearance are
Axial T2WI MR on the same patient shows the comcal
thickening _ but there is also an associated soft tissue
I
typical of stress fracture, for which this young man was mass" The mass contains punctate ossification _.
treated with no improvement. ItMSK Req). This is an early parosteal osteosarcoma. It MSK Req).
61
m
Q)
lONG BONE, SURFACE (JUXTACORTlCAl) LESION
l/)
>-
.c
0-
m
Q)
~
Q) Osteosarcoma, Parosteal Periosteal Chondroma
c: (Left) Late,al radiograph
o
CD shows an advanced
Ol parostealosteosarcoma, with
c:
o mature bone appearing to
--l
wrap around the cortex EiI
"0 leaving a cleft where the
Ql
l/) lesion is not attached to the
III
CD surface =. The tumor bone
>- is more mature centrally than
.-Eo
III
c:
peripherally. (Right) AP
radiograph shows the typical
appearance of periosteal
< chondroma, with matrix
arising from the osseous
surface III. There is mild
cortex -=
scalloping of the underlying
destruction.
but not overt
Periosteal Chondroma Periosteal Chondroma

shows a surface lesion
containing faintmatrix.
and causing minimal
cortex III. This is a surface
lesion, without marrow
involvement. (Right) Axial
bone CT confirms the faint
matrix and surface mass.
as well
scalloping =-
as minimal cortical
Periosteal
chondroma & periosteal
osteosarcoma cannot be
differentiated by the
imaging; statistics favor the
former, which was biopsy
proven.
Myositis Ossificans {Mimic} Myositis Ossificans {Mimic}

periosteal reaction" & soft
tissue mass containing faint
matrix. ina teenager.
Though this could represent
a surface sarcoma, it must be
remembered that myositis
can also elicit reaction from
adjacent bone. (Right)
Coronal T2Wf FS MR of the
same patient shows the high
signal 50ft tissue II mass II that
surrounds a halo of low
signal material =. This halo
is the maturing periphery of
myositis; the surrounding
high signal is edema. (t MSK
Req).
I
62
lONG BONE, SURFACE (JUXTACORTICAl) LESION l>
:l
...•
Ql
o
3
'<
OJ
Ql
tJI
Osteochondroma (Mimic) Osteochondroma (Mimic) <1l
(Left) Lateral radiograph C.
shows an ossific mass. in r
a position suggestive of o
:l
paroslea/osteosarcoma. The <C
character of the mass, OJ

o
including zoning, must be :l
C1>
assessed, usually by axial
imaging, before final s:
C1>
diagnosis is made. (Right)
Axial bone CT of the same
or
'0
patient shows that the mass
:T
'<
tJI
in fact arises from the femur, C1>
with continuous cortex and Cl
marrow extending from the

bone into the mass" This
feature is diagnostic of
osteochondroma rather than
parosteaJ osteosarcoma.

shows a large lesion that
appears to be surface in
origin. There is apparent
mild scalloping of the cortex
• with large soft tissue
mass extending posteriorly
••. Axial imaging is needed
for further definition. (Right)
Axial bone CT in the same
patient shows that the mass
arises eccentrically or from
the cortex, but not the
surface.:l of the bone.
There is a thin osseous rim
surrounding the mass _
Other imaging showed fluid
levels in this ABC.
Osteosarcoma, Periosteal Osteosarcoma, Periosteal

radiograph shows definite
tumor osteoid formation at
the osseous surface" that
is less mature at the surface
than centrally. There is no
disturbance of the underlying
bone. (Right) Axial bone CT
confirms the immature
osteoid forming at the
osseous surface _ without
invasion of the underlying
bone. The appearance ;s
typical of periosteal
osteosarcoma.
I
63
ro
Ql
LONG BONE, SURFACE (JUXTACORTICAL) LESION
l/)
>,
.c
a.
ro
Qi
~ Florid Reactive Periostitis & Bizarre
Ql Tug Lesion (Mimic) Osteochondromatous Proliferation
c (Left) Axillary lateral shows
o
OJ heterotopic bone formation
Cl • & cortical resorption at
C
o the site of the deltoid
-l
insertion _ This represents
1:l a "tug" lesion of the deltoid
Ql
l/) but could be mistaken for a
Ol
OJ surface lesion of bone.
>, (Right) Oblique radiograph
E shows bone formation
•..o
Ol
adjacent to & surrounding
C the third metatarsal •.
< Florid reactive periostitis or
bizarre osteochondromatous
proliferation likely arise
secondary to trauma and
result in surface bone
formation.
High Grade Surface Osteosarcoma High Grade Surface Osteosarcoma

soft tissue tumor located
immediately adjacent to the
surface of the humerus" It
contains an osteoid matrix
that appears moderately
amorphous & aggressive.
Differentiating between
surface osteosarcoma and
periosteal/parosteal
osteosarcoma is difficult on
the radiograph. (Right)
Coronal T1 C+ FS MR shows
the lesion. to be larger
than suspected by
radiograph. By location &
appearance, it is a high
grade surface osteosarcoma.
Subperiosteal Ganglion
radiograph shows a surface
lesion that does not contain
matrix but has elicited
horizontal periosteal reaction
•. There is subtle and
non-aggressive scalloping of
the underlying cortex •.
(Right) Axial T2WI MR
confirms the surface origins
and shows the lesion to be
fluid signa/m It confirms
the surface origins and the
subtle cortical scalloping _.
This proved to be an unusual
surface lesion~ a
subperiosteal ganglion.
I
lONG BONE, SURFACE (JUXTACORTICAl) lESION
Subperiosteal Abscess
shows subtle loss of posterior
cortical bone integrity _.
There is no other overt
destruction. The 50ft tissues
show obliteration of the fat
planes EiIIthat would
normally be expected to be
present. (RighI) Sagittal T1
C+ MR in the same patient
confirms cortical loss _.
There is also a large abscess
arising from the subperiosteal
location Ell Yersinia pestis
was cultured; plague had
been reported in the region
where this teenager had
been camping.
Parosteallipoma
shows fluffy bone formation
arising from posterior cortex
_ that appears to be
reactive rather than tumor
bone. There is a faint
suggestion of fat density
surrounding it EiII. (tMSK
Req). (Right) Axial bone CT
in the same patient shows
the reactive bone {ormation
_ and the surrounding
lipoma Ell Occasionally
when a lipoma arises
adjacent to a long bone, it
elicits this type of reaction. It
is termed parosteallipoma.
(tMSK Req).

sclerotic, rounded, normal
bone arising from the cortex
•. these are osteomas. An
osteoma involving a long
bone should raise the
question of a polyposis
syndrome. This patient had
"hundreds" of colonic
polyps. (Right) Axial T1 C+
FS MR from the same patient
shows a small osteoma _
but also shows a huge soft
tissue mass Ell. The mass
was low signal on all
sequences and shows
minimal enhancement; this is
a classic desmoid tumor.
I
65
ro
Q)
LONG BONE, CENTRAL DIAPHYSEAL LESION, NON-AGGRESSIVE
Cf)
>-
.r:
a.
.~ DIFFERENTIAL DIAGNOSIS o Usually some chondroid matrix is present,
o, but may be lytic
ro Common
Q) o May scallop endosteum, but otherwise is
2 • Enchondroma or appears non-aggressive
Q)
c • Paget Disease o Often an incidental finding; usually
o • Langerhans Cell Histiocytosis (LCH)
CO asymptomatic
Ol
C
• Fibrous Dysplasia • Paget Disease
o • Unicameral Bone Cyst (UBC)
---' o Common in adults
"0 • Fibroxanthoma (Non-Ossifying Fibroma) o Lesion usually originates at subchondral
Ql
I/)
I1l
• Aneurysmal Bone Cyst, Thin Bones bone and proceeds into diaphysis
CO • Chronic Osteomyelitis • May be extensive, involving the majority
>.
..
E
o
I1l
C
Less Common
of diaphysis
o Lesion may originate at mid-diaphysis
<l: • Bone Infarct (usually tibia) and extend proximally or
• Radiation Osteonecrosis distally
• Hyperparathyroidism, Brown Tumor • With diaphyseal origin, lesion usually
• Tuberculosis begins in anterior cortex
• Fungal Osteomyelitis o Lesion always results in bone enlargement
o Appearance ranges from lytic to mixed
Rare but Important
lytic/sclerotic
• Vascular Tumors • Trabeculae appear coarsened &
• Neurofibromatosis disordered, but usually overall
• Desmoplastic Fibroma appearance is not aggressive
• Tuberous Sclerosis • Leading edge of lesion has straight
• Mastocytosis sclerotic line
• Langerhans Cell Histiocytosis (LCH)
ESSENTIAL INFORMATION o Lesion of childhood
o Often polyostotic, with axial & flat bones
Key Differential Diagnosis Issues involved as well as long bones
• Non-aggressive central diaphyseal lesions are o Long bone lesions may be metaphyseal or
much more common in 1st three decades epiphyseal, but diaphyseal is common
• Hint: "Common" lesions are MUCH more o Appearance ranges from lytic geographic
common than others (non-aggressive) to extremely aggressive
o Very few choices of diagnoses in adults
• Fibrous Dysplasia
• Enchondroma, Paget disease, chronic o Lesion of childhood and young adults
osteomyelitis o Often polyostotic, with flat bones & skull
o Relatively few choices in children frequently involved
• LCH, Fibrous dysplasia, UBC, chronic o Long bone lesions usually central &
osteomyelitis diaphyseal
• Many of the other lesions in the differential • Metaphyseal & epiphyseal extension is
require special circumstances common
o Gigantic NOF
• Central location is most common, but
o Thin bone location of NOF or ABC
cortical lesions occur as well
o Underlying abnormality: Radiation, renal
o Mild expansion of bone with thinning of
osteodystrophy endosteal cortex
Helpful Clues for Common Diagnoses o Subtle "ground-glass" matrix is most
• Enchondroma common, though lesion may be lytic
o Adult lesion, generally in metaphysis o Bone is soft, resulting in bowing
o Common lesion, so diaphyseal location is deformities
also relatively common • Unicameral Bone Cyst (UBC)
o Common; generally a lesion of childhood
I
66
LONG BONE, CENTRAL DIAPHYSEAL LESION, NON-AGGRESSIVE »
::l
• Adult lesions tend to be pelvic or o May be diaphyseal in either child or adult,

-
III
o
3
'<
humeral usually from direct trauma al
III
o Lesion begins in metaphysis o Chronicity results in sclerotic margin & VI
<D
surrounding reactive bone formation a.
• As it becomes less active, metaphysis
r
grows away, leaving it in diaphyseal Helpful Clues for Less Common Diagnoses o
:J
position • Sickle Cell Anemia
<C
OJ
o Lytic lesion with mild expansion of bone o Bone infarcts may appear lytic and o
:J
& thinning of endosteal cortex non-aggressive, though often not
CD
o Usually asymptomatic unless develops visualized on radiograph

pathologic fracture • Radiation Osteonecrosis
• Fracture may result in a "floating o Mixed lytic & sclerotic disordered bone
fragment", pathognomonic for UBC o No soft tissue mass or cortical disruptions
• Fibroxanthoma (Non-Ossifying Fibroma) • Hyperparathyroidism, Brown Tumor
o Common lesion of childhood and young o Brown tumor may occupy central
adulthood diaphysis
o Generally metaphyseal & cortically based o Generally well-marginated, though not
lesion sclerotic
o It is the exceptional cases that fit into the o Surrounding bone is osteopenic &
central diaphyseal differential trabeculae are coarsened
• Giant NOF may occupy the entire width • Tuberculosis
of a long bone & extend well into o Destruction tends to be slower & less
diaphysis aggressive than bacterial osteomyelitis
• NOF in a thin bone (ulna, fibula) may • Lesion may appear well-defined & have
occupy entire width of bone little reactive change in host bone
o Lytic & well-circumscribed when active • Fungal osteomyelitis appears similar
o Natural history is to heal in with sclerosis,
then remodel to normal bone Helpful Clues for Rare Diagnoses
• Aneurysmal Bone Cyst, Thin Bones • Vascular Tumors
o Common lesion of childhood & young o Range from non-aggressive to aggressive
adults o Lower extremities predominate
o Generally eccentric & metadiaphyseal • Neurofibromatosis

o Exception is in thin bones (ulna, fibula) o Bone dysplasia results in pseudarthroses &
where it occupies entire width deformities
• Chronic Osteomyelitis
Enchondroma
Lateral radiograph shows typical enchondroma

punctate chondroid matrix located centrally within the
with Lateral radiograph shows an expanded lytic/scleroUc
lesion arising in the diaphysis of the tibia with a sharply
I
femoral diaphysis. There is a small region of endosteal marginated leading edge" Once Paget disease fully
scalloping" but no other suggestion of aggressiveness. expands, it may appear central.
67
ro LONG BONE, CENTRAL DIAPHYSEAL LESION, NON-AGGRESSIVE
Ql
'"
>-
J:::
a.
.~
o,
ro
Q; Langerhans Cell Histiocytosis (LCH) Fibrous Dysplasia
~ (Left) Anteroposte,ior
Ql radiograph shows a central
c
o lytic lesion with narrow zone
CO of transition" It is mildly
Ol
C expanded and has slight
o endosteal scalloping. LCH
-l
has a range of presentations
"0
Ql but often is less aggressive.
en''""
radiograph shows a lyUc &
>- ground-glass density mildly
•..Eo expanded central lesion of

the diaphysis which
'"
c significantly thins the cortex
< •. There is a daughter
lesion seen proximally •.
This is typical fibrous
dysplasia.
Unicameral Bone Cyst (UBC) Fibroxanthoma (Non-Ossifying Fibroma)

radiograph shows a central
lytic lesion in the diaphysis of
the humerus which has mild
endosteal scalloping •.
UBC often is
metadiaphysea/; purely
diaphyseal location such as
this is somewhat unusual.
well-marginated lesion
located slightly eccentrically
within the diaphysis. NOF
may appear to be more
central when it is large and
be more difficult to diagnose.
Aneurysmal Bone Cyst, Thin Bones Chronic Osteomyelitis

lesion in the fibular diaphysis
that is expanded but not
aggressive. This is an ABC,
which may become centrally
located when expanding the
width of a thin bone such as
the fibula. (Right) AP
radiograph shows mild
expansion of the fibula, with
endosteal thickening nearly
obliterating the marrow
space" as well as thick
cortical reactive bone. The
paUent had hit the leg 1 year
earlier & developed chronic
osteomyelitis.
I
68
LONG BONE, CENTRAL DIAPHYSEAL LESION, NON-AGGRESSIVE }>
:;,
..•.
III
o
3
'<
OJ
III
tII
Bone Infarct (1)
(Left) Lateralradiograph 0-
shows extensive chronic r
bone infarct involving the o
:::J
tibial diaphysis in a sickle cell to
patient There is mixed lytic (IJ
o
8, sclerotic bone which has a :::J
<ll
disordered appearance.
(Right! AP radiograph shows ;;::
<ll
a non-aggressive lytic lesion Qj
III containing ,
pseudotrabeculations IlIl
o
0;-
This is a nonspecific
appearance that proved to "::T
'<
en
be bone infarct. When <ll
Q)
dystrophic calcification is
present, the diagnosis of
infarct is more
straightforward.
Radiation Osteonecrosis
radiograph shows mixed
lytic/sclerotic disordered
bone throughout the entire
humerus. in a patient who
received whole bone RT.
This is typical of radiation
osteonecrosis, along with the
radiation-induced
osteosarcoma E!II. (Right!
Lateralradiograph shows
diffusely abnormal bone
density, with coarsened
trabeculae (HPTH). There is
abnormal bowing, as well as
several hyperossified round
lesions. whichare Brown
tumors.
Tuberculosis
lytic diaphyseal lesion with a
narrow zone of transition
and regular periosteal
reaction •. There is no
other host reaction. This is
TB osteomyelitis in a patient
who also had pulmonary
disease. (Right! Lateral
radiograph shows a
non-aggressive lytic
expanded lesion in the
fibular diaphysis. There is
pseudotrabeculation • 8, a
pathologic fracture ••.
Lesion is predominantly low
signal on MR but enhances,
typical of desmoid.
I
69
ro lONG BONE, DIAPHYSEAL lESION, AGGRESSIVE: ADULT
OJ
en
>-
.<::
c.
.~ DIFFERENTIAL DIAGNOSIS o Permeative change may be highly
o, aggressive, with aggressive-appearing
ro Common
Q5 periosteal reaction
::2; • Osteomyelitis o May not be able to differentiate from
OJ
c: • Metastases, Bone Marrow aggressive tumor
o • Multiple Myeloma (MM)
CO o May elicit reactive bone formation,
en • Lymphoma
c: including endosteal thickening
o • Ewing Sarcoma
-l o MR demonstrates abscess & fascial fluid
"tl
Q)
• Plasmacytoma • Metastases, Bone Marrow
III • Hyperparathyroidism, Brown Tumor o May be highly permeative & therefore
'"
10
less Common extremely subtle
>-
E • Chondrosarcoma, Conventional o Often more apparent with MR or PET/CT
o
.•...
• Malignant Fibrous Histiocytoma, Bone • Multiple Myeloma (MM)
'"
c:
<I: • Fibrosarcoma o MM may be so highly infiltrative that it is
• Osteosarcoma, Conventional inapparent on radiograph
• Fibrous Dysplasia • May appear as osteoporosis
• Angiosarcoma, Osseous • Usually discovered on MR or PET/CT
• Eventually develops lytic lesion that
Rare but Important
appears more focal than permeative
• Adamantinoma o Plasmacytoma generally arises in pelvis,
• Hemophilia: MSK Complications spine, or metaphyses
• Radiation-Induced Sarcoma • Rarely may be diaphyseal, particularly if
• Tertiary Syphilis pubic ramus is considered a diaphyseal
equivalent
ESSENTIAL INFORMATION • Lymphoma
o Frequently found in long bone diaphyses
Key Differential Diagnosis Issues o Highly permeative; may have cortical
• Hint: Most common diagnoses in this breakthrough with large & infiltrative soft
differential have been called "small round tissue mass
blue cell" lesions o May elicit prominent bone reaction,
o All have similar appearance on radiograph:
including endosteal thickening
Permeative, lytic, with periosteal reaction, o May have a bony sequestrum
cortical breakthrough, & soft tissue mass
• Ewing Sarcoma
o These lesions include both benign &
o Age range is 5-30, so Ewing sarcoma may
malignant entities be seen in young adults as well as children
• Osteomyelitis o Involvement of long bones is generally in
• Metastases the younger portion of age range, but
• Myeloma lymphoma diaphyseal involvement may still be found
• Ewing sarcoma in adults
o MR may help differentiate by showing
o Generally arises in mid-diaphysis, with an
abscess, but tumor necrosis may appear aggressive permeative pattern
similar o Aggressive periosteal reaction, cortical
• Hint: Most infiltrative lesions may initially breakthrough, often large soft tissue mass
be so permeative that radiograph appears o May elicit prominent reactive bone
normal formation, located within osseous margins
o MR or PET/CT makes diagnosis
but not soft tissues
Helpful Clues for Common Diagnoses • May elicit dense endosteal thickening
• Osteomyelitis • Hyperparathyroidism, Brown Tumor
o Diaphyseal location seen more frequently o Brown tumor is generally geographic
in adults than children, particularly rather than permeative
following trauma
I
70
LONG BONE, DIAPHYSEAL LESION, AGGRESSIVE: ADULT :>
o Surrounding bone may appear so o Generally has amorphous osteoid matrix

-
::l
III
o
3
'<
abnormal as to mimic aggressive process in bone & soft tissues, though may be lytic OJ
III
o Watch for other resorptive patterns to • Fibrous Dysplasia VI
<1l
verify HPTH o Long bone lesions may be lytic or have 0-
ground-glass matrix r
Helpful Clues for Less Common Diagnoses o
::l
o Expanded, thin cortex but no reaction CD
• Chondrosarcoma, Conventional OJ
o Rarely will degenerate to fibrosarcoma o
o Common lesion, but most frequently ::l
o Pathologic fracture may make the lesion C1l
metaphyseal or meta-diaphyseal
• Diaphyseal chondrosarcoma is unusual
appear more aggressive s:
C1l
• Angiosarcoma, Osseous 5i,
o If permeative or aggressive, likely higher
o Lytic permeative aggressive lesion o
grade lesion than is usually seen Q)
o Predilection for lower extremities '0
o Chondroid matrix suggests diagnosis, but :::T
o Often polyostotic '<
VI
lesion may be entirely lytic C1l
Q)
• Malignant Fibrous Histiocytoma, Bone Helpful Clues for Rare Diagnoses
o Primary MFH metaphyseal/diaphyseal • Adamantinoma
• Secondary MFH usually metaphyseal, o Diaphyseal/meta-diaphyseal, tibia
associated with bone infarcts o Lesion originates in cortex, may be
o Lytic, permeative, periosteal reaction, aggressive but usually not permeative
cortical breakthrough o May become malignant with associated
• Fibrosarcoma increase in degree of aggressiveness
o Unusual lesion in diaphysis of long bone • Hemophilia: MSK Complications
o Rarely fibrous dysplasia may degenerate o Pseudotumor may appear highly
into fibrosarcoma aggressive, with periosteal reaction &
• Appearance is of fibrous dysplasia cortical scalloping
(ground-glass matrix, central diaphysis) • Subperiosteal or cortical bleeds
with superimposed destructive change • Femur frequently involved long bone
• Osteosarcoma, Conventional • Radiation-Induced Sarcoma
o Common lesion, but usually metaphyseal o Whole long bone radiation may result in
or meta-diaphyseal radiation osteonecrosis
• Diaphyseal osteosarcoma is unusual • Radiation-induced sarcoma may arise
o Permeative, aggressive, with cortical (average 10-14 years post treatment)
breakthrough & soft tissue mass
Osteomyelitis Metastases, Bone Marrow
Oblique radiograph shows a highly permeative lytic

lesion of the fibula, with periosteal reaction • and
Anteroposterior radiograph shows a subtle permeative
mid-humeral lesion with endosteal scalloping" The
I
cortical breakthrough Ell Radiograph cannot extent of the lesion cannot be determined on this image.
differentiate between aggressive tumor & osteomyelitis. It proved to be metastatic fibrosarcoma.
71
roCl> LONG BONE, DIAPHYSEAL LESION, AGGRESSIVE: ADULT
(/)
>.
.c
a.
.~
o,
ro
Q) Multiple Myeloma (MM)
~ (Left) Sagittal STIR and AP
Cl> radiograph of the humerus
C
o shows a large humeral
In diaphyseal lesion detected
Ol
c on MR that is not visible on
o radiograph. The marrow
-' infiltration in myeloma may
"t:l
Cll be so subtle & permeative as
(/)
to be detected only on MR
1Il
In or PET/CT. (Right) Lateral
>. radiograph of the femur
-
o
E
1Il
C
<
shows a large diaphyseal
permeative
reactive
lesion, eliciting
bone in the form of
endosteal thickening •
while thinning the
endosteum in another region
Ell. This lesion is lymphoma.

shows an aggressive
permeative lesion with
associated periosteal
reaction _ in a 23 year old.
The radiograph does not
differentiate between
osteomyelitis, lymphoma,
Ewing sarcoma, and other
such diaphyseal lesions.
(Right) Axial T2WI MR in the
same patient shows the
diaphyseal lesion 10 have a
huge soft tissue mass _
with associated edema. No
abscess was shown
post-contrast. The lesion
proved to be Ewing sarcoma.
Plasmacytoma
lytic expanded moderately
aggressive lesion occupying
the entire superior pubic
ramus. a diaphyseal
equivalent. Appearance is
typical for plasmacytoma,
which frequently arises in the
pelvis. (Right) Oblique
expanded, diaphyseal lesion
that has thinned the
endosteum and appears
moderately aggressive _.
The bone density is
abnormal and patchy; the
findings are typical of a
brown tumor of HPTH.
I
72
lONG BONE, DIAPHYSEAL LESION, AGGRESSIVE: ADULT »
~
...•
III
o
3
'<
ell
III
tII
Malignant Fibrous Histiocytoma, Bone (1)
(Leh) AP ,adiograph shows a 0-
large, lytic, expanded, r
permeative lesion occupying o
:J
the diaphysis. There is a <0
pathologic fracture, with CD
o
matrix extruded into the 50ft :J
CD
tissues. The matrix is
chondroid, typical of :s:
CD
chondrosarcoma. (Right) AP a;
,
aggressive mid-diaphyseal 9
OJ
lesion, with cortical
breakthrough, soft tissue "::T
'<
en
mass, and periosteal CD
OJ
reaction. The diagnosis is
MFH, surprising only
because it occurred in a
teenager.

shows underlying fibrous
dysplasia (FO), with
correction of bowing
deformity. A highly
aggressive fibrosarcoma is
superimposed". FO will
rarely degenerate into this
malignant tumor. (Right) AP
radiograph shows an
aggressive, permeative,
diaphyseal lesion that has
cortical breakthrough & is
producing a tumor osteoid
•• Though it is unusual for
an osteosarcoma to arise in
the mid-diaphysis, there is no
other possible diagnosis.
Radiation-Induced Sarcoma
long-term fibrous dysplasia
with ground-glass matrix,
involving the entire humeral
diaphysis. There is focal
expansion that makes this
case of fibrous dysplasia
appear more aggressive ••.
This proved to be a healing
fx. (Right) AP radiograph
shows a shorr humerus with
abnormal marrow: Radiation
osteonecrosis. The
mid-diaphysis shows an
aggressive radiation-induced
osteosarcoma containing
tumor bone in the sofllissue
mass.
I
73
<1l
OJ
LONG BONE, DIAPHYSEAL LESION, AGGRESSIVE: CHILD
Cf)
>.
.<:
a.
.~ DIFFERENTIAL DIAGNOSIS o Osteomyelitis
o, o Ewing sarcoma
<1l
Q) Common o Lymphoma
::2' • Osteomyelitis, Pediatric o Chondrosarcoma
<ll
C • Ewing Sarcoma
o
[]) • Langerhans Cell Histiocytosis (LCH) Helpful Clues for Common Diagnoses
CJ)
• Leukemia • Osteomyelitis, Pediatric
c
o o Usually metaphyseal in children, but
--1 • Osteosarcoma
'tl • Metastases, Bone Marrow diaphyseal with direct trauma
CIl
VI • Lymphoma o Highly aggressive & permeative, often with
III
[]) reactive sclerosis & periosteal reaction
>. Less Common • Ewing Sarcoma
•..Eo
III
• Malignant Fibrous Histiocytoma, Bone
o Common in long bones in children
C o Highly aggressive permeative lesion,
« • Chondrosarcoma, Conventional cortical breakthrough & soft tissue mass
• Adamantinoma o Elicits reactive bone formation
• Radiation-Induced Sarcoma • May have appearance of tumor osteoid &
Rare but Important mimic osteosarcoma
• Hemophilia • Reactive bone NOT in soft tissue mass in
• Congenital Syphilis Ewing, but present in osteosarcoma
o May appear polyostotic since it may
present with osseous metastases
ESSENTIAL INFORMATION • Langerhans Cell Histiocytosis (LCH)
Key Differential Diagnosis Issues o Ranges in appearance between geographic
• Hint: Most common of these lesions fall non-aggressive and highly aggressive
into the small, round, blue cell category • When aggressive, is permeative & may
o All have an appearance that may be have soft tissue mass
indistinguishable from one another • May be indistinguishable from the
o Must consider each of these diagnoses with malignant lesions in the differential
this aggressive appearance o Often polyostotic
• Osteomyelitis o Beveled edge of skull lesion may help
• Ewing sarcoma distinguish
• Langerhans cell histiocytosis • Leukemia
• Leukemia o Usually polyostotic
• Metastases o May be so highly infiltrative that it is not
• Lymphoma visible on radiograph; MR makes diagnosis
o Hint: Note that in each of these cases, • Osteosarcoma
lesion may be polyostotic o Common lesion, but usually is
• Hint: Ewing sarcoma & osteosarcoma metaphyseal
usually have a distinct appearance from one o Less frequently is diaphyseal; if it is lytic in
another this location, may not be distinguished
o Occasionally they can be from other lesions in the differential
indistinguishable, if o Usually some tumor osteoid is visible
• Osteosarcoma is diaphyseal & lytic • Metastases, Bone Marrow
• Ewing sarcoma is metadiaphyseal & has o Usually polyostotic in children
sclerotic reactive bone formation o Metaphyseal is more frequent, but may be
• Hint: In these cases, watch for tumor diaphyseal
osteoid formation in soft tissue mass; o Neuroblastoma is most frequent in
this can only occur in osteosarcoma children
• Hint: Rarely, four of these lesions may be • Lymphoma
aggressive, yet induce endosteal & cortical o 50% of childhood lymphomas are
thickening polyostotic at presentation
I
74
LONG BONE, DIAPHYSEAL LESION, AGGRESSIVE: CHILD l>
:J
...•.
III
o
o Highly aggressive; metaphyseal more o Generally at least 7 years post radiation 3
'<
frequent than diaphyseal (RT), so seen in teenagers t1J
III
Helpful Clues for Less Common Diagnoses o Highly aggressive region in bone that VI
Cll
shows underlying radiation-related Co
• Sickle Cell Anemia r
o Early bone infarcts (particularly dactylitis)
abnormality o
:J
• Usually osteosarcoma; tumor osteoid <0
present with periosteal reaction t1J
o Consider locations likely to be radiated in o
o With evolution of infarct, will see mixed :J
childhood CD
lytic & sclerotic pattern
• Often longitudinal, involving entire • Long bones (Ewing sarcoma, lymphoma) ~
CD
diaphysis • Spine (Wilms tumor, leukemia) Oi
• Remember that bone infarct need not be
o Watch for underlying signs of radiation 6
iii
serpiginous and subchondral, especially osteonecrosis -0
::T
• Mixed lytic & sclerotic, disordered bone '<
in sickle cell patients VI
CD
o Watch for growth deformities associated OJ
• Malignant Fibrous Histiocytoma, Bone
o Unusual lesion in children, may be seen in
with radiation
teenager • Long bone may be short if subjected to
whole bone radiation (physes at risk for
o Aggressive, may be metaphyseal or
vascular injury in RT)
diaphyseal
o No other distinguishing characteristics • Spine may develop scoliosis if spine not
completely included in radiation field
o Watch for port-like distribution of osseous
o Uncommon in children
o Should be considered if subtle matrix is
abnormalities, indicating RT
seen in diaphyseal lesion of teenager Helpful Clues for Rare Diagnoses
o May induce endosteal thickening rather • Hemophilia
than showing cortical breakthrough o Pseudotumor appears aggressive: Soft
• Adamantinoma tissue, intraosseous, & subperiosteal bleeds
o Almost invariably tibial metadiaphysis; o Femur most commonly involved long
cortically based bone
o Generally only moderately aggressive • Congenital Syphilis
initially o Periosteal reaction, infiltrative appearance
• May become aggressive & malignant
• Radiation-Induced Sarcoma
Osteomyelitis, Pediatric Osteomyelitis, Pediatric
AP ,adiog,aph shows a highly aggressive lesion in the

radial diaphysis •• in a 7 year old. There is prominent
Axial T 1 C+ MR on the same patient shows infiltration of
the marrow of the radius HI and a large soft tissue
I
periosteal reaction and cortical breakthrough. The fat abscess _ confirming the diagnosis of osteomyelitis.
planes are obliterated, indicating osteomyelitis. This child had direct trauma to the forearm.
7S
ro
C1l
LONG BONE, DIAPHYSEAL LESION, AGGRESSIVE: CHILD
(J)
>.
.r:
a.
ro
o,
ro
Qi Ewing Sarcoma
~ (Left) Lateral radiograph
C1l shows a permeative
c
o mid-diaphyseal lesion in a 10
CO year old. There is periosteal
Ol
C reaction III and a large soft
o tissue mass EiI' this is a
-l
classic age & appearance for
"t:l
Ql Ewing sarcoma. (Right)
(J)
III
CO highly permeative diaphyseal
>. lesion with prominent
E
-
periosteal reaction •.
o cortical breakthrough, & soft
III
C tissue mass EiI in an 8 year
< old. This case appears as
aggressive as the previous
case of Ewing sarcoma but
proved to be LCH.
leukemia Osteosarcoma
diffuse osteopenia in both
femoral diaphyses Ell along
lucent metaphyseal lines •
in a 5 year old. Though no
periosteal reaction is seen,
this must be interpreted as
aggressive; leukemia was
proven. (Right) Lateral
aggressive mid-diaphyseal
humeral lesion with Cadman
triangle" an aggressive
periosteal reaction. There is
tumor osteoid forming in the
soft tissue mass !Ill
diagnostic of osteosarcoma.

shows a permeative lesion
occupying the entire length
of the ulna, with extensive
periosteal reaction _ This 6
month old patient has
medulloblastoma metastases.
a lytic lesion with reactive
sclerosis occupying the
entire diaphysis and
metaphysis of the femur in a
7 year old African American
child _ There is periosteal
reaction and soft tissue mass.
The lesion is polyostotic; it
proved to be lymphoma.
I
76
lONG BONE, DIAPHYSEAL lESION, AGGRESSIVE: CHILD »
..o
:l
III
3
'<
tll
III
VI
Sickle Cell Anemia Malignant Fibrous Histiocytoma, Bone (1)
(Left) AP radiograph shows Co
periosteal reaction. and a r
permeative appearance in o
:l
most of the metacarpals and CO
phalanges in the hand of this CD
o
I year old African American' :l
CD
child. This is sickle cell
dactylitis. (Right) AP
permeative lesion occupying
the mid-diaphysis in a 13
year old. The lesion is
aggressive, with cortical
breakthrough and soft tissue
mass and prominent
periosteal reaction. MFH is
rare in children but certainly
does occur.
Chondrosarcoma, Conventional Chondrosarcoma, Conventional

shows mild expansion of the
diaphysis Ii!Il with endosteal
thickening. in a 17 year
old. This is suggestive of
osteomyelitis or Ewing
sarcoma, but
chondrosarcoma must also
be considered. (RighI) Axial
NECT of the same patient
shows endosteal thickening,
with a central chondroid
matrix ~ This matrix makes
the diagnosis of
chondrosarcoma. It is an
unusualdiagnos~ in
teenagers but must be
considered.
Adamantinoma
lytic lesion in the diaphysis of
the tibia of a 17 year old.
The lesion proved to be
entirely restricted to the
cortex _ which is typical of
adamantinoma. Note the
pathologic fracture _
(RighI) Axial T1 WI M R of the
same patient shows that the
tibial lesion is indeed based
entirely in the cortex HIlI. The
marrow is not entirely
normal, suggesting
involvement, which
contributes to the aggressive
appearance and behavior of
this lesion. (t MSK Req).
I
77
ctl
Q)
LONG BONE, AGGRESSIVE DIAPHYSEAL LESION WITH ENDOSTEAL THICKENING
VJ
>-
.r:
c.
.~ DIFFERENTIAL DIAGNOSIS o If not considered, endosteal thickening in
o, one of these lesions may lull the reader
ctl Common
Q) into thinking it is a benign process
~ • Osteomyelitis o MR should be performed to further define
Q)
c • Chondrosarcoma lesion
o
CIl Less Common Helpful Clues for Common Diagnoses
en
c • Lymphoma
o • Osteomyelitis
-l
• Ewing Sarcoma o Dense reactive bone formation, located
'1:l
Ql
VJ
both at the periosteum & endosteum
ctl
lD ESSENTIAL INFORMATION o Underlying lytic lesion may show
>- serpiginous tracking, proving the diagnosis
-
«
E
o
ctl
c
• Note: This discussion of endosteal
thickening does not include non-aggressive
• Chondrosarcoma
o Most are low grade & metaphyseal at
presentation
lesions o Need not have radiographically evident
o Stress fracture, stress reaction, & osteoid chondroid matrix
osteoma will show focal diaphyseal o Underlying lesion may not appear
endosteal thickening alarming
• Thickening should not be • May appear rather geographic
circumferential, as it is listed in • May be so permeative as to not be visible
diagnoses of this differential radiographically
• Note: All lesions in this differential diagnosis o Endosteal thickening is common in these
may appear much more aggressive than metadiaphyseallesions
shown in this discussion • In correct age group (30-60 years), must
o All may show permeative osseous alert reader to possibility of
destruction, aggressive periosteal reaction, chondrosarcoma
cortical breakthrough, and soft tissue mass
• Purpose of the differential is to remind us
that each of these lesions in the differential • Lymphoma & Ewing Sarcoma
o Most frequently has aggressive appearance
may have a non-aggressive appearance as
o Permeative change may be extremely
one of their manifestations
• Hint: Dense endosteal thickening should subtle, with only diaphyseal endosteal
force at least a consideration of these thickening seen
o Sequestrum suggests lymphoma
diagnoses
I Late,al ,adiograph shows permeative

throughout the proximal lemur III along with a local
change Coronal T 1 C+ FS MR in the same patient shows a local
fluid collection'" diffuse marr(Mt, & soft tissue edema
marginated lytic lesion EllI. There is dense periosteal & Ell and confirms the thick cortical reactive lxme
endosteal reaction" aJ/ typical of osteomyelitis. formation _ Staphylococcus was cultured.
78
lONG BONE, AGGRESSIVEDIAPHYSEAL lESION WITH ENDOSTEAL THICKENING »
.•.o
;j
III
3
'<
lXJ
III
III
Chondrosarcoma Chondrosarcoma lD
(Left) AP radiograph shows C.
chondroid matrix =:I with a r
surrounding permeative lytic o
::J
lesion ER indicating <0
chondrosarcoma. Note the CD
o
associated dense endosteal & ::J
(t)
(Right) AP radiograph shows s:
(t)
dense, regular endosteal &
periosteal reaction =- There
1ii
,
o
is an extremely subtle iii'
permeative change in the -0
:::r
adjacent marrow. No matrix '<
III
is seen. The diagnosis of (t)
OJ
chondrosarcoma is difficult
to make here, but age,
location, & reaction should
be suggestive.
radiograph shows a
permeative lytic lesion
centrally within the marrow,
associated with dense thick
endosteal & periosteal
reaction III. (Right) Lateral
radiograph of the same
patient shows not only the
cortical reaction" but also
endosteal scalloping III. The
permeative central lesion is
obvious. There is also a small
sequestrum iii present; this
is a finding that has been
described in primary
lymphoma of bone, though it
is also seen in osteomyelitis.

lytic permeative lesion in the
meta-diaphysis ~ that has
elicited dense periosteal and
endosteal reaction" This
is a child, and the diagnosis
should be either Ewing
sarcoma or osteomyelitis; the
former was proven at biopsy.
(Right) Lateralradiograph
shows thick, regular
endosteal and periosteal
bone formation •. There is
no obvious marrow lesion,
and this might be dismissed
as stress reaction. However,
Ewing sarcoma must be
considered and was proven.
I
79
LONG BONE, CORTICALLY BASED DIAPHYSEAL LESION, SCLEROTIC
DIFFERENTIAL DIAGNOSIS o Radiographs have range of appearance,

depending on stage
Common • Initially, focus of sclerotic cortical
• Stress Fracture, Adult thickening -
<1l
C
• Tibial Stress Syndrome • Linear fracture line sclerosis
o • Adductor Insertion Avulsion Syndrome
CO o MR
CJ)
c • Stress Fracture, Pediatric • Edema in marrow, cortex, and tissues
o • Osteoid Osteoma
-.J adjacent to cortex
"0 • Fibroxanthoma (Non-Ossifying Fibroma) • Fracture line usually seen well as linear
<1l
l/l
C'O
• Metastases, Bone Marrow low signal on Tl or fluid sensitive
CO • Chronic Osteomyelitis (Brodie Abscess) sequences, surrounded by edema
>- • Stress Fracture Related to Bisphosphonate
-
E
o
C'O
c
<C
Use
Less Common
• Tibial Stress Syndrome/Adductor
Insertion Avulsion Syndrome
o Results from repetitive stress at periosteal
• Melorheostosis insertion of tendons

• Fibrous Dysplasia o - Traction periostitis
• Site of medial soleus insertion at
Rare but Important posteromedial tibia - "shin splints"
• Osteoma • Site of adductor insertion at medial
• Paget Disease femoral diaphysis - "thigh splints"
o Radiographs show a spectrum of
ESSENTIAL INFORMATION abnormalities, depending on stage &
longevity of injury
• Normal
• Most urgent diagnoses on this list relate to • Subtle periostitis
those at risk for fracture completion • Focal sclerosis
o Stress reaction needs to be evaluated by
o MR shows marrow edema & linear fluid
MR for fracture; must be protected signal along the outer cortex
o Stress fracture needs MR evaluation for • Evaluate MR carefully for evidence bf
extent & to determine treatment fracture
• Hint: Maintain a high index of suspicion of • As long as no fracture line is shown,
stress reaction/fracture in subtrochanteric recovery is made with rest
region in patients on bisphosphonates • In continuum with stress fracture, which
• Hint: Remember the classic differential for may require more aggressive therapy;
focal diaphyseal cortical sclerosis: Osteoid differentiating the two is crucial
osteoma, stress fracture (reaction), Brodie • Osteoid Osteoma
abscess o Diaphyseal osteoid osteomas occur in the
Helpful Clues for Common Diagnoses cortex
• Stress Fracture, Adult or Pediatric • May be at the surface of cortex or deep,
o Common, especially in tibia at junction of cortex & marrow
o Results from increased or unaccustomed • Those that are deep are often closely
activities leading to abnormal stresses on associated with a nutrient vessel; do not
bone confuse the vessel with the nidus
• Repetitive axial loading o Lytic nidus may contain a small sclerotic
• Abnormal biomechanics central focus
• Excessive muscular forces o Lesion elicits tremendous cortical reaction,
o Stress reaction is first abnormality seen both periosteal and endosteal
• Cortical sclerotic focus of bone • Reaction may obscure the nidus
remodeling completely, making it impossible to
o If not protected at stage of stress reaction, differentiate on radiograph
develops stress fracture
I
80
lONG BONE, CORTICAllY BASED DIAPHYSEAL lESION, SClEROTIC »
• Axial imaging differentiates osteoid • Initial appearance: Focus of cortical

-
:::l
Ql
o
3
'<
osteoma from stress fracture & Brodie sclerosis lateral cortex at junction of OJ
Ql
abscess proximal & middle 3rd of femur (fl
(1)
• Fibroxanthoma (Non-Ossifying Fibroma) • Generally bilateral, though may develop Co
o Common lesion in children, generally at different rates r

o
:::l
meta diaphyseal • With minor trauma, develops a CO
OJ
o Cortically based except in small-diameter transverse fracture o
:::l
bones such as fibula o Patients have prodromal pain (groin, (1)
o With skeletal maturation, natural history is thigh) s:

CD
for NOF to heal, sclerosing from peripheral • Hint: Watch for lateral cortical Qi,
to central abnormality on pelvic imaging (usually o
Qi.
o Eventually most revert to completely at base of image) D
::T
normal bone • Need MR to determine risk of fracture '<
Ul
(1)
• Metastases, Bone Marrow o Patients need protection against fracture & Ql
o Rare cortical metastases are usually due to probable termination of drug

either lung or breast primaries Helpful Clues for less Common Diagnoses
o Either may be lytic or sclerotic
• Melorheostosis
o Weakens the bone, even when sclerotic; at
o Cortical & endosteal sclerosis; "dripping
risk for fracture candle wax" pattern
• Chronic Osteomyelitis (Brodie Abscess) o Generally monomelic & may follow
o May be within cortex; generally
sclerotomal distribution
well-defined borders
o Elicit prominent cortical reaction; may be
o May be cortically based, but generally not
difficult to differentiate from stress sclerotic with that presentation
reaction or osteoid osteoma
• Stress Fracture Related to Bisphosphonate Helpful Clues for Rare Diagnoses
Use • Osteoma
o Bisphosphonates inhibit osteoclasts, o Rare involvement of long bones; when
slowing osteoporosis present, suspect polyposis (Gardner
• Also inhibit bone turnover; it is syndrome)
suspected that this weakens bone • Paget Disease
o Fractures distinctively located in the o Rare initial lesion at tibial cortex,
subtrochanteric femur mid-diaphyseal; generally not sclerotic
since it is an early lesion
Stress Fracture, Adult
!.;Jte,al radiograph shows subtle cortical sclerosis.

the proximal dbial diaphysis. There is no other
at !.;Jteralradiograph obtained one week later in the same
paUent proves stress fracture, with the sclerosis now
I
characterizing finding, and the diagnosis is most Nkely crossing the bone in a linear fashion. MR proved the
stress reaction or early stress fracture. linear fracture line with surrounding edema.
81
roOJ lONG BONE, CORTICAllY BASED DIAPHYSEAL lESION, SClEROTIC
'">-
.I::.
0-
ro
iso
ro
Q) Tibial Stress Syndrome Tibial Stress Syndrome
OJ shows subtle periosteal
c:
o reaction at the tibial
CD
Ol
diaphysis =. this is an early
finding of tibial stress
c:
o syndrome in a young adult
-l
runner. (Right) Sagittal PO
'1:l
CIl FSEFS MR obtained at the
'"
01
CD
same lime as the previous
image shows edema within
>- the marrow" and in the
E
-o
01
c:
surface =
soft tissues at the cortical
but no fracture
line; this confirms tibial stress
~ syndrome and the patient
would be well-advised to
protect the leg.
Adductor Insertion Avulsion Syndrome

radiograph shows cortical
thickening at the medial
aspect of the mid-femoral
diaphysis III. This is typical
of adductor insertion
avulsion syndrome, proven
by MR. (Right) Lateral
cortical reaction of a healing
stress fracture 11:I in a 9 year
old who began an
unaccustomed exercise
activity. The fracture has
robust reaction and, with
protection, healed before
becoming complete.
Osteoid Osteoma
shows prominent cortical
reaction III in a child, seen
over a more extensive length
of the diaphysis than is
usually present with stress fx.
One must suspect osteoid
osteoma, with the lytic nidus
being obscured by the
reactive bone formation.
It MSK Req). (Right) Axial
NECT (same patient) proves
osteoid osteoma, a small
lytic nidus ~ adjacent to a
nutrient vessel ~ located
deep beneath the dense
cortical reactive bone •.
(tMSK Req).
I
82
lONG BONE, CORTICAllY BASED DIAPHYSEAL lESION, SClEROTIC :l>
-
:l
III
o
3
'<
lXl
III
l/I
Fibroxanthoma (Non-Ossifying Fibroma) Chronic Osteomyelitis (Brodie Abscess) ~
metadiaphyseal. NOFs, r
most frequently multiple in o
:l
neurofibromatosis. With to
skeletal maturation, the lytic aJ
o
lesions heal, with sclerotic :l
(1)
ossification. (Right) Lateral
radiograph of the femur ~
(1)
shows an irregular lytic Qi,
lesion containing a sclerotic
cente," both located
o
Ol
within a cortex which is "0
-::r
thickened with reactive bone '<
l/I
formation. This is typical of (1)
Ol
osteomyelitis; the central
sclerotic body is a
sequestrum.
Stress Fracture Related to Stress Fracture Related to

Bisphosphonate Use Bisphosphonate Use
dense cortical and endosteal
reaction in the
subtrochanteric region of the
femur. in a 70 year old
woman placed on
bisphosphonate therapy for
osteoporosis. (Right) Frog
lateral view shows linear
sclerosis in the same patient,
indicating fracture •. The
femur was not protected, &
the patient went on to a
displaced fracture. The
process occurred bilaterally.
Subtrochanteric fractures are
now recognized as a
complication of this therapy.
Osteoma
(Left) Sagittal PO FSEFS MR
shows a lobulated mass.
arising from the ulnar cortex
which was densely sclerotic.
At resection, it was
consistent with the dense
bone formation of
melorheosrosis. (Right) AP
osteomas" projecting from
the femoral cortex in this
patient with Gardner
syndrome. The contralateral
femur was involved as well.
In the absence of polyposis
syndromes it is distinctly
unusuallo find an osteoma
involving the long bones.
I
83
ell
(l)
LONG BONE, CORTICALLYBASED DIAPHYSEALLESION, LYTIC
rJl
>-
.r:
a.
.~ DIFFERENTIAL DIAGNOSIS • Generally ends up in metadiaphysis;
o, mid-diaphyseal location is rare
ell
Q) Common o Natural history is to fill in with normal
2 • Fibroxanthoma (Non-Ossifying Fibroma) bone (from periphery to center) and
(l)
c • Metastases, Bone Marrow disappear in adulthood
o
OJ • Paget Disease • Metastases, Bone Marrow
Cl
C • Osteomyelitis o Most frequently located in marrow of
o
....J • Osteoid Osteoma metaphysis
"C
CIl
• Fibrous Dysplasia o Diaphyseal & cortical location of
rJl
ell
• Aneurysmal Bone Cyst metastases is most suggestive of either
al
>- Less Common breast or lung primary lesion
-
C
E
o
ell
<I:
• Adamantinoma
• Tendon Injury (Tug Lesion)
• Osteofibrous Dysplasia
• Paget Disease
o Lesion usually originates in subchondral
region of bone & advances through
• Soft Tissue Mass Invasion (Mimic) metadiaphysis to diaphysis
• Langerhans Cell Histiocytosis o Occasionally long bone lesion will
• Hyperparathyroidism originate in diaphysis
• Most frequent bone for this occurrence:
Rare but Important
Tibia, anterior cortex
• Bacillary Angiomatosis
• Earliest lesion is lytic; has defined margin
• Hemophilia: MSK Complications as leading edge of lesion
• Hardware, Reactive Changes • Eventually extends to subchondral bone
• Osteomyelitis
ESSENTIAL INFORMATION o May originate in cortex, especially if
related to direct inoculation
o Watch for serpiginous pattern
• Cortically based lesions within the tibia o Generally will also see periosteal reaction
present a special circumstance o MR likely to show associated soft tissue
o Three lesions have a remarkably similar
fluid & abscess
appearance & propensity to occupy the
• Osteoid Osteoma
anterior cortex of tibia o Mid-diaphyseal lesion located in cortex
• Cortically based fibrous dysplasia • Often deep within the cortex, at margin
• Osteofibrous dysplasia with marrow
• Adamantinoma • Often associated with nutrient vessel
o These lesions have subtle pathologic
o Lesion is lytic, oval with regular margins
differences
• Lesion may have central ossific density
• May be considered to be in a spectrum of o Elicits significant reactive bone formation
pathology surrounding it; reactive bone may obscure
• Behavior may differ, since the lytic nidus
adamantinoma may have malignant
behavior o Most frequently, FD is central and
o Hint: Statistically, fibrous dysplasia is far
expansile within long bone
more frequent than the other two lesions o Occasionally, FD originates in cortex
Helpful Clues for Common Diagnoses • FD is such a common lesion that this
• Fibroxanthoma (Non-Ossifying Fibroma) presentation is not considered rare
o Extremely common lesion in children, • May expand and extend around the
especially about the knees cortex, surrounding normal marrow
o Cortically based, but generally originates • Cortical FD in the differential with
in metaphysis osteofibrous dysplasia & adamantinoma
• With skeletal growth, the metaphysis o Watch for additional lesions; FD is often
migrates away from lesion polyostotic, which may help distinguish it
I
84
LONG BONE, CORTICALLY BASED DIAPHYSEAL LESION, LYTIC »
• Aneurysmal Bone Cyst o In the radiographic & pathologic spectrum

-
:J
III
o
3
'<
o Usual location eccentrically within bone of cortical fibrous dysplasia/osteofibrous OJ
III
dysplasia/ adaman tinoma
• May expand so significantly that it
o Most frequent location is anterior tibial
'"
<0
Co
appears to arise within the cortex
cortex; generally proximal tibia r
• Rarely may actually arise within the o
::J
cortex; this is shown on axial imaging o May be fully lytic, or may contain a small (Q
OJ
o Generally retains a thin cortical rim; fluid amount of osteoid o
::J
levels are commonly seen on axial imaging • Soft Tissue Mass Invasion (Mimic) C1>

o Soft tissue mass adjacent to cortex may s:
C1>
cause focal erosion, mimicking mass 5i
• Adamantinoma originating within cortex 6
o Infrequently seen lesion 0;-
• Langerhans Cell Histiocytosis "0
::T
o Generally quite location-specific '<
o Location is usually central diaphyseal
• Anterior tibia, cortically based o Common lesion in children; rarely may '"
C1>
III
• Distal tibia more common than proximal
originate in unusual cortical location
o In the spectrum with cortical fibrous
o Range of behavior from aggressive to
dysplasia & osteofibrous dysplasia
indolent
• Cannot reliably distinguish by imaging
• Treated with wide excision, since its
o Brown tumor usually arises centrally in
behavior may be malignant (unlike the
marrow but may also be a cortical lesion
other lesions in its differential)
o Watch for other abnormalities in bone
• Tendon Injury (Tug Lesion) density, trabecular coarsening, and
o Any tug lesion may result in resorption of
resorption patterns
adjacent cortex
o Most recognized site is posteromedial Helpful Clues for Rare Diagnoses
distal femoral metadiaphysis • Bacillary Angiomatosis
• Site of insertion of adductor fibers o May be cortical
• Cortical resorption may have associated • Hemophilia: MSK Complications
periosteal reaction & small mass o Pseudotumor may arise from intracortical
• Termed cortical desmoid; location helps or subperiosteal bleed
differentiate from a more ominous lesion • Hardware, Reactive Changes
• Osteofibrous Dysplasia o Usually inert, but old hardware
o Infrequently seen lesion, generally in child occasionally causes adjacent cortical
or young adult reactive change
Metastases, Bone Marrow
AP ,adi08'aph shows a cortically based lytic lesion.

that proved to be NOF. These lesions are more
AP radiograph shows a cortically based non-aggressive
lesion. in an elderly patient. Metastatic disease must
I
frequently based in the metadiaphysis but are extremely be suspected; lung and breast are the most common
common; diaphyseallocadon should not be surprising. metastases to be located within the cortex.
85
m
Ql
lONG BONE, CORTICAllY BASED DIAPHYSEAL LESION, lYTIC
'">-
.c
a.
ro
is,
ro
(j) Paget Disease
~ (Leh) Lateral radiograph
Ql shows a cortically based lytic
c
o lesion in the tibial diaphysis
CO
OJ
=. This is an early
c manifestation of Paget
o disease. Although lesions of
-l
Paget disease usually
"0
Ql originate at the ends of long
'"ro
CO
bones, the tibia is an
exception and a diaphyseal
>- origin is not uncommon.
-
E
o
<U
C
<l:
obtained 2 years later on the
same patient shows classic
Paget disease, now with
mixed lytic & scferotic
lesions, extending to the
subchondral bone.
Osteomyelitis
shows a mildly expanded
lytic cortically based
diaphyseal lesion Ill. This 20
year old had normal lab
values, but this proved to be
Staphylococcal
osteomyelitis. (Right)
shows a cortically based lytic
lesion III in the diaphysis.
The appearance is typical of
an osteoid osteoma, with
dense surrounding sclerosis
=. This sclerosis
occasionally is so dense as to
obscure the lytic lesion.
Fibrous Dysplasia Fibrous Dysplasia

shows a lytic, mildly
expanded, corlicallesion in
the diaphysis of the tibia Ell
as well as a "daughter'!
lesion in the fibula Ill. The
tibial lesion is so large that
one cannot be certain that it
;s entirely cortical in location.
(t MSK Req). (Right) Axial
bone CT of the same patient
shows that the lesion is
entirely cortical and mildly
expanded with a
ground-glass matrix _
Findings are typical of
cortically based fibrous
dysplasia.
I
86
LONG BONE, CORTICAllY BASED DIAPHYSEAL LESION, LYTIC »
-
~
Ql
o
3
'<
OJ
Ql
VI
~
(Left) Lateral radiograph 0-
shows a rather complex lytic r
lesion originating in the o
:J
anterior cortex of the tibia <Cl
•• There appear to be OJ
o
several "daughter" lesions. :J
CD
Though (ibrous dysplasia
most Frequently arises within ~
CD
the central portion o( a long fii
bone, it is not rare for it to
,
occupy the cortex. rt MSK
o
OJ
Req). (Right) Sagillal TI WI "0
::r
MR of the same lesion shows '<
en
the lesion to be based CD
OJ
entirely within the anterior
corlex of the tibia" FO
was proven at excisional
biopsy.

lytic expansile diaphyseal
lesion that is based in the
cortex". This proved to be
an ABC, though it is unusual
for this lesion to be
diaphyseal, rather than
metaphyseal, and truly
cortically based, rather than
eccentric and expansile.
(Right) Axial T2WI MR of the
same lesion shows the true
cortical origin of the lesion
within the radius =. There
are a few fluid levels, but the
majority of the lesion was
solid, unusual for ABC.
Adamantinoma Adamantinoma
(Left) Lateralradiograph
shows a lytic lesion arising
within the anterior cortex of
the tibia" This lesion is an
adamantinoma, though
statistically a cortically based
Fibrous dysplasia is more
likely. (t MSK Req). (Right)
Axial T2WI MR of the same
patient shows the lesion to
be based entirely within the
anteriorcortex" This
adamantinoma is not
distinguishable from
cortically based FO or
osteofibrous dysplasia by
imaging. (tMSK Req).
I
87
roCIl LONG BONE, CORTICALLY BASED DIAPHYSEAL LESION, LYTIC
en
>-
.c
a.
.~
o,
m
Q5 Tendon Injury (Tug Lesion) Tendon Injury (Tug Lesion)
~ (Leh) Axillary lateral
CIl radiograph shows
c
o ossification of one of the slips
!Xl of the deltoid tendon _
Ol
c along with apparent lytic
o lesion in the cortex _ This
-' cortical" lesion" ;5 resorption
"0
Q) due to the avulsive injury.
en (Right) Axial bone CT shows
CU
lO an apparent cortically based
>- lytic lesion in the distal
E femoral metadiaphysis III
.•..o
cu This medial "Iesion" has also
c been termed a cortical
4: desmoid and is secondary to
tug injury of the adductor
tendon.
Osteofibrous Dysplasia Osteofibrous Dysplasia

shows a nonspecific anterior
tibial cortical lesion _
falling into the differential of
cortical fibrous dysplasia,
osteofibrous dysplasia, and
adamantinoma. (Right) Axial
STIR MR of the same case
shows the cortical nature of
the lesion ••. Biopsy proved
osteofibrous dysplasia. This
lesion ;s usually seen in
children or teenagers and is
distinctly unusual.
Soft Tissue Mass Invasion (Mimic) Soft Tissue Mass Invasion (Mimic)
shows a lytic lesion that
appears to be cortically
based •. Location is not
proven in this image, which
is not in tangent to the
lesion. (Right) Axial TI C+
MR of the same lesion shows
a 50ft tissue lesion that is
focally invading and eroding
the cortical bone _ This
proved not to be actually
cortically based but rather a
mimic. The lesion has a
target sign of low central
signal ~ and proved to be a
schwannoma.
I
88
LONG BONE, CORTICALLY BASED DIAPHYSEAL LESION, LYTIC »
::J
.•.o
III
3
'<
OJ
III
t/I
Langerhans Cell Histiocytosis (1)
Lateralradiograph
(Left) Q.
shows a cortically based lytic c-

lesion within the anterior O
::J
tibial meta diaphysis _ This (Cl
appearance and location are OJ

o
typical of adamantinoma. ::J
C1l
However, biopsy proved the
lesion to be Langerhans cell s:
C1l
histiocytosis. (Right) Lateral Qi,
radiograph from the same
patient obtained 3 months
o
0;.
later shows significant 1::l
::r
interval growth of the lesion '<
t/I
_ Rapid growth can be C1l
Q)
seen with LCH, as in this
case.
Hyperparathyroidism Bacillary Angiomatosis

radiograph shows a cortically
based lytic lesion Ell within
the bone that is extremely
osteoporotic, with coarsened
trabeculae. The patient has a
parathyroid adenoma; the
rocallesion is a brown
tumor. Although a brown
tumor is a common lesion, it
is most frequently located
within the marrow rather
than cortex. (Right) Lateral
radiograph shows a subtle
cortically based lytic lesion
_ which proved to be
bacillary angiomatosis in a
patient with HIV-AIDS.
Hemophilia: MSK Complications Hardware, Reactive Changes

radiograph shows cortically
based and surface
excavations _ with
prominent periosteal change
in this patient with
hemophilia. Intraoss€ouS and
subperiosteal bleeds result in
this bizarre appearance of
cortical destruction, termed
pseudotumor. (Right) Lateral
radiograph shows a grossly
loose plate & screws" and
scalloped destructive change
of the cortex. This proved to
be a granulomatous reaction
to the metal, a form of
particle disease.
I
89
ro lONG BONE, DIFFUSE CORTICAL/ENDOSTEAL THICKENING
Q)
(/)
>,
-<:
0..
.~ DIFFERENTIAL DIAGNOSIS o Additional findings: Subcutaneous edema,
o, phleboliths, varicose veins
ro Common
Q5 • Chronic Recurrent Multifocal
::2 • Paget Disease Osteomyelitis (CRMO)
Q)
c • Venous Stasis o Location: Long bone metaphysis
o • Chronic Recurrent Multifocal Osteomyelitis
CD o Findings range from radiographically
OJ
C
(CRMO) occult to exuberant new bone formation
o • Hypertrophic Osteoarthropathy
-' causing dense sclerosis of the majority of
"0
QI less Common the involved bone
(/)
111 • Melorheostosis • Hypertrophic Osteoarthropathy
CO
>. • Sickle Cell Anemia: MSK Complications o Symmetric, solid periosteal reaction
E thickens cortex
-o
111
C
<l:
• Juvenile Idiopathic Arthritis OIA) o Evaluate for underlying malignancy or
chronic pulmonary, cardiac or
Rare but Important
gastrointestinal disease
• Complications of Prostaglandins
• Engelmann-Camurati Disease Helpful Clues for Less Common Diagnoses
• Ribbing Disease • Melorheostosis
• Acromegaly o Begins as linear hyperostosis in proximal
• Intramedullary Osteosclerosis end of tubular bone
• Complications of Fluoride o Distal progression with progressive cortical
• Caffey Disease (Infantile Cortical thickening
Hyperostosis) o Usually limited to single extremity
• Pachydermoperiostosis o Typically follows sclerotome distribution
• Thyroid Acropachy • Sickle Cell Anemia: MSK Complications
• Ewing Sarcoma o Diffuse cortical infarction in the long
bones
o Diametaphysis may be widened by
ESSENTIAL INFORMATION infarction &/or chronic infection
Key Differential Diagnosis Issues o Endosteal splitting = linear increased
• Many of the differential diagnosis entities densities paralleling the cortices
have an overlapping appearance • May produce a bone-in-bone appearance
• Patient age, history & additional skeletal • Renal Osteodystrophy
findings can help differentiate o Location: Tubular bones most common,
pubic rami, spine
Helpful Clues for Common Diagnoses o Neostosis = rapid new bone formation in
• Paget Disease patients undergoing treatment
o Location: Long bones most common,
o Additional findings include generalized
pelvis, skull skeletal sclerosis, subperiosteal resorption,
o Early lytic lesions originate at the
joint erosions, vertebral endplate sclerosis
subchondral cortex of long bone o Rare in primary hyperparathyroidism
• Tibia is the exception, often originating • Juvenile Idiopathic Arthritis OIA)
in diaphysis o Location: Periarticular
o Sclerotic phase is less common than mixed
o Distribution: Localized or generalized
lytic & sclerotic phase
o Cortical & trabecular thickening results in Helpful Clues for Rare Diagnoses
overall enlargement of bone • Complications of Prostaglandins
o Bowing deformities, pathologic fractures o Location: Long bone diaphysis
• Venous Stasis o Distribution: Generalized
o Cortical thickening from solid periosteal o Correlate with drug therapy
reaction usually mild • Engelmann-Camurati Disease
o Location: Long bone diaphysis, skull
o Distribution: Bilateral, symmetric
I
90
lONG BONEr DIFFUSE CORTICAL/ENDOSTEAL THICKENING »
..
::J
III
o
o Exuberant endosteal new bone o Location: Tibia diaphysis; femur & tibial 3
'<
o Presents in childhood metaphysis less common O:J
III
o Autosomal dominant (differentiate from o Distribution: Unilateral or asymmetric
Ribbing disease) bilateral endosteal thickening
'c."
(1)
o Minimal cortical thickening & lacks r

• Ribbing Disease o
::J
o Location: Long bone diaphysis periosteal reaction to
CD
o Unilateral or bilaterally asymmetric • Complications of Fluoride o
::J
o Radiographically identical to Engelmann o Location: Tubular bones, symmetric (1)
disease & intramedullary osteosclerosis o Additional findings of tendon & ligament s::
(1)
o Eventual obliteration of marrow space & calcification Iii

circumferential bone growth • Caffey Disease (Infantile Cortical 6
OJ
o Presents after puberty Hyperostosis) -0
::T
o Autosomal recessive (differentiate from o Ossification begins in soft tissues and '<
en
(1)
Engelmann & intramedullary progresses to join cortex of underlying OJ
osteosclerosis) bone
o Can have similar appearance to stress o One or more long bones, mandible,
fracture, chronic osteomyelitis, metabolic scapula, ribs may be involved
disorder, endocrine disorder, bone-forming o Onset less than six months of age
malignancy o Spontaneous resolution; residual bowing
• Acromegaly uncommon
o Bone enlargement & flared long bone ends • Pachydermoperiostosis
o Clinically differentiated from other entities o Primary hypertrophic osteoarthropathy
by elevated growth hormone & IGF-l o Thick, shaggy periosteal reaction produces
o Additional findings: Thick skull, large cortical thickening
frontal sinuses, enlarged mandible, • Thyroid Acropachy
spade-like finger tufts, wide phalangeal o Location: Tubular bones of hands & feet;
bases, wide MCP joints, thick heel pad, long bones rare
posterior vertebral body scalloping o Correlate with hyperthyroidism treatment
• Intramedullary Osteosclerosis • Ewing Sarcoma
o Similar appearance to Engelmann & o Exceptionally rare to have dense, solid
Ribbing disease but is nonhereditary periosteal reaction obscure permeative
• Adult female is most commonly affected destruction of tumor
demographic o MR can evaluate for underlying
malignancy
Paget Disease
Anteroposterior radiograph shows the tibia shaft to be

significantly expanded • with a mixed sc1erotk and
Oblique radiograph shows a thickened appearance to
the distal tibial corlex _ This is due to smooth
I
lytic appearance. The lesion extends distally with a periosteal reaction. Additional signs of venous stasis
blade of grass or flame-shaped pal/ern Eil include phleboliths HI and subcutaneous edema S.
91
LONG BONE, DIFFUSE CORTICAL/ENDOSTEAL THICKENING
Chronic Recurrent Multifocal

Osteomyelitis (CRMO) Hypertrophic Osteoarthropathy
(Left) Coronal TI WI MR
OJ shows massive thickening of
c:
o the proximal left femoral
CO cortex •. The endosteal
OJ
c: bone has similarly extensive
o regions of sclerosis _
-l
Marked edema in the bone,
'0
GI soft tissues and a joint
III
l'll
effusion suggested
CO os.teosarcama. CRMO was
>. proven on biopsy. (Right)
E
-
o shows periosteal reaction of
l'll
c: the tibia that is so dense it
< presents as extremely thick
cortex Ell. More typical solid
periosteal reaction involves
the fibula ••.
Melorheostosis Sickle Cell Anemia: MSK Complications

radiograph shows abnormal
endosteal sclerosis involving
the medial aspect of the tibia
_ The dense sclerotic bone
seems to "flow" down the
long bone in a manner that
has been described as
dripping candle wax. (Right)
cortical thickening. of the
distal femoral diaphysis and
metaphysis. Linear increased
densities parallel to the
endosteal cortex. are due
to diffuse osteonecrosis in
sickle cell disease.
Complications of Prostaglandins
shows a dense linear
periostealreaction. that
thickens the femoral cortex.
The underlying bone density
is abnormal for a young
adult, with mixed lucency
and sclerosis, typical of renal
osteodystrophy /neostosis.
shows dense, thick, new
bone formation involving this
infant's humerus. and
forearm bones Ell One
should also consider diffuse
osteomyelitis or nutritional
deficiency in an infant with
long-term hospitalization.
I
92
lONG BONE, DIFFUSE CORTICAL/ENDOSTEAL THICKENING
Engelmann-Camurati Disease
radiograph shows disordered r
cortical and endosteal bone, o
::J
resulting in a cortical <C
thickening which is restricted OJ

o
to the diaphyses _. Note ::J
CD
the normal epiphyses and
metaphyses ElIl (Right) s:
CD
Anteroposterior radiograph Qj
shows marked endosteal and ,
periosteal cortical thickening
o
OJ •
• This was bilaterally "0
~
symmetric and involved the '<
CJ>
entire length of the CD
OJ
diaphyses, leaving the
metaphyses and epiphyses
unaffected.
Intramedullary Osteosclerosis Intramedullary Osteosclerosis

shows typical changes of
diffuse sclerosis in the tibial
diaphysis _ This finding
was bilateral, which is a
consistent feature of this
process. In some cases the
distal tibial metaphysis may
also be involved. (Right)
Coronal T7WI MR in the
same patient confirms the
sclerotic process with diffuse
low signal within the
medullary canal. There is
some sparing of the central
most area of the medullary
cavity Ill.
Caffey Disease (Infantile Cortical

Hyperostosis) Ewing Sarcoma
shows marked new bone
formation thickening the
cortex of the tibia _.
Ossification began in the soft
tissues. (Right) Lateral
radiograph shows
nonspecific endosteal &
periosteal thickening _
Although rare, one should
consider a permeative
tumor, masked by intense
bone reaction. Possibilities
include Ewing sarcoma,
lymphoma, and
chondrosarcoma. MR would
differentiate stress fracture
from underlying malignancy.
I
93
<1l
<I) TIBIAL METADIAPHYSEAL CORTICALLY BASED LESION
VJ
>-
.r:
Cl.
.~
o,
<1l
Common • Fibrous Dysplasia (FD)
Qj
2 • Fibrous Dysplasia (FD) o May be either central or cortically based
<I)
• Osteosarcoma, Parosteal (Mimic) when involving tibial metadiaphysis
c
o
[lJ
• Tibia is the exception; in other bones, FD
Less Common is only central in location
Cl
c • Osteofibrous Dysplasia
o o Cortically based lesions are lytic &
-l
• Adamantinoma expansile, appearing moderately aggressive
-c
ell
l/l Rare but Important o May "wrap around", involving cortex
III
[lJ • Osteosarcoma, Periosteal (Mimic) circumferentially
>. • Osteosarcoma, Parosteal (Mimic)
E
-«
o
III
r::
o Surface osteoid-producing
involve marrow
lesion; may
o Early lesions may mimic a cortically based

• Classic differential diagnosis lesion, but matrix differentiates it
o Hint: Generally cannot reliably Helpful Clues for Less Common Diagnoses
differentiate cortically based FD, • Osteofibrous Dysplasia
osteofibrous dysplasia, & adamantinoma o Lytic cortically based lesion seen reliably
from one another most frequently in tibial meta diaphysis
• Imaging characteristics are usually o Generally proximal 1/3; anterior bowing
indistinguishable o Patients generally < 30 years old
• Must offer all 3 diagnoses as a differential • Adamantinoma
o Hint: Cortically based FD is uncommon o Lytic cortically based lesion, generally
form of FD, but is far more common than anterior tibia
either osteofibrous dysplasia or o Often appears non-aggressive initially but
adamantinoma may progress to a more destructive lesion
o Hint: Osteofibrous dysplasia rarely is seen • May become malignant
beyond 3rd decade
• The 2 surface lesions (mimics) on this list Helpful Clues for Rare Diagnoses
can usually be recognized as such • Osteosarcoma, Periosteal (Mimic)
o Rare surface lesion, produces osteoid
o Generally are identified as surface lesions
o May mimic cortically based lesion if
o Generally have identifiable matrix
underlying bone is significantly scalloped
Fibrous Dysplasia (FD) Fibrous Dysplasia (FD)
I based lesion of the tibia=.

Lateral radiograph shows an extensive lytic corUcally
The lesion is 50 large that it =.
Axial TZWI MR in the same paUent shows high signal
intensity within the lesion which is restricted to the
may be difficult to confirm that it is restricted to the cortex. Though FD usually is located within the marrow.
cortex. (tMSK Req). it occasionally arises in the cortex of the tibia.
94
TIBIAL METADIAPHYSEAl CORTICAllY BASED lESION ~
::l
..•o
III
3
'<
OJ
III
t/I
Osteosarcoma, Parosteal (Mimic) Osteofibrous Dysplasia ~
(Left) Axial bone CT shows a a.
surface lesion consisting of r
mature bone _ wilh less o
:J
mature tumor bone formed <0
peripherally Ell. This is lhe OJ
o
lypical appearance of :J
parostealosteosarcoma. This
~
lesion may involve the cortex ~
and extend into the marrow,
ct>
iii
lhus mimicking a corlically
based lesion. (tMSK Req).
6
iij"
(Right) Axial bone CT shows "0
::r
a lytic lesion arising in the '<
(f)
anterior cortex of the tibia ct>
•• in a 23 year old. The ~
appearance is nonspecific
bul proved la be
osteofibrous dysplasia.
Adamantinoma Adamantinoma
(Left) Laleral radiograph
shows a lytic lesion arising
from lhe corlex of lhe libial
meladiaphysis" The lesion
does not appear la involve
the underlying marrow and
does not appear highly
aggressive. (t MSK Req).
(Right) Axial T2WI FS MR in
lesion la arise from the
corlex •• bulla exlend into
lhe adjacenl sofllissue Ell.
There is no marrow
involvement. Adamantinoma
can be locally aggressive and
even malignant. (t MSK
Req).
Osteosarcoma, Periosteal (Mimic) Osteosarcoma, Periosteal (Mimic)

radiograph shows a
bone-forming tumor arising
from lhe surface of lhe libia
••. There is no suggestion of
a permeative bone lesion
involving the cortex or
marrow (Right) Axial bone
CT in the same patient
shows the lesion to be arising
from lhe surface of lhe bone
_ There is no involvement
of the marrow or cortex.
Therefore it is a surface
lesion, though it mimics a
corlically based lesion.
I
95
l1l
Q)
LONG BONE, UNDERTUBULATION
rJl
>.
J:::
0..
l1l
DIFFERENTIAL DIAGNOSIS • Widens bone, while thinning endosteum
o, • May not have geographic border
Q)
l1l
Common o Polyostotic lesions could be misinterpreted
::2; • Multiple Hereditary Exostoses (MHE) as undertubulation; ground-glass density
Q)
c • Fibrous Dysplasia (FD) • Unicameral Bone Cyst (Mimic)
o • Unicameral Bone Cyst (Mimic)
CD o Metaphyseal or metadiaphyseal
OJ
c • Paget Disease (Mimic) o Central, with osseous expansion, thinning
o • Storage Diseases
....J the endosteal cortex
"0 o Gaucher Disease o Solitary lesion; watch for mildly sclerotic
CIl
rJl o Niemann Pick geographic margin; ± fallen fragment
III
aI o Mucopolysaccharidoses • Paget Disease (Mimic)
>.
E • Thalassemia o Expands the involved bone
-<
o
III
l::
o Generally easily distinguished by means of
the distinct border between normal &
Less Common abnormal bone ("blade of grass")
• Achondroplasia • Involvement of entire bone may mimic
• Ollier Disease undertubulation; mixed lytic/sclerotic
• Rickets (Healing) • Gaucher Disease
• Osteogenesis Imperfecta (01) o Storage disease resulting in expansion of
• Osteopetrosis metadiaphyses, especially of distal femora

• Engelmann-Camurati Disease • "Erlenmeyer flask" sign
o Hepatosplenomegaly, osteonecrosis
Rare but Important
• Niemann Pick
• Maffucci Syndrome o Lipid storage disorder
• Pycnodysostosis o Accumulates in bone marrow, leading to
• Hypophosphatasia undertubulation
• Scurvy (Healing) o Accumulates in lungs (Kerley B lines), liver
• Caffey Disease & spleen (hepatosplenomegaly), & brain
• Pyle Dysplasia (learning problems)
• Mucopolysaccharidoses
ESSENTIAL INFORMATION o Family of storage disorders with similar
morphologic abnormalities of the skeleton
Key Differential Diagnosis Issues o Long bones may be short & broad,
• Undertubulation: Widening of long bone particularly metacarpals
• Distinguish between solitary & polyostotic • Constricted proximal ends of
o Solitary: FD, unicameral bone cyst, Paget metacarpals gives a "fan-like" appearance
disease, chronic osteomyelitis • Thalassemia
o Polyostotic but generally monomelic: o Severe anemia - marrow hyperplasia
Oilier disease, Maffucci syndrome o Long bones lose all distinguishing
o Remainder are polyostotic & symmetric morphology ("squared")
Helpful Clues for Common Diagnoses o Severe osteoporosis
• Multiple Hereditary Exostoses (MHE) • Sickle Cell Anemia
o Most exostoses in MHE are elongated & o Osteonecrosis, bone infarcts are
sessile, along metaphyses predominant features
• Mimics actual metaphyseal widening o Rarely results in significant marrow
o ± Cauliflower-like exostoses hyperplasia
o Easily misinterpreted as a metaphyseal o May see mild widening of the
dysplasia or storage disorder! metadiaphyses, with patchy bone sclerosis
• Fibrous Dysplasia (FD) indicating widespread infarcts
o Lesion is usually central, metadiaphyseal, • Chronic Osteomyelitis
or diaphyseal
I
96
lONG BONE, UNDERTUBUlATlON :t>
.•
:J
III
o
o Chronic disease may show little • Osteopetrosis 3
'<
destructive change (permeative o Uniformly dense bones, axial, & lJl
III
destruction, periosteal reaction) appendicular skeleton VI
C1l
o Sclerosis & endosteal bone formation may o Abnormality is in osteoclastic activity; Co
predominate, resulting in widening of the with skeletal growth, ! remodeling r

o
:J
bone around the focus of infection • - Undertubulation of metadiaphyses <0
o May not have associated soft tissue abscess • - Bone-in-bone appearance lJl
o
:J
Helpful Clues for less Common Diagnoses • Engelmann-Camurati Disease C1l
o Dense sclerosis & bone accretion, 5':

• Achondroplasia C1l
endosteum and cortical bone
o Dysplastic metaphyses may reduce
o Only diaphyses affected; abrupt change to
¥
tubulation 9OJ
o Short bones make normal width of
normal-appearing metaphyses "0
::r
o Bilaterally symmetric '<
diaphyses appear undertubulated VI
C1l
OJ
• Ollier Disease Helpful Clues for Rare Diagnoses
o Dysplasia that affects metadiaphyses • Maffucci Syndrome
• Widening & abnormal growth o Ollier disease + soft tissue hemangiomas
metaphyses • Pycnodysostosis
• Vertical striations, ± chondroid matrix o Osteopetrosis + acroosteolysis
o Usually unilateral, - limb length • Hypophosphatasia
discrepancy o Osteopenic, bowed bones; similar
• Rickets (Healing) appearance to rickets
o Widened, frayed metaphyses may heal • Scurvy (Healing)
with a widened morphology o Collagen abnormality - periosteal
o Watch for abnormal bone density, elevation from metaphyseal corner fx
hyperossified brown tumors, neostosis o - Dense, thick periosteal healing bone
• Osteogenesis Imperfecta (01) mimics undertubulation
o 01 congenita: Multiple intrauterine fx - • Caffey Disease
short, broad, bowed long bones o Dense periosteal reaction -
o 01 tarda: Severe form results in undertubulation
overtubulation; less severe forms show o Self-limited; returns to normal by 2 years
fewer fractures, but undertubulation at the • Pyle Dysplasia
metadiaphyses o a.k.a., craniometaphyseal dysplasia; failure
o Severity of osteoporosis varies of modeling of long bones
Multiple Hereditary Exostoses (MHE) Multiple Hereditary Exostoses (MHE)
AP radiograph shows apparent widening of the

meladiaphyses of the femora & tibiae _ While this is
Anteroposterior radiograph shows widening & loss of
normal modeling of the femoral melaphyses _ Note
I
suggestive or a storage disease, it in fact represents also the widening of the pubic rami. These all represent
muluple sessile osteochondromas in MI-IE. sessile osteochondromas in a patient with MHE.
97
ro
Q)
lONG BONE, UNDERTUBUlATlON
11l
>-
~
C-
ro
(5,
ro
Q)
~ (Left) AP radiograph shows
Q) widening of the proximal
c
o meta diaphysis III with
CO normal distal metadiaphysis
Ol
C Ell of the tibia. The fibula
o shows similar features. The
--l
cortices are thinned, & there
"0
Ql is ground·glas5 matrix in the
CIl affected areas, typical of FD.
III
en (Right) AP radiograph shows
>- widening of the proximal
E metaphysis with thinning of
•..
o
III
the cortices" in a child
C with a solitary lesion. There
< is a fallen fragment sign ••
typical of a unicameral bone
cyst.

widening of the proximal
metadiaphysis •• with
abrupt change to normal
appearance distally Ell. The
cortices are thick, and there
is a mixed lytic/sclerotic
pattern, typical of Paget
disease. (Right) AP
radiograph shows apparent
undertubulation, with
widening of the femur along
its entire length III. A
norma/tibia is seen at the
edge of the image. Mixed
lytic & sclerotic change is
typical of Paget disease.
radiograph shows gradual
widening of the distal
meta diaphysis, without
thinning of cortex or osseous
destruction" This flaring
gives the appearance of an
"Erlenmeyer flask" and is
typical of Gaucher disease.
(Right) Posteroanterior
radiograph shows widening
of the metacarpals, with
proximal constriction giving
the fan appearance" that
is typical of the
mucopolysaccharidoses
storage diseases.
I
98
LONG BONE, UNDERTUBULATION
Thalassemia Thalassemia
diffuse abnormal modeling of
the bones, with widening of
the diaphyses and loss of the
expected metaphyseal
morphology. Cortices are
thin, & trabeculae are
abnormal. This is typical
marrow hyperplasia in
thalassemia. (Right) AP
of the metaphyses ••
extending to include"much of
the diaphysis. This widening
results from marrow
hyperplasia in a patient with
thalassemia.
Sickle Cell Anemia Chronic Osteomyelitis

shows patchy sclerosis
throughout the tibia,
representing extensive bone
infarction in a patient with
sickle cell disease. There is
minimal widening of the
proximal tibial metaphysis,
likely related to marrow
hyperplasia. This is less
extensive in sickle cell
disease than thalassemia.
widening of the metaphysis
•• with sclerosis
surrounding a lytic lesion.
This is typical chronic
osteomyelitis in a child.
Chronic Osteomyelitis
widening of the diaphysis of
the fibula" (compare with
adjacent tibia), with
extensive sclerosis and
cortical thickening. This
teenager had leg pain for I
year; this proved to be
chronic staphylococcal
osteomyelitis. (Right)
shows short, broad bones in
this case of achondroplastic
dwarfism. Undertubulation is
a prominent Feature in this
process.
I
99
ro LONG BONE, UNDERTUBULATION
Q)
(/)
>-
.<:
0-
ro
(5
cO
Ql Oilier Disease Rickets (Healing)
~ (Left) AP radiograph shows
Q) broadening of the
c
o metaphysis, with vertical
CD striations within it" All the
Cl
C metaphyses of the right
o lower limb showed similar
-1
undertubulation and the limb
"0
Q) was short; findings are
(/)
III
typical of Oilier disease.
CD (Right) AP radiograph shows
>- bowing & undertubulation of
E the distal femoral
-
o
ro
c
ct
metaphp-ses III in a case of
healing rickets, where the
widened and frayed
metaphyses are becoming
ossified. Remodeling may
occur with further treatment.
Osteogenesis Imperfecta (01)

radiograph shows bowing &
undertubulation of the femur
in a case of 01 tarda _
along with pathologic
Fracture. While more severe
cases of 01 tarda show
overtubulation, less severe
cases show fewer fractures
and metadiaphyseal
widening. (Right) AP
radiograph shows severe
shortening, osteoporosis, &
undertubulation • in the
long bones of a patient with
01 congenita, resulting from
multiple intrauterine
Fractures.
Osteopetrosis Engelmann-Camurati Disease

dense (marble) bones and
severe undertubu/alion of
the meta diaphyses _
Osteopetrosis results from
osteoclastic abnormality;
with skeletal growth,
remodeling cannot occur
normally. (Right) AP
radiograph shows diffuse
widening {undertubulation}
of the diaphyses of both
tibiae & fibulae. There is
increased density. Note that
the metaphyses are normal.
This is an early manifestation
of Engelmann-Camurati
disease.
I
100
lONG BONE, UNDERTUBUlATlON :l>
:l
..•o
III
3
'<
llJ
III
III
Engelmann-Camurati Disease Maffucci Syndrome CD
(Left) AP radiograph shows 0-
severe underwbulation of r
the diaphysis. along with o
:l
(Q
cortical and endosteal
thickening. The metaphysis is OJ
o
normal. and the findings :l
CD
were bilateral, all typical of
Engelmann-Camurati s:
co
disease. (Right) AP Qi,
radiograph shows
undertubulation of the
o
iii'
meta diaphysis, with '0
::T
chondroid matrix within the '<
en
lesion EH There were co
III
hemangiomas elsewhere in
this patienes 50ft tissues,
making the diagnosis of
Maffucci syndrome.

undertubulation of the long
bones, along with diffuse
increased density. This
either osteopetrosis or
pycnodysostosis; the patient
also had acroosteolysis,
making the latter the
diagnosis. (Right) AP
osteoporosis, bowing, &
undertubulation • of the
upper extremity. There is
also widening of the physis
• typical of
hypophosphatasia.

metaphyseal fracture. and
severely elevated periosteum
• along with osteoporosis
& the dense lines typical of
scurvy. As the injury heals,
the elevated perios"teum will
form bone, resulting in
undertubulation. (Right)
thick, dense periosteal
reaction involving all the
long bones. This infant also
had clavicle and mandibular
involvement, helping to
confirm the diagnosis of
Caffey disease,
I
101
co LONG BONE, OVERTUBULATION
Q)
(J)
>-
.s:::
a.
.~ DIFFERENTIAL DIAGNOSIS o Muscular atrophy ...•insufficient muscle
o, pull to promote normal growth of bones
co Common
Qi o Usually unilateral; limb length discrepancy
2 • Paralysis/Disuse • Cerebral Palsy
Q)
o Polio
c::
o o Spasticity with disuse atrophy of muscles ...•
co o Cerebral Palsy
insufficient muscle pull to promote
Ol
c:: • Neurofibromatosis normal growth of long bones
o
-' • Juvenile Idiopathic Arthritis OIA) o Patella alta common, with C-shaped
"Ql
(J)
Less Common patella
• Neurofibromatosis
m
ltl • Hemophilia
>- • Marfan Syndrome (Phalanges) o Long bone abnormality generally restricted
-
E
o
ltl
c::
«
• Muscular Disorders
o Arthrogryposis
o Muscular Dystrophy
to tibia/fibula
o Dysplasia of tibia, rather than
neurofibromas causing the abnormality
• Osteogenesis lmperfecta (01) o Bone may be bowed in any direction
o Often thin diaphysis; dysplastic bone at
Rare but Important
risk for pathologic (transverse) fractures
• Homocystinuria (Phalanges)
o May result in pseudarthrosis of either tibia
• Achondroplasia (Mimic)
or fibula at mid-diaphysis
• Hypophosphatasia
o Multiple fibroxanthomas (non ossifying
• Radiation
fibromas) may be present, especially
• Caudal Regression Syndrome around knee
• Epidermolysis Bullosa
• Juvenile Idiopathic Arthritis OIA)
• Progeria o Systemic variety of JIA results in prolonged
• Polymyositis/Dermatomyositis chronic illness
• Restrictive Dermopathy
o Chronic illness & muscle atrophy slows
• Hypopituitarism
growth of long bones
• Stickler Syndrome o Ends of long bones (metaphyses &
epiphyses) show overgrowth (ballooning)
ESSENTIAL INFORMATION due to chronic hyperemia at involved
joints
• Overgrowth of ends of bones emphasizes
• Abnormality in long bone modeling, gracile nature of diaphyses, giving overall
resulting in a relatively narrow diaphysis
impression of overtubulation
o Concentric narrowing of the shaft
o Typically related to chronic disease that Helpful Clues for Less Common Diagnoses
affects a growing skeleton • Hemophilia
• Most of listed processes involve all bones o Chronic illness delays growth, resulting in
• Those diseases that may have single or gracile (thin) long bones
non symmetric involvement (site may be o Ends of long bones (metaphyses &
predictable) epiphyses) show overgrowth (ballooning)
o Polio due to chronic hyperemia at involved
o Neurofibromatosis joints
o Hemophilia • Overgrowth of ends of bones emphasizes
o Arthrogryposis gracile nature of diaphyses, giving overall
o Muscular dystrophy impression of overtubulation
o Caudal regression syndrome o Knee, elbow, ankle most frequently
o Radiation involved with arthropathy
o Epidermolysis bullosa • Overtubulation therefore seen most
frequently in femur, tibia, & humerus
o Gender specific (male)
• Polio
I
102
LONG BONE, OVERTUBULATION »
::l
..•o
III
o Watch for dense effusions (deposition of • Achondroplasia (Mimic) 3

'<
hemosiderin from chronic joint bleeding) o Broadened, dysplastic metaphyses may OJ
III
& destructive arthropathy make diaphyses appear relatively thin VI
CD
• Marfan Syndrome (Phalanges) • Bones are not truly gracile but are short a.
o Arachnodactyly emphasizes the thin & of normal breadth r
o
:::J
diaphyses of hands & feet • Hypophosphatasia to
o Tarda form results in thin, fragile llJ

o Associated dural ectasia & posterior o
:::J
vertebral body scalloping diaphyses of long bones CD
• Arthrogryposis • Multiple fractures result in bowing s:

CD
o Congenital persistent contracture of o Growth abnormalities at physis resembling Ei
multiple joints those of rickets 6
OJ
• - Muscle atrophy, disuse - delayed • Wide zone of provisional calcification "0
:T
growth & gracile long bones • Fraying of metaphyses '<
VI
CD
o Lower extremity may predominate • Radiation ~
o Often associated congenital hip dislocation o Overtubulation extremely rare
& congenital foot deformities (club foot, • Requires a radiation field encompassing
congenital vertical talus) majority of diaphysis to cease growth
• Muscular Dystrophy across width of a tubular bone
o Muscle atrophy - disuse - delayed growth • Whole-bone radiation, such as for Ewing
& gracile long bones if occurs at young age sarcoma or lymphoma
• Osteogenesis Imperfecta (01) o Widening, fraying epiphysis/metaphysis
o Tarda form of 01 develops excessively thin with early fusion & subsequent shortening
long bones of bone is more common
o Severe osteoporosis • Caudal Regression Syndrome
o Bones are fragile, develop multiple o Variable degree of absence of sacrum,
fractures lumbar spine, & femoral heads
• Bowing may be severe o Muscle atrophy; nonambulatory - gracile
• Fracture callus may be prominent lower extremities
o Often infant of diabetic mother
• Homocystinuria (Phalanges)
o Contractures, muscle atrophy -
o Arachnodactyly emphasizes the thin
overtubulation
diaphyses of hands & feet
o Esophageal strictures, digital webbing
o Severe osteoporosis
Polio Cerebral Palsy
AnterofXJSler;Or radiograph shows asymmetry of the

& femora, with a gracife, undertubu/ated
tissues, pelvis,
soft Lateral radiograph shows a gracile femoral diaphysis=
alDng with a C-shapeelpatella HI. Note the patella alra.
I
femur III and hypoplastic iliac wing. on the right, The combinaUon is typical Df cerebral palsy, in which
compared with a normal left side. overtubulaUon of the long bones is common.
103
lONG BONEr OVERTUBUlATlON
Neurofibromatosis Juvenile Idiopathic Arthritis (JIA)

Q) radiograph shows severe
c
o bowing and overlubulalion
III of a dysplastic tibia" in a
Ol
c patient with
o
..J
neurofibromatosis. Note the
pseudarthrosis of the fibula
"0
Q) Eill not corrected with
VI surgery. (Right)
'"
III Anteroposterior radiograph
>. shows erosive change with
E
-'"
o
c
<
protrusio of the right hip •••
along with a severely gracile
right femur". The left side
is less significantly involved
in this chronically ill patient
with /lA. Note the
hypoplastic iliac wings.
Marfan Syndrome (Phalanges)

shows an extremely thin
femoral diaphysis'" along
with an overgrown epiphysis
1IIll. Along with the
destructive joint changes and
dense effusion, the findings
are typical of hemophilia.
Chronic illness contributes to
the overtubulation of the
long bones, which is
exaggerated by the distal
ballooning. (t MSK Req).
radiograph shows long, thin
diaphyses of the metacarpals
and phalanges in this patient
with Marfan syndrome.
(Left) Frontal radiograph

shows the extremely thin,
overtubulated forearm bones
•• in a patient with
arthrogryposis. Note the
apparent "webbing" at the
contracted elbow ••• as well
as lack of musculature.
radiograph shows severely
thinned and bowed forearm
bones, with a similar
appearance of the humerus.
There are pathologic
fractures" along with
bowing in this patient with
01 tarda.
I
104
lONG BONE, OVERTUBUlATION
Osteogenesis Imperfecta (01)

radiograph shows prolrus;o r
ffi along with severe o
::>
osteoporosis. The femora are <0
overtubulated Ell; bowing CD
o
deformities have been ::>
CD
treated with osteotomy and
intramedullary rodding s::
CD
6i,
radiograph shows thin
diaphyses of the metacarpals
o
ai'
and phalanges in this patient "0
~
with arachnodactyly and '<
(/)
osteopenia. The combination CD
Q)
is seen in homocystinuria.
Hypophosphatasia
radiograph shows short
bones of the limbs. The
metaphyses are broad and
(fat, giving the impression of
overtubulation. However,
the diaphyses are not truly
thinned in this patient with
achondroplasia. (Right)
shows thinning, bowing, and
deformity of the femora _
There is severe osteopenia,
which has worsened with
lime. Protrus;o and widened,
irregular phys€s contribute to
the diagnosis of
hypophosphatasia.
Radiation
radiograph shows a short
humerus, with thinning of
the distal diaphysis.
(compare size with the
normal thorax). This patient
had whole bone radiation as
a child for Ewing sarcoma,
resulting in growth
abnormalities. Radiation
sarcoma is also seen ••.
radiograph shows absence of
lumbar spine. and
hypoplastic iliac wings with
absent sacrum _ typical of
caudal regression. Note the
thin, ill-formed femora Ell.
I
105
OJ
GROWTH PLATE,PREMATUREPHYSEAl ClOSURE
~
CL
£
~ DIFFERENTIAL DIAGNOSIS o Hyperemia from chronic infection may

o
~
C) result in early fusion of entire physis
Common • Septic Joint
OJ
c
o • Fracture o Early fusion: Chronic hyperemia or direct
III
OJ less Common extension to physis if intracapsular (hip)
c
o • Osteomyelitis • Iatrogenic (Surgical)
-.J
• Septic Joint o Epiphysiodesis performed for angular
"t:l
ell
l/) • Iatrogenic (Surgical) deformity or short contralateral limb
<II
CO • Juvenile Idiopathic Arthritis OIA) • Juvenile Idiopathic Arthritis OIA)
>. • Oilier/Maffucci Syndrome (Mimic) o Chronic hyperemia at involved joints has
E
-
o
<II
C
<l:
• Radiation-Induced Growth Deformities
• Thermal Injury
2 growth-related consequences
• Epiphyseal/metaphyseal overgrowth
• Early fusion of physis ...•short limb
Rare but Important
o Knee> elbow> ankle, not symmetric
• Complicati.ons of Vitamin A
• Ollier/Maffucci Syndrome (Mimic)
• Hemophilia: MSK Complications o Short, broad, abnormally tubulated
• Meningococcemia metaphyses; often chondroid matrix
ESSENTIAL INFORMATION o Vasculitis from radiation puts physis at risk
o Nonviable physis ...•fusion & hypoplasia
Key Differential Diagnosis Issues o Watch for port-like distribution
• # & distributionof physes may be diagnostic • Thermal Injury
Helpful Clues for Common Diagnoses o Vessels supplying physes at risk,
• Fracture particularly in hands or feet
o Hyperemia in metadiaphyseaI fracture may •...• Short, stubby fingers in adults
result in early fusion of physis o Burn: Contractu res & calcification
o Salter injury (usually III, IV, or V) may o Frostbite: Abnormality spares the thumb
result in focal early bony bridging Helpful Clues for Rare Diagnoses
Helpful Clues for less Common Diagnoses • Complications of Vitamin A
• Osteomyelitis o Focal bony bridging across physis
o Usually located in metaphysis in child o Diffuse periostitis, coned epiphyses
• Occasionally, process will cross physis to • Hemophilia: MSK Complications
involve epiphysis ...•early fusion o Same as JIA, with dense effusions
Fracture Osteomyelitis
I Sagittal bone CT shows premature bony bridge (physeal

bar) lormed at site 01 physeal Iracture _ This partial
Coronal T2WI MR shows a melaphyseal locus 01
osteomyeliUs crossing the physis III and involving the
early fusion will result in relalive overgrowth anteriorly & epiphysis in an 8 yo. This involvemenl of the physis may
posteriorly, delorming the distal tibia. resull in early local bridging 01 the physis. (tMSK Req).
106
GROWTH PLATE, PREMATURE PHYSEAl ClOSURE ~
::l
,..,.
III
o
3
'<
OJ
III
Iatrogenic (Surgical) Juvenile Idiopathic Arthritis (J IA) 'Co"
to
radiograph shows typical r
Blount disease. involving a
:J
the medial tibia. Since this <C
results in tibia vara, III

a
prophylactic epiphysiodesis :J
is performed laterally E!Il
to
now showing closure of this G)
~
portion of the physis. (Right) a
Anteroposterior radiograph ~
::r
shows early physeal closure
\J
in this 76 year old with JIA. iil
This joint shows severe <ii
involvement, with
overgrowth of the epiphyses,
joint destruction, and
widening of the
intercondylar notch.
Oilier/Maffucci Syndrome (Mimic)

shows short ulna in a patient
with Oilier disease III
mimicking early physeal
closure. Short bone results
from metaphyseal dysplasia
rather than true early fusion.
hypoplastic left iliac wing.
in 20 year old who had
radiation therapy to left
hemipelvis as a child.
Vascular damage results in
early fusion of epiphyses &
apophyses, with cessation of
growth. Exostosis. is also a
complication of radiation.
Thermal Injury Meningococcemia

(Left) Posteroanterior
radiograph shows premature
closure of the physes of the
distal phalanges of digits 2-5
_ resulting in short, stubby
digits. This is due to vascular
damage from frostbite. Note
the normal physis and distal
phalanx of the thumb E!Il
typical of frostbite. (Right)
shows early bony bridging of
a portion of the physis of the
left hip. in a patient with
meningococcemia. Short
Umbs are often a
consequence of this process.
I
107
GROWTH PLATE, WIDENED PHYSIS
DIFFERENTIAL DIAGNOSIS a Salter IV: Fracture through epiphysis,

physis, & metaphysis; generally does not
Common result in physeal widening
(!)
c
o
• Physeal Fracture a Salter V: Crush fracture of physis; does not
en • Chronic Repetitive Trauma result in widening
Ol
c
o
• Slipped Capital Femoral Epiphysis (SCFE) • Chronic Repetitive Trauma
-.J • Renal Osteodystrophy (Renal 00) a In child, repeated microtrauma to a physis
"tl
Ql • Rickets results in resorption & appearance of
III
ltl
en Less Common widening
>. • Osteomyelitis a Analogous to Salter I injury
E
-
o
ltl
C
«
• Blount Disease
a Associated with competitive athletes
• Distal radius/ulna: Gymnasts
• Distal tibia/fibula: Runners
• Total Parenteral Nutrition
• Gigantism • Proximal humerus: Baseball pitchers
• Mucopolysaccharidoses • Slipped Capital Femoral Epiphysis (SCFE)
• Osteogenesis Imperfecta (01) a Slip direction generally posterior and
• Hypophosphatasia medial
a Results in appearance of widened physis &
Rare but Important
"short" capital epiphysis
• Hypothyroidism a Bilateral in 20-25%, but need not be
• Scurvy synchronous
• Copper Deficiency (Menkes Kinky-Hair a Optimal age range: 8-14
Syndrome) • Renal Osteodystrophy (Renal 00)
• Metaphyseal Dysplasias a Combined findings of rickets &
hyperparathyroidism (HPTH)
ESSENTIAL INFORMATION a Rickets results in widening of physis
.a Watch for HPTH as well
Key Differential Diagnosis Issues • Subperiosteal resorption
• Involvement of all physes rather than a • Subchondral resorption with collapse
single or few sites seen in several processes (particularly sacroiliac joints)
a Rickets & renal 00
• Rickets
a Total parenteral nutrition
a Similar appearance, whether renal or
a Gigantism
nutritional etiology
a Mucopolysaccharidoses
a Results from lack of mineralization of
a Osteogenesis imperfecta osteoid laid down at metaphyseal zone of
a Hypophosphatasia
provisional calcification
a Hypothyroidism
a Widened physis, often with fraying of
a Copper deficiency
metaphyses
a Metaphyseal dysplasias a Decreased bone density, smudgy
Helpful Clues for Common Diagnoses trabeculae
• Physeal Fracture Helpful Clues for Less Common Diagnoses
a Salter I: Fracture through physis; difficult
• Osteomyelitis
to visualize unless displaced a If metaphyseal osteomyelitis crosses
a Salter II: Fracture through physis,
physis, may result in slip of physis &
extending through metaphysis appearance of widening
• Metaphyseal portion may be subtle; a Watch for osseous destruction, periosteal
easier to visualize if displaced reaction
a Salter Ill: Fracture through physis, • Legg-Calve-Perthes (LCP)
extending through epiphysis a Osteonecrosis of femoral capital epiphysis
a Increased density, flattening,
fragmentation of epiphysis
I
108
GROWTH PLATE, WIDENED PHYSIS :t>
:J
...•
III
o
o Associated appearance of widened physis o Diffuse widening of physes 3
'<
o Optimal age range: 4-8 o Osteopenia OJ
III
• Blount Disease o Ranges from mild tarda form to severe IJl
(1)
o Fragmentation & abnormal ossification of destructive form Co
medial tibial metaphysis o Bowing of long bones with excrescences r

o
:J
o Focal "widening" of physis medially may help differentiate from rickets CO
May have "button sequestra" in skull CD

o Usually bilateral; results in tibia vara o o
:J
• Total Parenteral Nutrition Helpful Clues for Rare Diagnoses (1)
o Premature infant dependent on total

• Hypothyroidism
parenteral nutrition for a long period of o Severe retardation of skeletal maturation
time o Widened physes, short broad phalanges
o Diffuse widening of physes, thought to be
o Hip may show fragmentation of femoral
due to nutritional deficiency of copper capital epiphysis
o Indistinguishable from rickets, though true
• Appearance may be similar to
rickets does not appear prior to 6 months Legg-Calve-Perthes; watch for abnormal
of age bone age to differentiate
• Gigantism o Infant shows stippled epiphyses
o With overgrowth of gigantism, physes may
• Scurvy
appear mildly widened diffusely o Osteopenia, with sclerotic metaphyseal
• Mucopolysaccharidoses line (white line of Frankel) and sclerotic
o Delay in epiphyseal ossification may give
rim of epiphysis (Wimberger sign)
the appearance of a relatively widened o Corner metaphyseal fracture may cause a
physis slip & mild physeal widening
o Other manifestations: Fan-shaped carpus,
• Wide periosteal "reaction" due to
oar-shaped ribs, narrow inferior ilium with
subperiosteal hemorrhage
steep acetabular roof
• Copper Deficiency (Menkes Kinky-Hair
• Osteogenesis Imperfecta (01) Syndrome)
o 01 tarda may show physeal widening and
o Rare disorder resulting in physeal
mild slip of epiphyses
widening
o Other manifestations: Osteoporosis &
o Myeloneuropathy
more fractures than normally expected in
• Metaphyseal Dysplasias
a child
o Metaphyses flared & irregular with
• Hypophosphatasia apparent physeal widening
o Nearly indistinguishable from rickets
Physeal Fracture Chronic Repetitive Trauma
Frog lateral radiograph shows widening of the physis ••

due to a Salter /I fracture. The fracture line extends on
Anteroposterior radiograph shows osteolysis at the distal
radial epiphyseal plate EB a type of Salter I injury
I
through the meCilphysisIII Salter /I fractures are rarely occurring in gymnasts due to chronic repetitive trauma.
subtle; Salter I is more difficull to recognize. Note the similar abnormality involving the ulna.
109
<l> GROWTH PLATE, WIDENED PHYSIS
ro
Cl:
.r::
~
o
~
<.?
<l> Renal Osteodystrophy (Renal 00)
c (Left) Froglateral radiograph
o
!D shows a left SCFE (compare
Ol with normal right side). With
c
o the posteromedial slip of the
-l
head" the physis appears
'0 to widen III. (Right) AP
C1l
'"
nl
!D renal 00, manifest in the
» hips as rickets, with
E widening of the zone of
•...o
nl
provisional calcification •
and slip of the capital
C
ct epiphyses =.
There is also
typical hyperparathyroidism,
with widened sacroiliac
joints EiII due to subchondral
resorption and collapse on
the iliac side.
Rickets Osteomyelitis
radiograph shows a widened
physis •• at both the tibia
and femur due to nutritional
rickets. The abnormality is
secondary to the formation
of osteoid which is not
mineralized,' the appearance
is identical in rickets due to
renal 00. (Right)
shows metaphyseal
destruction EiII and
periosteal reaction secondary
to osteomyelitis. Infection
has crossed the physis,
resulting in widening III and
slip of the epiphysis Ia.
legg-Calve-Perthes (lCP) Blount Disease

dense, flattened femoral
capital epiphysis III in a
young child; this is LCPor
osteonecrosis. The
abnormality may result in
widening and fraying of the
metaphysis, as in this case
EiII. (Right) Anteroposterior
radiograph shows beaking &
underdevelopment of the
medial metaphysis of the left
tibia. This results in an
appearance of physeal
widening III The patient
has undergone
epiphysiodesis laterally to
address the growth inequity.
I
110
GROWTH PLATE, WIDENED PHYSIS >
-
:J
III
o
3
'<
III
III
Mucopolysaccharidoses III
(1)
(Left) Lateral radiograph C-
shows widening of the physis o
and fraying of the o
:J
metaphyses III in a case of <C
neonatal rickets; the patient OJ

o
was a 26 week premature :J
C1l
infant, now 3 months old.
Infants nourished for long Gl
..,
periods with total parenteral o
nutrition may develop the
:;:
:T
appearance of rickets. -U
(Right) AP radiograph shows Q)
typical skeletal findings of CD
dysostosis multiplex, with
inferior tapering of iHa, steep
acetabular roofs, & coxa
valga. The physes may
appear widened =.
radiograph shows osteopenia
and multiple healed fractures
typical of 01 tarda. The
physes are mildly widened
and slipped m. (Right)
widening of the physis =
that is reminiscent of rickets.
This is a mild case of
hypophosphatasia. In severe
cases, the bone density is
significantly reduced and the
phys€s show more significant
widening, with fraying of the
metaphyses.
Hypothyroidism Scurvy
widening of the physes
severe growth retardation in
=&
this 4 year old with

hypothyroidism. There is also
fragmentation of the right
femoral capital epiphysis lilt
which has been termed the
"cretinoid" hip. (Right) AP
findings of scurvy, with a
metaphyseal corner 11I:I
fracture. With such a
fracture, the physis may be
displaced & appear widened.
Note the wide periosteal
reaction =- related to
subperiosteal hemorrhage.
I
111
E
:J
PERIOSTEUM: AGGRESSIVE PERIOSTITIS
Q)
~
en
o
·C
Q) DIFFERENTIAL DIAGNOSIS o a.k.a., amorphous or complex
a.. o Irregular collection of reactive bone
'tl Common o Complex pattern can be due to rapid
<1l
en
III
• Osteosarcoma, Conventional tumor growth, infection, or fracture
!Xl • Ewing Sarcoma
>-
• Codman triangle
E • Malignant Fibrous Histiocytoma o Focal triangular elevation of calcified
•..o
III
• Metastasis periosteum at site of bone insertion
c: • Fracture Healing Process o Classically associated with malignancy, but
<
Less Common also seen with infection and trauma
• Osteomyelitis • Thin periosteal reaction, < 1 mm, is
• Leukemia equivocal for an aggressive process
• Osteosarcoma, Periosteal (Mimic) o May progress to either interrupted or solid
• Lymphoma periosteal reaction
Rare but Important Helpful Clues for Common Diagnoses
• Fibrosarcoma • Osteosarcoma, Conventional
• Angiosarcoma, Osseous o Location: Femur, tibia, humerus most
common
o Periosteal reactions: "Sunburst", "hair on
ESSENTIAL INFORMATION end", lamellated, solid thin, disorganized
Key Differential Diagnosis Issues o Codman triangle common
• Periosteal reaction or periostitis is the o Osteoid matrix visible in 80%
reaction of cortical bone to an insult o Wide zone of transition

• Differential diagnosis is aided by the pattern o Cortical breakthrough & soft tissue mass
& location of periosteal reaction, although • Ewing Sarcoma
the presence is nonspecific o Location: Tubular bones predominate if <
• Periosteal reaction is visible on radiographs 20 years old; flat bones if > 20 years old
10 days to 3 weeks post insult o Periosteal reactions: Lamellated, "hair on
o Periosteum is more active in childhood & end", solid thin

thus more likely to show osteoblastic o Codman triangle common
activity than in adults o Tumor permeates through cortex
• Aggressive periosteal reaction is also termed o Large soft tissue mass is common
"interrupted" o Lacks metaphyseal lucent lines
o Indicates a rapidly progressing process, • Malignant Fibrous Histiocytoma
benign or malignant o Location: Long bone metaphysis, pelvis
o Is in contrast to solid (more o Periosteal reactions: Thin or disorganized;
benign-appearing) periosteal reaction lamellated with pathologic fracture

• Main interrupted periosteal reaction patterns o Codman triangle uncommon
o Lamellated o Ill-defined, permeative lesion
o Spiculated o May arise secondarily in abnormal bone
o Disorganized • Metastasis
o Location: Multifocal
• Lamellated
o a.k.a., "onion skin" o Periosteal reactions: Thin, disorganized
o Multiple parallel layers o Lamellated & perpendicular periosteal
o Seen most commonly with hyperemic reactions are less common

entities • Sunburst-type periosteal reaction with
• Spiculated metastatic neuroblastoma
o a.k.a., "sunburst", "hair on end", "velvet" o Osteoblastic, osteolytic or mixed density
o Linear spicules of new bone radiate from underlying lesions

the bone cortex • Axial & proximal appendicular skeleton
• Divergent, perpendicular or sloping most common
• Disorganized
I
112
}>
..
::l
III
o
o Metastases 25x more common than • Also seen in metastatic neuroblastoma & 3
'<
primary bone malignancy rhabdomyosarcoma lJl
III
• Fracture Healing Process o Radiographs can be normal
o Location: Region of trauma • Osteosarcoma, Periosteal (Mimic)
'"
lD
C.
o Periosteal reactions: Thin, disorganized o Location: Surface of bone diaphysis \J

Ctl
~
o If soft tissue mass present, follow to o Periosteal reactions: Not periostitis o·
confirm resolving hematoma • Ossified tumor matrix produces similar '"CDc:
• Tumor will not resolve appearance to periosteal reaction 3
o Transverse long bone fracture without o Rare subtype, 1%, of osteosarcoma
significant trauma should increase o Underlying medullary canal uninvolved
vigilance for underlying pathologic lesion • Lymphoma
o Location: Long or flat bones
o Periosteal reactions: Thin or disorganized
• Osteomyelitis
o Cod man triangle unusual
o Location: Localized; long bones
o Moth-eaten lytic lesion
• Multifocal uncommon
o Periosteal reaction: Disorganized, thin,
• Soft tissue mass larger than bone
lamellated, spiculated destruction
o Cortical destruction late in disease
o Cod man triangle relatively common
o Lytic destruction of bone in acute phase Helpful Clues for Rare Diagnoses
most common • Fibrosarcoma
• Geographic with sclerotic margin o Location: Eccentric metaphysis of long
possible but rare tubular bones
o Look for associated air, sinus tract, o Periosteal reactions: Thin or disorganized
sequestrum o Codman triangle unusual
o Can mimic Ewing sarcoma, lymphoma, o Wide range of appearances: Circumscribed
leukemia to permeative
• Leukemia • Angiosarcoma, Osseous
o Location: Long bones in children, axial o Location: Long bones
skeleton in adults o Periosteal reactions: Thin or disorganized
o Periosteal reactions: Thin or lamellated; o Codman triangle unusual
"hair on end" in skull
o Radiolucent transverse metaphyseal bands
• "Leukemic lines"
Anteroposterior radiograph shows

periosteal reaction _
a "sunburst"
Note the permeative destruction
AnterofXJsterior radiograph shows a large, permeative
lesion with osteoid matrix and a wide zone of transition.
I
of the radius, with tumor osteoid formed in bolh the There is extensive periosteal reaction. and a large soft
bone and soft tissue mass. tissue mass III
113
E PERIOSTEUM: AGGRESSIVE PERIOSTITIS
:::l
Ql
(;j
o
.;::
Ql
a..
"tl
Gl Ewing Sarcoma Ewing Sarcoma
VI (Left) Anteroposterior.
III
en radiograph shows a highly
>- aggressive lytic lesion E!lI of
-E
o
III
c:
<l:
the proximal fibular
metaphysis that has
traversed the cortex. There is
a wide zone of transition, a
large 50ft tissue mass, and
aggressive appearing
periosteal reaction _.
shows Codman triangle of
aggressive periosteal reaction
•• along the anterior cortex
of the mid-femoral diaphysis.
There is underlying
permeative medullary lesion
and a subtle soft tissue mass.
Malignant Fibrous Histiocytoma Metastasis

lytic lesion E!lI arising in the
central diaphysis. There is a
wide zone of transition,
cortical breakthrough,
interrupted periosteal
reaction. and a 50ft tissue
mass. (Right) Lateral
radiograph shows a
medulloblastoma metastasis
E!lI in the proximal ulna with
a mixed lytic and sclerotic
appearance. Note the
marked aggressive,
perpendicular periosteal
reaction_
Osteomyelitis
shows a transverse
supracondylar distal
humerus fracture •.
Extensive disorganized
periosteal new bone
surroundsthe fracture.
due to the lack of proper
fracture immobilization.
shows a nightstick fraclure
site complicated by
osteomyelitis. There is
permeative bone destruction
E!il a dense central bone
sequestrum JIll and
disorganized surrounding
I
114
Osteomyelitis Osteosarcoma, Periosteal (Mimic)

permeative destructive
change of the proximal
radius EiIl along with
disorganized periosteal
reaction •. This could
represent either osteomyelitis
or an aggressive tumor. This
was found to be
staphylococcus
osteomyelitis. (Right) Axial
NEeT shows a lesion on the
surface of the tibia which
produces fairly
mature-appearing bone _
It does not involve the
marrow space.
Osteosarcoma, Periosteal (Mimic) lymphoma

shows spiculated osteoid
matrix. along the surface
of the bone. An MR showed
no involvement of the
marrow. This is a mimic of a
periosteal reaction since the
radiodense material is tumor
osteoid. (Right) Oblique
radiograph shows mildly
reaction. at the distal
tibia. Hypertrophic
osteoarthropathy or
osteomyelitis could be
considered, but MR
documented an extensive
underlying medullary lesion.
Angiosarcoma, Osseous
shows only a "smudginess"
of the bone trabeculae EiIl
as well as subtle interrupted
periosteal reaction _ These
findings represent an
extremely permeative and
aggressive underlying lesion.
(Right) Coronal NEeT shows
a destructive mass III in the
proximal tibia. There is
breech of the cortex. and
a small amount of
reaction _ Both infection
and malignancy were initially
considered in the differential
diagnosis.
I
115
E PERIOSTEUM: SOLID PERIOSTITIS
:::J
Q)
Ul
o
"C
Q) DIFFERENTIAL DIAGNOSIS o Distribution: Localized or generalized
CL
o Associated findings: Phleboliths, cellulitis
"0 Common • Psoriatic Arthritis
Ql
III
ltl
• Fracture Healing Process o Location: Periarticular, peripheral
In • Venous Stasis
>- ligament, and tendon insertions
E • Psoriatic Arthritis o Distribution: Localized or generalized
-
o
ltl
c:
<t
• Hypertrophic Osteoarthropathy
o Periosteal reaction: Solid, irregular
• Stress Fracture o Location: Any location is possible
• Chondroblastoma o Distribution: Localized
• Osteoid Osteoma o Periosteal reaction: Thick, dense
less Common o Underlying mixed sclerotic and lytic lesion
• Renal Osteodystrophy, Neostosis ± sequestrum
• Juvenile Idiopathic Arthritis alA) • Hypertrophic Osteoarthropathy
• Chronic Reactive Arthritis o Location: Long bone diaphyses
• Sickle Cell Anemia: MSK Complications o Distribution: Symmetric, generalized
• Metastases, Treated o Evaluate for underlying carcinoma or
• Melorheostosis (Mimic) chronic disease (thoracic or abdominal)
Rare but Important • Stress Fracture
o Location: Tibia, metatarsals, long bones,
• Complications of Vitamin A
pelvis, calcaneus
• Osteitis Condensans of Clavicle
o Distribution: Localized
• Chronic Recurrent Multifocal Osteomyelitis
o Periosteal reaction: Linear, ovoid, or
• Complications of Vitamin D
concentric
• Chondroblastoma
• Thyroid Acropachy
o Location: Along metadiaphysis adjacent to
• Pachydermoperiostosis
epiphyseal chondroblastoma
• Engelmann Disease (Engelmann-Camurati)
o Periosteal reaction: Thick, solid, or layered
• Physiologic Periostitis, Lower Extremity
o Lytic epiphyseal lesion with variable
• Caffey Disease (Infantile Cortical
chondroid matrix and variably sclerotic
Hyperostosis)
border
• Scurvy
• Osteoid Osteoma
• Secondary Syphilis
o Location: Femur, tibia, fibula, humerus
o Periosteal reaction: Thick & dense; blends
ESSENTIAL INFORMATION with thickened cortex
o Central lucent nidus
o Intraarticular location has paucity of
• Thick, solid periosteal reactions typically periosteal new bone
reflect a nonmalignant underlying process
o Exception: Hypertrophic osteoarthropathy Helpful Clues for less Common Diagnoses
o Very rarely seen in osteosarcoma, Ewing • Renal Osteodystrophy, Neostosis
sarcoma, and untreated metastases o Location: Phalanges, metatarsals,
metacarpals
o Seen in healing phase
• Fracture Healing Process
o Periosteal reaction: Wide range depending
o Location: Periarticular, ligament and
on motion at fracture site during healing tendon insertions
• Greater motion = greater disorganization
o Distribution: Localized or generalized
o Periosteal reaction from traumatic and
• Chronic Reactive Arthritis
pathologic fractures can be similar
o Location: Calcaneus, metatarsals, lower leg
• Venous Stasis o Distribution: Localized
o Location: Lower extremity
• Sickle Cell Anemia: MSK Complications
I
116
:I>
PERIOSTEUM: SOLID PERIOSTITIS
..
~
III
o
o Location: Tubular bones of hands & feet o Calcified ligaments and tendons 3
'<
(dactylitis), long bones • Ossified posterior longitudinal ligament OJ
III
o Distribution: Generalized common
o Osteosclerosis
'"
~
Q.
• Metastases, Treated
-0
o Solid periosteal reaction most common in • Thyroid Acropachy C1l
~
treated metastases
• Melorheostosis (Mimic)
o Location: Metacarpals, metatarsals
o Periosteal reaction: Solid, "fluffy" border ..'"
o'
C1l
c
o Sclerosing bone dysplasia produces o History of treatment for hyperthyroidism 3
endosteal &/or cortical ossification, not • Pachydermoperiostosis
true periosteal reaction o Primary form of hypertrophic
o Sclerotomal distribution common osteoarthropathy
o Periosteal reaction: Thick, shaggy
o Male predominance with onset at puberty
• Complications of Vitamin A
• Engelmann Disease
o Location: Ulna, lower leg, metatarsals,
(Engelmann-Camurati)
clavicle o Diaphyseal broadening of long bones
o Retinoid drug administration in teens
• Physiologic Periostitis, Lower Extremity
o Location: Long bones, symmetric
o Location: Medial end of clavicle
o Infants up to 6 months of age
o Sclerosis of normal-sized bone with solid
• More common in premature infants
periosteal reaction
• Chronic Recurrent Multifocal
Hyperostosis)
Osteomyelitis
o Location: Jaw, long bone diaphysis,
o Location: Long bone metaphysis, clavicle,
clavicle, scapula, ribs
spine
o 1st seen in infants < 6 months of age
o Radiographically ranges from occult to
mimicking osteosarcoma • Scurvy
o Location: Long bones
• Complications of Vitamin D o Follows location of subperiosteal bleed &
o Rickets = wide physes; cupped, frayed
subsequent calcification
epiphyses
• Secondary Syphilis
o Periosteal elevation from unmineralized
o Location: Long bones, skull
osteoid or occult fracture
o Periosteal reaction: Solid with short
spicules
o Location: Tubular bones, symmetric
Anteroposterior radiograph shows a healing fracture Ell

of the distal femoral diaphysis. Smooth, solid periosteal
Anteroposterior radiograph shows solid periosteal
reaction •• along both sides of the fibula. These
I
reaction • is present along the medial cortex due to findings were present bilaterally and are associated with
the fracture and placement of locking scre\NS. subcutaneous edema" from venous insufficiency.
117
E PERIOSTEUM: SOLI D PERIOSTITIS
:J
Q)
eno
·C
Q)
a..
"C
Q) Psoriatic Arthritis Psoriatic Arthritis
III
en"' radiograph shows subtle,
>- solid periostitis" and
-"'
<
E
o
c:
cartilage narrowing at several
joints HI The presence of
periostitis makes rheumatoid
arthritis unlikely. (Right)
shows solid to perpendicular
periostitis" along the
medial edge of the distal
phalanx of the great toe. The
productive changes seen
here are typical of both
psoriatic arthritis and chronic
reactive arthritis.
Chronic Osteomyelitis Chronic Osteomyelitis

(Left) Radiograph of the
forearm shows solid, mature
periosteal reaction 11II along
the radius. Early in the
course of the disease,
permeative destructive
changes of the underlying
bone were visible. (Right)
Coronal T1 C+ MR shows a
proximal medial metaphyseal
lesion 11II crossing the physis
into the epiphysis, with
extensive marrow edema, a
well-defined rim of
enhancement, and periosteal
elevation _. A Brodie
abscess was found at
surgery.
radiograph shows exuberant
periosteal reaction at the
proximal tibia IIIand a less
prominent reaction involving
the distal femur" and
fibula HI These changes
were secondary to lung
cancer. rt MSK Req). (Right)
Oblique radiograph shows
symmetric, solid periosteal
reaction. along the radius
and ulna. Secondary causes
are far more common than
primary; thus occult
malignancy should be
excluded when these
findings are encountered.
I
118
PERIOSTEUM: SOLID PERIOSTITIS :>
-
::J
III
o
3
'<
III
III
VI
Stress Fracture Stress Fracture (l)
(Leh) Coronal TSE TRIM MR a.
shows bone marrow edema -U
III in the area of stress and (l)
~
increased signal in the o·
VI
muscles. and periosteum r0-
III Radiographs were c
normal at this time. (Right) 3
in the same patient ten
weeks later shows dense
circumferential periosteal
new bone formation. in
the area of the stress
fracture.
Chondroblastoma
epiphyseal lesion of the
humerus Ell. The lesion
contains a faint calcific
matrix III and has a dense
periosteal reaction in the
metaphyseal region III
typical for this diagnosis.
fRight) Axial NEeT shows a
cortically based osteoid
osteoma with a typical
lucent nidus III. It is
surrounded by densely
sclerotic cortical thickening
and periosteal new bone III
Renal Osteodystrophy, Neostosis Juvenile Idiopathic Arthritis (JIA)

fLeft) Posteroanterior
radiograph shows an
exuberant healing response
in this patient being treated
for renal disease. The finger
shows conventional
neostosis, with dense
periosteal new bone
formation along the
phalanges III (Right) Lateral
radiograph shows solid
periosteal reaction along the
phalanges III with soft tissue
swelling, but normal joints.
The differential diagnosis
includes juvenile idiopathic
arthritis, sickle cell dactylitis,
and tuberculosis dactylitis.
I
119
E PERIOSTEUM: SOLID PERIOSTITIS
::l
Q)
U;
o
'C
Q)
ll.
"0
QI Chronic Reactive Arthritis Sickle Cell Anemia: MSK Complications
'"'"
III radiograph shows soft tissue
>- swelling of the index finger,
-E
o
c'":
<l:
as well as cartilage
narrowing in the DIP_
Additionally, there is
prominent periostitis at the
middle phalanx •. (Right)
shows a typical instance of
sickle cell dactylitis in a
baby. Solid periosteal
reaction. surrounds
several metacarpals. These
findings were present
bilaterally.
Metastases. Treated Melorheostosis (Mimic)

radiograph shows a treated
lung carcinoma metastasis
Ell. The lesion was initially
lytic with an aggressive
periosteal reaction. After
radiation therapy, it became
sclerotic with a solid
periosteal reaction _
radiograph shows sclerosis
involving endosteal Ell and
periosteal. portions of the
cortex. The tibia was a/50
involved. A sc/erotomal
distribution is often present
but is not seen in this case.
Complications of Vitamin A Osteitis Condensans of Clavicle

solid periostitis at the ulna
• in this patient who was
overdosed with vitamin A by
his zealous mother. Several
other bones showed similar
solid periostitis. (Right) Axial
NECT shows dense sclerosis
• and solid periosteal new
bone. involving the
medial right clavicle. The
opposite clavicle is normal
Ell. This can be due to
chronic recurrent
osteomyelitis or SAPHO
syndrome.
I
120
PERIOSTEUM: SOLID PERIOSTITIS »
:J
..•o
III
3
'<
lJl
Chronic Recurrent Multifocal III
VI
Osteomyelitis (t)

shows a mixed sclerotic and "U
lytic lesion. with ~
(t)
prominent solid periosteal o'

VI
reaction _ A similar lesion CD
was present in the sacrum. c
Diagnosis required open 3
biopsy after a percutaneous
biopsy specimen was
inconclusive. (Right)
shows fluffy periosteal
reaction and soft tissue
swelling involving multiple
phalanges _ There is also
clubbing of the digits. in
this patient treated for
hyperthyroidism.
Engelmann Disease
Pachydermoperiostosis (Engelmann-Camurati)
radiograph shows solid
periosteal reaction
the metacarpals and
=
along
phalanges. There were no

joint changes, underlying
lesions, or metabolic disease.
Solid periosteal reaction was
present throughout the body.
(tMSK Req). (Right)
shows marked endosteal and
periosteal cortical thickening
_ The process was
bilaterally symmetric and
involved the entire length of
the diaphyses but spared the
metaphyses and epiphyses.
radiograph shows subtle
diffuse increased density of
the lower extremity long
bones, resulting from subtle
solid periostitis _ Findings
are particularly prominent
along the diaphyses and
were bifaterally symmetric.
osteopenia with metaphyseal
corner fractures _ termed
Pelken fractures. With these
fractures, the patient may
develop an extensive
subperiosteal bleed,
elevating the periosteum _
I
121
E PERIOSTEUM: BIZARRE HORIZONTAL PERIOSTEAL REACTION
::J
OJ
(j)
o
-;::
OJ DIFFERENTIAL DIAGNOSIS • Hint: In presence of a focus of odd,
Q.
horizontal periosteal reaction, look for
"C Common other bones showing more
Cll
III
l'O • Hypertrophic Osteoarthropathy (HOA) normal-appearing periosteal reaction
CO • Renal Osteodystrophy, Neostosis
>- • Renal Osteodystrophy, Neostosis
E less Common o Renal osteodystrophy, when active, shows
•..
o
l'O • Parosteal Lipoma subperiosteal resorption along metaphyses
l::
« • Hemophilic Pseudotumor of long bones
• Fibromatosis o When in a healing phase, shows new bone
• Juvenile Aponeurotic Fibroma formation
• Osteosarcoma (Mimic) • Most prominent appearance when renal
• Skull Hemangioma (Mimic) osteodystrophy was severe and adequate
• Thalassemia (Mimic) treatment is first instituted
• Aneurysmal Bone Cyst (Mimic) • New bone formation along periosteum
gives an appearance of dense linear
Rare but Important
periosteal reaction, but is neostosis
• Soft Tissue Tumor Adjacent To Bone • Neostosis rarely has an exuberant
• Subperiosteal Ganglion horizontal extension
• New bone is also seen in a round pattern,
I ESSENTIAL INFORMATION filling in and healing brown tumors
• New bone is also seen as a diffuse density
Key Differential Diagnosis Issues within long bones
• True bizarre horizontal periosteal reaction is o Hint: When suspecting neostosis, watch
uncommon for coarsened trabeculae, brown tumors
o Most of the entities generally present with (perhaps hyperossified), & patterns of
linear, regular periosteal bone formation residual resorption
o Occasional bizarre appearance may be
confusing; this list addresses these Helpful Clues for less Common Diagnoses
uncommon instances • Parosteal Lipoma
o Soft tissue lipoma, adjacent to long bone
Helpful Clues for Common Diagnoses • Most do not elicit a reaction
• Hypertrophic Osteoarthropathy (HOA) • Occasionally, juxta-osseous lipoma elicits
o Periosteal reaction in the appendicular
extensive horizontal periosteal reaction
skeleton, with either 1 or 2 etiology
0 0
• Hint: The adjacent lipoma has all

o Primary HOA (pachydermoperiostosis)
characteristics typical of lipoma
• Dense periosteal reaction along • Hemophilic Pseudotumor
diaphyses of long bones o Pseudotumor arises from recurrent
• Associated clubbing of fingers bleeding episodes affecting bone
• Associated thickening of skin on • Soft tissue
forehead and dorsum of hands • Subperiosteal
o Secondary HOA
• Intraosseous
• Dense periosteal reaction along o Several effects on bone, depending on
diaphyses of long bones source of bleeding
• Associated clubbing of fingers • Expansion, with thinning of endosteum
• Associated thoracic (lung cancer) or • Extrinsic scalloping of cortex
abdominal abnormalities • May have long horizontal spicules of
o Though the periosteal reaction is usually bone, either as reaction or from the
thick & linear (whether primary or extrinsic scalloping
secondary etiology), it may occasionally o Most common sites: Iliac wing, femur,
project horizontally calcaneus
• Horizontal projection, if localized, might o Hint: Gender specific; often has
mimic a surface osteosarcoma oligoarticular disease (knee, elbow, ankle)
I
122
PERIOSTEUM: BIZARRE HORIZONTAL PERIOSTEAL REACTION >
:l
...•
III
o
• Fibromatosis • Parallel to long bone, but interrupted 3
'<
o Soft tissue fibrous mass; benign but locally • Cod man triangle [Xl
III
invasive, not respecting compartments o Uncommonly, tumor osteoid extends III
(I)
o Hint: MR is suggestive of diagnosis horizontally from underlying long bone, Co

-0
• Infiltrative rather than having the giving the appearance of horizontal ctl
~
pseudocapsule seen with sarcomas periosteal reaction o·
III
• Fluid-sensitive sequences often have low o Hint: Underlying bone shows highly roc
signal & are inhomogeneous permeative destruction, usually with 3
• Intense enhancement tumor osteoid formation
o Adjacent osseous structures • Skull Hemangioma (Mimic) &
• Generally not affected Thalassemia (Mimic)
• May cause destruction, especially in o Hemangioma (focal) & thalassemia
hand/foot: Pressure erosion (diffuse) skull disease
• Rarely elicit horizontal periosteal o Expands the diploic space
reaction o Trabeculae extending between inner &
• Juvenile Aponeurotic Fibroma outer tables give the appearance of
o Child with soft tissue mass, generally in sunburst periosteal reaction
forearm or hand • Aneurysmal Bone Cyst (Mimic)
o With growth, often causes bowing or o Eccentric metaphyseal lytic lesion, usually
extrinsic erosion of adjacent bones with thin cortical rim
• Generally no osseous reaction to the o MR usually distinctive, showing fluid-fluid
adjacent slow-growing mass levels; not specific
• Rarely, bizarre horizontal periosteal o Lesion usually completely lytic, but may
reaction is seen contain pseudotrabeculations
o May develop dystrophic calcification • If cortical rim is so thin as to not be
o Hint: Location, patient age, & MR suggest visible, pseudotrabeculations may mimic
the diagnosis horizontal periosteal reaction
• Local infiltration Helpful Clues for Rare Diagnoses
• Fluid-sensitive sequences often have low • Soft Tissue Tumor Adjacent To Bone
signal areas & are inhomogeneous o Rarely elicits horizontal periosteal reaction;
• Intense enhancement nonspecific
• Osteosarcoma (Mimic) • Subperiosteal Ganglion
o Osteosarcoma generally elicits an
o Rare location of lesion; horizontal reaction
aggressive periosteal reaction
Hypertrophic Osteoarthropathy (HOA) Renal Osteodystrophy, Neostosis
AP radiograph shows bizarre tibial periosteal reaction

Ell. Surface tumor might be considered, except for the
AP radiograph shows exuberant new bone formaUon
arising from the glenoid III and humeral metaphysis.
I
more regular periosteal reaction seen at the fibula & in this patient with renal disease, treated by dialysis.
femur •. Diagnosis: Lung cancer. (t MSK Req). Treatment may result in new bone formation.
123
E PERIOSTEUM: BIZARRE HORIZONTAL PERIOSTEAL REACTION
:>
III
eno
.<:
III
a..
"0
CIl Parosteal Lipoma Parosteal Lipoma
l/)
ns (Left) Lateral radiograph
aI shows horizontal periosteal
>- reaction arising from the
E
-
o
ns
c:
«
posterior femoral shaft.
with adjacent fat density in
the soft tissues Ell (tMSK
Req). (RighI) Axial bone CT
the horizontal periosteal
reaction arising from the
osseous surface. again
with the surrounding fat
density Ell The fat is typical
of lipoma; when it is in close
proximity to bone, it may
elicit bizarre periosteal
reaction; the combination is
termed parosteallipoma.
Hemophilic Pseudotumor Fibromatosis

radiograph shows several
sites of horizontal periosteal
reaction arising from the
femoral shaft. in a young
man with hemophilia. There
is also cortical scalloping.
The changes are due to
subperiosteal bleeds. (RighI)
bizarre horizontal periosteal
reaction. to a soft tissue
aggressive fibromatosis lesion
that causes local scalloping
of the bone. This reaction is
a rare manifestation of
fibromatosis.
Juvenile Aponeurotic Fibroma Osteosarcoma (Mimic)

(Left) Oblique radiograph
shows a juvenile aponeurotic
fibroma, that has caused
scalloping of both the
forearm bones. The ulna
shows tremendous periosteal
reaction. occasionally
seen in this disease. (RighI)
AP radiograph shows severe
horizontal (sunburst) osteoid
formation in a 50ft tissue
mass arising from the distal
radius in a child. There is
permeative change & osteoid
tumor bone formation in this
osteosarcoma. The
horizontal bone ;s osteoid
rather than reactive bone.
I
124
PERIOSTEUM: BIZARRE HORIZONTAL PERIOSTEAL REACTION »
-
:J
III
o
3
'<
lJl
III
<II
Thalassemia (Mimic) m
shows a large hemangioma "U
ct>
of the skull, expanding the ~
outer table. with a o'
<II
honeycomb appearance of r0-
the trabeculations ffi This is c
not a true periosteal reaction. 3
shows the "hair on end"
appearance of the skull" in
a patient with thalassemia.
This in fact is not a periosteal
reactive process but
represents the widened
diploic space required for
the erythropoietic needs in
this severe anemia.
Soft Tissue Tumor Adjacent To Bone

what appears to be dense
••. In reality, these are
pseudolrabecuJations within
the wall of an ABC; the thin
outer rim is faintly seen
superimposed on the radius
••. (Right) Axial NEeT
shows normal underlying
bone but prominent
• related to a large
adjacent soft tissue mass HI.
This is a rare osseous
reaction, in this case to a
malignant fibrous
histiocytoma.

shows a surface lesion of
bone, slightly scalloping the
cortex and containing
horizontal osseous
projections III that could
represent either reaction or
pseudotrabeculations.
(Right) Axial T2WI MR of the
same lesion as previous
image shows the fairly thick
osseous projections.
within the cystic lesion. This
proved to be a subperiosteal
ganglion cyst with dense
cortical reaction.
I
125
E
::J
PERIOSTEUM: PERIOSTITIS MULTIPLE BONES/ACROPACHY, ADULT
Q)
iil
o
°C
Q) DIFFERENTIAL DIAGNOSIS o Clubbing of fingers
a.. o Patients complain of joint pain
"0 Common • Because of site of pain, radiograph is
ell
IJl
C1l
• Hypertrophic Pulmonary Osteoarthropathy often of wrist/hand or ankle/foot
to (HPOA) • Periosteal reaction is often seen only on
>-
• Extrathoracic Hypertrophic
•..Eo
C1l
Osteoarthropathy
the corner of the radiograph, involving
the diaphysis of long bone
c: • Vascular Insufficiency
« • Small bones of hand or foot may be
Less Common involved, less frequently than long bones
• Subperiosteal Resorption (Mimic) • Extrathoracic Hypertrophic
• Renal Osteodystrophy, Neostosis Osteoarthropathy
• Psoriatic Arthritis o Less common etiology of hypertrophic
• Pachydermoperiostosis osteoarthropathy than HPOA
• Chronic Reactive Arthritis o May be associated with biliary disease,
• Thyroid Acropachy cirrhosis, inflammatory bowel disease
o Radiographically identical to HPOA
Rare but Important
• Vascular Insufficiency
• Tuberous Sclerosis o Periosteal reaction in lower extremity,
• Hypervitaminosis A particularly tibia & fibula
• Hypervitaminosis D o Varicosities, cellulitis, & phleboliths
• Complications of Retinoids
• Fluorosis Helpful Clues for Less Common Diagnoses
• Osteogenesis Imperfecta (01) Tarda • Subperiosteal Resorption (Mimic)
• Leukemia o Hyperparathyroidism or renal
osteodystrophy
o Subperiosteal resorption may be aggressive,
ESSENTIAL INFORMATION mimicking fluffy periosteal reaction
Key Differential Diagnosis Issues o Most common locations
• Multiple sites of periosteal reaction: Much • Radial aspect of middle phalanges (with
more limited differential than solitary bone severe disease, involves all phalanges,
involvement both radial & ulnar sides)
• Hint: Most important diagnosis is HPOA • Proximal medial humerus, tibia, femur
o Radiologist must direct clinician to look o Watch for suggestion that it is resorption
for lung pathology rather than added bony reaction
o May allow early detection of lung cancer • No solid cortex will be seen underlying
in a situation where there is no clinical the abnormality
suspicion of the disease • Bone density is abnormal, with
smudginess of trabeculae
• May have other sites of resorption
• Hypertrophic Pulmonary (subchondral, subligamentous)
Osteoarthropathy (HPOA) • May have brown tumors &/or soft tissue
o Multiple intrathoracic etiologies, including
calcification
infection, pleural disease, & congestive • Renal Osteodystrophy, Neostosis
heart failure, but most frequent is lung o When severe renal osteodystrophy is
cancer newly & adequately treated, it results in
o Elicits dense periosteal reaction in long
new bone formation
bones without underlying osseous • May take the form of periosteal new
abnormality bone, termed neostosis
• Periosteal reaction usually linear & o Watch for other new bone formation
regular • Hyperossification of brown tumors
• Occasionally it is exuberant, mimicking a • Increased bone formation on trabeculae
surface bone-forming tumor leads to overall increased density
I
126
PERIOSTEUM: PERIOSTITIS MULTIPLE BONES/ACROPACHY, ADULT »
..
:l
III
o
o Watch for underlying signs of renal o May have thyrotoxicosis 3
'<
osteodystrophy o May have clubbing of fingers tD
III
• Various patterns of resorption Helpful Clues for Rare Diagnoses III
<1l
• Bowing deformities • Tuberous Sclerosis
Co
-0
• Psoriatic Arthritis o Uncommon disease; periosteal reaction is C1l
::l.
o Early changes, even pre-erosive, include o
rare manifestation III
• Sausage digit: Swelling of entire digit 10
• Hypervitaminosis A c
• Periostitis: Fluffy bone formation along o May have undulating periosteal reaction 3
shaft and metaphyses o Soft tissue nodularity
o Later changes include aggressive erosive
o Intracranial hypertension
change; pencil-in-cup, arthritis mutilans
• Hypervitaminosis D
o Hand involvement with interphalangeal
o Enthesopathy, rare periostitis
joint predominance
• Pachydermoperiostosis o Usually productive change is in the form
o a.k.a., 1 hypertrophic osteoarthropathy
0
of spinal anterior bridging osteophytes

o Inherited condition, male> female
o Periosteal bone formation is uncommon
o Dense periosteal reaction along long bones
• Fluorosis
without underlying osseous abnormality o May have sacrospinous or sacrotuberous
o Associated thickening of skin of forehead
ligament calcification
& dorsum of hand
o Periosteal reaction less common than
o Pain & periostitis tend to be self-limited,
enthesopathy
resolving in adulthood o Osteoporotic or osteosclerotic;
• Chronic Reactive Arthritis metaphyseal dense lines
o As with psoriatic arthritis, early changes
• Osteogenesis Imperfecta (01) Tarda
• Sausage digit: Swelling of entire digit o Prominent callus formation at fracture
• Periostitis: Fluffy bone formation along sites & other sites of injury
shaft and metaphyses
• Leukemia
o Later changes mixed erosive & productive
o Periosteal reaction is uncommon
o Lower extremity predominates (ankle,
o Generally seen as osteoporosis on
forefoot, & calcaneus)
radiograph
• Thyroid Acropachy o Radiography is often normal
o Fluffy periostitis of phalanges
• Lesions demonstrated by MR
o Patient is usually euthyroid, having been
treated for thyroid disease
Hypertrophic Pulmonary Hypertrophic Pulmonary

Osteoarthropathy (HPOA) Osteoarthropathy (HPOA)
Anteroposterior radiograph shows dense periosteal

reaction along the femoral shaft IIJ. There were other
Anteroposterior radiograph shows dense periosteal
reaction along the femur _ fibula Ell and particularly
I
long bones similarly involved, all with normal underlying exuberant reaction along the tibia •. This proved to be
bone. This is HPOA; U,e patient had lung cancer. HPOA; the patient had lung cancer. ItMSK Req). 127
E PERIOSTEUM: PERIOSTITIS MULTIPLE BONES/ACROPACHY, ADULT
::J
Q)
ino
'C
Q)
(L
Extrathoracic Hypertrophic
"0
Q) Osteoarthropathy
Ul (Left) Antemposterior
C1l
III radiograph shows very
>. regular periosteal reaction
•..Eo
C1l
involving all metacarpals •.
Although one should
c: primarily suspect lung cancer
< with HPOA, in this case the
hypertrophic
osteoarthropathy was related
to liver cirrhosis. (Right) AP
periosteal reaction. along
the tibia. This was a bilateral
finding but only involved the
legs. This exclusive lower
extremity distribution favors
vascular insufficiency as the
etiology.

severe subperiosteal
resorption involving both the
~d~/.andumarBlswe
of the phalanges.
Occasionally the resorption
is so severe that it mimics
periosteal reaction. (Right)
Postemanterior radiograph
shows dense regular
neostosis •. new bone
formed in this patient with
end·stage renal disease,
placed on dialysis
approximately 6 months
earlier.
Psoriatic Arthritis Psoriatic Arthritis

soft tissue swelling of the
third ray, an appearance
termed a "sausage digit" _
as well as prominent
shaft of the proximal phalanx
_ This appearance is one
of the typical manifestations
of early psoriatic arthritis.
(Right) PA radiograph shows
soft tissue swelling of
adjacent digits, with
prominent periostitis _
There is some articular
damage as well, involving
interphalangeal joints, typical
of psoriatic arthritis.
I
128
PERIOSTEUM: PERIOSTITIS MUlTIPLE BONES/ACROPACHY, ADULT »
::l
...•
III
o
3
'<
lJl
III
Pachydermoperiostosis Pachydermoperiostosis VI
to
(Left) Anteroposterior Q.
radiograph shows prominent -U
<1l
periosteal reaction involving ~
all metacarpals & phalanges o·
VI
_ All the long bones had a r0-
similar appearance, & the c
skin of the patient's forehead 3
& dorsal hand was
thickened. The combination
makes the diagnosis of
pachydermoperiostosis.
(tMSK Req). (Right) Frontal
Tc99m bone scan in the
same patient shows diffuse
periosteal uptake in all long
bones, indicating extent of
periosteal reaction in this
patient with 1° HOA.
Chronic Reactive Arthritis Thyroid Acropachy

diffuse soft tissue swelling
along the 2nd ray, periostitis
_ and cartilage loss _
This is HIV-AIDS-related
arthritis, a variant of chronic
reactive arthritis. (Right) PA
radiograph shows lIufly
periostitis involving many of
the phalanges. in this
patient treated successfully
for hyperthyroidism eight
months earlier. There is
clubbing of the fingers. as
well.
Tuberous Sclerosis Osteogenesis Imperfecta (01) Tarda

wavy periosteal reaction
along all the metatarsals.
in a patient with tuberous
sclerosis. The appearance is
not specific; the history gives
the etiology in this case.
radiograph shows thick
iliac wing _ in this patient
with Oltarda. This mild form
of the disease often results in
hypertrophic fracture callus
& subperiosteal bleeds &
associated periosteal bone
formation.
I
129
E
::J
PERIOSTEUM: PERIOSTITIS MUlTIPLE BONES, CHILD
Q)
eno
·C
Q) DIFFERENTIAL DIAGNOSIS o Normal growth may be so rapid during
0.. first 6 months that new periosteal bone is
-c Common produced
Ql
VI
Cll
• Physiologic Periostitis • Symmetric, regular
III • Child Abuse • Resolves by 6 months of age
>-
E • Multifocal Osteomyelitis • Child Abuse
•...o
Cll
• Juvenile Idiopathic Arthritis OIA) o Always consider this diagnosis when
c: • Hypervitaminosis A
« periosteal reaction is seen in a child!
• Polyostotic Aggressive Bone Tumor o Often not symmetric
less Common o Often 2° to metaphyseal corner fracture
• Prostaglandin Periostitis • Fracture causes subperiosteal bleeding &
• Sickle Cell Dactylitis lifting of periosteum
o May occur without fracture 2° to normally
Rare but Important loose periosteum and a twisting injury
• Caffey Disease • Multifocal Osteomyelitis
• Renal Osteodystrophy (Mimic) o Congenital infections
• Leukemia • TORCH infections
• Scurvy • Congenital syphilis (may have "celery
• Complications of Chemotherapeutic Drugs, stalking" at metaphyses as well)
Methotrexate o Infections from newborn ICU: Generally
• Hypertrophic Osteoarthropathy, Cystic Streptococcus
Fibrosis o Multifocal osteomyelitis later in childhood
• Complications of Retinoids • Hematogenous spread (metaphyseal)
• Consider underlying disease: HIV/AlDS
ESSENTIAL INFORMATION or sickle cell anemia
o Tuberculosis (TB) involvement in hands:
Key Differential Diagnosis Issues Dactylitis is termed spina ventosa
• Periosteal reaction is common in a single • Juvenile Idiopathic Arthritis OIA)
bone, with a multitude of etiologies o First osseous manifestation may be
• Polyostotic periostitis is much less common; periostitis of hand or foot phalanges
the polyostotic nature and patient age helps o Later, joints will be involved
to limit the diagnosis o Differential is sickle cell & TB dactylitis
• Hint: Some etiologies are limited by patient • Hypervitaminosis A
age o Excessive intake of vitamin A results
o First appearance BEFORE6 months of age
initially in periosteal reaction
• Physiologic (should disappear by age 6 • Subtle at first but may become quite
months) dense & thick
• Congenital osteomyelitis • Painful
• Caffey disease o Continued use of excessive vitamin A may
• Prostaglandin periostitis lead to coned epiphyses
o First appearance AFTER6 months of age
• Polyostotic Aggressive Bone Tumor
• Juvenile idiopathic arthritis o Bone metastases
• Hypervitaminosis A • Ewing sarcoma presents with osseous
• Sickle cell dactylitis metastases as frequently as lung mets
• Renal osteodystrophy • Others to consider: Medulloblastoma,
• Scurvy neuroblastoma, osteosarcoma
• Hint: ALWAYSconsider the possibility of o Leukemia: Common but usually presents
child abuse/nonaccidental trauma with lucent metaphyseal bands or diffuse
Helpful Clues for Common Diagnoses osteoporosis
• Physiologic Periostitis • Periostitis is a rare manifestation
I
130
PERIOSTEUM: PERIOSTITIS MUlTIPLE BONES, CHILD
o Langerhans cell histiocytosis: Often • Watch for underlying abnormal bone

polyostotic; may be aggressive enough to density, signs of rickets (widening at
elicit periosteal reaction zone of provisional calcification)
o Severe renal osteodystrophy may result in
Helpful Clues for less Common Diagnoses
bone accretion when effective treatment is
• Prostaglandin Periostitis
initiated; mimics periosteal reaction
o Prostaglandins used for congenital heart
disease in infancy to keep ductus open • Scurvy
o Rare metabolic disease affecting collagen
o Dense, nonspecific periosteal reaction on
o Osseous manifestations
long bones
• Osteopenia
• Sickle Cell Dactylitis
• Sclerotic ring around epiphyses
o Generally young children « 7 years of age)
(Wimberger sign)
o Cold temperature ~ vasoconstriction of
• Sclerotic metaphyseal line (white line of
terminal vessels in phalanges ~ sludging of
Frankel)
sickled red blood cells ~ bone infarct
• Corner fractures at metaphyses
o Bone infarct may initially elicit periostitis;
• Subperiosteal bleed (especially with
eventually has mixed lytic & sclerotic
corner fracture) ~ elevates periosteum ~
appearance
reparative bone formation which mimics
Helpful Clues for Rare Diagnoses periosteal reaction
• Caffey Disease • Complications of Chemotherapeutic
o Rare disease manifests at birth Drugs, Methotrexate
o Painful periostitis of long bones o Rare periosteal reaction, nonspecific
o Involvement of clavicle & mandible is • Hypertrophic Osteoarthropathy, Cystic
suggestive of diagnosis since not usually Fibrosis
seen with other diagnoses o Lung disease may elicit hypertrophic
o Self-limited; spontaneously resolves over osteoarthropathy, just as in adults
first 2 years of life o Periosteal reaction that is painful, referred
• Renal Osteodystrophy (Mimic) to joints
o Severe subperiosteal resorption, especially • Complications of Retinoids
at the proximal humeral, tibial, or femoral o May induce productive bone changes
metaphysis or at the radial aspect of • Most frequently, large syndesmophytes
middle phalanx may mimic fluffy at anterior vertebral bodies
periostitis • Rarely, periostitis
Child Abuse
/Bleral radiograph shows dense, regular periosteal

reaction • in a 6 week old which was symmetric.
AP radiograph shows dense periosteal reaction •
represenUng healing following subperiosteal bleed from
I
There yvere no other abnormalities. Under the age of 6 a proximal metaphyseal corner fracture. The c/Jild had
months. rapid growth results in this normal appearance. other sites of periosteal reaction & fractures.
131
E PERIOSTEUM: PERIOSTITIS MULTIPLE BONES, CHILD
:>
Q)
ii5
o
'C
Q)
Q.
"en
41
(Left) Antemposterior
Child Abuse Multifocal Osteomyelitis
en'" radiograph shows periosteal
>- reaction. related to a
E metaphyseal corner fracture
.•..o seen only on the lateral
c'": view; fracture occurred 19
< days earlier. Periosteal
reaction should alert
radiologist to seek other signs
of nonaccidental trauma.
(Right) Antemposterior
radiograph shows periosteal
reaction along tibia. o( an
infant. Other bones were
similarly involved. Finding is
nonspecific but can be seen
with congenital infections
such as syphilis in this case.
Juvenile Idiopathic Arthritis UIA) Juvenile Idiopathic Arthritis UIA)

shows thin regular periosteal
reaction along many of the
phalanges. in this child,
along with soft tissue
swelling. (Right)
Posteroanterior radiograph in
the same patient also
demonstrates the periosteal
reaction _ The findings are
not specific but in this case
were the first manifestation
of /fA. In this age gmup,
sickle cell dactylitis would be
considered if the child was
black.
periosteal accretion along
the ulnar diaphysis _ This
was seen on other bonesl
including both legs. This 1
year old was being given
large doses of vitamin A.
shows thick & prominent
ulna _ Other bones
showed lytic lesions and
others showed simply
periosteal reaction in this
child with metastatic
medulloblastoma.
I
132
PERIOSTEUM: PERIOSTITIS MUlTIPLE BONES, CHILD »
-
::l
III
o
3
'<
llJ
III
Ul
Prostaglandin Periostitis Sickle Cell Dactylitis (1)
(Left) Late,a/,adiograph C.
shows thick, dense periosteal -U
reactionin the humerus. CD
:J.
as well as the bones of the o
Ul
forearm _ This infant had CD
been treated with c
prostaglandins for a cardiac 3
defect. (Right)
shows subtle periosteal
reaction. and underlying
bone abnormality in this
African-American child who
developed hand pain on the
first cold day of winter. This
represents a bone infarct in
sickle cell disease.
Caffey Disease Caffey Disease

shows dense periosteal new
bone formation along the
humerus as well as the radius
in this child. The child also
had mandibular periosteal
bone change, which is
considered highly suggestive
of Caffey disease. (Right)
thick, dense periosteal new
bone formation along all
long bones in a severe case
of Caffey disease. The
process is painful but
self-limited; this patient
returned to normal by 3
years of age.

what might be mistaken for
fluffy periostitis. along the
proximal humerus. This;s
aggressive subperiosteal
resorption in a patient with
renal disease; note the
rickets and slipped humeral
epiphysis _ (Right) AP
metaphyseal lines of Frankel
as well as a metaphyseal
corner fracture. in this
patient with scurvy. There
was a subperiosteal bleed,
and periosteal bone
formation is developing.
along the tibia.
I
133
"0
Q)
(/l
ARTHRITIS WITH NORMAL BONE DENSITY
co
(])
C DIFFERENTIAL DIAGNOSIS • Hand: 1st carpometacarpal (CMC),

'0
--, scapho-trapezoid-trapezium (SIT),
"0 Common interphalangeal (IP) joints
Cll
(/l
ltl
• Osteoarthritis (OA) • Distribution fairly symmetric
(])
• Erosive Osteoarthritis (EOA) o Density remains normal for the individual
>-
E • Gout • Erosive Osteoarthritis (EOA)
•...o
ltl
• Synovial Osteochondromatosis o a.k.a., inflammatory osteoarthritis
c: • Psoriatic Arthritis (PSA)
« • Pyrophosphate Arthropathy
o Retain normal density for the individual
• Focal periarticular osteopenia may occur
• DISH & OPLL (Mimics) during active inflammatory phase
• Pigmented Villonodular Synovitis (PVNS) o Majority of joint involvement is
• Neuropathic Arthropathy (Not Diabetic) productive (osteophyte-forming)
Less Common o IP joints (occasionally others) are erosive
• Hemochromatosis • Classic "gull-wing" appearance of direct
• Chronic Reactive Arthritis (CRA) subchondral erosion is often seen
• May have marginal & other erosive
Rare but Important
patterns
• Robust Rheumatoid Arthritis o Sites of involvement identical to OA
• Multicentric Reticulohistiocytosis
• Difference is the erosive character of the
IP joints
ESSENTIAL INFORMATION • Distribution is fairly symmetric
o Diagnosis of IP erosive disease depends on
other sites of involvement
• In all cases, discussion is not of end-stage • Productive or mixed erosive-productive
arthritis
involvement of CMC or SIT joints yields
o If joint is immobilized, by end-stage of
diagnosis of EOA
process bones will become osteopenic • Lack of involvement of other carpal
o Inflammatory processes, at end stage, will
joints or metacarpal phalangeal (MCP)
develop osteoporosis; this includes joints eliminates psoriatic or other
psoriatic arthritis, chronic reactive inflammatory arthritides
arthritis, gout, & robust RA
• Gout
• Patient may have the listed arthritides o Normal bone density retained unless other
superimposed on other processes which may patient factors are superimposed
make them osteopenic o Characterized by dense tophi, erosions
o Age & gender (senile, postmenopausal
with sclerotic margins
osteoporosis) o Relatively late cartilage destruction
o Metabolic bone disease
o Distribution
o Immobility (stroke, paraplegia: Disuse
• Rarely symmetric
osteoporosis)
• 1st metatarsophalangeal joint is classic
o Collagen vascular disease (systemic lupus
• Otherwise, remember that gout may be
erythematosus, dermatomyositis) seen anywhere!
o Use of steroids or other drugs causing
• Synovial Osteochondromatosis
osteopenia; alcohol abuse o Normal bone density retained unless other
Helpful Clues for Common Diagnoses patient factors are superimposed
• Osteoarthritis (OA) o Often (not exclusively) monoarticular
o OA is completely productive o Multiple round bodies of similar size
• Subchondral sclerosis, osteophytes • May not be visible on radiograph;
o Predictable sites of involvement diagnosed on MR
• Hip: 80% superolateral subluxation, 20% • Psoriatic Arthritis (PSA)
protrusio o Normal bone density retained unless other
• Knee: Varus> valgus deformity patient factors are superimposed
I
134
ARTHRITIS WITH NORMAL BONE DENSITY »
:;,
...•
III
o
• Exception may be periarticular • Knee: Patellofemoral compartment has 3
'<
osteoporosis seen during active earlier & more severe involvement than OJ
III
inflammatory process medial or lateral l/I
<Il
o May initially present as "sausage digit" • DISH & OPLL (Mimics) a.
• Ray distribution of soft tissue swelling o Mimic since joints not generally involved '-
Q.
::J
and periostitis o Bulky bridging anterior vertebral body
OJ
o May initially present as joint disease syndesmophytes (DISH> > OPLL) OJ
en
• Initially erosive; may become mixed o Both may have ossification of posterior <1>
a.
erosive-productive longitudinal ligament (OPLL > > DISH)
o Distribution • Pigmented VillonoduIar Synovitis (PVNS)
• Peripheral: Upper> lower extremity o Monoarticular; younger patient retains
• IP joints> MCP joints normal bone density
• Carpus: Not as predictable; pericapitate • Neuropathic Arthropathy (Not Diabetic)
• If spondyloarthropathy, bilateral but o One of features is retention of normal
asymmetric sacroiliac joint involvement, bone density (except diabetic)
bulky non-contiguous syndesmophytes o Others: Fragmentation, large effusion,
• Pyrophosphate Arthropathy disorder of joint
o Hemachromatosis has similar appearance Helpful Clues for less Common Diagnoses
radiographically to pyrophosphate • Chronic Reactive Arthritis (CRA)
arthropathy o Retains normal bone density; generally
• Hemochromatosis seen in males, young adult males
younger age than pyrophosphate o Peripheral: Lower> upper extremity
o Early phase erosive; mixed
o Spondyloarthropathy: Same as PSA
erosive-productive or purely productive
seen at end phase Helpful Clues for Rare Diagnoses
• Chondrocalcinosis frequently associated, • Robust Rheumatoid Arthritis
but may not be present o Continued use of joints in adult RA
• Retention of normal bone density in o Retention of bone density & large
absence of other patient factors subchondral cyst formation
o Distribution • Multicentric Reticulohistiocytosis
• Hand: MCP (especially 2nd & 3rd), o Nodularity soft tissues
radiocarpal (may also involve o Well-marginated erosions, especially IP
intercarpals with SLAC wrist deformity as joints
end result) o Occasional acroosteolysis
Osteoarthritis (OA) Erosive Osteoarthritis (EOA)
Anteroposterior radiograph shows large subchondral

cyst _ complete carti/age 1055 on the weight-bearing
Anteroposterior radiograph shows prominent erosions at
the 1sl carpometacarpal joint BI as well as an IP joint
I
surface, and osteophyte formation _ all typical of DA. •. Findings are of erosive osteoarthritis. Patient retains
NOle the normal bone density. normal bone density.
135
ARTHRITIS WITH NORMAL BONE DENSITY
"C
QI Gout Synovial Osteochondromatosis
VI (left) Oblique radiograph
I'<l
al shows a prominent dense
>. gouty tophus. along with
E an osseous erosion with
-o
I'<l
c:
overhanging edge _ The
bone density remains
< normal, as is typical of gout.
round osseous bodies.
within the elbow joint. The
bone density is normal, as is
expected with synovial
osteochondromatosis.
Psoriatic Arthritis (PSA)

radiograph shows IP erosive
disease, fusion of a DIP_
and enthesopathy •
Findings are typical of
psoriatic arthritis. Bone
density remains normal,
despite fairly advanced
disease. (Right)
shows advanced
with SLAC wrist deformity
• large subchondral cysts,
and chondroca/cinosis _
Despite the advanced wrist
disease, bone density
remains normal.
DISH & OPll (Mimics)

(left) lateral radiograph
shows large anterior bridging
osteophytes • but
otherwise normal vertebral
bodies. The concavity of the
anterior body is retained.
typical of DISH. Unlike
ankylosing spondylitis, DISH
retains normal bone density.
(Right) lateral radiograph
shows ossification of the
posterior longitudinal
ligament. & an anterior
osteophyte. typical of
OPLL. Bone density is normal
(process is not inflammatory
& normal motion is
retained).
I
136
ARTHRITIS WITH NORMAL BONE DENSITY »
::l
..•o
Ql
3
'<
OJ
Ql
VI
Pigmented Villonodular Synovitis (PVNS) Neuropathic Arthropathy (Not Diabetic) <1>
(Left) Anteroposterior Co
radiograph shows huge
'-
Q.
subchondral cysts on both
acetabular and femoral sides ..•
::l
of the joint in a patient with OJ

Q)
PVNS. Note that normal VI
Cl>
bone density is retained. Cl.

destructive changes in the
joint Ell resulting in
subluxation & fragmentation.
There are small osseous
fragments dissecting down
the leg" secondary to
overdistension of the joint.
Despite the severity of this
tabetic Charcot joint, bone
density remains normal.
Hemochromatosis Chronic Reactive Arthritis (CRA)

decreased cartilage width &
hooked osteophytes •• in a
young adult male with
hemochromatosis. As ;s
expected, bone density
remains normal. (Right)
Lateralradiograph shows a
large erosion, with
associated mild productive
change, at the posterior
calcaneus. This is typical, but
not pathognomonic of,
chronic reactive arthritis. The
normal bone density helps
differentiate it from
rheumatoid arthritis.
Robust Rheumatoid Arthritis Multicentric Reticulohistiocytosis

ulnar capping" large
subchondral cysts •• and
normal bone density in a
patient who has robust
rheumatoid arthritis. Note
the slight ulnar translocation
of the carpus. (Right) PA
radiograph shows soft tissue
nodules _ acroosteolysis
•• and well·defined IP
erosions Ell Normal bone
density ;5 retained. Findings
are typical of a rare disorder,
multicentric
reticuJohistiocytosis.
I
137
"0
Q) ARTHRITIS WITH OSTEOPENIA
en
co
co
C DIFFERENTIAL DIAGNOSIS o Purely erosive process; erosions are not
--,o well-marginated
"'C Common o Symmetric, typical distribution
<Il
VI
C1l
• Rheumatoid Arthritis (RA) • MCP, distal radioulnar, radiocarpal joint
to • Diabetic Charcot Joint • Uniform throughout knee
>- • Septic Joint
E • Uniform narrowing hip, with protrusio
-
«
o
C1l
c:
• Ankylosing Spondylitis (AS)
Less Common
• Diabetic Charcot Joint
o Charcot joints retain whatever bone
• Systemic Lupus Erythematosus (SLE) density was present prior to joint
• Juvenile Idiopathic Arthritis OIA) destruction
• Progressive Systemic Sclerosis (PSS) o Diabetic hands & feet are osteoporotic;
• Chronic Reactive Arthritis (CRA) neuropathic changes are atrophic
• Transient Osteoporosis (Mimic) • Septic Joint
• Hemophilia o Effusion & subchondral/cortical
• Inflammatory Bowel Disease Arthritis osteopenia are earliest changes
Rare but Important
o Osteopenia is hallmark of AS & occurs
• Amyloid Deposition diffusely and early in disease
• Adult Still Disease
• Other spondyloarthritides (psoriatic or
• Ochronosis CRA) do not have as early or widespread
• Wilson Disease osteopenia
• Mixed Connective Tissue Disease o Combination of osteopenia & spine fusion
• HIV-Associated Arthritis
puts spine at risk for fracture from minor
• Tuberculosis Septic Joint trauma
• Fungal Septic Joint
• Familial Mediterranean Fever Helpful Clues for Less Common Diagnoses
• Systemic Lupus Erythematosus (SLE)
o Osteopenia typical & widespread in SLE
ESSENTIAL INFORMATION • Due both to disease process & common
Key Differential Diagnosis Issues use of steroids
• Any highly inflammatory process will o Non-erosive deformities of hands & feet
present with FOCAL osteopenia • Simulates RA, but would expect erosions
o This includes diagnoses that are typically with the degree of deformity seen
considered to retain normal bone density, • Late in disease, mechanical erosions
including gout & psoriatic arthritis • Juvenile Idiopathic Arthritis OIA)
• Any end-stage arthritis that results in o Hyperemia from synovitis results in two
DISUSE will develop diffuse osteopenia typical features
• This list represents those arthritic diseases • Osteoporosis at involved joints
that most commonly PRESENT with • Overgrowth of epiphyses, but often early
osteopenia physeal closure - short limb
o The distinction in this list is not whether o Destructive arthritic process continues,
the processes present with osteopenia with erosions & cartilage loss
commonly or rarely, but the frequency o Systemic JIA may eventually show diffuse
with which the arthritis with osteopenia osteoporosis
occurs o Hemophilia has similar appearance to JIA
o Hemophilia may show "dense" effusions
• Hemosiderin deposition in synovium
• Rheumatoid Arthritis (RA)
• Low signal which "blooms" on MR
o Osteopenia is the hallmark of RA
• Progressive Systemic Sclerosis (PSS)
• Initially, with early inflammatory o Diffuse osteoporosis
change, location is juxtaarticular o Acroosteolysis with soft tissue calcification
• Later, with disuse, osteopenia is diffuse o Eventual mixed erosive/productive disease
I
138
ARTHRITIS WITH OSTEOPENIA l>
..
:J
III
o
• 1st carpometacarpal joint most severely o As in RA and JIA, juxtaarticular & eventual 3
'<
affected, with subluxation diffuse osteopenia develops OJ
III
• Chronic Reactive Arthritis (CRA) o Distribution of disease C/I
~
o During inflammatory phase of arthritis, • Identical to adult RA a.
develops juxtaarticular osteopenia • DIP and pericapitate predominance '-
Q
o Osteopenia is usually not widespread • Ochronosis ~
OJ
o CRA features o Osteoporosis is hallmark of disease III
C/I
• Bilateral asymmetric SI joint disease; o Usually extensive disk calcification CD
a.
bulky asymmetric syndesmophytes o Long-standing disease results in cartilage
• Peripheral disease favors lower extremity, breakdown and true arthritis
especially calcaneus • Wilson Disease
• Associated features: Urethritis (cervicitis) o Osteopenia in majority
& conjunctivitis o Excrescences, cortical irregularity, or small
• Transient Osteoporosis (Mimic) ossicles adjacent to bones
o Effusion & osteoporosis around a joint o Focal fragmentation - arthropathy
• Usually large joint (hip, knee) • Mixed Connective Tissue Disease
• MR shows effusion & marrow edema o Overlap (clinically & radiographically) of
o Differential is septic joint; must aspirate SLE, PSS, dermatomyositis, & RA
o Self-limited; does not affect cartilage o Osteopenia plus various manifestations of
• Inflammatory Bowel Disease Arthritis the above diseases
o Osteopenia is diffuse, usually related to • HIV-Associated Arthritis
steroid treatment of bowel disease o Usually incomplete clinical features of
o Arthritis pattern identical to that of AS CRA, but osseous features are same
• Symmetric SI disease, thin vertical spine • Tuberculosis & Fungal Septic Joint
syndesmophytes o Osteopenia is a routine feature
• Large proximal joint involvement o Slow but progressive destruction
o Little host reactive change
• Familial Mediterranean Fever
• Amyloid Deposition
o May develop arthropathy (usually hip)
o Amyloid usually occurs in patients with
o Initial osteoporosis & cartilage damage;
primary diseases resulting in osteopenia
eventual degenerative change
• End-stage renal disease, myeloma, RA
o Pain & disuse - focal osteopenia
AP radiograph shows uniform carli/age narrowing &

ligamentous laxity, with medial translation of the tibia
Oblique radiograph shows neuropaUlic joints al the
talonavicular. & calcaneocuboid _ Note the large
I
III Iypical of RA. The bones are so osteoporotic as 10 air collection in a lateral & plantar ulcer _ along with
have a mOlh-eaten appearance, a hallmark of RA. diffuse oSleopenia in U,isdiabetic foot.
139
1:l
Ql ARTHRITIS WITH OSTEOPENIA
'"
III
CO
C
'0
-,
"Ql Ankylosing Spondylitis (AS)
'"
I'll
CO
erosions & cartilage
>- destruction at the 5th MCP
E lEI. Both the 4th & 5th MCPs
-
~
o
I'll
r::
show severe osteopenia, due
to hyperemia. This 25 year
old man punched an
opponent in the mouth &
lacerated his knuckle. (Right)
syndesmophytes Ell.
ankylosis, & osteoporosis,
typical of A5. The
combination of limited
motion & osteoporosis
increases the risk of fracture
from minor injury, seen here
at the odontoid'"
Systemic Lupus Erythematosus (SLE)

diffuse osteopenia in a young
woman. There are severe
deformities that are not
erosive. Combination is
typical of 5L£. True
arthropathy with mechanical
erosions develops late in
disease. (Right) PA
osteopenia, MCP erosions
• and carpal fusion lEI in
a 22 year old. There is
overgrowth at the MCPs.
Findings are typical of !IA;
fusion would not be
expected in adult RA.
Progressive Systemic Sclerosis (PSS) Chronic Reactive Arthritis (CRA)

prominent acroosteolysis
with soft tissue calcification
__ typical of P55
(scleroderma). Bones are
typically osteopenic. Arthritis
develops late in the disease,
most frequently involving the
1st carpometacarpal joint
EllI. (Right) Lateral
radiograph shows effusion &
osteoporosis, secondary to
hyperemia in this young man
with chronic reactive
arthritis. eRA shows
osteopenia with active
inflammation, & has normal
density otherwise.
I
140
ARTHRITIS WITH OSTEOPENIA :I>
:l
..•o
Ql
3
'<
tll
Ql
III
Transient Osteoporosis (Mimic) Hemophilia tD
(Leh) AP radiograph shows Co
diffuse osteopenia of the '--
femoral head and, to a lesser Q.
extent, the acetabulum in a ;:l.
25 year old male. Note that tll
OJ
the cartilage width is normal III
C1>
•• Septic hip was Co
disproved, leaving transient
osteoporosis as a diagnosis
of exclusion. (Right) AP
osteoporosis, radial head
overgrowth" widening of
the intercondylar notch ••
and erosive articular disease.
This is all typical of
hemophilic arthropathy in
this 25 year old male.
Inflammatory Bowel Disease Arthritis

sacroillitis •• and a bowel
staple line" in this patient
with inflammatory bowel
disease arthritis. The
osteopenia is related to
steroid use as well as the
inflammatory process.
diffuse osteoporosis along
with erosive disease in the
MCP and carpal joints. The
patient does not have RA,
but rather amyloidosis,
related to underlying
multiple myeloma.
Osteoporosis is expected in
amyloidosis.
Adult Still Disease Ochronosis

(Leh) PA radiograph shows
diffuse osteoporosis. There is
fusion of a DIPjoint" as
well as erosions of the PIP
joints" the MCP joints are
relatively normal. The
adult Still disease. (Right)
shows diffuse oSleopenia,
typical of the disease process
in ochronosis. Late in the
disease, cartilage damage
and arthritis may occur •.
I
141
"0
Q) ARTHRITIS WITH PRODUCTIVE CHANGES
C/)
Cll
co
C DIFFERENTIAL DIAGNOSIS Helpful Clues for Common Diagnoses
--,o • Osteoarthritis (OA)
"t:l Common
Q) o OA is the classic purely productive
C/) • Osteoarthritis (OA)
Ol
aJ
arthropathy
• Gout
>- o Do not expect to see any erosions
• Pyrophosphate Arthropathy
-E
o
Ol
c:
<I:
• Abutment Processes
• Psoriatic Arthritis (PSA)
• Exception: Mechanical erosion if joint is
significantly malaligned
• Exception: Erosive (inflammatory) OA
o Location is useful adjunct in diagnosis
• DISH (Mimic)
• Chronic Reactive Arthritis (CRA) • Hand: IP joints> > MCP; 1st
• Inflammatory Bowel Disease Arthritis (IBD) carpometacarpal,
• Osteonecrosis (Mimic, with Secondary scapho- tra pezoid- tra pezi urn
Osteoarthritis) • Knee: Medial compartment often more
significantly involved, though may be
Less Common tri-compartmental
• SAPHO (Mimic) • Hip: Inferomedial osteophyte is most
• Retinoid Spondyloarthropathy (Mimic) prominent; usually superolateral
• Hemochromatosis subluxation femoral head
• OPLL (Mimic) • Gout
Rare but Important o Osteophyte formation is common, along
• Wilson Disease with normal bone density
o Focal erosions tend to be well-marginated,
often with productive change at edge
ESSENTIAL INFORMATION (overhanging edge)
Key Differential Diagnosis Issues o Location may be classic, but also may be
• Hint: Very few diseases are purely polyostotic with unusual locations
productive • Pyrophosphate Arthropathy
o Osteoarthritis o Earliest disease is erosive, then mixed
o DISH, OPLL, retinoid o End stage may be purely productive, with
spondyloarthropathy, SAPHO, abutment large osteophytes
processes • Has been described as "OA in an unusual
• Hint: Many processes may show coexistent distribution"
erosive and productive changes o Location is particularly useful for diagnosis
o Spondyloarthropathies (AS, PSA, IBD, CRA) • Carpus: Radiocarpal, often with
o Deposition arthropathies (gout, excavation of radius by scaphoid; may
pyrophosphate, hemochromatosis, result in SLAC (scapholunate advanced
Wilson) collapse) deformity
o One site may be predominantly • Hand: 2nd & 3rd MCP most commonly
productive, another erosive involved; other MCPs with advanced
• Hint: Processes that result in abnormal disease
alignment may result in mechanical erosions • Knee: Patellofemoral joint most
& productive changes prominently involved
o "Burned out" or inactive rheumatoid o Large subchondral cysts; normal density
arthritis o Chondrocalcinosis often present
• May appear confusing, with distribution o Hemochromatosis
of RAbut productive changes • Same appearance as pyrophosphate
superimposed on inactive erosive disease arthropathy, but in younger male patient
• Usually these have a mixed pattern, with • Abutment Processes
erosions seen as well as osteophytes o Most frequent is ulnar impaction due to
o Systemic lupus erythematosus ulnar positive variance
o Progressive systemic sclerosis
I
142
ARTHRITIS WITH PRODUCTIVE CHANGES »
:J
..•o
Ql
o Hamate & lunate may develop productive o DISH: Thoracic> cervical spine 3
'<
changes with SLAC wrist deformity o OPLL: Cervical> thoracic spine tc
Ql
o Impacted structure develops sclerosis, • Osteonecrosis (Mimic, with Secondary VI
(I)
osteophytes, subchondral cysts Osteoarthritis) Co

L
• Ankylosing Spondylitis (AS) o Severe & chronic AVN with flattening of Q.
o Disease begins as erosive (inflammatory) femoral head may develop secondary OA ~
OJ
o SI joints eventually fuse & spine develops • Osteophytes, eventual cartilage OJ
VI
productive changes (syndesmophytes & involvement (late) CD
C.
fusion) • Calcar buttressing along femoral neck
o Large proximal joints (hips, shoulders); Helpful Clues for less Common Diagnoses
erosive, mixed, or productive changes • SAPHO (Mimic)
o May have synchronous erosive change at o Sclerosis of anterior chest wall osseous
one site & productive change at another structures
o Diffuse osteopenia early in disease process • Clavicle, manubrium, ribs, costochondral
o IBD arthropathy, similar appearance cartilage
• Psoriatic Arthritis (PSA) o Not articular process; joints remain intact
o Disease begins as erosive (inflammatory) • Retinoid Spondyloarthropathy (Mimic)
o SI joints may eventually fuse & spine
o Use of retinoids may result in prominent
develops bulky syndesmophytes & may anterior syndesmophyte formation
fuse at facets o Entire spine may be involved
o Normal bone density usually retained o Generally facets are uninvolved & it is not
o PSA: Small peripheral joint involvement a true arthropathy
• Hands> feet o Suggestive of DISH, but in younger patient
• IP joints> MCP
• Chronic Reactive Arthritis (CRA) Helpful Clues for Rare Diagnoses
o Lower extremity peripheral joints • Wilson Disease
o Calcaneus> midfoot & forefoot> ankle o May produce "excrescences" of bone that
• DISH (Mimic) & OPLL (Mimic) mimic osteophytes

o Both may show large anterior bridging o May produce ossicles that mimic
osteophytes at spine (DISH> OPLL) osteophytes separated from underlying

o Both may ossify posterior longitudinal bone
ligament (OPLL > DISH) o Generalized osteoporosis
o Neither generally involves facets & o Eventually may develop true arthritis with
therefore is not a true arthritis mixed erosive/productive change
Osteoarthritis (OA) Gout
PA radiograph shows typical DIP involvement with OA.

There is loss of cartilage & osteophyte formation ••
PA radiograph shows productive changes in gout, with
osteophytes •• and overhanging edge" The disease
I
which broadens the base of the distal phalanges. On is active, with large dense tophi and adjacent erosion.
lateral view, these are especially prominent dorsally. 143
ARTHRITIS WITH PRODUCTIVE CHANGES
":a
Q)

aI classic pyrophosphate
>- arthropathy, with SLAC
E deformity & radiocarpal
.9 productive changes" as
~ well as hook-like osteophyte
oct formation at the MCP heads
11II.No erosive changes are
seen at this advanced stage.
(Right)PA radiograph shows
ulnar positive variance III
that has resulted in abnormal
load and abutment on the
lunate & triquetrum. The
lunate shows sclerosis and
osteophytes are seen at both
the lunate & triquetrum •.
Ankylosing Spondylitis (AS)

(Left)AP radiograph shows
what appears to be typical
OA, with osteophyte
formation. subchondral
cyst" and calcar
buttressing Ell. However,
this male is only 25 years
old, and another source for
these abnormalities must be
considered. (RighI) AP
radiograph in the same
patient shows bilateral SI
joint sclerosis and advanced
erosive. disease. The
patient has AS; note that the
manifestations are erosive in
the SI joint but productive in
the hip at this time.
Psoriatic Arthritis (PSA) DISH (Mimic)

tremendous productive
change in the form of
enthesopathy at the tips of
the malleoli •• in this patient
with psoriatic arthritis.
Though articular changes
almost always appear
erosive, earfy findings may
be productive, with
periostitis. (Right) Lateral
radiograph shows bulky
bridging anterior
syndesmophytes typical of
DISH Ell. Note that the
anterior concavity of the
vertebral bodies is retained
=:I & bone density is normal.
I
144
»
ARTHRITIS WITH PRODUCTIVE CHANGES
..
~
01
o
3
'<
Inflammatory Bowel Disease Arthritis III
01
III
Chronic Reactive Arthritis (CRA) (IBD) (l)
shows fluffy osseous '-
Q.
productive change atlhe
poslerior tubercle of lhe ~
calcaneus .:I as well as the
OJ
Ql
plantar aponeurosis insertion en
site _ This dense bone
production is seen about the
'"
0.
calcaneus with CRA. (Right)

Anleroposlerior radiograph
shows a large oSleophyle
ringing the lefl femoral head
Ell in a patient wilh
inflammatory bowel disease.
Nole lhe mixed
erosive/productive change at
lhe 51joints ., the patienl
has spondyloarthropalhy.
Osteonecrosis (Mimic, with Secondary

Osteoarthritis)
(Left) Anteroposlerior
flallening of lhe femoral
head from AVN _ This is a
chronic process, which has
resulled in secondary DA.
Note the ring oSleophyle al
the femoral head.:l as well
as calcar buttressing Ell
(Right) Coronal NECT shows
dense sclerosis of the lefl
manubrium _ Note that
the clavicle and joint are
normal; this is not a true
arthritis, but the sclerosis
may mimic this process.
Hemochromatosis
carli/age loss particularfy
involving lhe 2nd & 3rd MCP
joints, with oSleophyle
formalion _ A large
hook-like osteophyte is seen
allhe 3rd MC head III.
Findings in lhis young male
are typical of
hemochromalosis. (Right)
PA radiograph shows bony
excrescences arising from the
lunate. and radius III in a
patienl showing diffuse
osteoporosis. This productive
change is one of lhe
manifestations of Wilson
disease.
I
145
EROSIVE ARTHRITIS
DIFFERENTIAL DIAGNOSIS • Uniform involvement hip, knee,

shoulder, elbow
"'C Common • Erosive Osteoarthritis (EOA)
Ql
II)
I"(l
• Rheumatoid Arthritis (RA) o Erosive or mixed erosive/productive
10 • Erosive Osteoarthritis (EOA) change IP joints
>- • Gout
E o Involvement of 1st carpometacarpal
-
o
I"(l
c:
«
• Pigmented Villonodular Synovitis (PVNS)
(CMC) & scapho-trapezium-trapezoid
• Usually productive as in typical OA, but
• Ankylosing Spondylitis (AS) may be erosive
• Psoriatic Arthritis (PSA) o No other findings to suggest PSA
• Pyrophosphate Arthropathy • Gout
• Juvenile Idiopathic Arthritis OIA) o Erosions prominent when active; later
• Septic Joint show sclerotic margins
• Charcot, Neuropathic (Mimic) o Dense tophi, overhanging edges help
• Hyperparathyroidism (HPTH) (Mimic) suggest diagnosis
Less Common • Pigmented Villonodular Synovitis (PVNS)
• Arthroplasty Component Wear/Particle o Nodular synovitis directly invades bone
Disease (Mimic) o Monostotic; normal bone density
• Chronic Reactive Arthritis (CRA) o Low signal masses which enhance on MR
• HIV-Related Arthritis • Synovial Osteochondromatosis
• Inflammatory Bowel Disease Arthritis (IBD) o Multiple round bodies, ± ossified
• Hemophilia o Usually monostotic, with bodies entirely
• Amyloid Deposition intraarticular; occasionally extraarticular
• Systemic Lupus Erythematosus, Late (SLE) o May focally invade bone, causing erosion
• Progressive Systemic Sclerosis, Late (PSS) • Ankylosing Spondylitis (AS)
• Ochronosis (Alkaptonuria) o Early SI joint arthritis tends to be
• Tuberculosis & Fungal Septic Arthritis symmetric & is erosive, often - fusion
o Large proximal joints (hips, shoulders)
Rare but Important
• Erosive initially, may become mixed or
• Adult Still Disease purely productive
• Robust Rheumatoid Arthritis o With long-standing disease, small
• Multicentric Reticulohistiocytosis peripheral joints may become involved
o Osteoporosis develops early in disease
ESSENTIAL INFORMATION o IBD arthritis: Similar appearance
o Peripheral disease favors hands (especially
• Erosions may have different basic etiologies IP joints), but may involve feet as well
o Inflammatory: Majority of processes
• May initially be seen as sausage digit,
o Mechanical: Neuropathic, SLE with periostitis
o Direct invasion: PVNS, synovial
• Early joint disease is erosive; may
osteochondroma tosis become mixed or rarely productive
o Subchondral collapse: HPTH
o SI joints generally bilaterally asymmetric
Helpful Clues for Common Diagnoses • Early SI joint disease is erosive, but may
• Rheumatoid Arthritis (RA) progress to fusion
o The most classic solely erosive arthropathy • Syndesmophytes are productive, but
• Exceptions: Ulnar "capping" in active RA; facet disease begins as erosions,
OA may develop in inactive RA sometimes progressing to fusion
o Location is symmetric & constant • Pyrophosphate Arthropathy
• MCP, distal radioulnar joint, radiocarpal o Begins as erosive disease, often becomes
joint; eventually intercarpal joints and IP mixed erosive/productive & may
• MTPs, particularly 5th eventually appear purely productive
I
146
EROSIVE ARTHRITIS >
..
;]
III
o
o Location-specific o Since at joint surface, collapse mimics an 3
'<
• Hands: Radiocarpal, 2nd & 3rd erosion tD
III
metacarpals (Me) o Locations are typical III
(I)
• Knee: Patellofemoral compartment • IP joints, occasional carpal bones Co
involved earlier & more severely than (mimics PSA) '-

Q.
medial or lateral compartments • SI joints (mimics widening of early ~
OJ
o ± Chondrocalcinosis spondyloarthropathy) III
o Large subchondral cysts often present • Distal clavicle (mimics erosions of RA or '"
Ctl
Q.
• Juvenile Idiopathic Arthritis (JIA) traumatic osteolysis)

o Hemophilia Helpful Clues for Less Common Diagnoses
o Both diseases arise during childhood,
resulting in overgrowth of epiphyses Disease (Mimic)
o Both result in erosive joint disease
o Osteolysis from particle disease may mimic
o Location similar for both diseases: Knee>
erosion or subchondral cyst
elbow> ankle> hip • Chronic Reactive Arthritis (CRA)
o JIA often has ankylosis of carpal or IPs
o HIV-related arthritis: Similar appearance
o Hemophilia is gender-specific & may have
o Peripheral disease favors lower extremity
dense effusions due to hemosiderin (especially foot & calcaneus)
deposition in synovium o Sacroiliitis bilateral & asymmetric
• Septic Joint (Including TB & Fungal) • Amyloid Deposition
o Early changes: Effusion, hyperemia ~
o Deposition in cartilage, bone, synovium
osteopenia may ~ erosion
o ~ Cartilage destruction & focal erosions • Systemic Lupus Erythematosus, Late (SLE)
• Charcot, Neuropathic (Mimic) o Deforming, generally non erosive
o Cycle of unprotected abnormal motion ~
o Subchondral cysts, very rarely erosions
bone fragmentation & ligament instability • Progressive Systemic Sclerosis, Late (PSS)
~ subluxation, dislocation ~ further o Most patients eventually develop erosions
fragmentation o Acroosteolysis, soft tissue calcification
o "Erosions" mimicked by fragmentation
• Ochronosis (Alkaptonuria)
donor sites o Late in disease cartilage may fragment,
• Hyperparathyroidism (HPTH) (Mimic) leading to destructive disease
o One of the many types of bone resorption
is subchondral Helpful Clues for Rare Diagnoses
o Resorption & weight-bearing ~ collapse • Adult Still Disease: Erosive, as RA
Rheumatoid Arthritis (RA) Rheumatoid Arthritis (RA)
PA radiograph shows soft tissue swelling and marginal

erosions •• at the PIP joint. A marginal location (within
PA radiograph in the same patient shows the marginal
erosions III but a/50 much more advanced
I
the joint capsule but where bone is not protected by subchondral erosions in the MCP joints •. The
cartilage) is typical for earfy erosive change. osteoporosis & ulnar deviation is classic as well.
147
"0
<1> EROSIVE ARTHRITIS
Vl
<1l
CD
C
·0
....,
"t:l
Ql Erosive Osteoarthritis (EOA) Gout
Ul (Left) PA radiograph shows
<1l
CD erosive disease involving the
>. IPjoint" This is not
E specific, but when combined
.•..o<1l with arthritis at the 1st
c: carpometacarpal joint IEIII
< and scapho-trapezium-
trapezoid joint III the
diagnosis is confirmed as
EOA. (Right) Anteroposterior
erosive disease of the digits
o( the feet III of this elderly
male. Additionally, there is
dense tophaceous material,
as well as an overhanging
edge Ell all characteristic of
gout.
Pigmented Villonodular Synovitis (PVNS)

(Left) Coronal T2WI MR
shows a huge glenoid
erosion Ell and smaller
humeral head erosion ••
There is low signal material
lining the synovium •• as
well as the erosions. This is a
teenager; the findings are
typical o( PVN5. (Right) Axial
bone CT shows multiple tiny
ossified bodies. scattered
throughout the knee joint
and extending into the
extraarticu/ar 50ft tissues.
There are large pressure
erosions Ell in this patient
with aggressive synovial
chondromatosis.
Psoriatic Arthritis (PSA)

radiograph shows erosive
disease in moderately early
AS. 51joint shows widening
& mild sclerosis EIll hip
shows cartilage loss &
erosions •. Later in the
process, productive changes
& (usion will occur. (Right)
PA radiograph shows DIP
erosivedisease. thatis so
severe that it has been
termed "pencil-in-cup"
deformity & results in
"telescoping digits". Psoriatic
arthritis certainly may show
more mild disease, but this is
the end stage.
I
148
EROSIVE ARTHRITIS

erosions" along with large '-
subchondral cysts EiII and Q.
chondrocalcinosis in the ~
TFCC" The predominance CD
Ql
of radiocarpal disease is also
typical of pyrophosphate
'"a.
(\)
arthropathy. (RighI)
shows severe thinning of the
femoral neck from erosive
disease" (remember the
neck is intracapsular) as well
as a direct subchondral
erosion of the femoral head
EiII in a patient with
advanced /lA. There is
cartilage destruction as well.
Charcot, Neuropathic (Mimic)

contrast injected into a hip
joint following aspiration for
septic hip. The contrast
outlines severely thinned
cartilage & enters erosions in
the acetabulum" showing
the erosive nature of the
process. (Right) Oblique
radiograph shows "erosive"
disease at the Lisfranc joints
•• in this diabetic
neuropathic joint. Note the
offset of the metatarsals
relative to the tarsals. The
"erosions" are due to
fragmentation, followed by
resorption of the debris.
Arthroplasty Component Wear/Particle

Disease (Mimic)
what appears to be marginal
•• and subchondral EiII
erosions in the DIPs of a
patient with HPTH. The
disease causes subchondral
resorption, followed by
collapse which mimics
erosions. (Right) AP
lytic lesion" that might be
mistaken for erosion or
subchondral cyst related to
the underlying arthropathy.
However, this acetabular
component has "shed"
several metallic microspheres
_ resulting in osteolysis.
I
149
"0
OJ EROSIVE ARTHRITIS
III
ro
CD
C
'0
-,
"0
Gl Chronic Reactive Arthritis (CRA) H IV-Related Arthritis
III (Left) Lateral radiograph
l'll
CD shows a large erosion of the
>.
E
•...IIIo
calcaneus =-
posterior tubercle of the
This location
is typical of involvement by
c: CRA, which may be erosive
< initially. Later productive
disease will yield fluffy
periostitis. (Right) PA
radiograph shows swelling of
the index finger Isausage
digit) with narrowing of the
DIP" and periostitis"
This patient has HIV-AfD5;
such patients may develop
an arthropathy similar to
chronic reactive arthritis.

(IBD) Hemophilia
radiograph shows sclerotic &
eroded, but not yet fused, 51
joints". The patient has
staple lines indicating
ileoanal pull-through Ell for
IBD. The left hip has AVN
with collapse. secondary
to steroid use. IRight) Lateral
erosions. in the settingof
a large dense effusion.
typical of hemophilia. Note
the overgrowth of the patella
& femoral condyles relative
to the gracile diaphyses.
ItM5K Req).
Systemic Lupus Erythematosus, Late

Amyloid Deposition (SLE)
the DIP joints =-

radiograph shows erosions in
There is
nothing specific about the
erosion, but the patient also
had large soft tissue masses
over the dorsum of the wrist;
biopsy proved amyloid.
(Right) Oblique radiograph
shows severe subluxation
and swan neck deformities of
the digits, typical of the
deformities found in 5LE.
This is lale disease, and
mechanical erosions have
formed at the DIP III and
MCP •.
I
150
EROSIVE ARTHRITIS »
::::l
...•
III
o
3
'<
OJ
Progressive Systemic Sclerosis, Late III
VI
(PSS) Ochronosis (Alkaptonuria) (1)
(Left) PA radiograph shows Co
the acroosteolysis • and
50ft tissue calcifications.
'-
o
typical of progressive ~
OJ
systemic sclerosis. This is late OJ
disease, and the patient has VI
<1l
developed erosions Ell. The Co
1st CMC joint was

subluxated (not shown), as is
typical in late PSS. (Right)
shows diffuse osteoporosis
and severe erosive disease of
the hip _ Ochronosis may
develop cartilage
fragmentation and erosive
disease late in the disease
process.

osteoporosis, cartilage
destruction, and erosive
disease of the triquetrum,
ulna, radius, and lunate _
This is a septic radiocarpal
joint; aspirate proved a
fungal etiology:
Sporotrichosis. (Right) PA
radiograph shows IP erosive
disease. in a patient who
also has ankylosis of a DIP
joint El!l The findings could
be seen in either psoriatic or
adult Still disease; the
osteoporosis favors the latter,
which was proven.
Robust Rheumatoid Arthritis Multicentric Reticulohistiocytosis

severe erosive disease at the
MCPs • and the intercarpal
joints, in the distribution of
RA. There are large
subchondral cysts __
robust rheumatoid arthritis.
a combination of findings
typical of multicentric
reticulohistiocytosis. These
include nodular soft tissue
swelling __ acroosteolysis
__ and erosions at the DIP
joints El!l The soft tissue
nodules differentiate it from
psoriatic arthritis.
I
151
"0
(f)
Q) MIXED EROSIVE/PRODUCTIVE ARTHRITIS
ctl
en
C DIFFERENTIAL DIAGNOSIS • Appears identical to pyrophosphate
·0
-, arthropathy; occurs in younger males
"0 Common • Erosive Osteoarthritis (EOA)
Ql
III
III
• Pyrophosphate Arthropathy o IP joints show early erosions, may be
en • Erosive Osteoarthritis (EOA) mixed with osteophytes later
>-
E • Gout o 1st carpometacarpal (CMC) joint &
-o
III
c:
<l:
scapho-trapezium-trapezoid (SIT)
involvement confirms EOA as diagnosis
less Common • May be erosive, but usually productive
• Chronic Reactive Arthritis (CRA) • Gout
• Inflammatory Bowel Disease Arthritis (lED) o Early erosions develop sclerotic margins
• Hemochromatosis later, associated osteophytes
Rare but Important
o Early erosions SI joints, generally
• SAPHO bilaterally symmetric, followed by fusion
o Large proximal joints (hip, shoulder) may
ESSENTIAL INFORMATION show both erosions & osteophytes
o Smaller peripheral joints show mixed
disease, but involved only late in process
• Purely erosive arthritis (RA) drops off list o lED arthritis appears similar
• Purely productive arthritis (classic OA) and
• Psoriatic Arthritis (PSA) & Chronic
mimics (DISH, OPLL) drop off this list Reactive Arthritis (CRA)
• Hint: Most of the diagnoses on this list o Peripheral joints (hands predominate in
show erosive disease early, then progress to
PSA, foot/ankle predominate in CRA)
mixed & may end as purely productive • May have early periostitis, sausage digit
Helpful Clues for Common Diagnoses o SI joint disease bilateral but asymmetric
• Pyrophosphate Arthropathy o SI & peripheral joint disease begin erosive
o Erosions early (particularly articular surface but progress to productive
patella, radiocarpal joint) Helpful Clues for Rare Diagnoses
o Followed by osteophyte formation
• SAPHO
(particularly hook-like osteophytes at o Sclerosis (particularly anterior chest wall)
MCPs, patellofemoral joint) defines productive change
o ± Chondrocalcinosis
o Synovitis uncommon, actual erosions rare
o Hemachromatosis
Pyrophosphate Arthropathy Erosive Osteoarthritis (EOA)
I Lateral radiograph shaws a mid-patellar erosion ••

mixed with osteophytes •• in the patellofemoral joint of
PA radiograph shaws mixed disease, with osteophyte
seen at the IP of the thumb •• and predominantly
a middle-aged patient with meniscal chondrocalcinosis; erosive disease at the PIP joints" The CMC and STT
the diagnosis is pyrophosphate arthropathy joints showed productive change; this is EOA.
152
MIXED EROSIVE/PRODUCTIVE ARTHRITIS :l>
::::l
...•
III
o
3
'<
III
III
C/l
Gout (!l
(Left)Lateralradiograph Co
shows a large dense tophus, L
indicating gout in this elderly 2.
woman. There is osteophyte ~
formation. seen OJ
OJ
simultaneously with active en
Cll
erosive disease. a typical C.
pattern for gout. (Right) Axial
bone CT shows mixed
erosive/productive disease in
the axial skeleton, with
prominent erosions allhe
sternoclavicularjoints. at
the same time that the axial
skeleton is fused; this image
shows fusion at the
costovertebral joints •

productive disease in the
form of periostitis and
osteophytes • along with
erosions predominantly at
the DIPjoints _ There is
normal bone density; the
psoriatic arthritis. (Right) AP
radiograph shows complete
bilateral 51joint fusion" as
well as primarily erosive
disease in the left hip _
This may be a typical
appearance for AS, but the
patient has advanced CRA,
involving the more proximal
joints.
Hemochromatosis
(Left) AP radiograph in a 2/
year old woman with Crohn
disease shows erosive
change at the 51joint __
indicating
spondyloarthropathy. The
hip shows cartilage loss and
osteophyte formation ••.
The patient has /80
spondyloarthropathy. (Right)
PA radiograph shows mixed
erosive" and productive
• disease in a man with
hemochromatosis. The same
location and appearance
may be seen with
pyrophosphate arthropathy.
I
153
ARTHRITIS WITH LARGE SUBCHONDRAL CYSTS
DIFFERENTIAL DIAGNOSIS • Calcar buttressing (thickening of medial

femoral neck)
"t:l Common • Superolateral subluxation femoral head
CIl
VI
III
• Osteoarthritis (OA) • Sclerosis
al • Pyrophosphate Arthropathy • Cartilage narrowing in weight-bearing
>- • Rheumatoid Arthritis (RA)
E region
-
«
o
III
r::
• Gout
• Massive Osteolysis/Particle Disease
• Subtle osteophytes
• Pigmented Villonodular Synovitis (PVNS) o Subchondral cysts are a prominent part of
• Cysts, Chronic Repetitive Trauma the arthropathy
Less Common o Those in tibial condyle are not
• Giant Cell Tumor Tendon Sheath (Mimic) infrequently misdiagnosed as neoplasm
• Hemophilia • Knee pyrophosphate arthropathy often
• Juvenile Idiopathic Arthritis OIA) shows initial subtle erosive change at the
• Amyloid Deposition patellofemoral compartment
• Hemochromatosis • Chondrocalcinosis in meniscus or
hyaline cartilage may be subtle or absent
Rare but Important
o Those in carpal bones are multiple &
• Robust Rheumatoid Arthritis
prominent
• Often have associated radiocarpal disease
• Chondrocalcinosis in TFCC or hyaline
• Chronic Reactive Arthritis (CRA)
cartilage may be obvious, subtle, or
absent
ESSENTIAL INFORMATION • May have associated SLAC (scapholunate
advanced collapse) deformity
• Subchondral cysts may occur with any o Subchondral cysts may be huge
arthropathy
o Size tends not to be appreciated on
o Some diseases are particularly prone to
radiograph due to diffuse osteoporosis
large cyst formation
o MR shows extent of cyst formation, along
o This feature may be useful in suggesting a
with other abnormalities
diagnosis
• Gout
• Subchondral cysts may be so large that they o Subchondral cysts tend to be
mimic neoplasm
well-marginated unless active
o Hint: In diagnosing a subchondral
o May be mistaken for neoplasm
neoplasm, always look for a suggestion of
o Watch for associated findings
arthropathy
• Dense soft tissue tophi
• In weight-bearing bones, large subchondral
• Overhanging edge at osseous erosion
cysts may result in pathologic fracture
• Massive Osteolysis/Particle Disease
o Particularly in knee, secondary to
o Generally 4 considerations for lytic lesion
pyrophosphate arthropathy or gout
adjacent to arthroplasty
Helpful Clues for Common Diagnoses • Cyst related to underlying arthropathy,
• Osteoarthritis (OA) residual from arthroplasty placement
o Large subchondral cysts seen particularly • Metastasis or myeloma (patients are in
in acetabulum the age group for these lesions & they
• Termed "Egger cyst" must be considered)
o Cyst often is initial finding in OA of hip • Stress shielding (region of metaphysis
• Hint: Be careful not to misdiagnose that no longer carries significant weight,
Egger cyst as neoplasm resulting in osseous resorption)
o Watch for other subtle signs of hip OA • Massive osteolysis, relating to particle
disease
I
154
ARTHRITIS WITH LARGE SUBCHONDRAL CYSTS »
o Sources of particles: Breakdown of bone, o Overgrowth of epiphyses/metaphyses,

-
:J
III
o
3
'<
polyethylene, metallic beads, cement dense effusion may suggest diagnosis CD
III
• Watch particularly for asymmetry of • Juvenile Idiopathic Arthritis OIA) VI
(I)
acetabular cup liner or tibial tray liner to o Females more frequent; usually teenager or Co
indicate polyethylene wear young adult '-

Q.
o Osteolysis may be far greater in extent o Subchondral cysts can be large, along with 3-
OJ
than suggested on radiograph erosions & cartilage damage OJ
en
• CT with reformats demonstrates extent o Overgrowth of epiphyses/metaphyses CD
Co
of lysis & any pathologic fracture (ballooned epiphyses) may suggest
• Pigmented Villonodular Synovitis (PVNS) diagnosis
o Cyst formation may be large, or else o Cervical spine fusion suggests diagnosis
entirely absent • Amyloid Deposition
o On radiograph tend to be well-marginated o Deposits in bone may result in large
o Monoarticular lesion, generally teenager or subchondral cysts
young adult o Associated thickening & low MR signal of
o MR shows characteristic intraarticular low tendons & joint capsule
signal mass, either nodular or lining o Generally secondary: Myeloma or end
synovium stage renal disease predispose to amyloid
• Cysts, Chronic Repetitive Trauma • Hemochromatosis
o Fairly location-specific o Younger male patient, similar to
Helpful Clues for Less Common Diagnoses pyrophosphate arthropathy

• Giant Cell Tumor Tendon Sheath (Mimic) Helpful Clues for Rare Diagnoses
o Extraarticular mass within tendon sheath • Robust Rheumatoid Arthritis
o Most frequent site: Digits, especially hand o Continued use of involved joint during
o May cause focal osseous erosion, even on active disease results in synovial fluid
both sides of a joint, simulating articular being forced into subchondral bone
process with cyst formation • May result in large subchondral cyst
o Watch for soft tissue mass location, often formation
not centered over joint in question o Distribution similar to adult RA; bone
• Hemophilia density retained
o Male, usually teenager or young adult • Spondyloarthropathies (AS, PSA, CRA)
o Subchondral cysts can be large, along with o Small, but rarely large subchondral cysts
erosions & cartilage damage are seen
Osteoarthritis (OA) Pyrophosphate Arthropathy
Anteroposterior radiograph shows a large sulxhondral

cyst _ termed Egger cyst at this location. There is also
Anteroposterior
cyst • in
radiograph shows a large sulxhondral
a knee that also demonstrates
I
a 1055 of cartilage, superolateral subluxation, & chondrocalcinosis III. The combination is typical of
osteophyte formation, a"typical of osteoarthritis. pyrophosphate arthropathy
155
-0
Q) ARTHRITIS WITH LARGE SUBCHONDRAL CYSTS
(/)
ell
lD
C
·0
-,
"ns
Q)
Pyrophosphate Arthropathy Rheumatoid Arthritis (RA)
'"
lD
(Left)Posteroanterior
radiograph shows large
>- subchondral cys(S within the
-
E
o
ns
c:
ct
scaphoid, capitate, &
hamate, typical of
pyrophosphate arthropathy.
There is chondrocalcinosis in
the hyaline cartilage" as
well as the TFCC•
confirming the diagnosis.
(tMSK Req). (Right) Sagiual
T2WI FS MR shows large
subchondral cys(S ••
extending down the humeral
shaft Rotator cuff tear is
seen, with fluid in the
subdeltoid bursa Ell
common in RA.
Massive Osteolysis/Particle Disease

(Left)Axial CECTshows a
subchondral cyst occupying
the entire lateral femoral
condyle. The cyst is so
large that it simulates a
neoplasm. The patient had
gout of the first MTp, & this
"lesion" proved to be gout
as well. (tMSK Req). (Right)
Coronal bone CT shows
massive osteolysis in the
acetabulum. developing
from particle disease. The
source of the particles is
wear of the polyethylene
cup, demonstrated by the
asymmetric position of the
head within the cup Ell
Pigmented Villonodular Synovitis (PVNS) Cysts, Chronic Repetitive Trauma

shows a large subchondral
cyst occupying nearly the
entire glenoid. This is a
monoarticular process in a
15 year old. There is low
signal nodular materia/lining
the synovium Ell typical of
PVN5. (Right) Axial PO FSE
MR shows subchondral cys(S
Ell in a patient with
osteolysis of the distal
clavicle, related to chronic
repetitive trauma (a male
cheerleader who lifted
"stocky" cheerleaders). The
patient developed a fracture
through the cys(S.
I
156
ARTHRITIS WITH LARGE SUBCHONDRAL CYSTS >
::J
..•o
III
3
'<
Giant Cell Tumor Tendon Sheath CD
III
(Mimic) III
ltl
(Left) PA radiograph shows Q.
large "cystic" lesions

occupying the head of the
'-
Q.
1st MC and base of the ;:!.
adjacent phalanx ElIl CD
OJ
mimicking an arthritic
process. Howeve" the soft
'"
C1l
C.
tissue mass is not associated
with the joint •. This
proved to be a giant cell
tumor of the tendon sheath
with local invasion. (Right)
large subchondral cysts
occupying most of the talus
_ with an erosive process
of the tibiotalar joint in this
hemophilic patient.
Juvenile Idiopathic Arthritis (JlA) Amyloid Deposition

an end-stage elbow in a
patient with)fA. There is
widening of the trochlear
notch, complete loss of
cartilage with severe erosive
change lit and a large
subchondral cyst •. (Right)
large subchondral cyst
containing low signal
material ElIl along with
thickening of the rotator cuff
tendons •. This patient had
amyloid deposition involving
the shoulder, which may
result in formation of large
cysts. rtMSK Req).
Hemochromatosis Robust Rheumatoid Arthritis

large hook-like osteophytes
at the MCP joints ElIl along
with prominent subchondral
cysts _ This is
hemochromatosis; it is
sometimes forgotten that the
disease may have erosive
characteristics. (Right) PA
radiograph shows huge
subchondral cysts. in the
MCPs of a patient who has
erosive disease in the
distribution of rheumatoid
arthritis. With robust disease,
synovial ffuid is forced into
the subchondral bone,
forming large cysts.
I
157
"0
<l> ATROPHIC JOINT DESTRUCTION
<Il
ro
co
C DIFFERENTIAL DIAGNOSIS o Differentiate from rheumatoid arthritis by
"0
-, rapidity of destructive changes
1:1
Common • Diabetic Foot: Charcot
Gl
III
III
• Rheumatoid Arthritis o Location: Lisfranc, talonavicular,
ell • Septic joint intertarsal, hindfoot-midfoot (Chopart)
>. • Diabetic Foot: Charcot
E o Distribution: Unilateral, asymmetric
-
o
III
l::
«
• Syringomyelia: Charcot
Less Common
o Bone resorption & fragmentation
o Amount of debris varies; often resorbed,
• Hemophilia: MSK Complications resulting in atrophic destruction
• Tuberculosis Arthritis o Variable degree of reactive sclerosis
• Fungal Arthritis o Large joint effusion
o Joint subluxation or dislocation
Rare but Important o Can be difficult to distinguish neuropathic
• Rapidly Destructive Osteoarthritis of Hip joint from osteomyelitis
• Chondrolysis, Post-Traumatic • Sinus tract to bone favors osteomyelitis
• Confluent low signal on Tl WI favors
ESSENTIAL INFORMATION osteomyelitis
• Abscess next to bone favors osteomyelitis
Key Differential Diagnosis Issues • Syringomyelia: Charcot
• "Atrophic": Joint destruction with resorption o Location: Shoulder, elbow, cervical spine
of most debris & a relative paucity of o Distribution: Unilateral
reactive sclerosis o Bone fragmentation that mimics erosions
Helpful Clues for Common Diagnoses • Mild intraarticular bone debris common
• Rheumatoid Arthritis • Debris should not be confused with
o Location: Metacarpophalangeal, proximal tumor matrix (chondrosarcoma mimic)
interphalangeal, carpal joints, & similar • Extensive resorption of bone mimics
locations in feet are most common surgical resection
o Distribution: Polyarticular, bilateral, o Large joint effusion
symmetric • Clinically often mistaken for soft tissue
o Periarticular erosions, progress centrally mass
o Destruction may result in arthritis • Fluid can dissect away from joint
mutilans o No reactive change in the bone
o Demineralization o joint often subluxed or dislocated
o Ligamentous laxity - subluxation, o Image cervical spinal cord for syrinx
dislocation o Rapid destruction mimics septic arthritis
o Edematous synovium with effusion Helpful Clues for Less Common Diagnoses
o Intraarticular rice bodies
• Hemophilia: MSK Complications
o Rheumatoid nodules along extensor
o Location: Knee, elbow, ankle
surfaces or bony prominences o Distribution: Polyarticular, asymmetric
o Shoulder involvement associated with o Dense effusion from hemorrhage
rotator cuff tear & erosion of acromion o Synovitis & periarticular erosions
and distal clavicle • Can mimic Hill-Sachs deformity
• Septic joint o Subchondral cysts
o Location: Knee, hip, shoulder, spine
o Growth deformities
o Distribution: Monoarticular; polyarticular
• Overgrown epiphyses & metaphyses
less common from hyperemia
o Rapid cartilage & bone destruction
• Wide intercondylar notch of knee
o Involves entire joint
• Premature growth plate closure
o Large effusion, displaced fat pads
o Blooming signal on gradient echo MR
o Demineralization on both sides of joint
sequences from hemosiderin in joint
o Secondary osteoarthritis late
I
158
ATROPHIC JOINT DESTRUCTION :I>
::l
...•.
III
o
• Tuberculosis Arthritis • Low signal intensity lines on MR parallel 3
'<
o Location: Spine, hip, knee the subchondral bone IJl
III
o Distribution: Monoarticular o Lacks demineralization VI
lTl
o Slow clinical course compared with o Normal acetabulum excludes C.
pyogenic septic joint; little debris inflammatory or infectious arthritis '-

Q.
o Extensive marginal erosions • Chondrolysis, Post-Traumatic 3-
IJl
• More sclerotic rim than hemophilia o Location: Hip, shoulder OJ
VI
o Severe demineralization o Distribution: Monoarticular ct>
C.
o Preservation of joint space until late o History of trauma, surgery, burns or
o Growth disturbance if skeletally immature immobilization
o Spine involvement shows preservation of o Synovitis present
disc space & paravertebral abscess o Bone scan shows increased tracer uptake
• Fungal Arthritis on both sides of joint
o Location: Distal extremities
Alternative Differential Approaches
o Distribution: Monoarticular
• Monoarticular joint destruction &
o Indolent course
demineralization
o Marked osteoporosis
o Pyogenic infectious arthritis
o Destruction of joint space late
o Charcot joint
o Similar appearance to tuberculous arthritis
o Tuberculous infectious arthritis
Helpful Clues for Rare Diagnoses o Fungal infectious arthritis
• Rapidly Destructive Osteoarthritis of Hip o Chondrolysis, post-traumatic
o Location: Hip o Rheumatoid arthritis, monarticular
o Distribution: Unilateral o Chronic reactive arthritis
o Rapid onset of clinical symptoms • Polyarticular joint destruction &
o Rapid chondrolysis followed by osseous demineralization
destruction o Rheumatoid arthritis
o "Hatchet deformity": Absent femoral head o Progressive systemic sclerosis
with well-defined border of femoral neck o Hemophilia
• Neoplasm or avascular necrosis would o Chronic reactive arthritis
appear as a poorly marginated process o Lupus erythematosus, late
o May represent insufficiency fracture of the o Ankylosing spondylitis
femoral head
Rheumatoid Arthritis Rheumatoid Arthritis
lilteral radiograph shows severe destructive arthritis

producing uniform cartilage loss • with erosions
Anteroposterior radiograph shows destruction of the
shoulder joint _ Charcot from syringomyelia could be
I
involving all bones of the elbow There is diffuse considered but involvement was symmetric, which
osteoporosis and a large joint effusion. virtually never happens with Charcot joints.
159
"0
Ql ATROPHIC JOINT DESTRUCTION
III
III
CD
C
'0
--,
"tl Rheumatoid Arthritis Septic Joint
Q)
III (Left) Anteroposterior
III
CD radiograph shows carpal
>. collapse with probable
-
E
o
«'"
!:
fusion of some of the carpal
bones. Note the marked
narrowing of the intercarpal
spaces ~ and radiocarpal
joint ~ Degenerative
changes are minimal
compared to the degree of
joint space narrowing.
shows severe narrowing of
the interphalangeal joint of
the great toe" Osseous
destruction of the articular
surfaces has occurred along
both sides of the joint Ell
Diabetic Foot: Charcot Diabetic Foot: Charcot

(Left; Anteroposterior
radiograph shows resorption
of the talus, leaving the tibia
articulating with the
morphologically abnormal
calcaneus. and leaving
the navicular without
proximal articulation" The
calcaneocuboid joint is
disrupted Ell (Right) Lateral
radiograph shows dislocation
and erosive change of the
talonavicular joint Ell There
is a/so subluxation with
debris formation at the
calcaneocuboid joint III and
a hypertrophic nonunion of a
fibular fracture •.
Syringomyelia: Charcot
(Left; Anteroposterior
radiograph shows abrupt
cut-off of the humeral head
•. almost a surgical
appearance. Given the
extent of the osseous
destruction; the amount of
bony debris is small. This is
typical of Charcot shoulder
due to syringomyelia. (Right)
Coronal T1WI MR shows a
destroyed humeral head •.
surrounded by fluid in the
distended joint Ell The fluid
communicates between the
glenohumeral joint and
subdeltoid bursa through a
rotator cuff tear.
I
160
ATROPHIC JOINT DESTRUCTION :l>
:l
...•
III
o
3
'<
lJl
III
VI
Hemophilia: MSK Complications Hemophilia: MSK Complications nI
radiograph shows signilicant '-
erosive change _ as well as Q.
subchondral cyst lormation. ;?
Note the relative overgrowth CD
OJ
01 the distal lemur and VI
(l)
proximal tibia and the a.
widened intercondylar notch
~ (Right) Lateral
loss 01 cartilage width _ an
ellusion and subchondral
cyst formation in the elbow.
The prominently overgrown
radial head Ell is due to the
hyperemia resulting Irom the
repetitive bleeding episodes.
radiograph shows signilicant
destruction of the
glenohumeral joint ••.
While one might consider
neuropathic joint as a
diagnosis, it is important to
note the densely calcilied
mass in the right upper lobe
•• due to tuberculosis.
radiograph shows erosion
and demineralization. of
the 2nd through 5th
tarsometatarsal joints. This
indolent fungal infection was
due to Coccidioides immitis.
Rapidly Destructive Osteoarthritis of Hip Chondrolysis, Post-Traumatic

radiograph shows absence o(
the lemoral head. The
remaining femoral neck is
sharply marginated without
aggressive leatures _
known as the hatchet
delormity. (Right)
shows complete loss 01
cartilage" involving the lelt
hip. The lemoral head is
medially displaced indicating
slipped capital lemoral
epiphysis which was
previously stabilized, seen by
pin tracts _ Chondrolysis is
a known complication.
I
161
U
<Il ARTHRITIS MUTllANS
<f1
ro
CD
DIFFERENTIAL DIAGNOSIS • Scoring systems to grade joint mutilation are

rarely used except for research
"'C Common • Due to end-stage joint destruction,
Ql
I/)
l'Il
• Rheumatoid Arthritis differentiating between the differential
CO • Psoriatic Arthritis diagnosis entities is often not possible
>- • Charcot, Neuropathic
-
«
E
o
l'Il
c:
less Common
without clinical information
• Rheumatoid Arthritis
• Gout o 5% of cases lead to arthritis mutilans
• Hyperparathyroidism (Mimic) o MCP & PIP joints most severely affected
• Diabetes: MSK Complications o Decreased bone mineralization
• Chronic Reactive Arthritis • Psoriatic Arthritis
• Mixed Connective Tissue Disease o 5% of cases lead to arthritis mutilans
Rare but Important o Interphalangeal joints severely affected
• Congenital Insensitivity/Indifference to Pain o Erosions & periostitis
• Leprosy o Normal bone mineralization
• Cutaneous T Cell Lymphoma • Charcot, Neuropathic
o Joint destruction, distention,
disorganization, debris
ESSENTIAL INFORMATION o Mixed erosive & productive bone changes
Key Differential Diagnosis Issues o MR to help differentiate neuropathic from
• a.k.a., "Ia main en lorgnette", opera glass septic joint changes
hand, or resorptive arthropathy Helpful Clues for less Common Diagnoses
• Destructive form of arthritis involving the • Diabetes: MSK Complications
hands and feet o Due to neuropathic joint changes
• Resorption of bone ends with collapse of the o Most commonly in foot & wrist
soft tissues
• Produces "telescoping joints" and Helpful Clues for Rare Diagnoses
"pencil-in-cup" deformities; hint: This does • Congenital Insensitivity/Indifference to
not always indicate psoriatic arthritis Pain
o Rare cause of neuropathic joint
• Involvement is usually bilateral, regardless of
underlying cause o More likely to be polyarticular than classic
• Spontaneous joint fusion is common Charcot joints
Rheumatoid Arthritis Psoriatic Arthritis
I Oblique radiograph shows typical changes 01 arthritis

mutilans. The joints are severely eroded, producing
Oblique radiograph shows diffuse erosive change 01 the
metatarsophalangeal joints, with early pencil-in-cup
pencil-in-cup delormities _ subluxations III erosions •. The patient a/so had sacroiliitis &
dislocations IIiIl and resultant shortening 01 the digits. enthesopathy. typical 01 psoriatic arthritis.
162
ARTHRITIS MUTILANS »
-
:J
OJ
o
3
'<
Dl
OJ
Juvenile Idiopathic Arthritis (JIA) Gout
'a."
(l)
carpal fusion Ell and

extensive erosive change.
'-
Q.
The metacarpophalangeal ;::.
• and carpal. joint CD
Q)
spaces are narrowed and
deformed in this young adult
'"a.
(1)
patient with JIA. (Right) AP

radiograph shows erosions
involving nearly every joint
of the foot, resulting in
overall shortening of the
digits. They are large and
somewhat bizarre in
appearance. One of the
larger erosions is
juxtaarticular in location III
suggesting gout.
Hyperparathyroidism (Mimic) Chronic Reactive Arthritis

radiograph shows distal
interphalangeal joint
destruction. approaching
a pencil-in-cup appearance.
This patient had no true
arthropathy; she had
hyperparathyroidism,
resulting in subchondral
resorption & collapse. (Right)
shows predominantly erosive
change at the MTP. and
great loe IP joint" The
spondyloarthropathies may
exhibit erosive, productive,
or mixed patterns of arthritic
disease.
Congenital Insensitivity/Indifference to
Pain
shows severe deformity of
the ankle and hindfoot, with
destruction of the tibiotalar,
subta/ar, talonavicular, and
calcaneocuboid joints •.
The remaining joints in this
limb were normal. (Right)
shows marked destruction of
most of the phalanges.
Additionally, there is linear
calcification in the location
of a digital nerve" This
combination of Findings is
pathognomonic for leprosy.
(tMSK Req).
I
163
"0
Q) NEUROPATHIC OSTEOARTHROPATHY
en
ro
IJ)
C DIFFERENTIAL DIAGNOSIS o Syringomyelia: Shoulder> > elbow, hand
·0
--, o Paraplegia: Spine, below level of injury
"'C Common o Alcohol: Hip
C1l
III
CO
• Diabetes: MSK Complications o Syphilis: Knee> hip> spine
IJ) • Charcot, Syringomyelia o Congenital insensitivity or indifference to
>- • Charcot Spine, Paraplegia
E pain: Knee> ankle
•..o
CO less Common Helpful Clues for Common Diagnoses
c:
« • Charcot, Congenital Insensitivity to Pain • Diabetes: MSK Complications
• Charcot, Congenital Indifference to Pain o Generally atrophic & osteoporotic
• Charcot, Alcoholic o Lisfranc > Chopart > talonavicular
• Charcot, Syphilis o Early malalignment & fragmentation
• "Tall Man" Insensate Neuropathy o Later loss of integrity of arches &
Rare but Important associated ulceration/infection
• Charcot, lntraarticular Steroid Use • Charcot, Syringomyelia
• Charcot, Multiple Sclerosis o Clinical signs of "mass" (due to distended
• Charcot-Marie-Tooth Disease joint) mislead to diagnosis of tumor
• Riley-Day Syndrome • Destruction & debris in joint may
• Spinal Cord Compression mislead to diagnosis of chondrosarcoma
• Peripheral Nerve Tumors • Charcot Spine, Paraplegia
• Meningomyelocele o Generally stabilized at level of injury
• Polio o Uncontrolled motion & insensate distal to
• Leprosy stabilization lead to Charcot spine

o Differential is disk space infection (patient
population is prone to this as well)
Key Differential Diagnosis Issues • Charcot, Congenital Insensitivity to Pain
• Charcot joints usually classic & similar o Fragmentation multiple joints in child
o Disorganization of joint o Normal bone density; corneal & skin scars
o Osseous debris (though may be atrophic) • Charcot, Congenital Indifference to Pain
o Distension of joint (huge effusion) o Same as congenital insensitivity to pain
o Normal bone density (for the patient) • "Tall Man" Insensate Neuropathy
• Location may differentiate among etiologies o No other etiology found but tall stature
o Diabetes: Foot> > hand noted in this population
Diabetes: MSK Complications Charcot, Syringomyelia
I Sagittal radiograph shows disrupUon of the Chopart joint

•. with IitcJedebris bue distension at the dorsum of the
An/eroposterior radiograph shows destrucUon of the
humeral head, with cut-off appearance. Osseous debris
joint. There is also a fracture of the fibula •• not lines a distended axillary & subscapularis bursa •.
noticed by the paUent, who is diabeUc. Findings are typical of Charcot (rom syringomyelia.
164
NEUROPATHIC OSTEOARTHROPATHY »
-
j
Ql
o
3
'<
OJ
Ql
VI
Charcot, Congenital Insensitivity to Pain l1)
(Leh) Lateral ,adiograph C.
shows disruption at several L
thoracic vertebral bodies, Q.
with osseous debris _ MR ~
confirmed absence of OJ
OJ
abscess. This paraplegic Ul
CD
patient has an unstable spine Cl.
below his level of injury,

resulting in Charcot changes.
(Right) Sagitlal T2WI FS MR
shows a large effusion and
osseous fragmentation at the
posterior lateral femoral
condyle •. The
contralateral knee appeared
similar. This teenager proved
10 have congenital
insensitivity to pain.
Charcot, Syphilis
shows complete destruction
of the distal tibia, fibula,
talus, calcaneus, and
midfoot This teenager had a
similar appearing
contralateral knee. He has
congenital indifference to
pain. (Right) AP radiograph
shows fracture and
dislocation of the hip, along
with abundant debris within
a distended joint The
combination represents
Charcot joint; the patient
had tertiary syphilis. Typical
sites of syphilis Charcot joint
are hip, knee, & spine.
"TallMan" Insensate Neuropathy Charcot, Intraarticular Steroid Use

radiograph shows
neuropathic Choparl
(hindfoot/midfootJ joint Ell.
The patient had a peripheral
neuropathy but no
explanation for it other than
his tall stature. (Right) Lateral
radiograph shows large
effusion. as well as
fragmentation at the tibial
plateau Ell. This patient had
a long history of intraarticular
steroid injections, resulting in
neuropathic joint.
I
165
"0
<lJ ARTHRITIS WITH PRESERVED CARTILAGE SPACE
C/l
ro
co
C DIFFERENTIAL DIAGNOSIS • Disease progression results in relatively
-,o early marginal erosions & cartilage
"'C Common damage
<lJ
C/l
n:l
• Any Arthritis in Early Stages o Osteoarthritis (Early)
CO o Rheumatoid Arthritis (Early) • Early disease, especially in hip, may show
>. o Osteoarthritis (Early)
E subchondral cyst (Egger cyst) without
-o
n:l
c:
<l:
o Septic Joint (Early)
o Psoriatic Arthritis (PSA) (Early)
other findings
• Other early features: Osteophytes,
o Pyrophosphate Arthropathy (Early) subchondral sclerosis
o Ankylosing Spondylitis (AS) (Early) • Though radiographs show normal "joint
o Juvenile Idiopathic Arthritis OIA) (Early) space", may have cartilage damage
o Hemophilia (Early) o Septic Joint (Early)
o Chronic Reactive Arthritis (CRA) (Early) • May see distension of joint (effusion)
• Gout prior to cartilage damage
• Femoral Acetabular Impingement (FAI) • May have early deossification of articular
• Osteonecrosis (Mimic) cortex secondary to hyperemia
• Systemic Lupus Erythematosus o Spondyloarthropathies (PSA, AS, CRA)
• Pigmented Villonodular Synovitis (PVNS) • Early sacroiliac (SI) joint disease is
• Synovial Osteochondromatosis erosive, with apparent "joint widening"
Less Common • Even if joint space appears preserved,
• Infection with Low Virulence Organisms cartilage damage is present once erosive
o Tuberculosis disease is established
o Fungal • Peripheral joints may show early
• Silastic Arthropathy (Mimic) preservation of cartilage with
deossification secondary to hyperemia &
Rare but Important
synovitis
• Amyloid Deposition o Pyrophosphate Arthropathy (Early)
• Cartilage space retained in early disease,
ESSENTIAL INFORMATION despite cartilage damage
• Disease begins with erosions, progresses
Key Differential Diagnosis Issues to mixed or productive
• Hint: Condition of cartilage is dependent on • Highly location-specific: Radiocarpal,
stage in which it is evaluated MCP joints, patellofemoral compartment
o Initial stages of inflammatory arthritides of knee
retain normal cartilage width o Juvenile Idiopathic Arthritis alA) (Early)
o All arthritides, even those classically stated
• Early stages of hyperemia show
to retain cartilage, eventually may result in epiphyseal overgrowth & osteoporosis
cartilage destruction • Cartilage damage occurs later
• Hint: Even if cartilage width appears normal o Hemophilia (Early)
on radiograph, MR with contrast may show • Early stages of hyperemia from recurrent
fraying, focal defects, or delamination joint bleeds show epiphyseal overgrowth
Helpful Clues for Common Diagnoses & osteoporosis
• Arthritides that normally involve cartilage, • Cartilage damage & erosions occur later
presenting at early stage • Watch for dense erosions (hemosiderin
o Rheumatoid Arthritis (Early) deposition in synovium)
• With very early disease, synovitis may • Gout
result in distension of joint & apparent o Classic arthropathy said to preserve the
increase in cartilage width on radiograph cartilage over a relatively long term
• Early MR shows bone edema, synovitis, o Even in presence of large tophi, erosions,
tenosynovitis overhanging edges, cartilage may remain
intact
I
166
ARTHRITIS WITH PRESERVED CARTILAGE SPACE >
• Femoral Acetabular Impingement (FAI) o Cartilage damage is uncommon & late in

-
:J
'o"
3
'<
o FAI (cam or pincer mechanism), if not disease process lD
III
addressed, results in OA at a young age • Synovial Osteochondromatosis l/J
CD
• Cam mechanism: Decrease in femoral o Synovial metaplasia does not affect Co
L.
head/neck cutback (usuaIly lateral cartilage until late in process Q.
:J
femoral neck "bump") Helpful Clues for LessCommon Diagnoses OJ
• Pincer mechanism: Increase in anterior • Infection with Low Virulence Organisms Q)
Ul
or lateral femoral head coverage by o TB, fungal
CD
C.
acetabulum o Noted for slow joint destruction
o Early stage may show only the
o Osteopenia, late cartilage damage, little
morphologic abnormalities, with preserved host reaction
cartilage space • Silastic Arthropathy (Mimic)
• MR arthrogram may show cartilage o Careful observation required to identify
thinning, defect, or delamination, along relatively radiolucent silastic implant
with labral tear o Generally no metal associated with device
• Osteonecrosis (Mimic) o Rectangular implant may appear to
o AVN is not an arthritis; occurs on only one
"preserve" the joint space
side of joint o Most common locations: MCP, MTP, IP
• Preserved cartilage is a hallmark of AVN joints, carpal bone replacements
o Cartilage not affected until secondary OA
o As implant breaks down, osteolysis may
develops, late in process become prominent
• Systemic Lupus Erythematosus • Implants & bone around them break
o Noted for deformities without erosions or
down due to underlying osteoporosis &
cartilage damage ligamentous imbalance
• Particularly hand & foot deformities:
MCP, MTP, IP deviation/subluxation Helpful Clues for Rare Diagnoses
• Appears similar to RA, but severity of • Amyloid Deposition
deformities would have associated o MR shows low signal deposits in
erosions in RA subchondral bone, tendons, capsule
o Noted for avascular necrosis o Cartilage damage tends to be late
• Pigmented Villonodular Synovitis (PVNS) o Diagnosis generaIly secured by MR
o Erosions are direct, related to sites of o Association with multiple myeloma,
nodular masses end-stage renal disease, RA
Rheumatoid Arthritis (Early) Osteoarthritis (Early)
PA radiograph shows early RA with soft tissue swelling

about the Mep joints {I, 2nd PIP joint _ No erosive
AP radiograph shows one of the earliest signs of OA of
the hip, an Egger cyst _ At this early stage there is no
I
change is seen, but there is modest widening, rather cartilage narrowing, osteophyte {ormation. or change in
than narrowing of Mep joints •• related to synovitis. alignment
167
-0
CIl ARTHRITIS WITH PRESERVED CARTILAGE SPACE
'"ro
CD
C
'0
-,
"0
Gl Psoriatic Arthritis (PSA) (Early)
Anteroposterior
''""
CD
(Leh)
radiograph shows an early
>- septic hip (Staphylococcus)
E in a 29 year old diabetic.
o
•... There is an effusion, and the
c'": cortex of the femoral head
< has become indistinct.
due to hyperemia. No
cartilage narrowing is seen.
sofclissue swelling in a ray
distribution along the 3rd
digit _ Dense periostitis is
noted along the proximal
phalanx _ The apparent
cartilage narrowing allhe
PIPis due to flexion of the
joint.
Pyrophosphate Arthropathy (Early) Ankylosing Spondylitis (AS) (Early)

subchondral cysts. and
early hook-like osteophytes
• in the 2nd and 3rd
MCPs. This is typical of
either pyrophosphate
arthropathy or
hemochromatosis. Cartilage
is preserved early in the
disease. (Right) AP
radiograph shows bilateral
widening of the 51joints •
from erosive change in this
18 year old with AS. There is
a small osteophyte at the hip
•. Neither joint shows
radiographic evidence of
cartilage space narrowing.
Juvenile Idiopathic Arthritis (JIA) (Early) Hemophilia (Early)

early JIA, with soft tissue
swelling at the MC?s and
overgrowth of the
metacarpal head.
secondary to hyperemia.
There is no cartilage
narrowing at this point.
shows a huge joint effusion
••• as well as overgrowth of
the femoral condyles relative
to the diaphyses in this
teenaged male hemophilic.
The overgrowth is secondary
to hyperemia from repeated
bleeding episodes; cartilage
narrowing is not yet seen.
I
168
ARTHRITIS WITH PRESERVED CARTILAGE SPACE »
:3
..•o
III
3
'<
OJ
III
VI
Gout ~
(Leh) Lateral radiograph Co
shows oSleopenia but no
cartilage narrowing in this
'-
Q.
patient with chronic reactive ~
arthritis. loints of the foot OJ
OJ
showed more advanced VI
<1l
disease, but this early disease 0.
of the knee shows no true
erosive or cartilage change.
a large dense gouty tophus
• with prominent erosive
change and overhanging
edge. typical of fairly
advanced gout. Despite the
advanced disease, the
carli/age width" remains
normal.
Osteonecrosis (Mimic)
lateral femoral neck bump
• & retroversion of the
acetabulum. resulting in
FAIfrom the cam & pincer
mechanisms, respectively.
MR arthrogram showed a
large bucket-handle labral
tear, but cartilage was intact.
radiograph shows end-stage
AVN of the femoral head
with collapse. Despite
the severity of collapse, the
cartilage width is intact _
AVN does not affect the
cartilage until secondary OA
develops.
Silastic Arthropathy (Mimic)

(Leh) PA radiograph shows a
deforming arthritis, with
significant subluxation of the
Meps. The alignment
suggests RA, but in the
absence of cartilage
narrowing or erosions (as in
this case) SLEshould be the
diagnosis. (Right) Oblique
radiograph shows, at first
glance, normal cartilage
width. However, the
cartilage space is occupied
by a rectangular silastic
implant. which has a
flange anchoring it in the
phalanx.
I
169
WIDENED JOINT SPACE
DIFFERENTIAL DIAGNOSIS o Layering fat, serum, & cells on cross-table

lateral radiograph or cross-sectional
"0 Common imaging
Ql
II)
01
• Muscle Atony • Septic Joint
ClI • Ligament Injury o Wide joint space from effusion
>. • Hemarthrosis
-
E
o
01
c:
<l:
• Septic joint
• Retained Fracture Fragment
• Patellofemoral joint of knee most
common in adults
• Hip most common in children
o Sacroiliac & sternoclavicular joints at risk
• Subluxation/Dislocation in debilitated or immunosuppressed
• Entrapped Soft Tissue within Fracture patients
• Pigmented Villonodular Synovitis o Periarticular osteopenia progresses to
• Viral (Toxic) Synovitis cartilage & bone destruction
• joint Effusion, Unspecified o Reactive marrow & soft tissue edema
Less Common • Rheumatoid Arthritis
• Developmental Dysplasia of the Hip o Distribution: Bilateral, polyarticular,
• Nerve Injury, Unspecified symmetric
• Synovial Osteochondromatosis o Early joint space widening and
• Gout periarticular osteopenia

• Tuberculosis o Late joint space widening due to synovitis
• Legg-Calve-Perthes & joint effusion, uncommon
• Narrowed joint spaces more common
Rare but Important
• Retained Fracture Fragment
• Marfan Syndrome o Wide joint space from displaced bone
• Ehlers-Danlos fragment preventing reduction
• Acromegaly o Hip from posterior dislocation and
• Lipoma Arborescens, Knee acetabular fracture in adults
o Elbow from displacement of epicondyle in
ESSENTIAL INFORMATION children
o joint hemarthrosis
• Subluxation/Dislocation
• Numerous etiologies produce widening of o Wide joint space from joint incongruence
the joint space of varying severity o Posterior dislocation of shoulder & hip can
o Effusion, injury, cartilage thickening, bone
produce widened appearance
destruction • Entrapped Soft Tissue within Fracture
• May be entirely nonspecific on radiographs o Wide joint space from displaced soft tissue
Helpful Clues for Common Diagnoses preventing reduction
• Muscle Atony • Pigmented Villonodular Synovitis
o Wide joint space due to laxity of o Wide joint space from effusion &
surrounding musculature intraarticular deposits
o Commonly seen as inferior subluxation of o Distribution: Monarticular
humeral head after stroke or fracture o Nodules with low signal T1WI & T2WI and
• With fracture, can be misinterpreted as gradient echo "blooming"
indicating brachial plexus injury or o Underlying bone erosion may occur
hematoma o Knee> ankle> hip> shoulder
• Ligament Injury • Viral (Toxic) Synovitis
o Wide joint space from damage to o Wide joint space from effusion & synovitis
supporting soft tissues o Correlate with history of viral illness,
o Common in distal tibiofibular joint usually respiratory
• Hemarthrosis o Differentiation from a bacterial septic joint
o Wide joint space from effusion can be challenging & require aspiration
I
170
WIDENED JOINT SPACE »
::J
• Joint Effusion, Unspecified o Wide joint space from effusion & bone
-
Ol
o
3
'<
o Infectious, inflammatory, neoplastic, & destruction OJ
Ol
metabolic entities may all cause effusion o Distribution: Monoarticular 1Il
CD
o Pediatric hip effusion differential diagnosis • Spine> hip> knee a.
• Hemarthrosis (trauma), septic hip, o Slower clinical course than septic joint C-
O
juvenile idiopathic arthritis, & viral • Legg-Calve-Perthes ~

CD
(toxic) synovitis o Wide joint space from bone destruction or Q)
(J)
Helpful Clues for Less Common Diagnoses subluxation C1l

a.
o Preadolescent male children most
• Developmental Dysplasia of the Hip
common
o Wide joint space from joint capsule laxity
& other factors Helpful Clues for Rare Diagnoses
o Shallow acetabulum with laterally • Marfan Syndrome
subluxed femoral head o Wide joint space from ligamentous laxity
o Female newborns most common o Tall stature, scoliosis, rib notching
• Nerve Injury, Unspecified o Sternoclavicular & hip joint dislocation
o Wide joint space from effusion & bone • Ehlers-Danlos
destruction o Wide joint space from ligamentous laxity
o Joint disorganization, dislocation or o Triphalangeal thumbs
deformity o Radioulnar synostosis
o Neuropathic changes most common • Acromegaly
• Syringomyelia in shoulder o Wide joint space from cartilage
• Diabetes in ankle & foot hypertrophy
• Synovial Osteochondromatosis • Metacarpophalangeal most common
o Wide joint space from effusion & o Wide bones with normal cortex
intraarticular bodies o Spade-like phalangeal tufts
• Osseous or cartilaginous bodies are o Thick heel pad
usually visible on radiographs • Lipoma Arborescens, Knee
o Distribution: Monoarticular, large joints o Wide patellofemoral joint from
most common intraarticular lipoma
• Gout o Mass follows fat signal intensity on all
o Wide joint space from effusion & tophi sequences
• Tuberculosis
Muscle Atony
Anteroposterior radiographshows greater tuberosity.

and surgic~ll neck Ell fractures. Inferior subluxation.
Coronal
membrane.
STIR MR shows disruption of the interosseous
in an acute syndesmotic sprain. There is
I
of the humeral head is due 10 muscle alony and is a extensive sofl lissue edema 11:I withOul fracture. The
common finding after humeral neck fracture. anterior tibiofibular ligament was tom.
171
"0
Q) WIDENED JOINT SPACE
(/)
co
[Xl
C
--,o
"C
Q)
Hemarthrosis
(/)
CO
[Xl shows a large effusion ••
>. that widens the
E patellofemoral joint. A small
-<
o
CO
c:
fat-fluid level is present •.
A vertical lateral tibial
plateau fracture was visible
on additional views. (Right)
Sagittal T2WI FS MR shows
osteomyelitis of the distal
humerus secondary to septic
arthritis of the elbow. There
is a significant joint effusion
~ and diffuse soft tissue
edema Ell The effusion has
resulted in widening of the
radiocapite/lar joint space.

widening of the MCP joint
spaces. but no erosive
change or other indication of
arthropathy. This may be the
earliest manifestation of
rheumatoid arthritis, due to
synovitis. This patient was
rheumatoid factor positive &
later developed erosions.
(Right) Axial T2WI FS MR
shows an effusion and
synovitis widening the distal
radioulnar joint ~ Extensive
tenosynovitis HI is also
present. Erosions in the hand
and wrist were typical of
Retained Fracture Fragment Retained Fracture Fragment

radiograph shows an
entrapped medial epicondyle
Ell An avulsed medial
epicondyle may displace into
the elbow joint due to
contraction of the common
flexor muscles. (Right)
fracture of a large portion of
the anteroinferior femoral
head, leaving behind a large
donor site" A small
fracture fragment produces
mild widening" of the joint
space. These injuries were
due to a posterior hip
dislocation.
I
172
WIDENED JOINT SPACE »
-
~
III
o
3
'<
OJ
III
Subluxation/Dislocation Subluxation/Dislocation
(Leh) Anteroposterior,
'"
CD
Co
internal rotation radiograph
'-
Q.
shows joint space widening
• suggesting a posterior 2-
shoulder dislocation. The OJ
Ql
fact that external rotation
& standard axillary views
AP
'"n.
CD
could not be obtained

supports the diagnosis,
which was confirmed on a
lateral axillary view. (Right)
Axial bone CT shows the
right clavicle is both superior
and posterior in location.
relative to the normal left
clavicle EiIl This represents a
posterior dislocation of the
right sternoclavicular joint.
Pigmented Villonodular Synovitis Viral (Toxic) Synovitis

(Leh) Axial T1 C+ FS MR
shows a distended distal
radioulnar joint •. The joint
is filled by a complex
effusion containing multiple
nodular low signal
abnormalities, which
appeared to "bloom" on
gradient echo imaging.
"leardrop distance" (space
between proximal femoral
metaphysis & radiographic
teardrop) is slightly larger on
the right EiIII than the left •.
This indicates the presence
of an effusion.
Joint Effusion, Unspecified

(Leh) Sagittal PO FSEMR
shows a large joint effusion
EiIII widening the
patellofemoral joint and a
thickened medial plica •.
The medial plica is usually
present in knees, but when it
is thickened, it may
contribute to
chondromalacia. (Right)
shows a developmental
dysplasia with superior and
lateral dislocation of the left
femur. and a shallow
acetabular roof •. Compare
with the normally positioned
right hip joint EiIl
I
173
"0
CIl
WIDENED JOINT SPACE
en
ro
lD
C
'0
-,
"0 Developmental Dysplasia of the Hip
Ql
CIl (Left) Frogleg lateral
ltl
lD radiograph shows a shallow
» left acetabular roof. and
E subluxation of the left femur
•...o
ltl
laterally Ill. The right hip is
c: in normal position. (Right)
< Coronal T2WI MR shows a
destroyed humeral head.
surrounded by fluid in the
distended joint HI. The fluid
communicates between the
glenohumeral joint and
subdeltoid bursa through a
full thickness rotator cuff
tear. The findings are typical
of Charcot shoulder. As
expected, the etiology was
syringomyelia.
(Leh) Coronal STIR MR

shows axillary nerve
hyperintensity. related to
injury from a /uxatio erecta
shoulder dislocation (now
reduced). Though not shown
on the supine MR, in the
upright position the shoulder
"drooped", giving the
appearance of a widened
joint space & related to the
nerve injury. (Right) Lateral
tiny ossified bodies, too
numerous to count,
distending the elbow joint &
located in the anterior III &
posterior joint space •.
Tuberculosis
(Leh) Axial T2WI MR shows
a heterogeneous mass in the
distal radioulnar joint. It had
low signal intensity on both
TlWI and T2WI. This
mass had caused an erosion
in the ulna, typical of gout.
destruction of the
glenohumeral joint III with
prominent surrounding
osseous debris. The presence
of superior hilar retraction
III and a calcified lung mass
favored tuberculosis over
neuropathic change from
syringomyelia.
I
174
}>
WIDENED JOINT SPACE
..
:J
III
o
3
'<
1XI
III
VI
legg-Calve-Perthes (l)
(Left) Axial NEeT in the C.

same patient as prior image
'-
o
glenohumeral joint =-
shows destruction of the
effusion, and bony debris.

:J
III
OJ
(Right) Anteroposterior VI
C1>
radiograph shows an Cl.
abnormal femoral head ••

causing the superior joint
space to appear widened.
The femoral head is reduced
in height with apparent loss
of the lateral aspect of the
head. Rather than a true
defecl, this lateral loss of
femoral head bone is due to
the 1055 of ossification within
the cartilage of the head.
legg-Calve-Perthes Marfan Syndrome

sequelae of
Legg-Calve-perthes including
{fattening and broadening of
the femoral head (coxa plana
and coxa magna) 11IIII. The
medial joint space of the hip
appears widened 11IIII due to
subluxation. (Right)
shows arachnodactyly with
mildly widened joint spaces
but no other abnormality.
The feet also showed
arachnodactyly, along with a
planovalgus deformity,
typical of Marian syndrome.
Lipoma Arborescens, Knee

enlarged, "spade-like" distal
phalangeal tufts" &
widened joint spaces iii at
metacarpophalangeal joints
due to cartilage overgrowth
in patient with acromegaly.
(Right) Sagittal PO FSE MR
shows a very large lobulated
intraarticular mass = that
widens the patel/ofemoral
joint and has signal intensity
identical to that of
subculaneus fat. Mass is
located in both the
suprapatel/ar bursa and the
posterior joint space _.
I
175
"0
Q) ANKYlOSIS
en
ro
III
C DIFFERENTIAL DIAGNOSIS o Erosive disease affects hands more than
'0
.....,
other peripheral joints; feet also frequently
"0 Common affected
Cl>
II)
I'll
• Psoriatic Arthritis (PSA) • DIP > PIP> > MCP or MTP joints
!Xl • Juvenile Idiopathic Arthritis OIA) • Any joint may be affected in carpus;
>- • Surgical Ankylosis
E peri capitate distribution slightly
o
.•... • DISH (Mimic)
I'll predominates
c: • Ankylosing Spondylitis (AS)
« o Mixed erosive & productive disease
Less Common o Two possible end-stage appearances
• Tarsal Coalition • Fusion, especially at IP joints
• Carpal Coalition • Severe mutilating erosive disease;
• Chronic Reactive Arthritis (CRA) pencil-in-cup or telescoping fingers
• Septic Joint o 30-50% patients with psoriatic arthritis
develop spondyloarthropathy
Rare but Important
• Bilateral but asymmetric Sl joint disease
• Mixed erosive/productive
• Bulky lateral spine syndesmophytes,
• OPLL (Mimic) noncontiguous
• Fluorosis • May fuse facet joints
• Ochronosis
o Multiple presentations, some with
ESSENTIAL INFORMATION systemic symptomatology
o Earliest signs not erosive
• Periostitis of digits
• Note: Interphalangeal joints may appear • Hyperemia results in asymmetric growth
fused on AP view if digits are flexed of ossification centers
o Be certain to evaluate on lateral view
o Knee, elbow, ankle findings feature erosive
before presuming IP joint fusion disease & overgrowth (balloon joints)
• Spondyloarthropathies generally ankylose o Carpus features irregularity of bones &
only in axial skeleton frequent fusion
o Sacroiliac joints (SI]) and spine facet joints
o Cervical spine
o Peripheral joint fusion is rare in these
• Frequent fusion of bodies & posterior
diseases elements
• Hint: RA,JIA, & adult Still disease have • Fused bodies limited in growth potential;
different propensities to ankylose small relative to adjacent nonfused
o Adult RA almost never fuses
bodies
o JIA shows spinal & carpal fusion frequently
• Surgical Ankylosis
o Adult Still disease shows carpal fusion
o Surgical fusion is an option to treat a
occasionally painful joint
• Hint: Psoriatic arthritis is so predominant o Surgical fusion considered under
relative to the other nonsurgical etiologies of circumstances of pain limiting function
fusion of IP joints that it must be considered • If fusion will allow function of limb
in every case • If arthroplasty is not a viable choice
Helpful Clues for Common Diagnoses (particularly carpal, tarsal IP joints)
• Psoriatic Arthritis (PSA) o Most frequently fused joints
o Penetrance of psoriatic arthritis in patients • Carpal (especially 4-corner ulnar column
with skin psoriasis not clear fusion for radiocarpal OA)
• Reported 0.5-25% • MCP of thumb, IP of digits
o May present with sausage digit & • Tibiotalar, subtalar, hindfoot-midfoot
periostitis • DISH (Mimic)
I
176
»
ANKYLOSIS
..
~
III
o
o Bulky anterior bridging osteophytes may • Bulky asymmetric vertebral body 3
'<
mimic vertebral body fusion syndesmophytes to
III
• Body & facet joint fusion are not a part • May fuse facet joints VI
(1)
of this process o Peripheral arthritis generally lower Co
o Fusion of nonsynovial superior portion of extremity '-

Q.
SI joint is not a true ankylosis • Mixed erosive & productive ~
OJ
• Synovial portion of SI joint not affected • Foot & ankle, particularly posterior III
(J)
• Ankylosing Spondylitis (AS) tubercle calcaneus (1)

Co
o Prominent axial distribution of fusion • Septic Joint

• Bilateral symmetric SI joint disease o Ankylosis is rare end-stage result of septic
• Vertebral body & facet fusion; tends to arthritis, especially if untreated
be contiguous Helpful Clues for Rare Diagnoses
• Costovertebral & costosternal fusion • Rheumatoid Arthritis (RA)
o Peripheral joint disease
o Fusion extremely rare
• Mixed erosive/productive • Even surgical arthrodesis may be difficult
• Fusion in peripheral joints rare to accomplish
• Proximal large joints predominate • Rare partial bony bridging may be seen
• With long-standing disease, smaller more • Adult Still Disease
peripheral joint disease is seen o Occasional DIP fusion & carpal fusion
Helpful Clues for less Common Diagnoses (particularly pericapitate)
• Tarsal Coalition • OPLL (Mimic)
o Usually due to congenital lack of o May have bulky anterior bony bridging in
segmentation cervical spine
o Calcaneonavicular & subtalar (medial o Body & facet fusion not a part of the
facet) most frequent locations process
o Occasionally more widespread hindfoot • Fluorosis
fusion ...•ball & socket joint o Productive process rarely results in fusion
• Carpal Coalition • Ochronosis
o Usually congenital: Lunate-triquetral o Osteoporosis & eventual late cartilage
• Chronic Reactive Arthritis (CRA) breakdown rarely result in ankylosis
o Most rare of spondyloarthropathies
• Bilaterally asymmetric SI joint disease
Psoriatic Arthritis (PSA) Psoriatic Arthritis (PSA)
PA radiograph shows fusion of a DIP joint Ell Various

PIPjoints show marginal erosions" The pattern of IP
Lateral radiograph shows a single vertical
syndesmophyte III. along with complete fusion of the
I
inflammatory disease with erosions leading to fusion is facet joints of the cervical spine ••. Bone density is
typical of psoriatic arthritis. normal. This pattern may be seen in PSA.
177
"0
OJ ANKYLOSIS
VJ
ro
CD
C
'0
--,
"0
Cll
Juvenile Idiopathic Arthritis (JIA) Juvenile Idiopathic Arthritis (JIA)
VJ (Left) PA radiograph shows
ro
en fusion at the
>. trapezium-trapezoid. as
-
E
o
III
c:
<
well as ankylosis at the
trapezoid-capitate- 2nd
metacarpal ElII in a child
with irregularity of the carpal
bones. j/A frequently results
in carpal fusion. (Right)
fusion of the facets of
cervical vertebrae 2-6 •.
There is also fusion of
vertebral bodies 2·6 ElII
which occurred at a young
age, evidenced by the small
size of lhese bodies
compared with C7111:1.
(Left) PA radiograph shows a

"4 comer" fusion of the
ulnar column (lunate,
triquetrum, hamate, &
capitate) 11I:I. This is
performed, along with
scaphoidectomy, for
radiocarpal OA ••. Even
without hardware, lhis
procedure should be
recognized. (Right) AP
radiograph shows fusion in
the nonsynovial portions of
the SI joinls •• but no fusion
in the synovial porions ElII.
This is a fealUre lhal helps to
differentiate DISH from
spondyloarthropathies.
Ankylosing Spondylitis (AS)

(Left) Axial bone CT shows
osseous fusion between the
anterior 1st ribs &
manubrium. but severe
erosions without fusion at
the sternoclavicular joints
••. There is also ankylosis at
lhe arliculalions of ribs with
vertebral bodies & transverse
processes Ell in this patient
wilh AS. (Right) Lateral
radiograph shows a case of
advanced AS with severe
erosive disease as well as
complete subtalar fusion ••.
Axial is more common than
peripheral involvement in
AS.
I
178
ANKYLOSIS »
..
~
Ql
o
3
'<
OJ
Ql
VI
Carpal Coalition tD
(Left) Lateral radiograph Co
shows tarsal coalition of the '-
subtalar. talonavicular
Ei!l and calcaneocuboid •
joints. The patient is
..
Q.
::J
OJ
OJ
otherwise normal; coalition VI
C1>
is most commonly due to Co
failure of segmentation at the
embryologic stage. (Right)
this patient has a carpal
coalition, considered a
normal variant. This is a
failure of segmentation of the
lunate and triquetrum •.
the most frequent site of
carpal coalition.
Chronic Reactive Arthritis (CRA) Septic Joint

shows fusion of the facet
joints of the cervical spine
III in a patient with chronic
reactive arthritis. Fusion in
this spondyloarthropathy is
not as common as in
ankylosing spondylitis.
the sequelae of chronic
osteomyelitis. The patient
fractured his femur 25 years
earlier & was treated with
intramedullary rod. He
developed chronic
osteomyelitis, which
extended to the hip joint,
resulting in ankylosis •.
Rheumatoid Arthritis (RA)

shows a small site of fusion
in the cuboid-MT joint III of
a patient with RA.
Non-surgical fusion is rare in
patients with RA; when it
occurs, it is generally in the
hands or feet. An
insufficiency fracture of the
posterior calcaneal facet III
is also seen. (Right) PA
radiograph shows fusion at
the carpometacarpal joint &
lunocapitate joint •. Adult
Still disease often results in
pericapitate erosions which
may progress to fusion.
I
179
"0
Q) CALCIFIED INTRAARTICULAR BODY/BODIES
en
C\l
(])
C DIFFERENTIAL DIAGNOSIS o Location-specific in knee

o
...., • Lateral femoral condylar recess:
"C Common Associated with ACL injury
Ql
VI • Loose BodiesJImpaction Fracture Fragments • Anterior tibial plateau: Hyperextension
'"
al • Intraarticular Avulsion Fractures or direct injury, associated with PCL &
>- • Synovial Osteochondromatosis
E posterolateral corner injury
-«'"
o
c:
• Chondrocalcinosis
• Charcot, Neuropathic
o Shoulder: Bankart or reverse Bankart,
associated with dislocations
Less Common o Hip: Intraarticular fracture fragments
• Intraarticular Chondroma following reduction of hip dislocation
• Meniscal Ossicle o Loose bodies from osteochondral injuries:
• Steroid Injection Especially knee, ankle, & shoulder
• IntraarticuIar Avulsion Fractures
Rare but Important
o Location-specific in knee
• Trevor Fairbank (Dysplasia Epiphysealis
• Tibial spine: Anterior cruciate ligament
Hemimelica)
(ACL)
• Synovial Chondrosarcoma
• Intracondylar notch, posterolateral at
femoral condyle: ACL
ESSENTIAL INFORMATION • Intracondylar notch, anteromedial at
femoral condyle: PCL
• Hint: Do not mistake extraarticular avulsion o Cartilaginous or ossific bodies, arising
fracture or sesamoid bones for intraarticular from synovial metaplasia
bodies
o May be large (> 1 cm) or tiny, but all tend
o Fabella: Constant location posterior &
to be similar in size within a joint
lateral (lateral head gastrocnemius)
o May be entirely lucent by radiograph and
o Common extraarticular avulsions around
CT, seen only on MR
knee
• May be more prominently seen on either
• Segond fracture (lateral capsular T1 or T2, depending on body
avulsion) composition
• Avulsion of PCL extraarticular insertion o Generally monostotic
on tibia o Large effusion
• Reverse Segond fracture (medial coronary o May cause mechanical erosions
ligament avulsion) o Three different presentations
• Arcuate (fibular styloid) or fibular neck • Most common: Multiple bodies, scattered
avulsion freely throughout the joint
• Gerdy tubercle avulsion • Less common: Conglomerate
• Patellar sleeve avulsion intraarticular mass containing hundreds
• Tibial tuberosity avulsion (or Osgood of tiny bodies
Schlatter disease)
• Least common: Aggressive mass that
• Hint: Do not mistake calcific tendinitis or begins intraarticularly but extends into
bursitis for intraarticular body extraarticular tissues
o Shoulder is most common site of
• Chondrocalcinosis
confusion
o Most common sites are in fibrocartilage
• Calcific tendinitis in supraspinatus, • Triangular fibrocartilage complex (TFCC)
infraspinatus, subscapularis, or biceps in wrist
• Calcific bursitis in • Scapholunate or lunotriquetralligaments
subacromial/subdeltoid bursa of wrist
Helpful Clues for Common Diagnoses • Menisci of knee
• Loose Bodies/Impaction Fracture • Labrum of hip
Fragments
I
180
CALCIFIED INTRAARTICUlAR BODY/BODIES
..
:t>
::J
III
o
o Also seen in hyaline cartilage, appearing to o Atrophic variety 3
'<
"line" the cortex • Usually diabetic etiology (foot, hand) CD
III
• Knee, hip, pubic symphysis, elbow, wrist • Osseous fragments are resorbed VI
(tl
• Charcot, Neuropathic • Occasionally fragments are seen in large Co
effusions about the involved joint <-

o Neuropathic joints may be hypertrophic or Q.
atrophic ~
Helpful Clues for less Common Diagnoses OJ
o Hypertrophic variety contains all the Q)
• Intraarticular Chondroma VI
osseous debris of the breakdown of the o Rarely seen in any location other than
(l)
C.
joint & consequent appearance of loose Hoffa fat pad
bodies o Calcification is common; punctate,
• Fragments of various size popcorn, chondroid in appearance
• Contained within a large effusion (may o May cause focal mechanical erosion
present clinically as a "mass") • Meniscal Ossicle
• If effusion decompresses, the fragments o Ossicle within meniscus assumes triangular
are carried with the fluid into shape of meniscus
extraarticular positions o Usually posterior horn medial meniscus
• Decompression of shoulder usually o Follows marrow signal on all MR
carries fragments into subscapularis sequences
region • Steroid Injection
• Decompression of hip usually carries o Chronic intraarticular steroid injections
fragments into iliopsoas bursa rarely result in calcification lining
• Decompression of knee usually carries synovium
fragments distally along fascial planes
o Hypertrophic types Helpful Clues for Rare Diagnoses
• Shoulder (fragments seen in enlarged • Trevor Fairbank (Dysplasia Epiphysealis
axillary bursa & often extend through Hemimelica)
ruptured rotator cuff into subdeltoid o Intraarticular osteochondroma
bursa) o Follows appearance of mature bone on all
• Knee (fragments seen in hugely imaging

distended suprapatellar bursa; may o May be polyarticular but usually
decompress down fascial planes of leg) monomelic
• Hip (capsule is constricted; fragments o Causes growth deformity
extend around mid-cervical region; may • Synovial Chondrosarcoma
decompress into iliopsoas bursa) o Rare intraarticular cartilage lesion
Loose Bodies/Impaction Fracture Loose Bodies/Impaction Fracture

Fragments Fragments
uteral radiograph shows anterior shoulder dislocation

with Hill Sachs impaction al the postero/aleral humeral
Coronal oblique T2WI FSMR shows a large loose body
• arising from an impaction al the femoral trochlea.
I
head ~ and loose body represenling a Bankart fracture The body consists moslly of carlilage, with a thin edge
fragment. arising (rom the anterior glenoid. of cortex. On radiograph it is only fainlly seen. 181
"0
Ql CALCIFIED INTRAARTICUlAR BODY/BODIES
''""
co
C
o
....,
't:l
Ql Intraarticular Avulsion Fractures Intraarticular Avulsion Fractures
'"'"
CO
shows osseous body located
>- adjacent to the tibial spines
E
-'"
o
c:
<I:
11II. This is a large tibial spine
avulsion, slightly retracted by
the ACL, but without change
in alignment. (Right)
shows a large ossified body
within the intercondylar
notch ••. Based on location
on both AP and lateral
views, it can be determined
that this is a PCLavulsion of
from the intercondylar
notch.
Synovial Osteochondromatosis Synovial Osteochondromatosis

shows severa/large rounded
bodies within the elbow joint
HI. The fat pad is distended
•• demonstrating the
intraarticular location of the
bodies. This is typical
synovial chondromatosis.
(Right) Axial bone CT shows
an aggressive form of
synovial chondromatosis,
with multiple small calcified
bodies within the joint ••
There are also multiple
similar bodies 11II posterior
to the knee that erode the
femoral condyle but also
extend extraarlicularly.
Chondrocalcinosis Charcot, Neuropathic

chondroca/cinosis in the
cartilage at the scapholunate
joint IlII & scapholunate
ligament HI as well as within
the TFCC" in a patient
with pyrophosphate
arthropathy. rt
MSK Req).
a dislocated & destroyed
humeral head. There are
clouds of tiny osseous
fragments located within a
distended axillary bursa of
the glenohumeral joint ••.
This Charcot shoulder
resulted from cervical cord
syringomyelia.
I
182
CALCIFIED INTRAARTICULAR BODY/BODIES l>
:J
..•o
III
3
'<
III
III
VI
Charcot, Neuropathic Intraarticular Chondroma C1l
radiograph shows a C-
O
neuropathic joint in a patient
with tabes. There is ~
=
intraarlicular fragmentation
as well as dissection of
several small fragments
CD
III
VI
ell
C.
down the leg Ell from
overdistension of the joint by
the large effusion. (Right)
pad =
calcification within Hoffa fat
which has caused a
small erosion on the tibial
plateau III. This appearance
in this location is almost
invariably due to
intraarticu/ar chondroma.
Meniscal Ossicle
shows a faint
triangular·shaped ossification
located posteriorly within the
joint 11III. Although the
finding is nonspecific, the
triangular shape mimics that
of the meniscus and should
make one consider the
diagnosis of meniscal ossicle.
(Right) Coronal TlWI MR of
the same case shows the
ossification to follow marrow
signal and to be located in
the posterior horn of the
medial meniscus~. This
proves the diagnosis of
meniscalossicle.
Trevor Fairbank (Dysplasia Epiphysealis Trevor Fairbank (Dysplasia Epiphysealis

Hemimelica) Hemimelica)
radiograph shows fairly
mature ossific density =
which is shown to be
intraarticular on orthogonal
images. The bone arises from
the epiphysis, as is expected
in Trevor Fairbank disease.
(RighI) Anteroposterior
radiograph shows mature
bone {ormation arising from
the talus _ ending in an
intraarticular position. This is
a typical appearance for
Trevor Fairbank disease. It
may be polyarticular but is
usually monomelic.
I
183
CHONDROCALCINOSIS
DIFFERENTIAL DIAGNOSIS • Hint: Chondrocalcinosis seen in many

arthritic processes, but does not imply any
't:l Common one arthropathy; etiology may be
Q)
l/l
1tI
• Pyrophosphate Arthropathy "idiopathic"
aJ • Osteoarthritis • Hint: Chondrocalcinosis can nearly always
>- • Chronic Repetitive Trauma
E be attributed to those entities listed as
-
o
1tI
c:
<l:
• Idiopathic
• Gout
"common"; remainder rare
• Hyperparathyroidism/Renal OD Helpful Clues for Common Diagnoses

• Progressive Systemic Sclerosis • Pyrophosphate Arthropathy
o Most frequent arthritis associated with
Rare but Important chondrocalcinosis
• Paraneoplastic Syndrome o Distribution is diagnostic
• Hemochromatosis • Hand: Radiocarpal - SLACwrist
• Amyloid Deposition deformity; 2nd & 3rd MCP
• Acromegaly • Knee: Patellofemoral compartment
• Wilson Disease o Early erosions, followed by mixed &
• Hemophilia productive disease
• Hypothyroidism • Osteoarthritis
• Hypophosphatasia o Frequently seen in association with
• Diabetes chondrocalcinosis
• Ochronosis (Alkaptonuria) o Watch distribution: In hand, IP joints and
• Oxalosis 1st carpometacarpal (CMC)
• Chronic Repetitive Trauma
ESSENTIAL INFORMATION o Most frequent site is ulnocarpal abutment
due to positive ulnar variance
Key Differential Diagnosis Issues • Gout: Sodium urate deposits
• Chondrocalcinosis results from deposition of • Hyperparathyroidism/Renal OD
material in cartilage o Soft tissue calcification common,
o May be deposited in fibrocartilage including chondrocalcinosis
• Menisci, TFCC, labrum • Progressive Systemic Sclerosis
o May be deposited in hyaline cartilage o Soft tissue calcification common,
o May be deposited in surrounding soft including chondrocalcinosis
tissues as well: Ligaments, joint capsule o Associated acroosteolysis
Osteoarthritis
I PA radiograph shows extensive chondrocalcinosis in the

TFCC •• as well as the scapholunate ligament Ell and
PA radiograph shows chondroca/dnosis
TFCC"
involving the
There are typical findings of OA involving the
hyaline cartilage". There are large sulxhondral cysts 1st CMC" and scapha-trapezoid-trapezium Ell joints,
& a SLAC wrist deformity is developing. (tMSK Req). with sclerosis & early osteophyte formation.
184
CHONDROCAlCiNOSIS »
::l
..•o
Cll
3
'<
lD
Cll
VI
Chronic Repetitive Trauma C1l
(Leh) PA radiograph shows Q.
chondrocalcinosis in the '-

TFCC•• as well as the 2.
scapholunate ligament _ ~
Note that there is ulnar lD
III
positive variance; altered (fl
ctl
weight bearing through the C.
TFCC & lunate creates
chronic repetitive trauma.
chondrocalcinosis in the
hyaline cartilage" as well
as the joint capsule Ell in this
patient with generalized foot
pain. There was no
associated arthropathy or
discernible cause of the
deposition.

calcific density within and
around the TFCCand distal
radioulnarjoint" in a
young Polynesian male. This
is gout, with sodium urate
crystal deposition. (Right) PA
radiograph shows
TFCC". The bones are
diffusely abnormal in
density, with loss of
trabecular distinctness in this
patient with
hyperparathyroidism. No
other resorptive patterns are
seen in the wrist.
Progressive Systemic Sclerosis Paraneoplastic Syndrome

typical acroosteolysis ••
with soft tissue calcification
and chondrocalcinosis •• of
the TFCCin this patient with
scleroderma. The dislocated
1st carpometacarpal joint Ell
indicates chronicity. (Right)
shows chondrocalcinosis
within the pubic symphysis
& hip joint •• as well as
juxtaarticular calcification
_ This patient has known
lung adenocarcinoma &
para neoplastic syndrome,
resulting in hypercalcemia.
I
185
-0
<1l PERIARTICULARCALCIFICATION
CI)
CIl
co
C DIFFERENTIAL DIAGNOSIS Helpful Clues for Common Diagnoses
--,o • Calcific Tendinitis vs. Calcific Bursitis
"tl Common
QI o Character of calcification: Dense, globular,
CI) • Calcific Tendinitis
co'" • Calcific Bursitis smooth "toothpaste" appearance
>- o Calcific tendinitis located within tendon
E • Gout
•..o • Pyrophosphate Arthropathy (Mimic) • Usually within 1-3 em of insertion
• Follows the tendinous insertion
c'":: • Myositis Ossificans
< • Progressive Systemic Sclerosis throughout range of motion of adjacent
• Hyperparathyroidism joint; rarely changes shape
o Calcific bursitis located in position of
• Chronic Repetitive Trauma/Ligamentous bursa (often adjacent to tendon)
• Shape of calcific density often changes
Less Common from globular to more dispersed pattern
• Polymyositis/Dermatomyositis with range of motion of adjacent joint
• Thermal Injury, Burns • Gout
• Calcific Myonecrosis o Extraarticular calcification within soft
• Periosteal Chondroma tissue mass: Tophus
• Hemangioma, Soft Tissue o Character of calcification
• Synovial Sarcoma • Usually subtle amorphous increased
• Dystrophic Calcification, Soft Tissue Tumor density within mass
• Soft Tissue Chondroma • Rarely has focal, dense calcification
• Charcot, Neuropathic o ± Adjacent juxta/intraarticular erosions
• Paraneoplastic Syndrome • Pyrophosphate Arthropathy (Mimic)
Rare but Important o Calcification is intra articular & rarely
• Systemic Lupus Erythematosus capsular
• Synovial Osteochondromatosis, o Linear calcification located in either
Extraarticular fibrocartilage or hyaline cartilage
• Maffucci Syndrome o Watch for typical associated arthropathy
• Leprosy • Myositis Ossificans
• Pseudohypoparathyroidism o Character changes over time
• Tumoral (Idiopathic) Calcinosis • Calcification first seen 4-6 weeks
• Mesenchymal Chondrosarcoma following trauma
• Extraskeletal Osteosarcoma • Initial calcification is faint & amorphous
• Ochronosis immature osteoid
• Wilson Disease • With time, ossification matures, with
more mature bone formation seen
peripherally & circumferentially
ESSENTIAL INFORMATION • Progressive Systemic Sclerosis
Key Differential Diagnosis Issues o Calcification: Globular or sheet-like
• Radiograph is essential to differentiate types o Watch for attenuated soft tissues and
of calcification, which often have a distinct acroosteolysis
appearance (may limit the differential) • Hyperparathyroidism/Renal
o Mineralized osseous matrix: Ranges from Osteodystrophy
faint & amorphous to distinct trabeculae o Calcification: Focal, dense, or amorphous
surrounded by dense cortex o Character & location of calcification may
o Mineralized cartilaginous matrix: Punctate change with treatment
density, termed "popcorn" or "rings & arcs" • May completely resolve
o Dystrophic calcification: Ranges from • Renal osteodystrophy on dialysis: May
amorphous & cloudy, to linear or rounded, develop fluffy large soft tissue deposits
globular distinct calcification o Hint: Watch for the various resorption
patterns of osseous structures
I
186
PERIARTICULARCALCIFICATION »
..
::l
III
o
• Patients generally younger adults than 3
with other sarcomas OJ
• Polymyositis/Dermatomyositis III
• Lower extremity, particularly about the
o Calcification occurs after muscle
knee (but extraarticular), is most
'Co"
(1)
inflammation, degeneration, & atrophy '-

frequent location of synovial sarcoma Q.
o Proximal thigh muscles predominate'
• Charcot, Neuropathic ~
o Character of calcification OJ
o Intraarticular debris may dissect down OJ
• Dense sheet-like calcification is classic <Jl
fascial planes when joint is distended (1)
• Less than 50% of cases show this classic 0.

o Intraarticular debris may dissect into
appearance; may be globular/amorphous
adjacent bursa, particularly in shoulder
o Watch for complications of steroid use
o Character of calcification: Bone fragments
(avascular necrosis, osteopenia)
• Thermal Injury, Burns Helpful Clues for Rare Diagnoses
o Character of calcification: Globular • Systemic Lupus Erythematosus
o Contractures, acroosteolysis are associated o Rarely seen globular calcification
• Periosteal Chondroma o Most frequent in lower extremities
o Surface lesion may cause scalloping of • Synovial Osteochondromatosis,
underlying bone Extraarticular
o Calcification: Punctate, chondroid o Confluent mass may extend into soft
• Hemangioma, Soft Tissue tissues adjacent to joint
o Tangled vessels, usually in fatty stroma • Maffucci Syndrome
o Character of calcification: Round calcific o Phleboliths in hemangiomas associated
densities with lucent center (phleboliths) with multiple enchondromatosis
• Synovial Sarcoma vs. Dystrophic • Leprosy
Calcification in Soft Tissue Sarcomas o Calcification: Linear, in digital nerve
o Any soft tissue tumor may develop o Associated acroosteolysis
dystrophic calcification • Pseudohypoparathyroidism
o Character of calcification: Generally dense o Calcification: Globular, dystrophic
& dystrophic, either linear or globular o Associated findings: Short, obese
o Synovial sarcoma contains dystrophic individuals with brachydactyly (especially
calcification 20-30% more frequently than 1st, 4th, & 5th metatarsal/metacarpals)
other tumors • Tumoral (Idiopathic) Calcinosis
o Factors that may help differentiate o Paraarticular cloudy, toothpaste-like
synovial sarcoma calcification with normal underlying bone
Calcific Tendinitis
Anteroposterior
calcification"
radiograph shows a globular
superimfXJsedover the glenohumeral
Sagillal PO FSE MR of the same patient as previous
image shows tendon sheath fluid • and the
I
joint in an internally rotated shoulder radiograph. This is calcification •• associated with biceps tendon III
nonspecific, bur location suggests calcific tendinitis. confirming calcjfic tendinitis.
187
PERIARTICULAR CALCIFICATION
'tl
Q) Calcific Bursitis Calcific Bursitis
III (Left) AP external rotation
Cll
In radiograph shows fairly
>- dense calcification. in a
-
E
o
Cll
c::
«
position that could either be
supraspinatus calcific
tendinitis or subdeltoid
bursitis. (Right) AP internal
rotation of the same shoulder
demonstrates the density to
spread out in a thinner line
• & to remain in the
location of subdeltoid bursa.
Since it does not follow the
supraspinatus, the diagnosis
of calcific bursitis is
confirmed. Location of
calcification confirms
specific diagnosis.

shows distinct calcific
densities within the
olecranon bursa in a patient
with gout. Tophi more
frequently have amorphous
calcific density, but this
appearance is rarely seen.
shows mild and amorphous
increased density within a
gouty tophus .:II in the
olecranon bursa. This is a
more typical appearance of
gouty tophus than the dense
calcification seen in the
previous image.
Myositis Ossificans
radiograph shows joint
capsule chondrocalcinosis
•. Although usually seen
within the hyaline or
fibrocartilage, it may mimic
periarticular calcification
when it is capsular. (Right)
shows mature bone adjacent
to the 5th Mep after crush
injury without fracture 5
months prior. Mature
peripheral bone.
surrounding a less organized
center is typical of myositis
ossificans (fibroosseou5
pseudotumor of digits).
I
188
PERIARTICULAR CALCIFICATION
ProgressiveSystemic Sclerosis Hyperparathyroidism

shows dense sheet-like
calcification in the
'-
Q.
subcutaneous tissues, a ~
pattern seen in P55 Cll
OJ
(scleroderma) as well as CJ)
<1>
dermatomyositis. (Right) n.
shows periarticular
calcifications" in a patient
with hyperparathyroidism.
These are not sesamoids, as
they do not have an ossific
character.
Polymyositis/Dermatomyositis
bone density, subchondral
resorption at the 51!•• and
cloudy amorphous
periarticular calcification •.
This type of calcification not
infrequently develops in
patients on dialysis. (Right)
sheet-like calcification in the
subcutaneous and fascial
tissue planes •. This
appearance is classic for
dermatomyositis, though the
calcification may also be
globular in this disease.
Periosteal Chondroma Hemangioma, Soft Tissue

shows a surface lesion
containing chondroid matrix
which originated at the
proximal phalanx. and
extends to the distal phalanx
•• It excavates the
underlying bone, typical for
a periosteal chondroma.
(tM5K Req). (Right)
shows phleboliths • typical
of those found in soft tissue
hemangioma.
I
189
"0
Q) PERIARTICU lAR CALC! FICA TlON
Vl
11l
co
C
·0
-, Dystrophic Calcification, Soft Tissue
"C
Gl Synovial Sarcoma Tumor
Vl (Left) Lateral radiograph
1O
CO shows a 50ft tissue mass.
>. containing dystrophic
-
E
o
1O
c:
«
calcification. Any soft tissue
tumor may calcify, but
synovial sarcoma is the most
frequent; consider especially
when seen in the lower
extremity of young adults.
dystrophic calcification
within a sort tissue mass •.
Although synovial sarcoma
should be considered, any
tumor (such as this
schwan noma) may calcify.
Charcot, Neuropathic Charcot, Neuropathic

radiograph shows osseous
debris 11II contained within
the distended glenohumeral
joint. Though this is typical
for a Charcot shoulder, it is
often mistaken for
extraarticular calcification.
radiograph shows osseous
debris =:I dissecting down
fascial planes in a knee
showing destructive changes
of a Charcot joint. When the
effusion is large, it may
decompress distally like this.
Paraneoplastic Syndrome Systemic Lupus Erythematosus

radiograph shows
chondroca/cinosis 11II &
juxtaarticular calcification 11II:I
resulting from hypercalcemia
adenocarcinoma of the lung
and paraneoplastic
syndrome. (Right)
shows dense globular soft
tissue calcUkation • along
with avascular necrosis ffi
Occasionally SLEpatients
develop dystrophic
calcification, predominantly
in the lower extremities.
I
190
PERIARTICULAR CALCIFICATION ~
::::l
...•
III
o
3
'<
Synovial Osteochondromatosis, Synovial Osteochondromatosis, OJ
III
VI
Extraarticular Extraarticular <1l
shows hundreds of tiny
ossified bodies, both
'-
Q.
intraarticular and ;:!.
periarticular. This is aJ
III
conglomerate synovial VI
<1l
osteochondromatosis, a.
extending into surrounding
soft tissues. (Right) Axial
bone CT shows typical
round bodies within the
suprapatellar bursa. but
there is extraarticular
extension of the
conglomerate mass
extending into biceps &
surrounding the
neurovascular bundle Ell
Maffucci Syndrome
(Left) fA radiograph shows
multiple enchondromas
within the phalanges,
metacarpals, and an
associated soft tissue mass
_ The mass contains
phleboliths; the constellation
of findings is Maffucci
syndrome. rt MSK Req).
(Right) fA radiograph shows
acroosteolysis, which has
destroyed most of the
phalanges. Additionally,
there is linear calcification in
the location of a digital nerve
••. This combination of
findings is pathognomonic
for leprosy. rtMsK Req).
Pseudohypoparathyroidism Tumoral (Idiopathic) Calcinosis

radiograph shows subtle soft
tissue calcification adjacent
to the midfoot. Note the
short first metatarsal Ell This
combination of findings is
typical for
pseudohypoparathyroidism.
cloud-like periarticular
calcification. The
appearance is typical of, and
proved to be, tumoral
calcinosis.
I
191
"0
Q) MCP-PREDOMINANT ARTHRITIS
en
co
en
C DIFFERENTIAL DIAGNOSIS • Earliest: Radiocarpal, often with ulnar
-,o translocation of carpus
"C Common • Later: Midcarpal, intercarpal
CIl
en • Rheumatoid Arthritis (RA) • Pyrophosphate Arthropathy
co
en • Pyrophosphate Arthropathy o MCP involvement is hallmark
>-
E • 2nd and 3rd MCPs earliest & most
-
o
co
c:
<
Less Common
•
•
Hemochromatosis
Robust Rheumatoid Arthritis (Robust RA)
frequently involved
• IPs not involved
• Juvenile Idiopathic Arthritis alA) o Hook-like osteophytes are classic
• Systemic Lupus Erythematosus (Mimic) • May begin as erosive or mixed
o Normal bone density
Rare but Important
o Carpal involvement
• Jaccoud Arthritis (Mimic) • Radiocarpal, often with S-L dissociation
• May evolve to SLACdeformity
ESSENTIAL INFORMATION Helpful Clues for Less Common Diagnoses
Key Differential Diagnosis Issues • Hemochromatosis
• Hint: Character of MCP involvement may o Same appearance & distribution as
help differentiate pyrophosphate arthropathy
o Erosive: RA, robust RA,JIA, SLE, & o Younger adult male population
occasionally pyrophosphate & • Robust Rheumatoid Arthritis (Robust RA)
hemochromatosis arthropathy o Same appearance & distribution as RAt
o Productive or mixed: Pyrophosphate & with large subchondral cysts
hemochromatosis arthropathy • Juvenile Idiopathic Arthritis alA)
• Hint: Location of carpal involvement may o MCP > IP involvement; may have fusion
help differentiate o Carpal involvement variable
• Systemic Lupus Erythematosus (Mimic)
o Generally a nonerosive deformity
• Rheumatoid Arthritis (RA) • Hand deformities much more prominent
o MCP > > IP involvement
than erosive change
• Both earlier and more severe • Late erosions seen, MCP > IP
o Purely erosive disease
o Osteopenia (juxtaarticular; diffuse later) Helpful Clues for Rare Diagnoses
o Carpal involvement • Jaccoud Arthritis (Mimic)
o Same appearance as SLE
Rheumatoid Arthritis (RA) Rheumatoid Arthritis (RA)
I PA radiograph shows predominant MCP erosive disease

_ with large erosions & subluxation. There is minimal
PA radiograph shows early RA, with MCPs showing
uniform decrease in cartilage width. There is a small
IP disease, with only one site showing marginal erosions marginal erosion at a single MCP" The patient had
__ The MCP-predominant disease is typical of RA. no involvement of the IPjoints or the carpus.
192
Mep-PREDOMINANT ARTHRITIS l>
.•
::l
III
o
3
'<
o:J
III
VI
Hemochromatosis <ll
(Leh) Posteroanterior Co
radiograph shows cartilage '--
Q.
narrowing at the 2nd and
3rd MCPs, along with a large ~
hook-like osteophyte at the o:J
III
3rd MCP •. The IP joints VI
C1>
were normal. This pattern is a.
arthropathy. (Right)
shows cartilage narrowing
throughout the MCPs. There
are associated erosions. as
well as hook-like osteophytes
_ The IP joints were
normal. The pattern is typical
of hemochromatosis in this
middle-aged male.
Robust Rheumatoid Arthritis (Robust RA) Juvenile Idiopathic Arthritis (JIA)

(Leh) Posteroanterior
radiograph shows
MeP-predominant erosions
with large subchondral cysts
_ IPs show minimal
involvement. There is erosive
change seen throughout the
carpus. Cysts & normal bone
density are typical of robust
RA. (Right) Posteroanterior
radiograph shows MCP
erosive disease •. IPs are
not well seen but were
relatively normal. Erosions &
fusion are seen involving the
carpus in this teenager. This
MeP-predominate arthritis is
juvenile idiopathic arthritis.
Juvenile Idiopathic Arthritis (JIA) Systemic Lupus Erythematosus (Mimic)

radiograph shows
overgrowth of the epiphysis
as well as an erosion. at
the 3rd MCP. This was an
early isolated site of
involvement in a patient with
JIA. (Right) Posteroanterior
radiograph shows
subluxation and mild erosive
disease at the MCPs _ The
IPs and carpus are normal.
When the degree of
subluxation and deformity is
far greater than the erosive
change, SLEshould be
considered rather than
I
193
"0
Q) IP-PREDOMINANT ARTHRITIS
(/)
ro
co
C
·0 DIFFERENTIAL DIAGNOSIS • Periostitis, especially along shaft
--, o Late stages: Arthritis mutilans
'0 Common • Severe erosions ...•pencil-in-cup
Ql
II)
ltl
• Osteoarthritis (OA) • Severe erosions ...•telescoping digits
CO • Psoriatic Arthritis (PSA) o May have spondyloarthropathy
>.
E • Erosive Osteoarthritis (EOA) • Bilateral asymmetric sacroiliitis
-o
ltl
c:
<l:
Less Common
• Hyperparathyroidism (HPTH) (Mimic)
• Bulky, non-contiguous syndesmophytes
o Psoriatic skin rash generally present, but
arthritis may predate skin findings in 20%
Rare but Important
• Erosive Osteoarthritis (EOA)
• Chronic Reactive Arthritis (CRA) o Same distribution as OA
• HIV-AIDS Related Arthritis o Mixed erosive & productive disease, often
• Adult Still Disease resulting in "gull wing" deformity
• Amyloid Deposition • Deep central subchondral erosion of
• Multicentric Reticulohistiocytosis middle phalanx, with more marginal
erosions base of distal phalanx
ESSENTIAL INFORMATION • Marginal osteophytes
o DIP> PIP, but all may be involved
Key Differential Diagnosis Issues o MCPs not involved in absence of trauma
• Hint: Character of involvement may help o Carpal location: 1st carpometacarpal,
differentiate among these processes scapho- trapezoid- tra pezi um
o Erosive: All but OA may be purely erosive
• Generally productive, but may be erosive
o Productive: OA is purely productive
• Hint: This location of carpal disease may
o Mixed erosive/productive: PSA, CRA, HIV, serve as a differentiating factor from
EOA psoriatic arthritis
• Hint: Site of carpal involvement may help
differentiate among these Helpful Clues for Less Common Diagnoses
• Hint: Skin changes rarely may help with • Hyperparathyroidism (HPTH) (Mimic)
diagnosis o Subchondral resorption at phalanges is not
o Psoriatic rash an uncommon form of resorption
o Nodules in multicentric • Analogous to subchondral resorption at
reticulohistiocytosis distal clavicle or iliac side of sacroiliac
joint
• With use, subchondral bone may
• Osteoarthritis (OA) collapse; this may mimic an erosive
o Purely productive (osteophyte-forming)
pattern
o DIP > PIP joints, but all may be involved
• Critical evaluation shows the collapse is
o MCPs not involved unless prior trauma
not always as rounded as an erosion &
o Carpal location: 1st carpometacarpal
has a fairly distinct cortex
(CMC), scapho-trapezoid-trapezium (SIT) o Seen with either HPTH or renal
• These carpal locations are not involved osteodystrophy
in other arthridities & are a reliable o DIP is most frequent site, though seen in
differentiating feature PIP & even in carpals
• Psoriatic Arthritis (PSA) o Hint: Watch for other suggestions of
o Erosive> productive changes, but may be
HPTH in the hand
mixed • Most common: Overtubulation of
o DIP > PIP, but all may be involved
middle phalanges from subperiosteal
o MCPs not involved until late in disease
resorption (may not be active)
o Carpal location variable in proximal &
• Brown tumors
distal carpal rows; may be peri-capitate • Tuft resorption
o May present with a "sausage digit"
• Swelling of entire digit Helpful Clues for Rare Diagnoses
• Chronic Reactive Arthritis (CRA)
I
194
IP-PREDOMINANT ARTHRITIS l>
..•o
::::J
III
o Erosive> productive changes, but may be • Similar distribution to PSA (IP > MCP); 3
'<
mixed fusion OJ
III
o Feet> hands o Carpal involvement: Variable, but may be t/l
CD
o DIP > PIP, but all may be involved pericapitate C.
C-
o Tarsal involvement variable; may see • Amyloid Deposition O
::::J
enthesopathy o Deposition in soft tissues, synovium,
OJ
o Calcaneal involvement common (erosive cartilage, bone Ol
VI
change plus periostitis posterior tubercle) o Often have large soft tissue masses CD
C.
o May present with a "sausage digit" • Shoulders, wrists, ankles
• Swelling of entire digit • Masses described as "lumpy"
• Periostitis, especially along shaft o MR fairly distinctive, but not specific
o Late stages: Arthritis mutilans • Low signal (may be heterogeneous) on
o May have spondyloarthropathy T2
• Bilateral asymmetric sacroiliitis • Gout may have a similar MR appearance
• Bulky, non-contiguous syndesmophytes o Articular deposition results in erosive
o Other components of syndrome: Urethritis change; DIP is common site
(cervicitis), uveitis o Diagnosis proven by biopsy
• HIV-AIDS Related Arthritis o Most cases are secondary, with patients
o Similar manifestations to chronic reactive affected by
arthritis • Rheumatoid arthritis
o Hands = feet • Multiple myeloma
o IP > MCPjMTP • Renal osteodystrophy
o Erosive> productive changes, but may be • Multicentric ReticuIohistiocytosis
mixed o Rare disease with combination of
o May present with a "sausage digit" • IP erosions
• Swelling of entire digit • Acroosteolysis
• Periostitis, especially along shaft • Nodules on the digits
o May have incomplete syndrome of CRA
o Systemic symptoms similar to juvenile
idiopathic arthritis
o Rheumatoid factor negative
o Two arthritic manifestations
• Similar distribution to RA (MCP > IP)
Osteoarthritis (OA) Psoriatic Arthritis (PSA)
PA radiograph shows normal bone density &

osteophytes involving the DIP joinls •. The PIP joinls
PA radiograph shows severe erosive change at the DIP
joinls" with carti/age narrowing of the PIPjoinls. The
I
are not yet involved. MCPs are normal. As expected, IP joilll of the thumb has eroded to a penci/-in-cup
carpal involvemelll was at the 1stCMC & SIT joinls. deformity" with a clinically evident telescoping digit.
195
IP-PREDOMINANT ARTHRITIS
"0
Ql ErosiveOsteoarthritis (EOA) ErosiveOsteoarthritis (EOA)
III (Left) PA radiograph shows
nl
In subchondral central erosion
>- on the middle phalanx _
-
E
o
nl
c:
<
with marginal erosions and
osteophytes on the distal
phalanx Elll which result in
the "gull wing" deformity.
The appearance is typical of
fOA, which preferentially
affects the IP joints. (Right)
PA radiograph shows mixed
erosive & productive change
at the PIP joints. some
showing a gull wing
deformity. DIPs show only
cartilage narrowing. Carpus
showed tst CMC disease,
diagnostic of fOA.
Hyperparathyroidism (HPTH) (Mimic) Hyperparathyroidism (HPTH) (Mimic)

subchondral resorption &
collapse at the DIPs _
resulting from HPTH. The
hint in this case is the
overwbulation of the middle
phalanx __ resulting from
prior subperiosteal
resorption. (Right) PA
deformity at the DIPs.
resulting from subchondral
resorption & collapse in
HPTH. The frequent location
of subperiosteal resorption of
the middle phalanges.
results in overtubu/ation &
helps secure the diagnosis.
Chronic Reactive Arthritis (CRA) HIV-AIDS Related Arthritis

severe erosive disease in the
IP joints of the foot. The
MCPs are less severely
involved. The calcaneus (not
shown) had significant
erosions at the posterior
tubercle; all findings are
typical of CRA. (Right)
shows soft tissue swelling,
periostitis" and erosive
change at the DIP joint _ in
this HIV-positive patient
Locations and appearance of
arthritic changes are similar
to those of chronic reactive
arthritis.
I
196
IP-PREDOMINANT ARTHRITIS >
::I
..•
III
o
3
'<
lJl
III
Adult Still Disease Adult Still Disease
'"
lD
Q.
radiograph shows a fused

DIP" cartilage narrowing
'-
Q.
at other DIPs, and erosive ~
change at the PIPjoints •. lJl
OJ
The MCPs are relatively en
(1)
normal. This patient had 0.
systemic symptoms typical of
adult Still disease. (Right)
shows DIP disease" the
PIPand MCP joints were
normal. Pericapitate disease
in the wrist and systemic
symptoms helped confirm
the diagnosis of adult Still
disease.
Amyloid Deposition
cartilage 1055 and erosive
change isolated to the DIPs
=. This patient had
prominent soft tissue
nodularity around the wrist.
Synovial biopsy of the DIP
proved amyloid deposition.
(Right) PA radiograph of the
same patient shows nodular
50ft tissue swelling about the
wrist and forearm •. The
carpus shows no arthritic
change. With underlying
renal osteodystrophy, it is
not surprising that this is
secondary amyloid
deposition.
Multicentric Reticulohistiocytosis Multicentric Reticulohistiocytosis

erosions involving most joints
of this hand, but it
predominates at the DIP
joints •. Note also that
there is acroosteolysis •.
This combination might
suggest PSA but the
presence of nodularity
suggests multicentric
reticulohistiocytosis. (Right)
PA radiograph shows
acroosteolysis • along with
DIP erosions" Note the
nodularity along the digits.
The combination yields the
rare diagnosis of multicentric
reticulohistiocytosis.
I
197
-0
ClJ MONOARTHRITIS
en
C\l
CO
C DIFFERENTIAL DIAGNOSIS o Osteoarthritis (OA) is generally
o
-, polyarticular
-0 Common o Osteoarthritis generally is specific in
ClJ
II)
III
• Septic Joint location
CO • Osteoarthritis, Post-Traumatic o Trauma may result in abnormalities
>-
• Gout
-
E
o
III
c:
<
• Pigmented Villonodular Synovitis (PVNS)
predisposing a joint to osteoarthritis
• Fracture malunion
• Osteochondral defect
• Ligament laxity
• Viral (Toxic) Synovitis o If osteoarthritis is seen in an unusual
Less Common location, consider trauma as the etiology
• Hemophilia • OA is usually monoarticular in this case
• Giant Cell Tumor Tendon Sheath (Mimic) • Gout
• Chondrolysis, Post-Traumatic o Often is monoarticular initially
o Most common location: 1st metatarsal
Rare but Important
joint
• Tuberculosis o When monoarticular, appearance is
• Fungal generally classic
• Well-defined erosions, both intraarticular
ESSENTIAL INFORMATION & juxtaarticular
• Dense tophus
• MR shows largely low signal mass which
• Some processes are virtually always enhances
monoarticular
o Once gout is long-standing & untreated, it
o Pigmented villonodular synovitis
may be more difficult to diagnose
o Synovial osteochondromatosis
• Polyarticular, often involving unusual
o Viral (toxic) synovitis
joints
o Giant cell tumor of tendon sheath (mimic)
• May appear severely erosive
o Chondrolysis, post-traumatic
• Absence of tophi may complicate
• Some processes may be monoarticular or diagnosis
polyarticular
o Septic joint, whatever etiology
o Some etiologies tend to be monoarticular
o Gout
• Syringomyelia
o Charcot
• Diabetes (though occasionally
o Hemophilia
polyarticular)
Helpful Clues for Common Diagnoses o Some etiologies tend to be polyarticular
• Septic Joint • Tabes
o Effusion may be first clue • Congenital insensitivity or indifference
o Subchondral cortex may loose distinct to pain
"crispness" on radiograph o Classic locations of Charcot joint, related
o MR generally not necessary to etiology
• Confirms effusion • Diabetes: Ankle/foot, wrist
• May show cortical & marrow edema • Syringomyelia: Shoulder
• Nonspecific • Tabes: Knee, spine
o Blood studies may be normal (white cell • Congenital insensitivity/indifference to
count, erythrocyte sedimentation rate) pain: Knee, ankle
o Must maintain high index of suspicion • Paraplegia: Spine, distal to stabilized site
• Diagnosis is confirmed by aspiration of injury
• Aspiration should be considered urgent, o Classic appearance
particularly in hip • Osseous debris (though may be resorbed
• Osteoarthritis, Post-Traumatic in atrophic variety)
I
198
MONOARTH RillS :t>
..•o:J
III
• Distension of joint (large effusion, often o Hyperemia from bleeds in child result in 3
'<
presents as "mass", especially shoulder) epiphyseal/metaphyseal overgrowth to
III
• Disruption of joint o Inflammatory change may cause erosion, CIl
(l)
• Pigmented Villonodular Synovitis (PVNS) cartilage damage Co
o Always monoarticular o Iron deposition in synovium following '-

o
o Intraarticular nodular mass, either lining repeated bleeds may appear typical ;l
CD
synovium or conglomerate • Radiograph may show "dense" effusion
o Nodularity low signal to inhomogeneous • MR may show low signal deposits which '"en
Ctl
Q.
mixed signal on T2; blooms on gradient bloom on gradient echo

echo, enhances with contrast o Knee> elbow> ankle
o May result in large subchondral cysts, o May not be distinguishable by imaging
direct erosions from juvenile idiopathic arthritis OIA)
• Synovial Osteochondromatosis • JIA more frequently polyarticular
o Generally monoarticular • Giant Cell Tumor Tendon Sheath (Mimic)
o Multiple round bodies of similar size o Usually seen along tendon sheath of digit
• May be free within effusion o May cause extrinsic osseous erosion on
• May be conglomerate mass both sides of a joint, mimicking erosions &
• Bodies usually visible on radiograph, but arthritic process
may not be calcified enough to be seen o Hint: Soft tissue mass is usually not
o May cause erosions centered on the joint
o Rarely may extend extraarticularly • Chondrolysis, Post-Traumatic
• Viral (Toxic) Synovitis o Most frequently seen following pinning of
o Usually hip in child hip for slipped capital femoral epiphysis
o Effusion seen by radiograph or ultrasound o Rapid chondrolysis, must be distinguished
o No destructive osseous change from septic hip
o Must differentiate from septic joint Helpful Clues for Rare Diagnoses
• Usually requires aspiration, which will • Tuberculosis & Fungal
yield normal synovial fluid o Major distinguishing feature from bacterial
Helpful Clues for Less Common Diagnoses septic arthritis is lack of host reaction
• Hemophilia o Osteopenia generally prominent
o Usually monoarticular, though may o Cartilage destruction & erosions generally
involve more than one joint develop late in process
o Results from repeated intraarticular bleeds o May progress indolently
AP radiograph shows complete loss of cartilage III as

well as extensive erosive disease within the acetabulum
PA radiograph shows complete carUlage loss, erosive
destruction _ & soft tissue swelling •. Septic joint
I
III and femoral head. SepUc hip can develop must be considered allhis location since it is a common
destrucUve changes rapidly & is a clinical emergency. site of injury from punching an opponent in the mouth.
199
MONOARTHRITIS
'0
Ql Osteoarthritis, Post-Traumatic Gout
III (Leh) PA radiograph shows
CO
aI osteophytes at the junction
>. of the lunate & triquetrum
E Ell. This is associated with
•...COo ulnar positive variance _
c: Trauma from the overly-long
< ulna results in focal
osteoarthritis, termed ulnar
abutment syndrome. (Right)
shows a single juxtaarticular
erosion. at the 1st MTP
joint. There is associated soft
tissue swelling. This is an
early radiographic finding of
gout, diagnosed by type of
erosion & location.
Charcot, Neuropathic
radiograph shows cut-off
destruction of the humeral
head. and a large amount
of debris within a distended
axillary bursa. of the
glenohumeral joint. The
appearance is that of a
neuropathic joint. (Right)
shows very large
subchondral cysts on both
sides of the hip joint. The
bone density is normal, and
this is a monostotic process.
PVNS should be considered
in such a case and was
proven.
Pigmented Villonodular Synovitis (PVNS) Synovial Osteochondromatosis

shows a single posterior
femoral metaphyseal erosion
[;8 adjacent to a nodular low
signal mass ffi This is a
monoarticular process and
typical for PVNS. (Right)
multiple round bodies within
the elbow joint of a child,
distending the posterior.
and anterior. recesses of
the joint. This is typical
synovial
osteochondromatosis, which
is generally a monoarthritic
process.
I
200
MONOARTH RillS l>
::l
...•
Ql
o
3
'<
llJ
Ql
III
Viral (Toxic) Synovitis (!l
(Leh) Anteroposterior C.
radiograph shows a slightly t-
O
widened "teardrop distance'!
of right hip compared with ;a.
left (compare at IBJ. This llJ
OJ
indicates effusion; aspiration III
ctl
of the right hip showed clear C.
synovial fluid that proved to
be uninfected. (Right) Lateral
radiograph shows huge knee
effusion lID. Though there is
no cartilage destruction or
erosive change at this point,
overgrown Femoral
epiphyses & patella in this
young male suggest
hemophilic arthrWs.
Giant Cell Tumor Tendon Sheath

(Mimic)
shows erosions of the head
of the middle phalanx & base
of proximal phalanx III
mimicking an arthritic
process. There is a soft tissue
mass, not centered on the
joint lID. Mass is the primary
process, giant cell tumor of
tendon sheath, resulting in
extrinsic erosions of the
underlying bone. (Right)
shows cartilage narrowing
lID along with evidence of
old slipped capital femoral
epiphysis (medial slip =aJ&
pin tracks ElII.
Tuberculosis
(Leh) fA radiograph shows
erosive change involving the
entire midcarpal joint,
extending between the
scaphoid & lunate as well as
the bases of the metacarpals,
but sparing the radiocarpal
joint. There is cartilage Joss
and osseous destruction,
without reactive change.
(Right) fA radiograph shows
cartilage loss in the
radiocarpal joint, with
erosions involving both the
radiocarpal and distal
radioulnar joints.
extending across a ruptured
TFCC due to Sporotrichosis.
I
201
INTRAARTICULAR MASS
DIFFERENTIAL DIAGNOSIS • Bodies range in size from tiny speckled

calcifications to large bodies> 1 cm in
"tJ Common size (may appear lamellated), but each
Q)
Vl
III
• Loose Bodies case has bodies of a single similar size
a:l • Synovial Osteochondromatosis • Rarely, bodies may form a conglomerate
>- • Pigmented Villonodular Synovitis (PVNS)
E mass, making diagnosis difficult
-
«
o
III
c:
• Cyclops Lesion, ACL Reconstruction
• Meniscal Fragments
o Occasional associated erosions
o Bodies occasionally are radiolucent; only
• Gout effusion seen on radiograph
Less Common o MR: Signal varies with sequence & type of
• Nodular Synovitis body (osseous or cartilage)
• Lipoma Arborescens, Knee o Most frequent differentiating feature:
• Intraarticular Chondroma Multiple round, similar-sized bodies
.• Pigmented Villonodular Synovitis (PVNS)
Rare but Important
o Proliferation of hemorrhagic synovium
• Trevor Fairbank (Dysplasia Epiphysealis o Monoarticular, with large effusion
Hemimelica)
o Does not calcify except very rarely & very
• Synovial Chondrosarcoma late; this serves to differentiate PVNS from
• Synovial Hemangioma several items in this list
o May have large subchondral cysts/erosions
ESSENTIAL INFORMATION o MR appearance
• Synovial-based mass may be solitary
• Synovium may be thickened throughout
• Radiograph is essential to search for the joint, with nodularity
calcification within mass
• Nodularity may extend through capsular
• Specific location of mass within joint defects along juxtaarticular ligaments
(particularly knee) helps to differentiate
• Tl: Low signal, homogeneous (rare foci
Helpful Clues for Common Diagnoses of high signal lipid laden macrophages)
• Loose Bodies • T2: Variably low signal/inhomogeneous
o Osseous loose bodies • Moderate to intense enhancement
• Generally seen on radiograph • Gradient echo sequence: "Blooming" low
• If large enough, bodies may follow bone signal due to hemosiderin deposition
signal centrally, with cortex, on MR o Most frequent differentiating feature:
• Smaller osseous loose bodies will be low Blooming on gradient echo
signal on all sequences o If not a nodular mass, the diffuse synovial
o Cartilaginous loose bodies thickening may be indistinguishable from
• Not visualized on radiograph diffuse inflammatory synovitis, gouty
• Well-demonstrated on MR by synovitis, amyloid deposits, & hemophilic
surrounding effusion if > 5 mm in size arthropathy
• Watch for the osteochondral defects • Cyclops Lesion, ACL Reconstruction
along the articular surface! o Complication post ACL reconstruction
• Synovial Osteochondromatosis with very specific appearance
o Multinodular synovial membrane • Rarely seen following ACL injury
proliferation without surgery
o Usually monoarticular, but may be o Location-specific: Intercondylar notch,
polyarticular anterior to ACL, usually encroaching on
o Location: Intraarticular, bursal, or within Hoffa fat pad
tendon sheaths o Variable low signal on T1 MR, variable low
• Very rarely, extends extraarticularly to high signal on T2 MR
o Usually seen as multiple round bodies, • Meniscal Fragments
within an effusion
I
202
INTRAARTICUlAR MASS
.,...•
»
:l
o
o Medial meniscal fragment generally seen o May be indistinguishable from PVNS; 3
in intracondylar notch
o Lateral meniscal fragment generally seen
generally less hemosiderin
• Lipoma Arborescens, Knee
.,
'<
OJ
<II
m
superior/anterior to its own anterior horn o Small to large mass within knee joint c.
o Meniscal fragment large enough to mimic o May be nodular or may have frond-like '-
o
a mass generally arises from a extensions laden with lipid ;:!.
OJ
bucket-handle tear o MR signal follows fat on all sequences, Ql
<II
o Fragment is low signal on all sequences, high on T1 MR & low with fat suppression co
C.
following normal meniscus signal o Location and lipid signal is specific
o Watch for absence or significant decrease • lntraarticular Chondroma
in size of involved meniscus, particularly o Most frequently located in Hoffa fat pad
posterior horn & body o Usually calcified; may mimic conglomerate
• Gout synovial chondromatosis or the rare
o Intraarticular deposits: Low signal on T1, synovial chondrosarcoma
variable low to high signal on T2, intense Helpful Clues for Rare Diagnoses
enhancement • Trevor Fairbank (Dysplasia Epiphysealis
• May have adjacent erosions Hemimelica)
• May not be distinguishable from diffuse o Usually joints of lower extremity; may be
PVNS or synovitis polyarticular; unilateral
o Possible amorphous calcific density on o Multiple cartilage & bone bodies attached
radiograph, potential distinguishing to adjacent bone as an intra articular
feature exostosis; this is distinguishing factor
o Watch for juxtaarticular erosions &/or
• Synovial Chondrosarcoma
extraarticular tophi to aid in diagnosis o Very rarely causes intraarticular mass
Helpful Clues for less Common Diagnoses o Calcified chondroid may not be
• Nodular Synovitis distinguishable from conglomerate
o Benign proliferative synovitis arising from synovial chondromatosis or from
a single focal point of synovium intraarticular chondroma
o May arise anywhere in joint, but • Synovial Hemangioma
infrapatellar fat pad is most common site o Very rarely causes intraarticular mass
o Does not calcify o Phleboliths may help distinguish;
o Variable T1 signal, but usually low otherwise MR signal not useful
o Variable T2 signal; intense enhancement o Large draining veins, large erosions
loose Bodies Synovial Osteochondromatosis
=
Coronal oblique T2WI FS MR shows a large
osteochondral loose body arising from a
Coronal T2WI FS MR shows bodies, too numerous to
count, within the subdeltoid bursa, communicating with
I
delamination injury of the femoral trochlea. Loose the glenohumeral joint. The txxiies are similar in size,
Ixxlies are sometimes overlooked on MR examination. typical of primary synovial osteochondromatosis.
203
-0
Q) INTRAARTICUlAR MASS
III
CO
lD
C
'0
-,
"0
Gl
::l (Left) Sagittal T7 WI MR
m shows a conglomerate mass
>. within the suprapatellar
E bursa which follows bone
.B signal on MR •. This
~ proved to be synovial
< osteochondromacosis, which
occasionally presents as a
single mass rather than
multiple bodies. (Right)
Sagittal T2* GRE MR shows
large effusion and synovial
thickening with nodularity
lining the entire joint •.
Note that the nodules
"bloom" on this gradient
echo sequence due CO the
hemosiderin deposits.
Cyclops Lesion, ACL Reconstruction Meniscal Fragments

(Left) Sagittal T2WI FS MR
shows an intraarticular mass
11:I containing mixed low &
high signal intensity, anterior
to the ACL reconstruction,
and encroaching on Hoffa
fat pad. Location &
morphology is typical of
cyclops lesion. (Right) Axial
TlWI FS MR shows a mass
• located anterior to the
native anterior horn lateral
meniscus =.There is
absence of the posterior horn
& body of the meniscus; the
"mass" is the flipped
fragment of the
bucket-handle tear.
(Left) Sagittal T7 WI MR
shows a low signal mass in
the medial gutter of the
tibiotalar joint" This mass
remains mostly low signal on
all sequences, & there are
small associated erosions.
Biopsy proved gout. (Right)
Sagittal PO FSE MR shows
low signal nodular density
within Hoffa fat pad •. T2
signal was moderately high,
& the lesion enhanced
intensely. Differential
diagnosis is PVNS vs.
nodular synovitis. Location in
Hoffa fat pad favors the
latter.
I
204
INTRAARTICULAR MASS :l>
-
:J
ll>
o
3
'<
1XI
ll>
Lipoma Arborescens, Knee VI
Lipoma Arborescens, Knee It>
(Left) Sagittal PO FSEMR Co
shows a large mass located <-
within the suprapatellar Q,
bursa and knee joint_ The ~
mass follows the signal of CD
OJ
subcutaneous fat on all VI
ct>
sequences. Lipoma Co
arborescens may either be

mass-like or have frond-like
projections. (Right) Coronal
T1WI MR shows the
frond-like character of the
lesion. in a different
patient with lipoma
arborescens. Again, note the
signal of a lipomatous lesion_
contained within the knee.
Intraarticular Chondroma
shows multiple calcific
densities within Hoffa fat pad
•. The location and
appearance are typical of
intraarticular chondroma.
(Right) Sagittal T2WI FSEMR
of the same patient as
previous image shows the
mass to have virtually
replaced Hoffa fat pad ••.
The low signal regions within
the mass stayed low on all
sequences and represent the
calcified portions of the
lesion.

Hemimelical Synovial Hemangioma
(Left) Sagittal T2* CRE MR
shows posterior distension of
the joint capsule _
containing multiple bodies
•. Other sequences
confirmed the bodies follow
both bone & cartilage signal.
This is an intraarticular
exostosis (Trevor Fairbank
disease). (Right) Axial T1 C+
MR shows a large mass
occupying the knee joint _
causing significant tibial
erosion. Other images
demonstrated large
associated draining veins,
yielding the diagnosis of
synovial hemangioma.
I
205
ARTHROPLASTY WITH LYTIc/CYSTIC LESIONS
DIFFERENTIAL DIAGNOSIS o With loosening, component may subside

(change position) within bone
"1:l Common o Region of original placement may appear
Q)
VI
III
• Massive Osteolysis/Particle Disease as a cystic or lucent lesion
CO • Arthroplasty Loosening • Stress Shielding (Mimic)
>. • Stress Shielding (Mimic)
E o With placement of arthroplasty, line of
•...o
III
• Subchondral Cyst, Pre-Operative force through joint may alter
!: o Regions with less weight-bearing may
<t Less Common
• Arthroplasty Infection resorb bone, becoming more lucent
• Prior Lucencies in Revision • Greater trochanter region in THA
• Distal anterior femur in TKA
Rare but Important
• Subchondral Cyst, Pre-Operative
• Adjacent Metastasis/Primary Neoplasm o Residual large subchondral cysts appear as
lytic lesions
ESSENTIAL INFORMATION • Acetabular most frequent in THA
• Tibial most frequent in TKA
Key Differential Diagnosis Issues o Cysts often, but not always, curetted and
• Lytic or cystic lesions are frequently seen bone grafted at time of surgery
around arthroplasties, including total hip
(THA), total knee (TKA), total shoulder, & Helpful Clues for Less Common Diagnoses
total ankle • Arthroplasty Infection
• Some may be safely ignored; others need o Infection is not uncommon, but lytic
attention or may explain symptoms lesion related to infection is uncommon
• Hint: Remember to compare with prior o May be serpiginous
imaging to help determine acuity of lesions o Dense linear periosteal reaction
• Prior Lucencies in Revision
Helpful Clues for Common Diagnoses o Lytic regions from loosening or osteolysis
• Massive Osteolysis/Particle Disease mayor may not be curetted & bone
o Osteolysis resulting from inflammatory grafted at time of revision
reaction to particles of a specific size • Residual lucency mimics acute lesion
o Source of particles variable: Polyethylene,
metal, cement, osseous debris Helpful Clues for Rare Diagnoses
• Polyethylene wear is most frequent • Adjacent Metastasis/Primary Neoplasm
• Arthroplasty Loosening o Patient age group for arthroplasties is same
as that at greatest risk for metastases
Massive Osteolysis/Particle Disease Arthroplasty Loosening
I SagiClalbone a shows massive osteolysis involving the

tibia & talus ElII fol/owing lotal ankle arthroplasty. There
AP radiograph shows femoral component loosening
with subsidence (distal displacement of component) by
was no polyethylene \l\lE'ar, but a chronic fracture at the 2 em. This results in an apparent lytic lesion •
sile of tibial placement contributes osseouspartides. surrounding the proximal portion of the component.
206
ARTHROPLASTY WITH LYTIc/CYSTIC LESIONS »
::J
...•
III
o
3
'<
OJ
III
III
Stress Shielding (Mimic) CD
(Left) AntefOposterior C.
radiograph shows lucency t-
O
within the greater trochanter
•• of a THA. This is a typical ;:l.
location for stress shielding OJ
OJ
in a hip and should not be III
(!)
mistaken for a lytic lesion. C.
Note the pathologic fracture
• at this site of weakened
bone. (Right) Lateral
radiograph shows lucency at
the distal anterior femur ••
the typical location for stress
shielding in a TKA. The
diagnosis is confirmed by the
"streaming" of increased
density posteriorly HI
Subchondral Cyst, Pre-Operative Arthroplasty Infection

well-marginated lucency in
the subchondral region ••
There was no evidence of
component faOure of
polyethylene wear; this is
simply a subchondral cyst
that was present prior to
arthfOplasty placement.
a rounded lucency
surrounding the tip of the
femoral component ••
which does not continue
pfOximally. There is
tremendous dense periosteal
reaction ElII; the findings are
of infection.
Prior Lucencies in Revision Adjacent Metastasis/Primary Neoplasm

lucency along lateral aspect
of the femoral component
•• While this may be
concerning for pathology,
comparison with pre-revision
radiograph shows the same
lucency; it was due to
loosening of the prior
arthfOplasty. (Right) AP
radiograph shows lytic lesion
superior to a THA" This
patient has breast cancer; if
lesion was not present on
prior images (indicating
residual subchondral cyst),
metastatic disease must be
considered.
I
207
ClAViClE LESIONS, NONARTICULAR
DIFFERENTIAL DIAGNOSIS o Most common neoplasm in clavicle

o Most common: Breast, lung, prostate
Common o Osteolytic or osteoblastic
• Clavicle Fracture o ± Lesions in other bones
• Metastatic Disease • Rhomboid Fossa (Mimic)
~ • Rhomboid Fossa (Mimic) o Notch with sclerotic margins along inferior
(l)
:!2 • Multiple Myeloma surface of medial clavicle

=>
o
.r: Less Common o Attachment site of costoclavicular
(/)
• Radiation Osteonecrosis ligament
"ns
GI
VI
• Paget Disease • Multiple Myeloma
• Aneurysmal Bone Cyst o Multiple well-defined "punched out" lytic
aJ
>. • SAPHO lesions, endosteal scalloping
•..Eons • Osteitis Con den sans of Clavicle
• Ewing Sarcoma
o Solitary expansile lesion (plasmacytoma)
uncommon in clavicle
c
<{
• Leukemia & Lymphoma o Multiple other bones involved, including
• Cleidocranial Dysplasia ribs
Rare but Important Helpful Clues for Less Common Diagnoses
• Caffey Disease (Infantile Cortical • Radiation Osteonecrosis
Hyperostosis) o Most typical following radiation for breast
• Congenital Pseudoarthrosis cancer
• Friedrich Disease • Reduced incidence with newer delivery
• Fibromatosis Colli techniques
• Holt Oram Syndrome o Regional osteoporosis involving ribs,
• Oxalosis scapula, humeral head
• Mucopolysaccharidoses • Progresses to patchy lysis, sclerosis,
• Hypervitaminosis A fragmentation, destruction
• Asphyxiating Thoracic Dystrophy o Osteochondroma following radiation in
childhood
• Paget Disease
ESSENTIAL INFORMATION o Older patients
Key Differential Diagnosis Issues o Characteristic finding: Generalized
• List specifically excludes joint-based enlargement of bone
processes & resorption of distal end of • Cortical thickening is early finding
clavicle • Associated coarse trabecula
• List includes tumors with predilection for • Aneurysmal Bone Cyst
clavicle and is not fully inclusive o Children, teenagers
o Lytic expansile lesion ± septations at the
Helpful Clues for Common Diagnoses ends of bone
• Clavicle Fracture o MR: Fluid-fluid levels
o Most common pediatric fracture
·SAPHO
o Fall on outstretched hand or direct blow
o Synovitis, Acne, Pustulosis, Hyperostosis,
o Middle 1/3 most common
Osteitis
• Proximal fragment overrides distal • Wide spectrum of manifestations
fragment, 1-2 cm shortening, ± butterfly
• Commonly involves clavicle
fragment inferiorly o Chronic recurrent multifocal osteomyelitis
o Distal fractures 2nd most common, high
(CRMO)
incidence of nonunion, site of • Early: Ill-defined destruction, immature
stress-related fractures often aggressive periosteal new bone
o Medial fractures least common, usually
• Late: Irregular sclerosis, hyperostosis,
associated poly trauma mature periosteal new bone
• Metastatic Disease
I
208
CLAVICLE LESIONS, NONARTICULAR >
..
::J
III
o
• Involves 2 or more bones, either o Manifests by 6 months of age 3
'<
synchronous or metachronous o Irritability, swelling, bone lesions ~
III
• Usually seen in children but wide age o Progresses from cortical thickening & III
(1)
range lamellar new bone to diffuse cortical Co
o Sternoclavicular hyperostosis thickening, eventually remodels to normal (JJ

:T
• Congential Pseudoarthrosis o
• Older teenagers & adults, primarily men C
0-
• Unilateral or bilateral sclerosis & o Right clavicle, midportion ro
~
enthesitis of clavicle, sternum or both, ± o Atrophic with tapered sclerotic margins Gl
involvement of manubriosternal, 1st, o Angulated, apex points cephalad
2nd costochondral articulations • Friedrich Disease
• Osteitis Con den sans of Clavicle o Clavicular head sclerosis in children 2°
o Pain & swelling, middle-aged women trauma or emboli
o Related to chronic stress • Fibromatosis Colli
o Unilateral sclerosis inferior medial clavicle, o Well-defined notch along superior medial
inferomedial osteophyte clavicle at insertion of sternocleidomastoid
• Ewing Sarcoma muscle (SCM), SCM enlarged
o Adolescents & young adults • Holt Oram Syndrome
o Permeative destruction, aggressive o Clavicles hypoplastic, upturned creating
periosteal new bone, soft tissue mass "handle bar" appearance
• Leukemia & Lymphoma • Oxalosis
o Wide age range, especially lymphoma o Sclerosis with bulbous enlargement medial
o Aggressive destruction, periosteal new clavicle creating "drumstick" appearance
bone formation, soft tissue mass • Mucopolysaccharidoses
• Cleidocranial Dysplasia o Clavicles thick, short, widened
o Bilateral involvement ranges from o Thick ribs, small intercostal spaces
complete absence to varying degrees of o Abnormal epiphyses & vertebra
hypoplasia involving the distal ends • Hypervitaminosis A
o Associated wormian bones, symphyseal o Children only, cortical thickening,
anomalies, facial deformities, abnormal non-aggressive periostitis
dentition, short stature, scoliosis • Asphyxiating Thoracic Dystrophy
o Horizontal clavicles create "handle bar"
appearance
o Short ribs, narrow thorax create
Hyperostosis)
"bell-shaped" chest
Clavicle Fracture
Anteroposterior radiograph shows fracture of the medial

head of the clavicle •. This locaUon is much less
Anteroposterior radiograph shows an exlraarticular
fracture of Ule distal clavicle" located just lateral to
I
frequent than middle or distal and often has associated the coracoclavicular ligaments EiII. fCourtesy S. Hatem,
poly trauma. MO)
209
ClAViClE lESIONS, NONARTICUlAR
Clavicle Fracture Metastatic Disease

(Left)Anteroposterior
midshaft clavicle fracture ••
•..
Q) with a small inferior butterfly
:2 fragment El!l The proximal
::3 fragment is pulled upward
o
.r: by the sternocleidomastoid
(/)
muscle, and the lateral
"0 fragment is anchored by the
Ql
Ul coracoclavicular ligaments.
"'>.
al (Right) Anteroposterior
radiograph shows a sclerotic
.-E"'
o
c:
lesion of the distal 1/3 of the
clavicle" in this patient
with metastatic prostate
< carcinoma.
radiograph shows a defect
with well-defined sclerotic
margins along the inferior
medial clavicle III. This is
the typical appearance and
location of a rhomboid fossa
at the attachment of the
costoclavicular ligament.
radiograph shows mixed lytic
and sclerotic lesions within
the scapula, clavicle,
humeral head, and adjacent
ribs.:ll. The regional
distribution is a clue to the
diagnosis of radiation
osteonecrosis.
Paget Disease Aneurysmal Bone Cyst

radiograph shows thickening
and enlargement throughout
the medial clavicle" and
marked cortical thickening of·
the lateral border of the
scapula Ei!I in this patient
with polyostotic Paget
disease. (Right)
shows an expanded lytic
lesion at the distal end of the
clavicle IIIsurgically proven
to be an aneurysmal bone
cyst.
I
210
CLAVICLE LESIONS, NONARTICULAR »
..•o
j
III
3
'<
tll
III
<II
Osteitis Condensans of Clavicle Ewing Sarcoma ct>
(Left) Axial NECT shows 0-
typical case of osteitis (fJ
condensans of the clavicle. ::r
o
There is dense sclerosis and c
mature periosteal new bone c.
involving the medial right
,
CD
Gl
clavicle •. The medial left ,
clavicle is normal. (Right) c.
Anteroposterior radiograph CD
Ol
shows permeative :J
C.
destruction with aggressive
periostitis involving the C
"0
midclavicle in this 11 year "0
old with a large palpable soft ,CD
tissue mass. Biopsy »

confirmed Ewing sarcoma. 3
leukemia & lymphoma Cleidocranial Dysplasia

(Left) Coronal T1 WI MR
shows low signal intensity
marrow within the left
clavicle EllII and large
without significant cortical
destruction III. Lymphoma is
one tumor that may show
marrow involvement and a
soft tissue mass without
associated cortical
destruction. (Right) AP
both clavicles as well as
hypoplastic glenoid fossae
IlllI in this patient with
cleidocranial dysplasia (or
dysostosis).
Mucopolysaccharidoses Asphyxiating Thoracic Dystrophy

radiograph shows thick
c1avicles~ wide ribs, and
narrow intercostal spaces in
this patient with a
mucopolysaccharidosis
storage disorder. (Right)
shows classic findings of
asphyxiating thoracic
dystrophy including high
riding clavicles creating a
II handle bar" appearance.
Notice the short ribs creating
a bell-shaped chest.
I
211
DISTALCLAVICULARRESORPTION
DIFFERENTIAL DIAGNOSIS o Compare views of both shoulders with and

without weights; asymmetric AC joint ±
Common abnormal coracoclavicular distance
• Chronic Rotator Cuff Tear • Rheumatoid Arthritis
• Post-Operative o Synovitis leads to bilateral symmetric
~ • Acromioclavicular Separation (Mimic) resorption distal clavicles ± acromion
OJ
:2 • Rheumatoid Arthritis o Associated bilateral symmetric
::J
o
.c
• Post-Traumatic Osteolysis inflammatory arthritis hands, feet, wrists
CfJ
Less Common • Post-Traumatic Osteolysis
"'C
OJ • Hyperparathyroidism (HPTH) o Unilateral or bilateral depending on cause
<Il
<a
llJ • Renal Osteodystrophy • Bilateral common in weight lifters
>- • Progressive Systemic Sclerosis o May see periostitis
-
«
E
o
<a
l:
Rare but Important
• Septic Joint
o MR: Marrow edema, fracture or cysts

• Hyperparathyroidismm (HPTH)
o Bilateral symmetric resorption distal
ESSENTIAL INFORMATION clavicle & other sites
Key Differential Diagnosis Issues o Other findings: Soft tissue calcific deposits
• Hint: Unilateral vs. bilateral involvement • Renal Osteodystrophy
helpful in narrowing differential o Underlying mechanism is HPTH
o Associated ill-defined coarse trabeculae,
Looser's zones, pseudofractures
• Chronic Rotator Cuff Tear
• Progressive Systemic Sclerosis
o Unilateral or bilateral asymmetric
o Bilateral symmetric resorption of distal
o Decreased acromiohumeral distance clavicle ± acromion & other sites
o Pressure erosion of clavicle & acromion
o Other findings: Soft tissue calcification, IP
• Post-Operative joint erosions (pencil-in-cup), loss of soft
o Unilateral or bilateral resection of distal
tissues over distal phalanges in hand
clavicle in association with subacromial
decompression of rotator cuff tendons Helpful Clues for Rare Diagnoses
o Clavicle margin flared, sclerotic, no • Septic Joint
periostitis o IV drug abusers; unilateral destruction
• Acromioclavicular Separation (Mimic) clavicle & acromion, periostitis, effusion
o Unilateral following fall onto shoulder
Chronic Rotator Cuff Tear Post-Operative
I AP radiograph shows a high riding humeral head due to

chronic rotator cuff lear. The humerus has eroded the
AP radiograph shows blunting of the distal end of the
clavicle with a we"-defined sclerolic margin •. The
dislal clavicle III ACjoint widening & acromial erosion appearance is typical for a distal clavicle reseclian
HI are due to underlying rheumatoid arthritis. performed with a subacromial decompression.
212
DISTAL CLAVICULAR RESORPTION :>
-
::::J
III
o
3
'<
III
III
(II
Acromioclavicular Separation (Mimic) Rheumatoid Arthritis (l)
(LehJ Coronal T1WI MR a.
shows a large (J)
acromioclavicular joint ::r
o
effusion _ The clavicle is c:
superiorfy displaced relative 0:
(l)
to the acromion _ and the ~
joint is widened in this Gl
~
a.
patient with a type /If
acromioclavicular CD
OJ
separation. (RighI) ::::J
Anteroposterior radiograph a.
shows a typical case of long C
"0
term RA with severe "0
(l)
destruction of the humeral ~
head _ glenoid, distal
clavicle" and acromion.
Similar findings were present
in the left shoulder.
Post-Traumatic Osteolysis Post-Traumatic Osteolysis

radiograph shows resorption
of the distal clavicle EiIl The
end of the clavicle is sharply
marginated, & there is no
destruction in the remaining
bone. Periosteal new bone
formation is present •. The
acromion is unremarkable,
which helps to exclude a
joint-based process such as
infection or arthritis. (RighI)
Axial PO FSf MR shows the
presence of subchondral
cysts within the distal
clavicle Ell in this person
with post-traumatic
osteolysis.
radiograph shows significant
subchondral resorption of
the distal clavicle ••
simulating widening of the
AC joint in this patient with
hyperparathyroidism. (RighI)
shows multiple sites of bone
resorption in this patient with
renal osteodystrophy.
Changes include
subchondral resorption of
the distal clavicle. as well
as subligamentou5 resorption
at the attachments of the
coracoclavicular ligaments
Ell.
I
21l
PROXIMAL HUMERUS, EROSION MEDIAL METAPHYSIS
DIFFERENTIAL DIAGNOSIS • Concentric joint space narrowing,

chronic rotator cuff tear, osteopenia
Common o Predisposes to surgical neck fracture of the
• Rheumatoid Arthritis (RA) humerus due to fulcrum effect of glenoid
• Chronic Rotator Cuff Tear • Chronic Rotator Cuff Tear
~ • Hyperparathyroidism (HPTH) o Similar mechanism as rheumatoid arthritis
OJ
:2 • Renal Osteodystrophy without concentric joint space narrowing
::J
o • Shoulder Arthroplasty Impingement • Hyperparathyroidism (HPTH)
.c
(/)
Less Common o Subperiosteal resorption of the medial
"tl
Q)
• Normal Variant ("Upper Humeral Notch") humeral metaphysis is one of many
III
nl
• Hydroxyapatite Deposition Disease resorptive patterns in HPTH
CD
>. • Metastases, Bone Marrow o Other findings: Brown tumors, abnormal
-
<
E
o
nl
c:
• Leukemia
• Periosteal Chondroma
'Rare but Important
•
bone density with smudgy trabeculae
Renal Osteodystrophy
o Similar to hyperparathyroidism
• Shoulder Arthroplasty Impingement
• Sickle Cell Anemia: MSK Complications o Mechanical impingement of the native
• Hurler Syndrome proximal humeral metaphysis with the
• Gaucher Disease prosthetic glenoid component
• Syphilis
• Niemann Pick Helpful Clues for Less Common Diagnoses
• Normal Variant ("Upper Humeral Notch")
o Exaggerated convexity at the medial
ESSENTIAL INFORMATION humeral head-neck junction without
Key Differential Diagnosis Issues underlying abnormality
• Generally due either to mechanical erosion, o Smooth, intact cortex
resorption, or neoplasm • Metastases, Bone Marrow
o Lytic metastases may erode the cortex
• Leukemia
• Rheumatoid Arthritis (RA) o Subcortical demineralization of the medial
o Altered shoulder biomechanics places the
metaphyseal humeral cortex may be the
medial humeral metaphysis in direct initial radiographic finding of leukemia
contact with the inferior glenoid, resulting • Region is commonly visible on standard
in a mechanical erosion chest radiographs
Rheumatoid Arthritis (RA) Chronic Rotator Cuff Tear
I Coronal NEeT shows an erosion • in the medial

hume,al metaphysis, due to chronic rotator cuff tear &
AP radiograph shows a chronic rotator cuff lear, with
erosion of the acromion and clavicle III severe
elevaUon of the humeral head. Joint space narrowing & osteoporosis, and mechanical erosion of the medial
osteoporosis confirm the diagnosis of RA. humeral metaphysis ED. The paUent has severe RA.
214
PROXIMAL HUMERUS, EROSION MEDIAL METAPHYSIS »
::J
..•.
III
o
3
'<
OJ
III
II>
Cl>
(Left) Anteroposterior C.
radiograph shows abnormal (J)
general bone density with ~
o
indistinct trabeculae. There is c
subperiosteal resorption at a:
CO
the proximal humerus. as ~
well as severe subchondral Gl
~
resorption at the distal Q.
clavicle. and a Brown CD

OJ
tumor in the rib Ell. (Right) ::J
Q.
shows subtle subperiosteal C
"0
resorption at the medial "0
co
~
humeral metaphysis. and
a lytic lesion within the »
humeral metaphysis IIIIl 3
consistent with a Brown
tumor.
Metastases, Bone Marrow leukemia

• in the medial metaphysis
of the proximal humerus.
The bone cortex is destroyed
by the tumor. (Right)
shows typical leukemic bone
changes of lucent
metaphyseal bands and
erosion of the medial
metaphysis within the
proximal humeri _ These
may be the initial
radiographic findings of
leukemia.
Periosteal Chondroma
meta diaphyseal lesion •
that does not have obvious
matrix or soft tissue mass.
Differential dx would include
periosteal chondroma,
periosteal osteosarcoma, and
a cortically based lesion with
a very thin rim, such as
fibrous dysplasia or
aneurysmal bone cyst.
subtle medial metaphyseal
erosion. due to congenital
syphilis; there is also an
acromial fracture Ell from
non-accidental trauma.
I
215
GLENOHUMERAL MALALIGNMENT
DIFFERENTIAL DIAGNOSIS o Atony of rotator cuff muscles

• Hanging Cast
Common o Inferior pseudosubluxation
• Rotator Cuff Tear (RCT) or Atrophy • Weight of cast pulls humerus inferiorly
• Humeral Head Rotation (Mimic) • Osteoarthritis
~ • Surgical Neck Fracture o Posterior translation 2° glenoid remodeling
Ql
:Q • Hanging Cast o Superior migration if associated RCT
:::J
o
.<::
• Osteoarthritis
(fJ Helpful Clues for Less Common Diagnoses
Less Common • Instability
"0
Q)
III
• Instability o Anterior or posterior translation
III
co • Intraarticular Fluid o Labral, glenohumeral ligament, RCT
>. • Neurologic Injury o Multidirectional instability
E
o
•... Rare but Important • Intraarticular Fluid
III
r:: • Intraarticular Mass o Inferior, anterior, or posterior translation
< or joint space widening
o Effusion, hemarthrosis
ESSENTIAL INFORMATION • Trauma, infection, arthritis
Key Differential Diagnosis Issues 0. Overdistention by intraarticular contrast
• Shoulder joint capacious & highly mobile • Exacerbates pre-existing instabilities
o Stability mainly from soft tissue support • May predispose to dislocation
o Any soft tissue insult can produce • Contrast volume should not exceed 20
malalignment cc, typically 8-14 cc
• Drooping shoulder: Inferior • Neurologic Injury
pseudosubluxation o Inferior pseudo subluxation
o Leads to weakness of rotator cuff muscles
• Especially axillary nerve injury
• Rotator Cuff Tear (RCT) or Atrophy
o Superior migration 2° loss of soft tissues Helpful Clues for Rare Diagnoses
between acromion & humeral head • IntraarticuIar Mass
• Humeral Head Rotation (Mimic) o Joint space widening, anterior or posterior
o Maintain normal relationship between translation
long axis scapula & center humeral head o Capacity of joint means alignment rarely
• Surgical Neck Fracture altered by mass or intraartIcular body
o Inferior pseudosubluxation
Rotator Cuff Tear (RCT) or Atrophy Rotator Cuff Tear (RCT) or Atrophy
I Anteroposterior radiograph
abutting the acromion.
shows humeral head
due to tear and retraction of
Coronal oblique PO FSE M R shows extensive disruption
of the supraspinatus tendon, leading to loss of distance
the intervening rotator cuff tendons. The humeral head between the humeral head and acromion and supedor
is superiorly migrated relative to the glenoid. migration of the humeral head.
216
}>
GLENOHUMERAL MALALIGNMENT :J
,..,.
III
o
3
'<
tll
III
<Jl
Humeral Head Rotation (Mimic) Surgical Neck Fracture <l>
(Left) Axial T1WI FS MR Co
shows an anterior labraltear (f)
••. The humeral head is ::r
o
internally rotated, creating c
the appearance of posterior a:
ctl
subluxation. Note that the ~
center of the humeral head Gl
~
remains along the long axis 0..
of the glenoid. (Right) AP CD

Q)
radiograph shows a drooping :J
0..
shoulder & inferior
subluxation of the humeral C
TI
head, accompanying a TI
CD
surgical neck fracture of the ~
proximal humerus. With
humeral neck fracture, the
droop most frequently results
from muscle atony.
Instability Instability
(Left) Axial T1 WI FS MR
shows posterior subluxation
of the humeral head,
creating narrowing of the
joint posteriorly relative to
anterior •. There is 1055 of
the discrete triangular
contour of the posterior
labrum El!l which is tom.
(Right) ABER T1WI FS MR
to good advantage
accompanied by significant
=
shows an anterior labral tear
subluxation of the humeral

head.
Intraarticular Fluid Intraarticular Mass

(Left) Axial T2WI MR shows
widening of the
glenohumeral joint. in this
patient with a massive
rotator cuff tear and a large
effusion. Normally only a
thin layer of fluid separates
the two articular surfaces.
shows osteosarcoma arising
in the proximal humerus. A
large 50ft tissue mass is
present El!l displacing the
humeral head anteriorly
relative to the glenoid •.
I
217
ANTEROSUPERIOR LABRALVARIATIONS/PATHOLOGY
DIFFERENTIAL DIAGNOSIS • Prevalence increases with increasing

patient age
Common o Space between labrum & glenoid cartilage
• Superior Sublabral Recess (Sulcus) confined to 11 to 1 o'clock position
• Sublabral Foramen • In region of biceps attachment where the
~ • SLAPLesions I-IV labrum is most loosely attached
QJ
:2 • SLAPLesions V-X o Parallel course to glenoid cartilage
~
o
J::
• Biceps Labral Complex, Type 1 o Classically described as not extending
Cf) • Biceps Labral Complex, Type 2 behind biceps anchor, but exceptions have
"tl
Cll
• Biceps Labral Complex, Type 3 been documented
VI
<0 Less Common o Smooth free edge of labrum & width < 2
lC
>. • Sublabral Foramen with Superior Sublabral mm helps differentiate from tear
E o May be continuous with a sublabral
•...o<0 Recess (Sulcus)
r:: • Buford Complex foramen
< • Pseudo-SLAP Lesion • Sublabral Foramen
• Thin Anterior Labrum with Thick Inferior o a.k.a., sublabral hole
Glenohumeral Ligament o Normal variant in 11-15% of population
o Focal detachment of labrum from glenoid
at 12 to 2 o'clock position
ESSENTIAL INFORMATION • Anterior to biceps attachment
Key Differential Diagnosis Issues o Smooth border of labrum
• Normal labrum has wide variety of normal o Has medial slip coursing posteromedially
shapes, sizes, & attachments to glenoid
o Labral normal variants are most common • Differentiate from tears, which are
in 11 to 3 o'clock positions typically oriented laterally, away from
o Variants typically do not extend posterior glenoid
to biceps tendon attachment • SLAP Lesions I-IV
o Uncommon cases of normal variants have o Type I
been reported below 3 o'clock position & • Fraying of superior labrum without
posterior to biceps biceps involvement
• SLAPlesion = superior labral anteroposterior • Traumatic injury in young patients
lesion • May be degenerative in elderly patients
o Features favoring tear over normal variant o Type II
= irregular margin, lateral orientation of • Labrum & biceps torn from superior
abnormal signal, extension posterior to glenoid
biceps tendon, presence of perilabral cyst • Most common type of SLAPlesion
& > 2 mm separation from glenoid • Type IIA = anterosuperior labral tear
o Tears often centered at biceps tendon • Type lIB = posterosuperior labral tear
attachment • Type IIC = anterior & posterior labral tear
o Anterosuperior labral tears are less • Types lIB & IIC associated with
common than anteroinferior tears infraspinatus tears
o Causes include repetitive motion • Differentiate from superior sublabral
(throwing & swimming), trauma, recess by irregular labral edge
degeneration o Type III
• Chronically inflamed folds of synovial tissue • Superior labrum bucket handle tear
may mimic labral tear or fraying • May be displaced into joint space
• Biceps tendon remains attached to
glenoid
• Superior Sublabral Recess (Sulcus)
• Associated with fall on outstretched arm
o Most common normal variant in superior
o Type IV
labrum, seen in up to 73% of population
I
218
ANTEROSUPERIOR LABRAL VARIATIONS/PATHOLOGY l>
::::l
...•
III
o
• Bucket-handle tear + lateral extension • Biceps Labral Complex, Type 1 3
'<
into biceps tendon o No space between glenoid rim and biceps OJ
III
• Similar to a type III with involvement of tendon insertion & superior labrum III
(tl
biceps • Biceps Labral Complex, Type 2 0-
• May be seen along with type II tear o Small sulcus between glenoid rim and m
:::r
• Associated with fall on outstretched arm biceps tendon insertion & superior labrum o
c
• SLAP Lesions V-X • Biceps Labral Complex, Type 3 0:
ct>
~
o Type V o Large sulcus between glenoid rim and
• Anterior inferior glenoid/labral injury + biceps tendon insertion & superior labrum
superior extension to superior labrum & o Meniscoid projection into joint space
biceps o Can mimic a SLAP type II lesion
• Associated with fall on outstretched arm Helpful Clues for Less Common Diagnoses
& glenohumeral instability
• Sublabral Foramen with Superior
o Type VI
Sublabral Recess (Sulcus)
• Anterior or posterior flap tear of labrum o a.k.a., "double Oreo cookie" sign
with biceps tendon separation
o Mimics of this sign = superior labral tear in
o Type VII
place of the superior sublabral recess or
• Superior labrum & biceps tear extending
volume averaging with superior
into middle glenohumeral ligament
glenohumeral ligament
• Associated with acute injury &
• Buford Complex
glenohumeral instability
o Normal variant in 1.5% of population
o Type VIII
o Absent anterosuperior labrum
• Superior labrum tear with posterior o Thick, cord-like middle glenohumeral
extension
ligament
• More extensive than type lIB
• Ligament attaches directly on
• Associated with posterior dislocation
anterosuperior glenoid
o Type IX
• Can mimic a displaced labral tear or a
• Complete or near complete detachment sublabral foramen
of the labrum circumferentially
• Pseudo-SLAP Lesion
• Associated with traumatic injury o Sulcus between biceps tendon origin &
o Type X
superior labrum
• Superior labrum tear extending into
o Variable depth of sulcus: Deep sulcus can
rotator interval or structures that cross
mimic SLAP lesion
the interval
Superior Sublabral Recess (Sulcus) SLAP Lesions I-IV
Coronal oblique T1 C+ FS MR arthrogram shows

con(Jasr in a smooth bordered recess. berween the
Coronal oblique T1WI FS MR arthrogram shows a SLAP
rype I rear. There is also a supraspinatus tendon lear
I
labrum and glenoid. The conlour follows the curvature _ with 1 em or retraction.
of the glenoid.
219
ANTEROSUPERIOR LABRAL VARIATIONS/PATHOLOGY
(Left) Coronal oblique TI WI

FS MR arthrogram shows a
SLAP lype II tear. Abnormal
~
Q) high signal in the labrum.
:E
::>
extends anteriorly to
o posteriorly and involves the
.<: biceps anchor •. (Right)
en Coronal oblique TI WI FS MR
'1:l arthrogram shows a SLAP
C1l
f/l type IV lesion, with a
'"
al bucket-handle tear.
extending into the biceps
>-
E tendon Ell. The labral tear is
-
o
«'"
c:
extensive, but most
important for classification is
extension into the biceps
tendon.
SLAP Lesions V-X

(Left) Coronal oblique T IWI
tear involving the entire
anterior labrum •. This is
an extensive SLAP injury.
Abnormal signal extending
anteroinferior to
anterosuperior classifies it as
lype V. (Right) Axial TI WI FS
MR arthrogram shows a
SLAP type VII lesion, with
anterior to posterior extent
• in the labrum with
maceration of the biceps
tendon" Extensioninto
the middle glenohumeral
ligament makes it a more
extensive injury.
SLAP Lesions v-x SLAP Lesions v-x

(Left) Axial TI WI FS MR
shows an almost
circumferential SLAP type
VIII tear. This SLAP lesion
continues both anteriorly
and posteriorly •. If the
tear had been completely
circumferential, it would
have been classified as type
IX. (Right) Axial TlWI FS MR
arthrogram shows a SLAP
type IX lesion, consisting of a
circumferential tear. of [he
labrum along with an
associated longitudinal tear
of the superior glenohumeral
ligament Ell
I
220
ANTEROSUPERIOR lABRAl VARIATIONS/PATHOLOGY :l>
:l
...•
III
o
3
'<
OJ
III
VI
l1>
(Left) Coronal oblique TI C+ Q,
FS MR arthrogram shows the (f)

biceps tendon. firmly ::T
o
adherent to the labrum and c
superior glenoid. This is a a:
CD
type 1 or slab type biceps ~
labral complex. (Right)
Coronal oblique TlWI MR
shows a relatively shal/ow
sulcus. lying between the
biceps labral complex and
glenoid. This is a type 2 or
intermediate type biceps
labral complex. Note the
smooth border of the sulcus
and parallel orientation to
glenoid cartilage.
Sublabral Foramen with Superior

Sublabral Recess (Sulcus)
(Left) Coronal oblique TI C+
deep sulcus. lying
between the biceps labral
complex and glenoid. This is
a type 3 or meniscoid type
biceps labral complex.
(Right) Coronal oblique
T2WI FS MR arthrogram
shows the "double Greo
cookie" sign. From medial to
lateral, the layers of the
cookie correspond to the
glenoid cortex ~ +
subIabraI recess. + labrum
~ + biceps/superior labrum
sulcus. + biceps tendon
~
(Left) Axial TI C + M R
arthrogram image of the right
shoulder shows the anterior
superior glenoid labrum is
absent _ The middle
glenohumeral ligament is
thickened. The posterior
labrum Ell has abnormal size
and shape due to a tear. This
tear is unrelated to the
Buford complex. (Right)
Sagittal oblique TI C+ MR
arthrogram in the same
patient as prior image best
demonstrates the thickened
middle glenohumeral
ligament.
I
221
E FLUID COLLECTIONS ABOUT THE SHOULDER
~
~Q)
a. • Rheumatoid arthritis: Osteopenia,
a.
:J
"0
erosions, joint space loss, synovial
C Common hypertrophy, ± rice bodies
1'O
Q) • Effusion • Psoriatic: Bilateral involvement, normal
"0
~ o Osteoarthritis mineralization, bone proliferation
~ o Inflammatory Arthritis o Crystalline Arthropathy
Q)
"0 o Crystalline Arthropathy • Gout, pyrophosphate (CPPD),
:::l
o o Charcot, Neuropathic hydroxyapatite (HADD)
L
(fJ • Bursitis • Gout: Prefers acromioclavicular joint,
"0
ell
• Tendon Tear difficult to distinguish from
l/l
1'O • Labral Cyst osteoarthri tis
al
>- Less Common • Pyrophosphate: Normal mineralization,
E bilateral involvement, chondrocalcinosis
-«
o
l'O
C
• Bicipital Tenosynovitis
• Hemarthrosis • Milwaukee shoulder: Mixed crystals
(HADD, CPPD, etc.) with rapid
• Hematoma
• Muscle Injury glenohumeral & rotator cuff (RC)
• Ganglion Cyst destruction
o Charcot, Neuropathic
• Synovial Cyst
• Iatrogenic • Osteolysis, joint dissolution, subluxation,
• Infection ± debris; due to cervical syringomyelia,
o Septic Joint diabetes
o Soft Tissue Abscess • Bursitis
o Bursae: Subacromial/subdeltoid,
Rare but Important subcoracoid, coracoclavicular,
• Venous Distension (Mimic) supraacromial
• Neoplasm o Inflammation due to subacromial
• Synovial Osteochondromatosis impingement, RC tear, arthropathy
• Amyloid Deposition including HADD, etc.
o Calcific bursitis: Focal ~ SI nodules due to
ESSENTIAL INFORMATION HADD, particularly near RC
• Tendon Tear
Key Differential Diagnosis Issues o t SI within tendon substance with
• Fluid may be blood, inflammatory complete or partial tendon fiber disruption
transudate, purulent exudate, iatrogenic o Look for tendon retraction
• Hint: Evaluate in ALL 3 planes to locate • Labral Cyst
• Hint: Consider surrounding tissues to o Thin-walled fluid collection, ±
further characterize multilobulated, ± direct connection to
Helpful Clues for Common Diagnoses labral tear; posterior location most
• Effusion common
o Synovial transudate due to arthropathy o Hint: Cyst location helps reader find the
o Intraarticular (glenohumeral, associated labral tear; posteroinferior &
acromioclavicular) posterosuperior are most common
o Osteoarthritis Helpful Clues for Less Common Diagnoses
• Osteophytes, joint space loss, normal • Bicipital Tenosynovitis
bone mineralization, subchondral o Tendon sheath inflammation
sclerosis & cysts; ± loose bodies of o Look for accompanying long head biceps
varying sizes tendinopathy, subluxation, dislocation
o Inflammatory Arthritis • Hemarthrosis
• Rheumatoid arthritis, SLE, psoriatic, o Typically related to acute trauma, look for
ankylosing spondylitis, juvenile surrounding osseous, soft tissue injury
idiopathic arthritis
I
222
FLUID COLLECTIONS ABOUT THE SHOULDER :l>
::l
...•
Ql
o
o In absence of injury, consider vascular o Septic Joint 3
'<
malformations, hemophilia • Effusion, synovial hypertrophy, avid OJ
Ql
o Look for fluid/fluid level (hematocrit enhancement; ± marrow edema; VI
(1)
effect) diagnosis by aspiration a.
• Hematoma o Soft Tissue Abscess en

::T
• Focal fluid collection with thickened, o
o Intramuscular or along fascial planes <::
o Acute « 48 hrs): Tl isointense to muscle irregular, enhancing wall 0:
...,
(1)
o Subacute « 30 days): t SI on T1 & T2 G)

Helpful Clues for Rare Diagnoses ...,
(methemoglobin) • Venous Distension (Mimic) 0-
(1)
o Chronic: Heterogeneous; ~ SI if
o Tubular structure becomes evident when
hemosiderin evaluated in 3 planes; typically seen in
'"
::J
0-
• Muscle Injury C
spino glenoid notch "0
o Related to acute or subacute muscle fiber "0
• Neoplasm ...,
(1)
disruption (grade 2, 3 muscle strain) o May incite shoulder effusion :l>

o Associated hematoma
• Pigmented villonodular synovitis: 3
• Ganglion Cyst Effusion; heterogeneous nodular mass
o Thin-walled fluid collection, ± multiple
may be subtle
septations, no visible connection to joint • Synovial Osteochondromatosis
o May be seen anywhere around shoulder
o Multiple relatively similar sized filling
girdle defects within joint effusion
• Synovial Cyst • Typically in glenohumeral joint
o Thin-walled fluid collection, ± multiple
• May be bursal
septations, connected to joint o Synovial lining metaplasia, multiple
o Typically related to acromioclavicular joint
cartilaginous nodules, ± calcification (may
o May result in large soft tissue "mass"
appear as fluid if not calcified)
• Iatrogenic • Amyloid Deposition
o Intramuscular, intraarticular, postsurgical
o History of chronic hemodialysis
effusion or seroma o Effusion, synovial thickening, bulky
o History is key to diagnosis
erosions, rotator cuff tear
o Intraarticular fluid on T2/STIR imaging
o Look for intermediate to ~SI masses in
may be native or injected; look at Tl for t periarticular soft tissues = "shoulder pad"
SI if fluid results from dilute gadolinium
sign
injection
• Infection
Osteoarthritis Inflammatory Arthritis
Coronal oblique T2WI F5 MR shows acromioclavicular

osteoarlhritis with joint effusion • & osteophytes _
Axial T1 C+ F5 MR shows a glenohumeral effusion 0
51) • with enhancing hypertrophic synovium Ell in
I
Note glenohumeral joint effusion Ell & small 50ft tissue rheumatoid arlhritis. There is bicipital tenosynovitis •
ganglion ~ as well. with similar enhancement ~
223
FLUID COLLECTIONS ABOUT THE SHOULDER
Charcot, Neuropathic Bursitis

(Left) Coronal oblique T2WI
MR shows destruction of the
humeral head ~ & glenoid
'-
CIl
Ii8 disruption of rotator cuff,
~ & debris & distension of the
::l glenohumeral ~ &
o
.c subdeltoid" spaces, all
(f)
typical of Charcot joint.
"0 (Right) Coronal oblique PO
QI
Ul F5E F5 MR shows a large
'"
lD subacromial/subdeltoid
bursal effusion" in a
>-
E patient with osteoarthritis of
-'"
o
c:
~
the glenohumeral" &
acromioclavicular HI joints.
The chronic effusion
contains thin septations E£
Tendon Tear Tendon Tear

(Left) Coronal oblique PO
F5E F5 MR shows a partial
undersurface supraspinatus
tendon tear as a small focal
fluid (t 51) •• collection
along the tendon articular
surface. (Right) Coronal
oblique T2Wf F5 MR shows
a massive rotator cuff tear
Ell with retraction to the
glenoid rim with extensive
effusion in the glenohumeral
•• & acromioclavicular ~
joints as well as the
subacromial bursa with
superior subluxation. of
the humeral head.
labral Cyst Hematoma

(Left) Axial PO F5E F5 MR
shows a thin-walled
multiseptate cyst" arising
from a small posterior labral
tear Ell. There is effusion in
subdeltoid bursa" as well
as the subcoracoid recess of
the glenohumeral joint Ii8
(Right) Coronal oblique PO
F5E F5 MR shows
heterogeneous (t to ~ 51)
subdeltoid" &
intraarticu/ar. mass
representing chronic
hematoma & a focal t 51
area of acute hemorrhage Ell
due to recent fall in this
patient taking Coumadin.
I
224
FLUID COLLECTIONS ABOUT THE SHOULDER :>
::::l
...•
III
o
3
'<
en
III
t/I
(l)
(Leh) Axial PO FsE Fs MR Q.
shows a large fluid collection (j)

• representing acute ::r
o
hemorrhage in a patient who c
Q.
sustained a pectoralis major
muscle tear ~ with ~
<T>
retraction. (Right) Sagittal PO

FsE Fs MR shows a
thin-walled multi/obulated
cyst'" just distal to the
spinoglenoid notch ffi It
does not arise from glenoid
labrum & therefore
represents a ganglion rather
than a paralabral cyst.
(Left) AP fluoroscopic spot

radiograph obtained during
arthrography shows
glenohumeral contrast
flowing through a massive
RC tear. into & through
the acromioclavicular joint,
~ & into ~ the large
synovial cyst Ell arising from
the superior surface of the
joint. (Right) Axial TZWI MR
shows a septic shoulder joint
••• as well as abscesses Ell
in the anterior soft tissues
that have resulted in rupture
of the pectoralis major
muscle •.
Neoplasm Synovial Osteochondromatosis

(Leh) Coronal oblique TZWI
Fs MR shows a
subacromial/subdeltoid
effusion'" as t 51with a
focal nodule of intermediate
51Ell in the subdeltoid
bursa. Note the slight
heterogeneous. 51focus IIIl
in the pigmented
villonodular synovitis. (Right)
Coronal oblique TZWI Fs MR
shows multiple loose bodies
Ell within the subdeltoid
bursa effusion. all of
uniform size, typical of
synovial
I
225
E
~ RADIAL DYSPLASIAS/APLASIA
ro
OJ
~
o
LL
"0 DIFFERENTIAL DIAGNOSIS Helpful Clues for Diagnoses
C
ro Common • Fanconi Anemia
~ o Thumb aplasia or short metacarpal
o • Fanconi Anemia
.D
o Absent or malformed navicular
W • Holt-Dram Syndrome
o Brachydactyly, clinodactyly
"0
Q)
• Thrombocytopenia-Absent Radius (TAR)
VI
Syndrome • Holt-Dram Syndrome
III
CO o Brachydactyly, camptodactyly, &
>- Less Common clinodactyly
-
E
o
III
C
<l:
• Klippel Feil
• VATERAssociation
• Trisomy 18
o Thumb aplasia or malformation ±
triphalangeal thumb
o Abnormal navicular ± fusion
• Trisomy 13-15 o Os centrale
• Radioulnar Synostosis • Trisomy 18
• Dyschondrosteosis o Thumb aplasia or short metacarpal
Rare but Important o Ulnar deviation of MCP joints
• Pseudothalidomide Syndrome o Clinodactyly, syndactyly
• Thalidomide Embryopathy • Trisomy 13-15
• Fetal Varicella Syndrome o Polydactyly, clinodactyly
• Fetal Valproic Acid Exposure o Triphalangeal thumb
• Cornelia de Lange Syndrome o Broad thumb distal phalanx
• Radial Clubhand • Dyschondrosteosis
• Ulnar Clubhand o Decreased carpal angle
• Mesomelic Dysplasias o Carpal fusion
• Oculo-Auriculo-Vertebral Spectrum o Cone-shaped epiphyses
• Nail Patella Disease (Fong) • Cornelia de Lange Syndrome
o Short, wide thumb metacarpal
o Clinodactyly, brachydactyly
ESSENTIAL INFORMATION o Volar-radial curvature of fifth digit distal
Key Differential Diagnosis Issues phalanx (Kirner deformity)
• Radial hypoplasia, dysplasia, & aplasia are • Ulnar Clubhand
associated with many congenital syndromes o Aplasia or hypoplasia of the ulna with
and skeletal dysplasias radius deformity
o Forearm radiographs are often nonspecific o Thumb present, absent 4th and 5th digits
Fanconi Anemia Fanconi Anemia
I Anteroposterior
=:I that is fused =
radiograph shows a dysplastic radius
to the ulna. The thumb is absent as
are the trapezium and scaphoid bones. The distal carpal
Posteroanterior radiograph shows an absence of the
radius and thumb. There is clinodactyly 01 the filth digit
1llEl. Skeletal changes in this entity range lrom
row is dysplastic. nonexistent to major congenital malformations.
226
RADIAL DYSPLASIAS/ APLASIA »
..
:J
III
o
3
'<
llJ
III
VI
Holt-Oram Syndrome VATER Association It>
(Leh) AP radiograph shows Co
an absence of the radius, !J}
trapezium, and scaphoid. 0-
The thumb is severely o
:E
dysplastic •. A small III
triangular bone proximal and :J
Q.
radial to the capitate likely Tl
represents an as centrale. o
~
anatomic variant. fRight) PA CD
III
radiograph shows
phocomeUa with near
3
complete aplasia of the
radius, a short curved ulna
_ and absent scaphoid
and thumb. The findings
were bilateral, and the
patient also had renal
abnormalities.
Trisomy 18
aplasia of the radius and
hypoplastic thumb.
Overlapping fingers III and
ulnar deviation of ihe
are common findings. (Right)
fusion of the proximal radius
to the ulna _ The degree
of fusion and location in the
forearm is variable. This
bony fusion can be
congenital, due to lack of
segmentation, or
post-traumatic, due to
fracture or hetero~opic
ossification most commonly.
Ulnar Clubhand Nail Patella Disease (Fong)

the ulna. The radius" is
dysplastic and bowed. The
thumb and index finger are
absent, which is unusual.
This infant is too young to
definitively assess for carpal
abnormalities. (Right)
Oblique radiograph shows a
hypoplastic radial head _
which results in osteoarthritis
of the elbow and an
increased carrying angle.
This a/so causes relative
elongation of the ulna, with
subluxation of the distal
radioulnar joint.
I
227
E
~ FOREARM DEFORMITY
ro
~
Q)
o
LL
"0 DIFFERENTIAL DIAGNOSIS • Bowing ± radial head dislocation
C
ro • Madelung Deformity
Common o Ulnar, volar distal radius angulation
3
o • Fracture, Malunion
.a o Decreased carpal angle
W • Post-Operative o Distal ulna dorsally subluxated
"0
Ql
• Osteomyelitis o Unilateral or bilateral
III
nl
CD Less Common • Ollier Disease
>. • Multiple Hereditary Exostosis o Multiple enchondromas preferentially
E
-
«
o
nl
C
• Madelung Deformity
• Ollier Disease
involving extremity long bones &
phalanges
• Cartilaginous dysplasia involving the
• Radioulnar Synostosis
• Osteogenesis lmperfecta metaphyses
• Maffucci Syndrome • Endosteal scalloping, chondroid matrix
o Skull involvement ± mild platyspondyly
Rare but Important
a Up to 30% will develop bone malignancy
• Fanconi Syndrome • Pelvis> shoulder> femur> proximal
• Holt-Oram Syndrome tibia
• Thrombocytopenia Absent Radius Syndrome • Radioulnar Synostosis
• VATERAssociation a Developmental or post-traumatic
• Paget Disease a Bones are small with developmental causes
• Trisomy 18 due to lack of muscular stress
• Trisomy 13-15 • Osteogenesis Imperfecta
• Dyschondrosteosis a Multiple healed fractures
• Thalidomide Embryopathy a Wide metaphyses with thin cortices
• Cornelia de Lange Syndrome a Bowing deformities
• Ulnar/Radial Clubhand • Maffucci Syndrome
• Mesomelic Dysplasia a Multiple enchondromas, as in Ollier
• Nail Patella Disease (Fong) o Soft tissue cavernous hemangiomas with
• Klinefelter Syndrome phleboliths
• Camptomelic Dysplasia a Be vigilant for malignant transformation

ESSENTIAL INFORMATION • Fanconi Syndrome
Helpful Clues for Common Diagnoses a Thumb aplasia or short metacarpal
• Fracture, Malunion a Absent or malformed navicular

o History of trauma most helpful o Brachydactyly, clinodactyly
o Focal deformity or deformities with a Renal abnormalities
sclerosis and lack of additional findings • Holt-Dram Syndrome

o Bowing fracture in young children a Brachydactyly, camptodactyly, &
• Post-Operative clinodactyly
o Joint replacement after trauma, infection, a Thumb aplasia or malformation ±
inflammatory or degenerative disease triphalangeal thumb
o Amputation after neoplasm, trauma, or a Abnormal navicular ± fusion
severe infection a Os centrale

• Osteomyelitis • Thrombocytopenia Absent Radius
o Deformity or bowing of affected bone Syndrome
• More common in lower extremities a Radius absent with thumb present
o Bony sequestrum, sinus tract o Malformed ulna

a Carpal bone hypoplasia or fusion
Helpful Clues for Less Common Diagnoses o Humerus may be absent
• Multiple Hereditary Exostosis o 5th digit middle phalanx
o Short ulna due to exostoses
hypoplastic/absent
I
228
FOREARM DEFORMITY :>
:J
.•.o
Q)
• VATERAssociation o Hips dislocated 3

'<
o a.k.a., VACTEL,VACTERL,VACTER o Cardiac, renal, & intestinal abnormalities tlJ
Q)
o Multiple birth defects • Cornelia de Lange Syndrome (fl
(1)
• Vertebral anomalies o Short, wide thumb metacarpal Q.
o Clinodactyly, brachydactyly m
• Anal atresia IT
• Cardiac defect o Volar-radial curvature of fifth digit distal o
::E
• Tracheoesophageal fistula phalanx (Kirner deformity) OJ
:J
• Renal abnormalities • Ulnar/Radial Clubhand Cl.
-n
• Limb abnormalities o Absence of the ulna/ulnar ray or o
~
(1)
o Radial dysplasia or aplasia radius/radial ray is associated with OJ
o Thumb hypoplasia or triphalangeal thumb numerous different syndromes & 3

o Hypoplastic fifth digit middle phalanx dysplasias
• Paget Disease • Mesomelic Dysplasia
o Enlargement of bone o Short, curved radius
o Thick cortex o Madelung deformity
o Coarse trabeculae o Short metacarpals
o Bowing more common in lower • Nail Patella Disease (Fong)
extremities o Hypoplastic radial head & capitellum
• Trisomy 18 • Asymmetric joint development
o Thumb aplasia or short metacarpal • Degenerative arthritis
o Ulnar deviation of MCP joints • Limited elbow extension
o Clinodactyly, syndactyly • Increased carrying angle .
• Trisomy 13-15 o Lax finger joints
o Polydactyly, clinodactyly o Absent or hypoplastic patella
o Triphalangeal thumb o Iliac horns
o Broad thumb distal phalanx • Klinefelter Syndrome
• Dyschondrosteosis o Radioulnar synostosis
o Decreased carpal angle o Short metacarpals
o Carpal fusion o Capitate malformation
o Cone-shaped epiphyses • Camptomelic Dysplasia
o Bowed tibia, short fibula, valgus knee o Short, angulated upper extremities
• Thalidomide Embryopathy o Radial head dislocation
o Radial malformation or aplasia o Squared distal phalanges
o Thumbs usually are present o Fifth digit clinodactyly
Fracture, Malunion Fracture, Malunion
Anteroposterior radiograph shows a severe lateral

condylar fraclure malunion. The capitellum is
Lateral radiograph shows a healed bone fracture with
volar bowing of the radius _ One method to assess
I
significantly displaced proximally •• with a normally for malrotalion is to identify the coronoid process" on
articulated radial head III. The ulna" is subluxated. the opposite side from the ulnar styloid process Ell
229
E
~ FOREARM DEFORMITY
<Il
~
III
o
LL
"0
C
<Il
:;: Post-Operative Osteomyelitis
o (Left) Oblique radiograph
.0
W shows placement of a total
"0 elbow arthroplasty. The ulna
QI is dorsally subluxated" at
VI
III the distal radioulnar joint.
CD The radial head is dislocated
>. •• and the radial neck is
E
•..
o
III
eroded. (Right) Oblique
radiograph shows a focal
C deformity of the radius ••
~ There is an expanded lytic
lesion present in the
proximal shaft. A pathologic
fracture has healed. The
remainder of the radius and
the ulna are normal. The
infecting agent was
blastomycosis.
radiograph shows a sessjle
exostosis EiII bridging
between the forearm bones,
resulting in synostosis and
growth deformities. There is
a Madelung deformity of the
wrist. Additional exostoses
involve the phalanges ••.
deformities of both the
radius and ulna. Bony
excrescences III from
multiple hereditary exostoses
have caused the deformities,
including decreased carpal
angle and growth
disturbance.
Madelung Deformity Madelung Deformity

radiograph shows a medially
angulated distal radial
articularsurface. and a
long distal ulna •. The
radiocarpal joint spaces EiII
are severely narrowed due to
advanced secondary
degenerative change. (Right)
Lateralradiograph in the
same patient as the prior
image shows dorsal
subluxation/dislocation of
the ulna" This subluxation
occurs because the sigmoid
notch on the medial side of
the distal radius has not
formed.
I
230
FOREARM DEFORMITY »
-
:J
Dl
o
3
'<
llJ
Dl
VI
Oilier Disease ell
(Left) Lateral radiograph Q.
shows a short, malformed [1::!

ulna and dislocated radial rr
head 11II. Lesions with
o
:E
chondroid matrix, III
representing enchondromas, :J
0.
are seen in the distal ulna III
and the metacarpals HI
"
o
~
l1>
III
radiograph shows extremely
thin and osteoporotic bones.
3
There are multiple new and
old fractures with bowing of
the bones _ This
autosomal recessive subtype
of osteogenesis imperfecta
usually results in death soon
after birth.
Maffucci Syndrome VATER Association

radiograph shows a severely
Foreshortened forearm, with
metaphyseal deformities due
to multiple enchondromas
11:I. Soft tissue hemangiomas
were present elsewhere,
Maffucci syndrome. (Right)
shows a very short forearm.
The ulna" is short and
bowed, but the radius III is
nearly completely absent.
The scaphoid is absent, as is
the thumb. The patient also
had significant renal
abnormalities.
Paget Disease Nail Patella Disease (Fong)

shows the radius to be
bowed" and enlarged. The
osseous cortex is thickened
11:I and the trabeculae are
coarse, typical of Paget
disease. (Right)
shows characteristic
congenital radial head
dislocation, with
morphologic distortion of
both the radial head III and
capitellum _ The knee
showed absence of an
ossified patella, typical of
nail patella disease.
I
231
"0
C CARPALCYSTIc/LYTIC LESIONS
ro
I
"0
C
ro DIFFERENTIAL DIAGNOSIS o Normal joints or 2° osteoarthritis
Ul
.;::
• Gout
Common
s: • Osteoarthritis
o Bilateral asymmetric erosions, overhanging
"0 edges, soft tissue nodules, joint space
ell
l/)
• Pyrophosphate Arthropathy narrowing occurs late
co • Chronic Repetitive Trauma
CD • Ganglion, Intraosseous
>. • Gout o Solitary, communicates with joint
-E
o
co
c
ct
• Ganglion, lntraosseous
• Ulnar Abutment Syndrome
Less Common
• Ulnar Abutment Syndrome
o Ulna positive deformity, ulna abuts lunate;
subchondral sclerosis, cysts
• Brown Tumor Helpful Clues for Less Common Diagnoses
• Rheumatoid Arthritis • Brown Tumor
• Hemochromatosis o Often single lesion, bone resorption of
Rare but Important HPTH, periarticular calcium deposits
• Pigmented Villonodular Synovitis (PVNS) • Rheumatoid Arthritis
• Amyloid Deposition o Bilateral symmetric, periarticular
• Sarcoidosis osteoporosis, uniform joint space
narrowing, erosions/cysts, soft tissue
• Hemochromatosis
ESSENTIAL INFORMATION o Osteoporosis, chondrocalcinosis, large
Helpful Clues for Common Diagnoses subchondral cysts, uniform joint space
• Osteoarthritis narrowing, subchondral sclerosis,
o 1st carpal-metacarpal & osteophytes; mimics pyrophosphate
scaphomultangular joints, normal bone Helpful Clues for Rare Diagnoses
mineralization, joint space narrowing, • Pigmented Villonodular Synovitis (PVNS)
subchondral sclerosis, osteophytes, o Single compartment distribution, multiple
subluxation, loose bodies cystic lesions, MR with low T1 & T2 signal
• Pyrophosphate Arthropathy • Amyloid Deposition
o Chondrocalcinosis (TFCC, lunotriquetral & o Osteopenia, cysts & erosions, joint space
scapholunate ligaments, articular normal or widened, bulky soft tissue
cartilage), bilateral asymmetric radiocarpal masses, intermediate T2WI signal
involvement • Sarcoidosis
• Chronic Repetitive Trauma o Well-defined cystic lesions
Pyrophosphate Arthropathy
I Oblique radiograph
space narrowing with
shows scaphomultangular joint
associated sufxhondral CyslS _
PA radiograph shows sulxhondral cysts in the capitate
& hamate III scapholunate ligament tear Ellt TFee
Isolated involvement of this joint may be seen with chondroca/cinosis •• & radioscaphoid narrowing, all
osteoarthritis or epPD deposition disease. common findings in pyrophosphate arthropathy.
232
CARPAL CYSTIC/lYTIC LESIONS l>
:J
...•
Ql
o
3
'<
llJ
Ql
III
Chronic Repetitive Trauma Gout III
(Left) Sagittal T2WI FS MR a.
shows cystic lesions within
the volar and dorsal surfaces
of the lunate" attributable
to chronic repetitive trauma
in the dominant hand of this
carpenter. (Right)
shows multiple cysts and
erosions involving the distal
ulna, triquetrum, lunate,
capitate" with
accompanying radiocarpal
and mid-carpal joint space
narrowing. A large soft tissue
tophus is characteristic of
gout •.
Ulnar Abutment Syndrome Rheumatoid Arthritis

radiograph shows an ulnar
plus variance (the ulna is
longer than the radius). This
variance results in impaction
on the lunate. In this case
there is a cyst and sclerosis
in the lunate at the point of
impaction" (Right)
Coronal TI C+ FS MR shows
erosive changes in the carpal
bones" as well as
extensive synovial pannus
formation penetrating into
the osseous erosions iii in
this patient with rheumatoid
arthritis.

shows cysts in the lunate,
capitate, and hamate _.
The cysts are well-defined
and are all within the
mid-carpal joint space.
Localization to one
compartment is typical of
PVNS of the carpus. (Right)
shows diffuse osteopenia of
the carpus. Large,
well-defined cysts with
sclerotic margins are present
in the distal radius, lunate,
scaphoid and trapezium ••
in this patient with biopsy
proven amyloidosis.
I
233
"0
C ABNORMAL RADIOCARPAL ANGLE
C1l
I
"0
C
C1l DIFFERENTIAL DIAGNOSIS o Carpal bone fusion
iil o Drumstick phalanges
Common o Delayed bone age
~
"0
• Fracture, Malunion • Multiple Hereditary Exostosis
Ql
tI)
• Madelung Deformity o Madelung deformity
III
en • Turner Syndrome o Short ulna & fibula
>- • Multiple Hereditary Exostosis o Metaphyseal exostoses with exostosis apex
E
-
o
III
C
<l:
Less Common
• allier Disease
"dripping" away from joint
o Cortex and marrow space of exostosis is
• Marfan Syndrome contiguous with underlying bone
• Maffucci Syndrome o Onset in infancy and early childhood
• Cleidocranial Dysplasia o Watch for malignant degeneration, usually
• Multiple Epiphyseal Dysplasia chondrosarcoma
• Down Syndrome (Trisomy 21) Helpful Clues for Less Common Diagnoses
Rare but Important • Ollier Disease
• Arthrogryposis o Multiple enchondromas: Lytic lesions with
• Mucopolysaccharidoses cartilaginous matrix
• Hurler Syndrome o Longitudinal steaks of alternating lucency
• Morquio Syndrome & sclerosis in metaphyses
• Mesomelic Dysplasia o Resultant bone deformity
• Dyschondrosteosis (Leri-Weill) • Madelung deformity
• Otopalatodigital Syndrome • Long bones, tubular bones of hands/feet,
• Frontometaphyseal Dysplasia pelvis, ribs
• Arthroophthalmopathy Syndrome o Increased risk of malignant transformation
• Chondroectodermal Dysplasia (Ellis-van • Marfan Syndrome
Creveld) o Long fingers (arachnodactyly)
• Larsen Syndrome • Third finger> l.Sx metacarpal length
• LEOPARDSyndrome o Clinodactyly
o Vertical talus, flatfoot
o Protrusio deformity of hips
ESSENTIAL INFORMATION o Enlarged paranasal sinuses
Helpful Clues for Common Diagnoses • Maffucci Syndrome
• Fracture, Malunion o Madelung deformity
o Malunion may result in increased or o Same as allier Disease + cutaneous
decreased carpal angle hemangiomas (phleboliths)
o Post-traumatic decreased carpal angle may o Increased risk of malignant degeneration
be differentiated from Madelung deformity • Cleidocranial Dysplasia
by lack of volar radial tilt o Increased carpal angle
• Madelung Deformity o Long second & fifth metacarpals
o V-shaped, steep radLocarpal joint o Short middle phalanges
producing a decreased carpal angle o Cone-shaped epiphyses
• Short radius with volar bowing o Delayed bone age
• Triangular distal radial epiphysis • Multiple Epiphyseal Dysplasia
• Carpal bones wedged together with o Flat epiphyses cause increased carpal angle
lunate at apex o Small, irregular, fragmented epiphyses
• Dorsal subluxation or dislocation of ulna o Short tubular bones of hands & feet
o Numerous potential etiologies of this o Delayed bone age
deformity • Down Syndrome (Trisomy 21)
• Turner Syndrome o Increased carpal angle
o Madelung deformity o Dislocated radial head
o Short fourth metacarpal/metatarsal o Dysplastic fifth digit middle phalanx
I
234
ABNORMAL RADIOCARPAL ANGLE >
.•o
::3
III
o Pseudoepiphysis of hands o Madelung deformity 3

'<
o Variable skeletal maturation o Turner syndrome llJ
III
o Fracture, malunion VI
«>
o Multiple hereditary exostosis Q.
• Dyschondrosteosis (Leri-Weill)
o Oilier disease
o Madelung deformity
o Maffucci syndrome
o Mesomelic dwarfism
o Mucopolysaccharidoses
o Short, curved tibia
o Hurler syndrome
o Short metacarpals & metatarsals
o Morquio syndrome
• Chondroectodermal Dysplasia (Ellis-van
o Mesomelic dysplasia
Creveld) o Dyschondrosteosis (Leri-Weill)
o Enlarged distal radius causing increased
• Madelung deformity
carpal angle
o Trauma
o Bony spike at distal humeral metaphysis
o Turner syndrome
medially o Multiple hereditary exostosis
o Short, heavy tubular bones
o Ollier disease
o Ninth carpal bone
o Maffucci syndrome
o Delayed skeletal maturation
o Dyschondrosteosis (Leri-Weill)
• Larsen Syndrome o LEOPARD syndrome
o Increased carpal angle
• Increased carpal angle (> 135 degrees)
o Short metacarpals & distal phalanges
o Fracture, malunion
o Spatulate thumbs
o Marfan syndrome
o Multiple accessory ossicles
o Cleidocranial dysplasia
• LEOPARD Syndrome o Multiple epiphyseal dysplasia
o Lentigines, EKG conduction abnormalities
o Down syndrome (trisomy 21)
Ocular hypertelorism, Pulmonary stenosis:
o Arthrogryposis
Abnormal genitalia, Retardation of growth,
o Otopalatodigital syndrome
Deafness (LEOPARD)
o Frontometaphyseal dysplasia
o Madelung deformity
o Arthroophthalmopathy syndrome
o Decreased bone age
o Chondroectodermal dysplasia (Ellis-van
o Hypoplastic fifth digit
Creveld)
o Syndactyly or soft tissue webbing
o Larsen syndrome
Alternative Differential Approaches
• Decreased carpal angle « 125 degrees)
Posteroanterior
radiocarpal joint _
radiograph shows a V-shaped
decreasing the normal radiocarpal
Posteroanterior radiograph shows a developmentally
steep distaf radius arUcular surface • and a dorsally
I
angle. The patient had a remote distal radius fracture dIslocated ulna _ as confirmed on the lateral view.
and resultant malunion. 235
ABNORMAL RADIOCARPAL ANGLE
Turner Syndrome Multiple Hereditary Exostosis

"tl
CIl radiograph shows a short,
III
n:l curved radius =:I and a
lD dislocated ulna 11:I with
>. resultant decreased carpal
E
-
«
o
n:l
c:
angle. Carpal bone fusion
and a short fourth
metacarpal are not seen in
this case but are often also
present. fRight)
shows a sessile exostosis 11II:I
resulting in synostosis and
decreased forearm growth
including a decreased carpal
angle. The rounded densities
on the phalanges =:I are
exostoses protruding volar/y.
Oilier Disease Marfan Syndrome

an abnormally short ulna
with cartilage type matrix"
distally. Several similar
lesions involve the
metaphyseal regions of
multiple metacarpals and
phalanges =:I. The
polyostotic nature and
cartilaginous matrix suggest
enchondromatosis. (Right)
PA radiograph shows a
flattened (increased)
radiocarpal angle =:I and
long fingers 11:I relative to
the metacarpal length. The
appearance of the hands is
otherwise normal.
Multiple Epiphyseal Dysplasia

epiphyses =:I causing an
increased carpal angle. Note
the excrescences .:I arising
from the metaphyses. This
epiphyseal abnormality
results in short, stubby
bones, particularly in the
hands and feet. (Right)
flattened radiocarpal angle
••. Several of the carpal
bones are fused" Note
the gracile radius & ulna and
atrophy of the musculature,
typical of arthrogryposis.
I
216
ABNORMAL RADIOCARPAL ANGLE »
::l
...•
III
o
3
'<
OJ
III
Ul
Mucopolysaccharidoses <1>
(Left) Posteroanterior Co
radiograph shows a
decreased radiocarpal angle
=. The metacarpals are
short, broad, and constricted
proximally. This
"fan-shaped" appearance EilI
is classic for
mucopolysaccharidoses.
findings similar to the prior
image. There is a decreased
radiocarpal angle III and
the metacarpals are short &
constricted proximally EilI.
The middle and distal
phalanges. have pointed
ends.
Mesomelic Dysplasia Dyschondrosteosis (leri-Weill)

V-shaped (decreased)
radiocarpal angle =.
Both
the radius and ulna are short
mesomelic dysplasia. The
radius is curved •. (Right)
severely narrowed
radiocarpal angle •. The
radius is short and bowed
•. The distal ulna is dorsally
subluxed, although difficult
to appreciate on this image.
The widened distance EilI
between the radius and ulna
is typical of
dyschondrosteosis.
Chondroectodermal Dysplasia (Ellis-van

Creveld)
beginnings of a flat
(increased) radiocarpal angle
•. The metacarpal. and
forearm iii bones are short.
Skeletal maturation is
delayed in this patient.
radiograph shows a flat
(increased) radiocarpal angle
•. Multiple accessory
ossicles • in the wrist are
typical. The third through
[;fth metacarpals are short
EilI. Note the thick soft
tissues of the thumb EB
typical of Larsen syndrome.
I
237
(/)
Q) ARACHNODACTYl Y
o
I-
"t:J
C
<Il DIFFERENTIAL DIAGNOSIS o Dural ectasia with lumbar vertebral body
~ scalloping
Q)
OJ Common o Spondylolisthesis, ± spondylolysis
C
u:: • Marfan Syndrome o Aortic root dilatation; may dissect
"'C • Ehlers-Danlos ascending aorta
Ql
VI
III
• Localized Giantism (Mimic) o Lens dislocation, myopia
al o Pectus carinatum or excavatum
>- less Common
E • Homocystinuria o Hypermobility of joints
.•..o
III • Congenital Contractural Arachnodactyly • Ehlers-Danlos
C
« o Dural ectasia with lumbar vertebral body
Rare but Important
scalloping
• Myotonic Dystrophy o Hypermobility of joints
• Multiple Endocrine Neoplasia Type llB o Skin hyperextensibility
• Frontometaphyseal Dysplasia o Multiple aneurysms (friable vessels)
• Stickler Disease • Localized Giantism (Mimic)
• Chromosome XYY(Klinefelter) Syndrome o Vascular malformations, macrodystrophia
• Ichthyosis Syndrome lipomatosa, Klippel Trenaunay Weber
• Cleidocranial Dysplasia
• Homocystinuria
ESSENTIAL INFORMATION o Arachnodactyly plus osteopenia
Key Differential Diagnosis Issues o May have joint laxity
• Arachnodactyly is a rare condition, so the • More frequently develop joint
list of "common" diagnoses is relative contractures
• Arachnodactyly itself is nonspecific; clinical o Pectus carinatum or excavatum
or rarely other radiographic features may o Lens subluxation, myopia
differentiate the diagnoses o Mental deficiency
• Metacarpal index> 8.8 (male) or 9.4 (female) o Thromboembolic episodes
o Obtained by dividing the sum of the • Congenital Contractural Arachnodactyly
lengths of 2nd through 5th metacarpals by o Long thin limbs, scoliosis, joint
the sum of their respective widths contractures
o No eye or cardiac abnormalities
• Marfan Syndrome
Marfan Syndrome Marfan Syndrome
I Posteroanterior radiograph shows fairly uniform

elongation of the metacarpals, and especially proximal
Lateral radiograph from the same patient shown in the
phalanges, in a patient with Marian syndrome. vertebral bodies=.

previous image shows posterior scalloping and tall
typical of and helping to confirm
the diagnosis of Madan syndrome.
238
ARACH NODACTYl Y :I>
j
..•.
III
o
3
'<
III
III
Localized Giantism (Mimic) Localized Giantism (Mimic)
'"
<ll
Co
radiograph shows
overgrowth of the 2nd and
Jrd digits contributing to a
":J
(Q
(l)
focal "arachnodactyly". This i.il

patient had Klippel OJ
:J
Trenaunay Weber syndrome. a.
(Right) AP radiograph shows -l
focal overgrowth of the 1st,
o
(l)
2nd, and Jrd digits of the

en
foot (compare with 4th and
5th toes). This may mimic
arachnodactyly, though it is
not as uniform as would be
expected for true
arachnodactyly. In this case,
the patient had
macrodystrophia lipomatosa.
Homocystinuria Homocystinuria
fairly uniform elongation of
the metacarpals and
especially proximal
phalanges, allowing the
nonspecific diagnosis of
arachnodactyly. The bones
are osteopenic. (Right)
Lateral radiograph in the
image shows the bones are
diffusely osteoporotic. There
is mild platyspondyly from
multiple compression
fractures. The combination
of arachnodactyly and
osteopenia is seen with
homocystinuria.
Ichthyosis Syndrome Ichthyosis Syndrome

arachnodactyly. There is also
irregularity along the skin
surface _ clinically the skin
disease was proven
ichthyosis. (Right) Lateral
radiograph obtained 8 years
later in the same patient as
the previous image shows
prominent spondylosis ••.
This was present throughout
the spine in this 22 year old
and resulted (rom use 01
retinoids for the skin disease.
(tMSK Req).
I
239
Cf)
Q) SOFT TISSUE MASS IN A FINGER
o
f--
""0
C
III DIFFERENTIAL DIAGNOSIS a Enhances more intensely than fibroma of
Cf)
L tendon sheath
Q)
OJ Common a Lacks surrounding soft tissue edema
C
LL • Mucoid Cysts • Hematoma
"0 • Giant Cell Tumor Tendon Sheath a Absence of central enhancement helps
CIl
VI
III
• Hematoma differentiate from hemorrhagic tumor
CO • Gout a Surrounding soft tissue edema
>.
E • Soft Tissue Abscess • Gout
.•..o
III
• Infectious Tenosynovitis a Multiple gouty tophi often present
C
<l:
• Foreign Body • Tophi may show mild, irregular
a Paint Gun Injury enhancement
• Granulation Tissue a Bone erosions with overhanging edges
• Fibroma of Tendon Sheath • Soft Tissue Abscess
• Glomus Tumor a Thick, irregularly enhancing border
• Epidermal Inclusion Cyst a Central nonenhancing necrosis or debris
• Rheumatoid Nodule • Infectious Tenosynovitis
less Common a Fluid & debris in tendon sheath
• Progressive Systemic Sclerosis a More prominent enhancement than

• Tumoral (Idiopathic) Calcinosis inflammatory tenosynovitis
• Heterotopic Ossification • Foreign Body
• Soft Tissue Chondroma a Wide variety of embedded material can
• Hemangioma, Soft Tissue produce an inflammatory response

• Arteriovenous Malformation a Tends to have superficial location
• Pyrophosphate Arthropathy a Paint Gun Injury
• Lead in paint is visible on radiographs
Rare but Important
• Fibroma of Tendon Sheath
• Malignant Fibrous Histiocytoma
a Mass is isointense or hypointense to
• Chondrosarcoma skeletal muscle on T1WI & T2WI MR
• Metastasis, Subcutaneous
a May have very low signal regions of
• Lipoma, Soft Tissue collagen within mass
• Tenosynovial Chondromatosis a Enhancement variable
• Klippel Trenaunay Weber Syndrome
• 50% moderate to marked enhancement
• Acral Myxoinflammatory Fibroblastic
• 50% little to no enhancement
Sarcoma
• Glomus Tumor
a Soft tissue mass centered in nail bed
ESSENTIAL INFORMATION a Pressure erosion of distal phalanx
a No matrix
• Rheumatoid Nodule
• Mucoid Cysts a Soft tissue mass associated with changes of
a a.k.a., ganglion cyst
rheumatoid arthritis
a Follows fluid signal intensity on all
a Pressure erosion of underlying bone
sequences
a Thin peripheral rim of enhancement Helpful Clues for Less Common Diagnoses
• Lacks central enhancement • Progressive Systemic Sclerosis
a Located near joint or tendon sheath a Lobulated soft tissue calcifications
a May have loculations or internal a Additional findings of soft tissue atrophy
septations & acroosteolysis

• Giant Cell Tumor Tendon Sheath • Tumoral (Idiopathic) Calcinosis
a Low to intermediate signal mass on Tl WI a Calcified masses around joints
&T2WI MR a Associated with chronic renal disease
• Preferential location along volar aspect a More common around large joints
of finger • Heterotopic Ossification

I
240
SOFT TISSUE MASS IN A FINGER »
~
..•.
Cll
o
o Ossified mass in soft tissues • Chondrosarcoma 3
'<
o Cleavage plane between mass & bone o Soft tissue mass originating from a ttJ
Cll
o Matures peripheral to central destructive bone lesion VI
(l)
• Soft Tissue Chondroma o Chondroid matrix usually present a.

o Most common site in hand is proximal -n
o Mass with chondroid matrix :J
o Adjacent to bone surface phalanx CO
CD
~
• Hemangioma, Soft Tissue • Metastasis, Subcutaneous VI
OJ
o Slightly higher signal than muscle on o Nonspecific, heterogeneously enhancing :J
0.
TlWIMR mass most common -I
o
o Very high signal on T2WI MR o History of malignant melanoma or high CD
VI
o Internal septa, lobulated borders grade adenocarcinoma

o Fat & fibrous tissue may be visible in • Lipoma, Soft Tissue
addition to vascular channels o Fat signal intensity on all MR sequences
o Can be difficult to differentiate arteries o Thin septations without solid soft tissue
from veins nodules
• Cavernous hemangioma is most o May produce mass effect on neurovascular
common subtype structures in confined spaces, e.g., carpal
• Arteriovenous Malformation tunnel
o Enlarged vascular channels • Tenosynovial Chondromatosis
o Marked vascular enhancement o Multiple round to oval cartilaginous or
o May contain fat osseous bodies of similar size within
• Pyrophosphate Arthropathy tendon sheath
o Lobulated calcified mass • Commonly visible on radiographs
o Additional findings of chondrocalcinosis & o May cause pressure erosion of adjacent
narrowing of radiocarpal and bone
metacarpophalangeal joint spaces • Klippel Trenaunay Weber Syndrome
o Bone and soft tissue hypertrophy
o Capillary hemangiomas & varicose veins
• Malignant Fibrous Histiocytoma
o Arteriovenous fistulas are rarely found in
o Soft tissue mass with heterogeneous signal
enlarged regions
+ enhancement on MR
• Acral Myxoinflammatory Fibroblastic
o May have well-defined borders
Sarcoma
o Hemorrhage & edema can obscure
o Ill-defined mass in distal extremity
underlying mass
o Can mimic an inflammatory process
Giant Cell Tumor Tendon Sheath Giant Cell Tumor Tendon Sheath
Posteroanterior radiograph shows a 50ft tissue mass III

causing smooth, extrinsicerosion. around Ulethumb
Oblique T2WI MR shows a large intermediate signal
intensity sort tissue mass _ which erodes the adjacent
I
metacarpophalangeal joint. bones and surrounds the flexor tendon of the thumb.
241
'"
Q)
o
SOFT TISSUE MASS IN A FINGER
t-
"0
C
ro
~
'"
Q)
Ol
C Gout Infectious Tenosynovitis
u:: (Left) Posteroanterior
"0 radiograph shows an
CIl impressive soft tissue tophus
'"
01
1IJ
Ell, with density typical of
sodium urate deposition.
>- There is a large erosion at the
E
.-
o
01
c:
PIP that has resulted in a
classic overhanging edge _
(Right) Axial T1 C+ FS MR of
< the second finger shows
abnormalenhancmgsoh
tissue ~ around and
particularly deep to the
superficialis • and
profunda Ei!I flexor tendons
of the digit. This was caused
by a puncture wound with
secondary infection.
Foreign Body Foreign Body

demonstrates an ill-defined,
ovoid nodularlesion" in
the volar soft tissues of the
distal aspect of the fifth
finger. This collection is
isointense to muscle and
abuts the skin surface.
(Right) Sagittal T2WI FS MR
in the same patient as the
the nodular lesion =

previous image again shows
has high signal on T2WI.

which
There was moderate

enhancement except for a 2
mm focus that likely was the
clinically-reported rose thorn
fragment.
Paint Gun Injury Granulation Tissue

shows radiodense foreign
materia'. in the soft tissues
of the index finger. Paint gun
injuries in which there is skin
penetration have this typical
appearance due to the lead
in the paint. (Right) Axial
T2WI MR shows an
ill-defined enhancing lesion
Illl!l along the dorsal aspect of
the proximal interphalangeal
joint of the index finger. The
extensortendon. is
visualized within this
enhancing lesion. The
patient had a history of finger
laceration.
I
242
SOFT TISSUE MASS IN A FINGER »
..o
:J
Cl
3
'<
lJl
Cl
III
Fibroma of Tendon Sheath Glomus Tumor Cll
(Left) Axial T7 C+ FS MR 0-
with subtraction shows an
inhomogeneously enhancing
mass III abutting the mildly
"
:J
(Q
C1l
enhancing flexor tendon
~
III
sheath III. The mass had OJ
OJ
intermediate to low signal on 0-
T7 WI and T2WI. A giant cell --1
tumor of tendon sheath
o
C1l
III
could have a similar
appearance. (Right) Axial
T2WI MR demonstrates a
well-defined, solid,
subungual tumor IllII that
extends radially and ulnarly
to almost surround the shaft
of the distal phalanx. The
lesion moderately enhanced.
Glomus Tumor Epidermal Inclusion Cyst

(Left) Axial T7 C+ FS MR
demonstrates a mass III
involving subungual space of
the distal long finger. It is
well-defined, solid, and
moderately enhancing.
shows a lytic lesion involving
the terminal phalanx III.
There is circumferential soft
tissue swelling and
suggestion of invasion from
the 50ft tissues beneath the
nail bed. This makes either
glomus tumor or epidermal
inclusion cyst the most likely
diagnosis; the latter was
proven.
Rheumatoid Nodule Progressive Systemic Sclerosis

radiograph shows a focal soft
tissue nodule III with
bone HI. There is second
metacarpophalangeal joint
space narrowing, along with
marginal erosions along the
radial side of the metacarpal
head _ all typical of
rheumatoid arthritis. (Right)
shows multiple lobular
calcifications. which have
a predominantly periarticular
location. The calcifications
produce palpable 50ft tissue
masses.
I
243
Vl
OJ SOFT TISSUE MASS IN A FINGER
o
t-
"0
c::
III
~
Vl
OJ
Ol
c:: ProgressiveSystemic Sclerosis Tumoral (Idiopathic) Calcinosis
u::: (Left) Posteroanterior
"0 radiograph shows several
Gl (oci of soft tissue dystrophic
Vl
calcification" most
'"
lD notably seen around the
>- base o( the first metacarpal
-
E
o
'"
c::
~
ElilI. The terminal phalanges
show acroosteolysis
tapered soft tissues. (Right)
• with
tumoral calcinosis II
involving the soft tissues of
the thumb. Soft tissue
calcification is particularly
prominent in patients with
renal osteodystrophy once
they are treated with dialysis.
Tumoral (Idiopathic) Calcinosis Tumoral (Idiopathic) Calcinosis

radiograph shows soft tissue
calcification III in a patient
with end-stage renal disease,
now on dialysis. There are
no other abnormalities to
suggest renal
osteodystrophy. (Right)
shows calcified soft tissue
masses = and vascular
calcifications ElilI. Findings
are consistent with
osteomalacia and dystrophic
calcification due to chronic
renal disease.
Heterotopic Ossification Heterotopic Ossification

(Leh) Oblique radiograph
shows an ossified mass III in
the soft tissues dorsal and
ulnar to the third digit middle
phalanx. There is a cleavage
plane between the bone and
ossification in the soft tissue.
radiograph demonstrates a
nonspecific, irregular soft
tissue calcification." This
was presumed to represent
post-traumatic soft tissue
calcification due to instability
in this manual laborer.
I
244
SOFT TISSUE MASS IN A FINGER :>
::l
..•o
Ql
3
'<
OJ
Ql
VI
Soft Tissue Chondroma Hemangioma, Soft Tissue CD
(Leh) Posteroanterior Co
radiograph shows a ::!1
nonspecific mass IIlI in the :>
<0
soft tissues adjacent to the CD
distal interphalangeal joint.
~
VI
The mass contains faint OJ
:>
calcification. On excision, Co
this was identified as a -l
o
periosteal chondroma. CD
VI
(Right) Lareral radiograph
shows bulky soft tissues, with
fatty stroma of the forearm
and hand ••. Although no
phleboliths are present, this
proved ta be a hemangioma.
Arteriovenous Malformation Metastasis, Subcutaneous

(Leh) MRA shows a large
arteriovenous malformation
• in the circumferential
subcutaneous soft tissues of
the ring finger,
predominanrly at the level of
the middle and proximal
phalanges. There was no
involvement of the
underlying bone except for
overgrowth. (Right) Axial T1
C+ FS MR shows a
moderately enhancing mass
.witha2mm
hypo-enhancing area, which
is nonspecific. Metastatic
adenocarcinoma was found
on biopsy.
Tenosynovial Chondromatosis
(Leh) Lateral T2WI FS MR
shows a large soft tissue
mass" at the dorsal aspect
of the hand which extended
into the base of the third
digit. Numerous oval bodies
are highly suggestive of
chondromatasis. (Right)
shows diffuse hypertrophy
III of rhe second and third
digits and metacarpals
involving both the bony
structures and subcutaneous
fat. which is markedly
thickened and can be
mass-like clinically.
I
245
If)
Q) ACROOSTEOLYSIS
o
I-
-0
C
ro DIFFERENTIAL DIAGNOSIS o Generally a clean transverse or oblique
....
If)
osseous edge
Q)
OJ Common o 2-3 adjacent: Snowblower or lawn mower
C
u: • Trauma: Amputation injury
'tl • Hyperparathyroidism (HPTH) • Hyperparathyroidism (HPTH)
Q)
Ul
1tI
• Progressive Systemic Sclerosis (PSS) o Resorption of the tufts of distal phalanges
llJ • Thermal Injury is one of the resorptive processes in HPTH
>.
E o Thermal Injury, Frostbite
• May be subtle, or severe, with dissolution
.•..o
1tI
o Thermal Injury, Burns of entire tuft
c
<I: Less Common • Overlying soft tissues remain normal in
• Psoriatic Arthritis (PSA) size (no tapering)
• Vasculitis o Hint: Watch for other signs of HPTH
o Raynaud Disease • Subperiosteal, subligamentous,
• Diabetes (Neuropathic) subchondral resorption
• Congenital Indifference/Insensitivity to Pain • Soft tissue or vascular calcification
• Meningococcemia • Brown tumors
• Progressive Systemic Sclerosis (PSS)
Rare but Important
o Resorption of tufts is common
• Leprosy o Associated tapering of distal soft tissues,
• Lesch-Nyhan
matching that of osseous resorption
• Hajdu-Cheney Acroosteolysis Syndrome
o May have globular soft tissue calcification
• Polyvinyl Chloride (PVC)
o Systemic abnormality: Involvement of
• Occupational Acroosteolysis
lungs, GI system (particularly esophagus)
• Pycnodysostosis
• Thermal Injury, Frostbite
o Frostbite in adult may result in tuft
• Amniotic Band Syndrome resorption
• Progeria o Frostbite in child results in injury to
• Pachydermoperiostosis
epiphyses of distal phalanges
• Sarcoidosis
• Resorption of epiphyses & cessation of
growth -+ short distal phalanges
• Venom Induced Complications o Usually have normal thumb
• Complications of Dilantin
• When cold, thumb is usually curled into
palm and protected
ESSENTIAL INFORMATION • Thermal Injury, Burns
o Soft tissue contractu res
o Acroosteolysis, involves both bone and
• Hint: Presence & character of soft tissue soft tissues
calcification may help make diagnosis
o May have associated globular soft tissue
o HPTH: Globular soft tissue calcification &
calcification
small vessel calcification
o PSS (a.k.a., scleroderma): Globular Helpful Clues for Less Common Diagnoses
calcification very often present • Psoriatic Arthritis (PSA)
o Thermal injury (burns): Globular o Distal tuft resorption may be absent,
calcification, infrequently present subtle, or severe
o Leprosy: Linear calcification in digital o Distal tuft may be sclerotic ("ivory tuft")
nerve o Hint: Watch for other signs of PSA
• Hint: First 6 diagnoses on list are far, far • "Sausage digit" type of soft tissue swelling
more prevalent than others • Periostitis
• Erosive or mixed erosive/productive
articular disease, particular
• Trauma: Amputation interphalangeal joints
I
246
ACROOSTEOl YSIS »
::l
..•o
Ql
• End stage: Arthritis mutilans, with o Acroosteolysis may be severe, involving all 3
'<
telescoping digits and pencil-in-cup phalanges as well as metacarpals [ll
Ql
deformities o Linear calcification of digital nerve
• Lesch-Nyhan
'"
CD
Co
• Vasculitis
o Any type of vasculitis may affect small
terminal vessels in digits
o X-linked disorder of male children
o Compulsive self-mutilation by biting
"
::l
to
<1l
~
o Raynaud and systemic lupus fingers & lips Ul
OJ
erythematosus are typical o Both soft tissue & osseous destruction OJ
Co
o Results in acroosteolysis & loss of soft • Hajdu-Cheney Acroosteolysis Syndrome -l
o
tissues, often with ulceration o Osteolysis, particularly of distal phalanges <1l
Ul
• Diabetes (Neuropathic) hands & feet

o Neuropathic osseous destruction of o May have skull abnormalities (Wormian
terminal digits not as common as bones, dolichocephalic skull with basilar
neuropathic joint disease impression, delayed suture closure)
o Fragmentation of bone • Polyvinyl Chloride (PVC)
o Hint: Watch for other signs of diabetes o Fairly distinct form of acroosteolysis, with
• Charcot joints, especially Lisfranc lucency crossing the neck of distal phalanx
• Small vessel calcification & consequent shortening
• Congenital Indifference/Insensitivity to o Tuft & soft tissues usually intact
Pain • Occupational Acroosteolysis
o Neuropathic fragmentation & destruction o Guitar players rarely develop
of terminal digits acroosteolysis, with lucency crossing neck
o Often associated scarring of soft tissues of distal phalanx (mimicking PVe)
(particularly from burns on stove, but any • Pycnodysostosis
trauma may be causative) o Combination of diffuse osseous density &
o Hint: Patient also may have corneal acroosteolysis
scarring & Charcot joints involving lower • Multicentric Reticulohistiocytosis
extremity o Combination of acroosteolysis, DIP
• Meningococcemia erosions, & nodules on fingers
o Usually involves epiphyses, with coning; • Amniotic Band Syndrome
true acroosteolysis is rare o Band may cause necrosis & amputation of
fingers in any pattern, depending on
entrapment
• Leprosy
Progressive Systemic Sclerosis (PSSl
PA radiograph shows severe acroosleolysis involving all

the digits" The bones are oSleoporolic, and there is
PA radiograph shows acroosleolysis, most severe at the
3rd terminal phalanx" The pa!ienl has significanl SOfl
I
prominenl subperiosleal resorp!ion al the radial aspecl !issue calcifica!ion as well; the findings are typical of
of the phalanges 11:I in lhis pa!ienl with HPTH. progressive systemic sclerosis fa.k.a., scleroderma).
247
'"o
Ql ACROOSTEOLYSIS
t-
"0
C
III
~
'"
Ql
Ol Thermal Injury, Frostbite
c Thermal Injury, Frostbite
u:: (Left) Posteroanterior
"0 radiograph shows absence of
III epiphyses of terminal digits
In'""'
2-5. indicating injury.
This results in shortening of
>- the terminal digit, a form of
E
-"'
<
o
c
acroosteolysis. The epiphysis
is at greater risk than the tuft
for thermal injury. Note the
thumb is normal Elll typical
of frostbite. (Right) Lateral
terminal phalanges of digits
2-5 III & normal length of
terminal phalanx of the
thumb Elll sequela of
frostbite during childhood.
Thermal Injury, Burns Psoriatic Arthritis (PSA)

shows severe contractu res of
digits 1 & 2, with more mild
contractures of the other
digits. There is significant
acroosteolysis at all the
terminal phalanges
combination is
=-
The
typical of
burn injury. (Right) Oblique
radiograph of both thumbs
shows acroosteolysis of the
tufts. in a patient with
psoriatic arthritis. Note the
erosive changes involving the
interphalangeal joints.
Acroosleolysis is seen with
moderate frequency in
psoriatic arthritis.
Psoriatic Arthritis (PSA) Vasculitis

changes of end-stage
psoriatic arthritis, including
erosive change and ankylosis
at the great toe Elll These
patients may develop
prominent acroosleolysis •
as in this case. (Right)
shows early acroosteolysis
IlII and soft tissue tapering
with ulceration" in a
patient with lupus vasculitis
and dry gangrene.
I
248
ACROOSTEOl YSIS :to
-
::l
III
o
3
'<
D:l
III
III
Raynaud Disease leprosy Cl)
(Left) Posteroanterior Co
radiograph shows tapering of "T1
the soft tissues of the
terminal phalanges =
with
osteolysis involving the right
::l
<C
C1l
en
thumb and both index OJ
::l
fingers. The findings are a.
nonspecific, but this patient -1
had Raynaud disease. (Right)
o
C1l
III
shows severe acroosteolysis
involving all the fingers, most
significantly the 4th & 5th
digits m. Additionally, there
is linear calcification of a
digital nerve =: this is
pathognomonic for leprosy.
(tMSK Req).
Polyvinyl Chloride (PVC) Pycnodysostosis

radiograph shows shortening
of the terminal phalanges of
digits '-3, with lucent lines
crossing the tufts =. This is
a typical acroosteolysis
pattern for polyvinyl chloride
workers. It is a/so rarely seen
in guitar players. (Right) AP
bones & acroosteolysis of the
terminal phalanges HI.
There is a/50 a transverse
metatarsal =
fracture through the 5th
& other bones
(not shown). This
combination is typical of
pycnodysostosis.
Multicentric Reticulohistiocytosis Amniotic Band Syndrome

acroosteolysis •• associated
with nodularity and erosive
change at the
interphalangeal joint m. The
combination of features is
typical of a rare diagnosis,
multicentric
reticulohistiocytosis. (Right)
PA radiograph shows severe
3rd fingers =
acroosteolysis of the 2nd and
along with a
pressure erosion on the
proximal phalanx of the
thumb. This was the only site
of abnormality in this patient
with amniotic bands.
I
249
'"
<I)
a
ACROOSTEOSClEROSIS
I-
"0
C
Ctl DIFFERENTIAL DIAGNOSIS o Very uncommon finding, even for
'"~ "common" diagnoses
<I)
Ol Common o Sclerosis is typically subtle
C
u:: • Normal Variant
• Psoriatic Arthritis Helpful Clues for Common Diagnoses
"<l)
III • Rheumatoid Arthritis • Normal Variant
Cll
ell • Enostosis (Bone Island) o Endosteal thickening
>. o Young adult female predominant
E • Osteopoikilosis
•...o • Progressive Systemic Sclerosis • Psoriatic Arthritis
Cll
c o Asymmetric polyarthritis, distal
• Sarcoidosis
« interphalangeal joint involvement
less Common • Rheumatoid Arthritis
• Fracture Healing Process o Bilateral, symmetric joint changes
• Chronic Osteomyelitis o Marginal erosions & MCP ulnar deviation
• Osteopetrosis • Osteopoikilosis
• Systemic Lupus Erythematosus o Multiple bone islands
• Lymphoma, Hodgkin o Clustered around joints
• Hepatitis o Differentiate from sclerotic metastases
• Osteonecrosis • Sarcoidosis
Rare but Important o Lacy appearance of phalanges
• Paget Disease Helpful Clues for less Common Diagnoses
• Hyperparathyroidism • Chronic Osteomyelitis
• Hyperparathyroidism, Healed Brown Tumors o Permeative destruction early with late
• Thermal Injury, Frostbite sclerotic changes ± sequestrum
• Melorheostosis • Osteopetrosis
• Metastasis, Osteoblastic o Diffuse bone sclerosis that lacks definition
• POEMS between medulla & cortex
• Foreign Body
• Tuberous Sclerosis Helpful Clues for Rare Diagnoses
• Thermal Injury, Frostbite
o Focal or asymmetric distribution with
ESSENTIAL INFORMATION adjacent normal digits possible
Key Differential Diagnosis Issues • Tuberous Sclerosis
o Irregular sclerotic & lytic lesions
• Increased density of the terminal phalanges
throughout skeleton
Psoriatic Arthritis Progressive Systemic Sclerosis
I Posteroanterior radiograph shows faint sclerosis •

the distal tuft of the digit. The presence of periosteal
of Posteroanterior radiograph shows increased density of
the distal phalangeal tufts _ a nonspecific finding that
new bone. sugges/.Sthe diagnosis of psoriatic arthritis. is reflective of scleroderma in this case.
250
ACROOSTEOSCLEROSIS l>
-
;:,
III
o
3
'<
Hyperparathyroidism, Healed Brown III
III
t/l
Chronic Osteomyelitis Tumors (l)
sclerosis of the index finger ,.,
distal phalanx in this diabetic :::>
<0
patient with treated C1l
osteomyelitis ••. Note the
~
t/l
prior amputation III of the III
:::>
third digit and severe c.
atherosclerotic disease ~ -l
o
(Right) Posteroanterior C1l
sclerotic focus =
radiograph shows a round
in the tuft
of the index finger. This
(f)
finding developed after the

patient was treated for
hyperparathyroidism,
increasing the likelihood that
it represents a healed Brown
tumor.
Thermal Injury, Frostbite Melorheostosis

shows the terminal
phalanges of the second
through fifth digits to be
short and faintly sclerotic =.
Note that the terminal
phalanx of the thumb is
norma! in size Ell. This
represents the sequela of
frostbite during childhood.
shows sclerosis of the index
finger distal tuft ••. Sclerosis
of the proximal and middle
phalanges of the second and
third digits 11II is also due to
melorheostosis.
Tuberous Sclerosis
radiograph shows two dense
foci •• surrounded by a
lucent region in the distal tuft
of the index finger. The
patient had embedded
sewing needle fragments
with a surrounding
epidermoid inclusion cyst.
appearance of the ring finger
distal tuft III. This may be
partially artifactual due to
multiple lytic lesions. A soft
tissue mass adjacent to the
sclerotic area was due to a
periungual fibroma.
I
251
'"o
Q) PHALANGEAL CYSTIc/LYTIC LESIONS
I-
"0
C
Cll DIFFERENTIAL DIAGNOSIS o Watch for loss of cartilage width & pattern
'"'-- of DIP joints predominating
Q)
0> Common • Gout
C
LL • Enchondroma o Inactive erosions are well-marginated &
"0 • Osteoarthritis (OA) may give appearance of lytic lesion
Ql
VI
III
• Gout o ]uxtacortical erosions may distract from
CO • Aneurysmal Bone Cyst (ABC) the arthritic appearance
>- • Giant Cell Tumor (GCT)
E o Cartilage destruction is late in process;
-
o
III
C
«
• Osteomyelitis
• Hyperparathyroidism, Brown Tumor (HPTH)
may not appear to be an arthritis
o Watch for dense soft tissue tophi
• Arthroplasty Component Wear/Particle • Aneurysmal Bone Cyst (ABC)
Disease o Lytic, expansile
• Giant Cell Tumor Tendon Sheath (Mimic) o Generally < 30 years of age
Less Common o Usually have fluid-fluid levels
• Unicameral Bone Cyst (UBC) • Giant Cell Tumor (GCT)
• Glomus Tumor o Lytic, expansile
• Epidermal Inclusion Cyst o Unlike GCT in other bones, may occur
• Sarcoidosis prior to skeletal maturation
• Robust Rheumatoid Arthritis o MR: Generally solid lesion with some focal
low signal regions on T2; occasional
Rare but Important fluid-fluid levels
• Langerhans Cell Histiocytosis (LCH) • Osteomyelitis
• Ollier Disease o Digits at risk for direct inoculation via
• Maffucci Syndrome trauma
• Vascular Tumors, Osseous o Great toe distal phalanx particularly at risk
• Fibrous Dysplasia (FD) • Nail bed base is directly adjacent to
• Amyloid Deposition periosteum of distal phalanx
• Tuberous Sclerosis • "Stubbed toe" may result in nail bed
hematoma & subsequent infection
ESSENTIAL INFORMATION o Lytic destruction, periosteal reaction
Key Differential Diagnosis Issues (HPTH)
• Hint: Watch for associated arthritic process o Often multiple
• Hint: True non-aggressive lytic phalangeal o Lytic, generally geographic
lesions most commonly are one of the o Watch for other signs of bone resorption
following • Subperiosteal (generally radial side,
o Enchondroma> > ABC, GCT, UBC middle phalanx), endosteal
o If there is no matrix present in an
• Tuft acroosteolysis
enchondroma, may not be able to • Arthroplasty Component Wear/Particle
differentiate by radiog]japh; MR is useful Disease
Helpful Clues for Common Diagnoses o Silastic & similar arthroplasties used in
• Enchondroma hand & foot
o Most common true lesion of phalanges o Breakdown is common due to instability,
o Lytic ± chondroid matrix malalignment
o May be expansile/bubbly, appearing more o Particles elicit synovitis & particle disease,
aggressive than it acts resulting in massive osteolysis
• Osteoarthritis (OA) o Osteolysis can be so prominent that the
o Subchondral cyst formation occasionally prosthesis may be overlooked
predominates relative to osteophyte • Giant Cell Tumor Tendon Sheath (Mimic)
formation, especially in erosive OA o Soft tissue mass arising in tendon sheath
I
252
PHALANGEAL CYSTIC/LYTIC LESIONS l>
o Focal extrinsic bone erosion may appear as Helpful Clues for Rare Diagnoses
-
::l
Ql
o
3
'<
lytic lesion • Langerhans Cell Histiocytosis (LCH) III
Ql
o Watch for soft tissue mass adjacent to VI
o Rare lytic lesion, usually in young child ltl
lesion o May be geographic or more aggressive,
C.
-n
o MR: Mass mostly low signal on T2;
with rapid growth ::l
co
enhances o Often polyostotic CO
~
VI
Helpful Clues for Less Common Diagnoses • allier Disease Ql
::l
• Unicameral Bone Cyst (UBe) o Multiple enchondromas in phalanges, Cl.
-l
o Less common but radiographically usually with chondroid matrix o
CO
indistinguishable from lytic enchondroma, o Usually other long bones affected as well VI
ABC, GCT o Often unilateral limb involvement

o Most commonly seen in skeletally • Maffucci Syndrome
immature patient o Similar to allier, but with soft tissue
• Glomus Tumor hemangiomas
o Dermal hemangiopericytoma, commonly o Watch for phleboliths
located beneath nail bed • Vascular Tumors, Osseous
o Causes extrinsic scalloping of dorsal cortex o Range of benign to malignant vascular
distal phalanx; if large, appears on tumors may involve phalanges
radiograph as lytic lesion o Similar range of appearance from benign
o Nonspecific MR low signal Tl, high signal to aggressive
T2, enhancing lesion o Often polyostotic
o Diagnosis suggested by location o Lower extremity> upper extremity
• Epidermal Inclusion Cyst • Fibrous Dysplasia (FD)
o Benign lesion of cutis or subcutis o Rare involvement of digits, similar to FD
o May result in local invasion of phalanx, elsewhere
usually terminal • Amyloid Deposition
• Sarcoidosis o Subchondral cysts, erosions may mimic
o Lytic, often "lacy" pattern in phalanges lytic lesion, especially DIP
• Robust Rheumatoid Arthritis o Watch for lumpy soft tissue masses
o Large subchondral cysts develop in RA o Low T2 signal on MR
patient with continued activity • Tuberous Sclerosis
o Watch for multiple digit involvement, o Rare lytic lesion, non-aggressive
particularly MCP disease o May have dense periosteal reaction
Enchondroma
PA radiograph shows lytic phalangeal lesion containing

chondroid matrix" There is a pathologic fracture"
PA radiograph shows a large lytic geographic lesion •.
There is no chondroid matrix present. Even without
I
Appearance is classic for enchondroma, the most matrix, enchondroma is the most likely diagnosis,
common osseous lesion of the phalanges. (t MSK Req). though olher lesions are not excluded. (tMSK Req).
253
tJl
o
f-
"0
c::
ro
~
tJl
Q)
0> Osteoarthritis (OA)
c:: Gout
u::: (Left) PA radiograph shows
lytic "lesions" within
'0
Ql subchondral bone of middle
III
III phalanx _ Note that the
[Q process is articular; there is
>. carlilage loss & marginal
E erosions are present. This is
•...oIII erosive osteoarthritis;
c:: subchondral cysts may give
< the appearance of lesions.
a lytic lesion in the proximal
phalanx __ of a young adult
with end-stage renal disease.
Lesion proved to be a gouty
deposit, which is not
uncommon in such patients.
Gout Aneurysmal Bone Cyst (ABC)

radiograph shows mulliple
well-circumscribed Iylic
lesions located on either side
of the distallP joint_
There is joint space
narrowing as well, suggesling
an arthritic process. Note the
soft tissue tophus •. The
findings are typical of gout.
shows a Iylic lesion at the
distal end of the bone __ in
a young adult. Without
matrix, ABC or GCT should
be considered, in addition to
enchondroma. Biopsy
proved the lesion to be ABC.
Aneurysmal Bone Cyst (ABC) Aneurysmal Bone Cyst (ABC)

Iylic lesion expanding and
occupying the entirety of the
distal phalanx __ . The
appearance is nonspecific; it
could represent
enchondroma, ABC, GeT; or
several other lesions. (Right)
Sagittal T2WI FS MR of the
same patient shows multiple
fluid levels occupying the
enlire lesion _ Although
fluid levels can occur in
other lesions, their presence
makes ABC the most likely
diagnosis; this was proven at
surgery. (t MSK Req).
I
254
PHALANGEAL CYSTIC/lYTIC lESIONS :t>
:J
...•
III
o
3
'<
OJ
III
Giant Cell Tumor (GCT) Giant Cell Tumor (GCT) III
(1)
(Leh) PA radiograph shows Q.
expanded Iylic lesion in

subchondral aspect of a
phalanx _ Image shows no
":J
to
CD
differentiating features Cil
between ABC, GeT, or lytic OJ
:J
enchondroma; at biopsy this a.
was GCT. (Right) PA -;
o
radiograph shows a Iylic, CD
III
moderately aggressive lesion
in subchondral region of a
phalanx. There is no sclerotic
margin, & there is cortical
breakthrough _ This is
more aggressive than
expected for lytic
enchondroma, but not for
GeT.
Hyperparathyroidism, Brown Tumor

Osteomyelitis (HPTH)
(Leh) Oblique radiograph
shows moderately aggressive
lytic lesion of bone adjacent
to nail bed in a child's great
toe _ Trauma from
stubbing the toe may result
in infection due to intimate
relalionship of nail bed to
periosteum. (Right) PA
radiograph shows mulliple
Iylic lesions of phalanges _
which are non·aggressive but
otherwise nonspecific.
Mulliplicity should make one
consider Brown tumor of
HPTH. In addition, there is
endosteal resorption •.
confirming diagnosis.
Hyperparathyroidism, Brown Tumor Arthroplasty Component Wear/Particle

(HPTH) Disease
radiograph shows lytic lesion
in a phalanx _ itself
otherwise nonspecific.
However. there is also
prominent subperiosteal
resorplion Ell & tuft
resorplion _ making
diagnosis of HPTH. (Right)
shows lytic lesions involving
both metatarsal & proximal
phalanx of great toe _.
There is fractured silastic
arthroplasty III; this has
resulted in silas tic particles
inducing particle disease &
associated osteolysis.
I
255
Vl
o
I-
"0
c:
III
~
Vl
Q)
Giant Cell Tumor Tendon Sheath Giant Cell Tumor Tendon Sheath
Ol (Mimic) (Mimic)
c:
u: (Left) fA radiograph shows
soft tissue swelling that is
"t:l
Q) massive, surrounding much
Vl
III of the thumb III. There are
al a/50 lytic lesions involving
>- the metacarpal and phalanx
•..Eo
III
EllI. Note that there is no
cartilage loss; this is not an
c: articular process. (Right)
< Oblique T I WI MR on the
same patient shows a large
low signal 50ft tissue mass
• with extension into the
bone" It is this focal
invasion by GCT of the
tendon sheath which causes
osseous lesions.
Unicameral Bone Cyst (UBC) Glomus Tumor

(Left) fA radiograph shows a
lytic lesion in the metaphysis
III Note that the patient is
skeletally immature.
Although enchondroma,
ABC, or GCT may have a
similar appearance, patient's
age is more suggestive of
UBC (Right) Axial TlWI MR
shows a 50ft tissue mass
beneath the nail bed III that
causes extrinsic scalloping on
the underlying terminal
phalanx" Note typical
location & appearance for
glomus tumor. Radiograph
would show scalloping or a
lytic lesion.
Epidermal Inclusion Cyst Sarcoidosis

radiograph shows extrinsic
invasion of the terminal
phalanx from a soft tissue
mass III It results in a
well-defined lytic lesion. The
appearance and location are
typical for either glomus
tumor or epidermal inclusion
cyst; the latter was proven.
shows non-aggressive lacy
trabeculated lytic lesions of
phalanges III typical for
osseous sarcoidosis.
I
256
PHALANGEAL CYSTIC/LYTIC LESIONS :>
:;,
...•
III
o
3
'<
OJ
III
Robust Rheumatoid Arthritis Langerhans Cell Histiocytosis (LCH) VI
ell
subchondral cysts so large as -n
to appear as lytic lesions ••. :;,
CO
The fact that they are C1l
multiple & all adjacent to a in
destroyed joint makes III
:;,
diagnosis of arthropathy; RA Co
in patients who continue ~
activity results in this
o
C1l
VI
appearance. (Right) PA
radiograph shows a
nonspecific lytic lesion in the
phalanx". History is of
extremely rapid growth of
the lesion in a very young
patient, which helps suggest
the unusual diagnosis of LCH
in a phalanx.

lytic lesions, some expanded
& containing a chondroid
matrix" Appearance &
multiplicity = multiple
enchondromatosis or Oilier
disease. (tMSK Req).
lytic lesions that have
significantly distorted the
phalanges. There are also
several calcified phleboliths
•. indicating the presence
of a soft tissue hemangioma.
This combination = Maffucci
syndrome.
Vascular Tumors, Osseous Amyloid Deposition

an expanded & destructive
lesion. associatedwith a
large soft tissue mass. The
lesion is aggressive &
nonspecific. Vascular tumors
may occur in distal bones &
feet more commonly than
hands. (Right) Oblique
radiograph shows lytic
lesions in the digits HI as
well as lumpy soft tissue
swelling about the wrist ••
Lesions have the nonspecific
appearance of subchondral
cysts, but the character of
the soft tissue masses
suggests amyloid deposits.
I
257
l/J
Q)
SESAMOIDITIS
o
I-
"0
C
OJ DIFFERENTIAL DIAGNOSIS a Acute: Sharp irregular margins, intense
~ marrow edema; CT often useful to define
Q)
Ol Common osseous detail
C
LL • Osteoarthritis a Chronic: Fracture nonunion similar to
1J • Stress Reaction bipartite sesamoid with smooth, rounded,
ell
l/J
III
• Fracture well-corticated margins
III
>. Less Common Helpful Clues for Less Common Diagnoses
E • Osteonecrosis
-
o
III
C
~
• Arthritis
• Plantar Plate Tear
• Osteonecrosis
a Initially marrow edema; evolves to
sclerosis, ~ SI on Tl & T2; may fragment
• Tendon Injury • Arthritis
Rare but Important a Arthritides involving hallux may recruit
• Infection sesamoids
• Neoplasm • Gout: Erosions, overhanging edges
• Rheumatoid: Osteopenia, erosions
• Psoriatic: Mixed erosive-productive;
ESSENTIAL INFORMATION periostitis
Key Differential Diagnosis Issues • Plantar Plate Tear
• Typically refers to 1st toe medial & lateral a Hyperextension injury; fibrocartilaginous
sesamoids, though any sesamoid can be disruption, partial or complete
involved • Tendon Injury
a Ranges from tendinosis (t SI & thickening)
Helpful Clues for Common Diagnoses to complete disruption
• Osteoarthritis
a Joint space narrowing, osteophytes, Helpful Clues for Rare Diagnoses
subchondral edema/cysts, sclerosis • Infection
a Look for hallux valgus or rigidus a Soft tissue infection: Swelling; ± abscess
• Stress Reaction a Osteomyelitis: Cortical disruption, ±

a Repetitive injury periostitis
a Presents as t SI on fluid-sensitive • Neoplasm
sequences; ± ~ 51on Tl; may progress to a Soft tissue: Giant cell tumor of tendon
fracture sheath; pigmented villonodular synovitis
a Osseous: Extremely rare
• Fracture
Osteoarthritis Osteoarthritis
I Sagittal PO FSE FS MR shows cartilage loss •

sulxhondral marrow edema Ell & osteophytes ~ in
Sagittal bone a reformation shows osteoarthritis of
multipartite sesamoid articulating with the metatarsal
this melalarsal·sesamoid joint with early osteoarthritis. head. Note joint space narrowing • sulxhondral
There is a small joint effusion. sclerosis ~ & osteophyte Ell
258
SESAMOIDITIS l>
..•o::l
Cll
3
'<
llJ
Cll
Stress Reaction Fracture III
(l)
(Left) Coronal PO FSE FS MR C.
shows intense lateral 'Tl
sesamoid edema (t 51) Ell & ::l
<0
a small joint effusion" in (1)
this runner with stress

~
III
response of the sesamoid, ll>
::l
related to ill-fitting shoes. C.
(Right) Sagittal T2' GRE MR -l
o
showsthesharp,i~egu~r (1)
III
margins" of a mid-body
sesamoid fracture. A
bipartite sesamoid has
regular, rounded borders;
this differentiates it from a
fracture.
Osteonecrosis Arthritis
(Leh) Axial T7 WI MR shows
lateral sesamoid sclerosis (.
51) •• due 10 chronic
osteonecrosis. The sesamoid
was! 51 on all sequences
including STIR imaging (not
shown). Note the normal
bipartite medial sesamoid
•• (Right) Sagittal T7WI MR
shows a • 51 intracapsular
process eroding the 1st
metatarsal neck ••
sesamoid" & proximal
phalangeal base Ell. This
also showed. 51 on T2 (not
shown). This is
aspiration-proven gout.
Plantar Plate Tear Infection

(Left) Coronal NECT shows
abnormal widening between
the medial sesamoid & 1st
metatarsal head Ell due 10
tear of medial collateral
ligament & plantar plate •.
This football player
presented with "lUrf" toe
due to extreme dorsiflexion
with simultaneous varus
misalignment. (Right) Lateral
radiograph shows medial
sesamoid osteomyelitis in a
diabetic with cortical
destruction HI soft tissue
swelling, & an air-filled sinus
Iract •• eXlending 10 the
bone.
I
259
(/)
<1l SHORT METACARPAL/METATARSAL
o
f-
"0
C
ro DIFFERENTIAL DIAGNOSIS • Trauma
~ o Crush injury, bayonet apposition of
<1l
OJ Common fracture fragments may result in
c
LL • Idiopathic (Normal Variant) shortening
"'C • Trauma
Ql Helpful Clues for less Common Diagnoses
VI
III less Common • Osteonecrosis
co
>- • Osteonecrosis o Freiberg necrosis: Fragmentation &
-
E
o
III
C
<
• Juvenile Idiopathic Arthritis alA)
• Turner Syndrome
• Noonan Syndrome
collapse of MT heads
• Usually 2nd MT; collapse leads to
shortening
• Hypothyroidism o Sickle cell: Bone infarct rarely results in
• Hypoparathyroidism cessation of growth
Rare but Important • May see dactylitis (periosteal reaction)
• Fetal Alcohol Syndrome o Thalassemia
• Mucopolysaccharidoses • Short broad MCs and MTs generally due
• Multiple Hereditary Exostoses to marrow hyperplasia; osteonecrosis
• Oilier Disease rarely may contribute
• Maffucci Syndrome • Juvenile Idiopathic Arthritis OIA)
• Achondroplasia o Involvement of joint in child causes
• Hypochondroplasia hyperemia
• Chondrodysplasia Punctata • Initially causes overgrowth of epiphyses
• Poland Syndrome & metaphyses
• Pseudohypoparathyroidism / • Chronic hyperemia may result in early
Pseudo- Pseudohypoparath yroidism fusion & resultant shortening of bone
• Fanconi Anemia o Generally not uniform or symmetric
• VATERAssociation involvement
• Basal-Cell Nevus Syndrome • Turner Syndrome
• Multiple Epiphyseal Dysplasia o 4th MC most common; may involve 3rd &
• Diastrophic Dysplasia 5th
o Often have Madelung deformity of carpus
o May have metaphyseal excrescences
ESSENTIAL INFORMATION • Noonan Syndrome
Key Differential Diagnosis Issues o Short stature, kyphoscoliosis
• Short metacarpal (Me) or metatarsal (MT) is o Short fingers, syndactyly
usually nonspecific o Klippel Feil
o Uncommonly, other features may be • Hypothyroidism
present which lead to a diagnosis o Severely delayed bone age
• Consider whether all digits are involved; if o Uniformly short MC, MT, phalanges
this is the case, differential is more limited o Fragmented ("cretinoid") femoral capital
o Hypothyroidism epiphysis
o Mucopolysaccharidoses • Hypoparathyroidism
o Achondroplasia o Osteoporosis, calvarial thickening
o Hypochondroplasia o Subcutaneous & basal ganglion
o Noonan syndrome calcification
o Hypoparathyroidism o Premature fusion of physes results in
o Chondrodysplasia punctata shortened bones, 4th & 5th MC & MT
most frequent; 1st may be involved
• Idiopathic (Normal Variant) Helpful Clues for Rare Diagnoses
o Far and away the most common reason for • Fetal Alcohol Syndrome
a solitary short MC or MT o Growth retardation, scoliosis
o Renal hypoplasia & anomalies
I
260
SHORT METACARPAL/METATARSAL l>
:J
...•
Dl
o
o Microcephaly & malformations of brain o Lumbar spine similar to achondroplasia, 3
'<
• Mucopolysaccharidoses with short pedicles & narrowing OJ
Dl
o Short MC with proximal constriction, interpediculate distance t/I
<Il
results in "fan-shaped" carpus • Chondrodysplasia Punctata a.
"Tl
o Oar-shaped ribs, ]-shaped sella o Multiple epiphyseal dysplasia; epiphyses
:J
• Multiple Hereditary Exostoses become calcified in first year of life <0
CD
~
o Osseous exostoses arising from o Short-limbed dwarfism
metaphyseal portions of bones • Poland Syndrome
'":J
OJ
n.
o May result in shortening & distortion of o Unilateral aplasia of chest wall -I
o
involved bone; mechanical distortion of musculature CD
adjacent bone o May have short MC and syndactyly '"

• Ollier Disease • Pseudohypoparathyroidism /
o Multiple enchondromas; dysplasia of Pseudo-Pseudohypoparathyroidism
metaphyses results in disturbed growth & o Phenotypic features of
shortened bone hypoparathyroidism
o Tends to be monomelic but not all bones • 4th & 5th MC or MT shortening is most
of the limb may be affected common, followed by 1st
o Increased risk of degeneration to • Soft tissue & basal ganglia dystrophic
chondrosarcoma calcification often present
• Maffucci Syndrome o Due to end organ resistance to parathyroid
o Same as Ollier disease, but with soft tissue hormone, so levels of parathormone are t
hemangiomas (phleboliths may be seen) • Osteopenia; variable radiographic
o Bones of hand may be distorted features of hyperparathyroidism
grotesquely • Fanconi Anemia
• Achondroplasia o Growth retardation
o Uniform shortening of MC, MT, phalanges o Skeletal anomalies, usually thumb
o Decreased interpediculate distance & short o Renal anomalies, microcephaly
pedicles in lumbar spine • VATERAssociation
• Spinal stenosis o Multisystem (vertebral, anorectal, tracheal,
• Posterior vertebral body scalloping esophageal, renal)
• HypochondropIasia o Radial side anomalies
o Metaphyseal dysplasia - short stature • Hypoplastic radius
• Variable shortening to absence of
radial-sided metacarpal & digits
Trauma Osteonecrosis
PA radiograph shows a patienl who had a crush injury

when she was 8 years of age. In addition to carpal and
Anteroposterior radiograph shows flattening &
fragmentation of the heads of metatarsals 2 and 3 •.
I
dislal forearm fusion, the growth plales of melacarpals 3 This is typically secondary to Freiberg osteonecrosis.
& 4 were affecled, resulting in early fusion. Wilh collapse, lhe melalarsals become short
261
'"o
Q) SHORT METACARPAL/METATARSAL
I-
"0
C
ell
~
'"
Q)
Cl Juvenile Idiopathic Arthritis (JIA)
C Turner Syndrome
u:: (Left) Oblique radiograph
"tl
shows diffuse shortening of
Q) the metacarpals. With
'"'"
llJ
involvement of joints by]lA,
there is hyperemia. This
>- chronic hyperemia may
•..Eo result in initial overgrowth,

followed by early fusion and
'"
c
<t
relative shortening. (Right)
PA radiograph shows
shortening of the 3rd through
5th metacarpals. Though this
may be seen in several
syndromes, in this case it is
due to Turner syndrome.
Madelung deformity is often
present as well, though it is
not in this case.
Hypothyroidism Mucopolysaccharidoses
metacarpals and phalanges.
None of the epiphyses are
ossified, yet the patient is 4
years of age. Severely
delayed bone age resulting in
short metacarpals and digits
is typical of hypothyroidism.
metacarpals with constricted
proximal ends 11II. This
results in a "fan-shaped"
wrist that is typical of the
mucopolysaccharidoses.
Multiple Hereditary Exostoses Oilier Disease

short metacarpals 3 and 4
(compare with metacarpal
2). Osseous excrescences
are seen extending from the
metaphyses of involved
metacarpals 11II. These are
exostoses, which may
interfere with normal growth.
a short 4th metatarsal with
an expanded lytic lesion
involving both metatarsal.
& adjacent phalanx. This is a
patient with Oilier dz; the
metaphyseal dysplasia results
in arrested growth &
consequent short bones.
I
262
SHORT METACARPAl/METATARSAL >
:J
-
III
o
3
'<
[D
III
Maffucci Syndrome Achondroplasia III
<D
(Left) Posteroanterior a.
radiograph shows short TI
metacarpals, along with :J
<C
severe distortion of all the C1)
bones. Each bone shows an en
expanded lesion resulting in OJ
:J
shortening. Note also the a.
phleboliths in the soft tissues; -l
o
the complex is Maffucci C1)
III
syndrome. (Right)
shows short. broad
metacarpals and phalanges.
This is typical in this infant
with achondroplasia, who
will continue to have short
bones through skeletal
maturity.
Pseudohypoparathyroidism / Pseudohypoparathyroidism /
Pseudo-Pseudohypoparathyroidism Pseudo-Pseudohypoparathyroidism
radiograph shows subtle soft
tissuecalcification. as
well as a short first metatarsal
Ell. These illustrate the
combination of Findings
which make the diagnosis of
pseudohypoparathyroidism
or pseudo-
radiograph shows all the
metacarpals to be short
(most significantly, the first.
fourth, and fifth); there is
evidence of previous coning
of the epiphyses, now fused
and resulting in short digits.
Fanconi Anemia VATER Association

an absent radius as well as
short, bowed ulna. The
entire ray of the thumb is
absent. This is an extreme
example of radial dysplasia
seen in Fanconi anemia.
Other cases may show just
shortened bones. (Right) AP
radiograph shows
hypoplastic radius & absent
thumb, part of the VATER
syndrome. The patient had
renal anomaUes as well. This
is an extreme example; other
cases may show shortened
bones on the radial side of
the extremity.
I
263
(/)
Q) ULNAR DEVIATION (MCP JOINTS)
o
f-
"0
C
ro DIFFERENTIAL DIAGNOSIS o Erosions & soft tissue calcification are
~
(/)
uncommon; deformities are reducible
Q)
OJ Common • Psoriatic Arthritis
c
LL • Rheumatoid Arthritis o Interphalangeal joints severely affected
"0 • Systemic Lupus Erythematosus (SLE) o Erosions & periostitis
CIl
(/)
ltl
• Psoriatic Arthritis o Normal bone mineralization
en • juvenile Idiopathic Arthritis OIA) • Juvenile Idiopathic Arthritis OIA)
>. • Mixed Connective Tissue Disease
E o Juvenile onset of oligoarthritis or
•...o
ltl Less Common polyarthritis
C
<l: • Septic joint o Marginal erosions with joint space
• Charcot, Neuropathic narrowing
• jaccoud Arthropathy o ± Ankylosis
• Ehlers-Danlos • Mixed Connective Tissue Disease
o Globular or sheet-like periarticular
Rare but Important calcification
• Mass, Unspecified Helpful Clues for Less Common Diagnoses
• Pigmented Villonodular Synovitis (PVNS) • Septic Joint
• Trisomy 18 o Bone & joint destruction
• Exotic Infection • Charcot, Neuropathic

• Frontometaphyseal Dysplasia o Fragmented bone debris common
o Indolent course
• Jaccoud Arthropathy
ESSENTIAL INFORMATION o Subluxation & ulnar deviation of 2nd
Key Differential Diagnosis Issues through 5th MCP joints
• Ligamentous laxity or damage -+ joint o Reducible deformities
deviation to subluxation • Ehlers-Danlos
o Hypermobile joints often with normal
Helpful Clues for Common Diagnoses radiographs
o Polyarticular, bilateral, symmetric Helpful Clues for Rare Diagnoses
o MCP & PIP joints most severely affected • Pigmented Villonodular Synovitis (PVNS)
o Decreased bone mineralization o Typically monoarticular; polyarticular is
• Systemic Lupus Erythematosus (SLE) exceptionally rare
o Predisposition to osteonecrosis o Hemosiderin deposition
I Posteroanterior radiograph shows metacarpophalangeal

joint dislocation/subluxation with ulnar deviation ••
Posteroanterior radiograph shows erosive changes of the
metacarpophalangeal joints with ulnar deviation =.
and severe narrowing of the interphalangeal joints 11II. There is a marginal erosion 1:1 at the 4th digit PIPjoint.
264
ULNAR DEVIATION (Mep JOINTS) l>
-
::::I
01
o
3
'<
Dl
01
Systemic Lupus Erythematosus (SLE) Systemic Lupus Erythematosus (SLE) II>
<ll
(Leh) "Open book" C.
radiograph shows severe :!1
subluxation at the MCP joints ::::I
•. The reducible to
(1)
deformities are more severe

~
II>
when the hand is not ll>
::::I
supported (as in this a.
position, as opposed to the -l
PA view, where the hand is
o
(1)
II>
placed on the cassette).
radiograph shows ulnar
deviation" of the 2nd
through 5th MCP joints. This
joint subluxation was
reducible. The
interphalangeal joints are
diffusely narrowed •.
Psoriatic Arthritis Multicentric Reticulohistiocytosis

radiograph shows volar and
ulnar subluxation of the
_ There is severe erosive
disease of the
interphalangeal joints .,
more prominent than of the
MCPs. These findings are
typical of psoriatic arthritis.
erosions of the distal
interphalangeal joints. and
thumb interphalangeal joint
Ell as well as ulnar
deviation" of the 5th MCP
joint.
Mass, Unspecified Trisomy 18

deviation of the 5th
metacarpophalangeal joint
secondary to osseous mass
••. The mass developed
secondary to trauma and has
been termed fibroosseous
pseudolumor of the digit.
Any mass in the web space
may result in ulnar deviation.
shows ulnar deviation _ of
the metacarpophalangeal
joints in an infant with radial
aplasia" and a short ulna
Ell The patient has a known
chromosomal abnormality.
I
265
(/)
Q) SWELLING & PERIOSTITIS OF DIGIT (DACTYLITIS)
o
f-
"D
C o ± Erosions and cartilage narrowing
ell DIFFERENTIAL DIAGNOSIS
~
(/) • Osteomyelitis
Q)
en Common o SweIling, periosteal reaction
c
l.L • Psoriatic Arthritis, "Sausage Digit" o Osseous destruction, ± sequestrum
"0 • Osteomyelitis • Juvenile Idiopathic Arthritis OIA)
Q)
(/) • Juvenile Idiopathic Arthritis OIA) o Swelling and periostitis of multiple digits
nl
CO
Less Common may be initial sign of JIA
>-
E • Chronic Reactive Arthritis, "Sausage Digit" o Seen in younger children; may not have
-
o
nl
C
«
• HIV-AIDSRelated Arthritis
• Sickle Cell Disease, "Hand-Foot"
developed joint or overgrowth symptoms
Rare but Important • Chronic Reactive Arthritis, "Sausage Digit"
• Fibroosseous Pseudotumor of Digits o SweIling along ray, not at single joint
• Tuberculosis, "Spina Ventosa" o Periostitis, especially along shafts of digits
• Sarcoidosis o ± Erosions & cartilage narrowing
• Secondary Syphilis • HIV-AIDS Related Arthritis

• Mycobacterium Marinum o Same as chronic reactive arthritis
o Do not overlook possibility of infection
• Sickle Cell Disease, "Hand-Foot"
ESSENTIAL INFORMATION o Periosteal reaction to osseous infarct
• Periostitis may be the earliest manifestation • Fibroosseous Pseudotumor of Digits
of 4 forms of arthritis o Similar appearance to myositis ossificans
o Psoriatic arthritis, JIA, chronic reactive • Tuberculosis, "Spina Ventosa"
arthritis, HIV-AIDSrelated arthritis o Fusiform sweIling & periostitis; eventual
o May not have cartilage narrowing or expanded lytic lesion; children> adults
erosions at this early stage • Sarcoidosis
• Periostitis may be reactive o Subtle periostitis seen with MR
o Infection, various sources • Secondary Syphilis
o Infarction, granulomatous, trauma o Periosteal reaction, bone destruction
Helpful Clues for Common Diagnoses • Mycobacterium Marinum
• Psoriatic Arthritis, "Sausage Digit" o Contact with fish spines
o Swelling along ray, not at single joint o Nonspecific swelling & periostitis
o Periostitis, especially along shafts of digits
Psoriatic Arthritis, "Sausage Digit" Psoriatic Arthritis, "Sausage Digit"
I PA radiograph shows tremendous soft tissue swelling of

the third digit'" along with prominent periostitis of the
PA radiograph shows second & third "sausage digits",
with soft tissue swelling 11:I and periostitis HI This
proximal phalanx and metacarpal III This may be an patient has erosive changes in the DIP joints; all findings
early indication of psoriatic arthritis. ft MSK Req). are typical of psoriatic arthritis.
266
SWELLING & PERIOSTITIS OF DIGIT (DACTYLITIS) l>
::::l
...•
Ql
o
3
'<
al
Ql
Osteomyelitis Juvenile Idiopathic Arthritis (JIA) tI>
(D
(Left) PA radiograph shows 0.
sort tissue swelling and
periosteal reaction •. "
::::l
<0
Additionally, there is an oval CD
density with surrounding
~
(f)
lysis" which is diagnostic III

::::l
of sequestrum in 0.
osteomyelitis. (Right) PA -l
radiograph shows soft tissue o
CD
(f)
swelling and periostitis
involving the proximal
phalanges. of a child. This
was the first manifestation of
jlA in this patient; erosions
and joint disease were not
seen until later, as the
disease progressed.
Chronic Reactive Arthritis, "Sausage

Digit" HIV-AIDS Related Arthritis
"sausage digit" of the fourth
toe • of a young male who
also has symptoms of
urethritis and uveitis. The trio
of findings make the
diagnosis of chronic reactive
arthritis. With the
radiographic findings alone,
psoriatic arthritis or infection
should be considered.
shows soft tissue swelling
and periostitis" This
constitutes a "sausage digit".
There is also mild cartilage
loss. in this HIV-positive
patient.
Sickle Cell Disease, "Hand-Foot" Fibroosseous Pseudotumor of Digits

radiograph shows periostitis
of several of the small bones
of the hand •. This is an
African American child who
had her first episode of hand
pain; this dactylitis is due to
reaction to bone infarcts.
dense periosteal reaction of
the fourth and fifth
metacarpals _ This is
maturing; the patient had a
crush injury 3 months earlier.
The reactive change is
similar to myositis ossificans
& is also called florid reactive
periostitis.
I
267
u lESIONS CROSSING A DISC SPACE
.!!1
o
ctl
~
.n DIFFERENTIAL DIAGNOSIS o Granulomatous: Tuberculosis; disc
Q)
t::
Q)
destruction late; may track along anterior
~ Common longitudinal ligament creating multiple
Q)
c • Fusion noncontiguous lesions; ± soft tissue

"C
• Vertebral Body Osteomyelitis calcification
Ql
VI
• Pseudoarthrosis o Early: Endplate edema, disc enhancement
III
a:l less Common o Late: Disc narrowing, end plate destruction,
>- sclerosis ± iliopsoas or epidural abscess
E • Multiple Myeloma
•..
o
III
• Lymphoma • Pseudoarthrosis: History of surgery,
c: • Metastatic Disease ankylosing spondylitis, DISH, ochronosis
« o Narrow disc space; endplate sclerosis;
Rare but Important fragmentation; vacuum phenomenon
• Giant Cell Tumor
• Sarcoma Helpful Clues for less Common Diagnoses
• Chordoma • Multiple Myeloma: Adults; punched-out
lytic lesions, expansile lesion(s) or
permeative destruction; ± disc destruction
ESSENTIAL INFORMATION • Lymphoma: Any age, most frequently
Key Differential Diagnosis Issues young adult
• Lesion may extend through disc space or via o May cause destruction of intervening disc
paraspinal soft tissues • Metastatic Disease: Breast, lung

• Neoplasm: Aggressive bone destruction, Helpful Clues for Rare Diagnoses
periostitis, soft tissue mass common • Giant Cell Tumor: Young adults; expansile,
• Hint: Age & history are key factors lesion, well-defined non-sclerotic margins
Helpful Clues for Common Diagnoses • Sarcoma
• Fusion (congenital): Narrow anteroposterior o Ewing sarcoma: Teens & young adults
vertebral dimension, narrow disc space, o Osteosarcoma: Teens & young adults, 2nd
normal end plates; cervical spine peak older adults; ranges lytic to sclerotic ±
• Fusion (surgical): Marrow & trabecular soft tissue ossification
continuity; end plates not seen o Chondrosarcoma: Mesenchymal type;
• Vertebral Body Osteomyelitis: Debilitated women 3rd & 4th decades; ±
& immunocompromised patients mineralization
o Pyogenic: Typically single level • Chordoma: Any age, adults most common
o Fungal: Candida, immunocompromised o Sacrum> clivus> remainder of spinal axis
Fusion Vertebral Body Osteomyelitis
I Sagittal TlWI MR shows a solid surgical fusion at C6-7

• with continuous marrow signal between the two
Sagittal TZWI MR shows a destructive process involving
C7 & Tl (not seen on this image) with a large
vertebral bodies. prevertebral mass & relative sparing of the intervertebral
discs. Typical of an indolent (TB or funga/) infection.
268
LESIONS CROSSING A DISC SPACE »
..
::l
III
o
3
'<
lD
III
Pseudoarthrosis III
11l
(Leh) Sagittal TI WI MR a.
shows prior solid fusion at
::l
L4·5. There is an irregular CD
low signal extending through :<
C1l
L5-S1 disc space and ;:::l.
through the posterior C1l
elements, indicative of
pseudoarthrosis •. (Right)
-.
cr
III
Sagittal TlWI MR shows o

en
multiple thoracic vertebra ()
with abnormal low T I signal

within the body and
posterior elements, crossing
a disc space. There is a large
paravertebral" and
epidural HI mass. The
appearance is typical for
lymphoma.
Metastatic Disease Sarcoma

(Left) Coronal T2WI FS MR
shows a large mass
destroying the right side of
T7 & T8 crossing but sparing
the disc space, involving the
right ribs & costo-vertebral
joint. Multiple flow voids ••
are present within this
metastatic renal cell
carcinoma. (Right) Sagittal
T1Wl MR shows a lobulated
so(t tissue mass III involving
multiple contiguous vertebral
bodies, crossing but sparing
the intervening discs, with
extension into the neural
foramina and spinal canal.
Diagnosis: Ewing sarcoma.
Sarcoma Chordoma
(Left) Sagittal T2WI MR
shows an aggressive mass
arising from the L5 vertebral
body and extending into the
posterior elements, spinal
canal, paraspinous 50ft
tissues and into the sacrum
HI in this patient with
telangiectatic osteosarcoma.
(Right) Sagittal STIR MR
shows a large destructive
mass involving L4 and L5
bodies and intervening disc
space. with posterior
epidural extension and
extension into neural
foramen HI. This patient has
a chordoma.
I
269
()
.!a
DISCAL MINERALIZATION
o
~
Cll
• Early graft is visible; late - solid fusion
.0
a> DIFFERENTIAL DIAGNOSIS
t with bridging bone end plate to endplate
a> Common
~ or pseudoarthrosis with collapsed graft
a> • Degenerative Spondylosis
C • Cages: Help retain graft within disc
• Surgical Spinal Fusion space, carbon fiber cages identified by
'0
Ql
II)
• Discography (Mimic) tantalum markers
III
r:rJ • DISH • Bone filler/graft substitute: Morselized
>- • Vertebroplasty Cement (Mimic) fragments or plug of material with
E • Congenital Fusion
•...oIII geometric shape (due to preparation for
c: • Pyrophosphate Arthropathy insertion)
oCt
Less Common • Discography (MimiC)
• Ankylosing Spondylitis (AS) o Contrast material within disc space
• Hemochromatosis • Disc normal (especially if control) or
• Juvenile Idiopathic Arthritis OIA) degenerative
• Hyperparathyroidism o Patterns of contrast distribution
• Amyloid Deposition • Irregularly distributed through disc:

• Tuberculosis Degeneration
• Into epidural space: Annular tear
Rare but Important • Into canal within herniated fragment
• DISH
• Acromegaly o Bulky anterior vertebral body ossification
• Paraplegia involving 4 or more contiguous vertebral
• Polio levels
• Idiopathic, Childhood o Disc space normal or narrowed, lacks other
changes
ESSENTIAL INFORMATION o May see lucency between vertebral corner
& anterior ossification
Key Differential Diagnosis Issues • Anterior longitudinal ligament tightly
• Hint: Distinguishing post-operative findings adherent at mid portion of anterior
from other causes is essential; with the vertebral cortex
exception of ochronosis, disc calcification is • Less tightly attached at vertebral corners
rarely the defining feature of an entity • Vertebroplasty Cement (Mimic)
• Fusion from long standing immobilization: o Dense material contiguous with cement
AS, DISH, JIA, surgical fusion within collapsed vertebra
• Hint: Disc space height can be useful o Indicates fracture or perforation of
feature; may be increased, normal, or endplate
decreased • Congenital Fusion
• Common associated nonspecific findings o Usually isolated to one level
include endplate sclerosis, osteophyte o Vertebra with diminished anterior to
formation, vacuum phenomenon posterior dimensions
Helpful Clues for Common Diagnoses o Narrowed but otherwise normal disc space
• Degenerative Spondylosis o ± Fusion of posterior elements
o Older patient population • Pyrophosphate Arthropathy
o Thoracolumbar junction most common o Calcification in outer fibers of annulus
o ± Other degenerative changes • Mimics syndesmophytes of ankylosing
• Surgical Spinal Fusion spondylitis
o Long standing immobilization leads to disc o Disc space normal or narrowed
mineralization & eventual fusion o ± Ligamentum fIava calcification
• Disc space height may be narrowed as o Favors lumbar spine
part of underlying degenerative process Helpful Clues for Less Common Diagnoses
o Interbody fusion • Ankylosing Spondylitis (AS)
I
270
DISCAl MINERALIZATION »
o Preserved disc spaces
-
::::J
III
o
3
'<
o Squaring vertebral bodies llJ
o Syndesmophyte formation (ossification III
III
o Thick linear mineralization within ~
Sharpey fibers), tightly adherent to a.
multiple levels, lumbar spine
vertebral corner
predominance
o Spinal osteoporosis if long standing
o Osteoporosis, disc space narrowing,
o Associated sacroiliac joint fusion,
subchondral sclerosis, vacuum
enthesopathy, large joint arthritis
phenomenon, lack of osteophytes
• Hemochromatosis
o Overall appearance may mimic ankylosing
o Mimics pyrophosphate arthropathy
spondylitis, including SI, facet joint fusion,
large joint involvement, enthesopathy,
o Predominately cervical spine
ligament mineralization
o Preserved disc spaces
• Acromegaly
o Associated spinal fusion
o Enlarged disc space
• Hyperparathyroidism o Increased vertebral body width (AP &
o Mimics pyrophosphate arthropathy
medial-lateral)
• Amyloid Deposition o Posterior vertebral scalloping
o Favors cervical spine
o Osteophytes
o Disc space narrowed, may progress to
• Paraplegia
end plate irregularity, sclerosis,
o Variable changes range from disc space
fragmentation
narrowing, endplate sclerosis, osteophytes
o Underlying cause of dialysis
& vacuum phenomenon to paravertebral
spondyloarthropathy
ossification mimicking ankylosing
• Tuberculosis spondylitis or psoriasis
o Initially adjacent endplate destruction
• Polio
with fragmentation
o Changes similar to paraplegia, see above
o Increased density 2° mineralization occurs
• Idiopathic, Childhood
during healing phase, progresses to o Cervical spine, one or multiple discs
ossification o Involves nucleus pulposus
o Kyphosis
o Systemic symptoms: Fever, elevated WBC,
o May involve multiple contiguous or
pain, spontaneous resolution without
noncontiguous disc spaces
sequelae
o MR: Inflammatory changes
Surgical Spinal Fusion
Lateral radiograph shows mineralization of the annuJ~r

fibers •• with sparing of /he nucleus pulposus III In
Lateral radiograph shows 3 level interbody fusion. At
C4-5 the grah is partially extruded •• At C5-6 sol1d
I
this patient wi/h disc degeneration . fusion is seen E!!lI. A pseudoarthrosis is present at (6-7
•• with overgrowth of the endplates.
271
u
Ul
DISCAl MINERALIZATION
(5
(ij
~
.0
Q)
t
Q)
~
Q)
C (Leh) Lateral radiograph
shows interbody fusion with
"Q)
III
cages. The cages are
identified by the tantalum
'"
1XI markers _ The graft
>- material appears as irregular
E density within the cages Ell
•..
o (Right) Sagittal CT
'"
l: myelogram shows interbody
« cages at L2-3 and L4-S Ell
The graft material within the
cages is difficult to
appreciate. At LJ-4 interbody
fusion has been performed
with a plug of calcium
hydroxyapatite graft 1IlI.
(Leh) Sagittal bone CT shows

contrast material within
multiple disc spaces
following discography 1IlI.
Contrast extravasation
posteriorly at L4-S E!II is the
result of a disc herniation.
(Right) Sagittal bone CT
shows extensive anterior
longitudinal ligament
ossification of DISH"
accompanied by extensive
ossification of the posterior
longitudinal ligament Ell
Discal calcification is present
at several levels including
CS-6 and C6-7111.
Vertebroplasty Cement {Mimic}

shows cement within the
disc space between two
vertebra that have been
treated with vertebroplasty
=:I. The cement is
contiguous with the cement
in the inferior vertebral body.
shows congenital fusion of
C3 and C4 as well as CS and
C6 Ell Widened facet joints
at C2-3 and C4-S =:I are the
result of abnormal motion.
The odontoid is absent, and
there is widening of the
atlantodental distance.
I
272
DISCAL MINERALIZATION

shows linearcalcification.
in a degenerated-appearing
disc. The disc is narrowed
with endplate sclerosis.
Vacuum phenomenon is
present in the disc above.
These findings are
nonspecific. However,
characteristic findings of
CPPD were present
elsewhere in the skeleton.
(Right) Sagittal TlWI MR
shows typical squaring of the
lumbar vertebral bodies and
diffuse disc calcification (TI
hyperintense) from long
standing AS.
Juvenile Idiopathic Arthritis OIA)

shows fusion from C2-4
involving the vertebral
bodies & posterior elements.
Extensive discal
mineralization is present
within the C]-4 disc space
•. These findings are
commonly seen in juvenile
idiopathic arthritis. (Right)
Sagittal bone CT shows disc
space narrowing at many
levels. Diffuse annular
mineralization mimicking
syndesmophyte formation
• is present at two levels in
this patient with
hyperparathyroidism.
Tuberculosis Ochronosis (Alkaptonuria)

(Left) Sagittal NECT shows
destruction of L5 and S 1
centered at the intervertebral
disc, with anterofiSlhesis of
L5 on S 1 in this patient with
tuberculous vertebral body
osteomyelitis. Extensive
paraspinal soft tissue mass is
present. In this active stage,
the density. is likely from
endplate fragmentation.
shows diffuse osteoporosis,
dense Unear calcification of
most of the discs. with
little endplate sclerosis or
osteophyte formation in this
patient with ochronosis.
I
273
OSSIFICATION/CALCIFICATION ANTERIOR TO Cl
OJ
E
~ o a.k.a., longus colli calcific tendinitis
o DIFFERENTIAL DIAGNOSIS
C
..0
o Hint: Symptomatic with pain, fever,
« Common elevated WBC
OJ
c • Calcium Pyrophosphate Deposition Disease o Amorphous density inferior to Cl arch
.6-
C/l
Less Common o Soft tissue swelling may be extensive
OJ
~ • Hyperextension (Teardrop) Fracture
OJ
a.. • Hydroxyapatite Deposition Disease (HADD)
• Hyperextension (Teardrop) Fracture o Older, osteopenic patient
-c
C1l
• Accessory Ossicle o Pain, history of trauma
C/l
III
• Avulsion Fracture Anterior Arch Cl o Soft tissue swelling
III
>- • Stylohyoid Ligament Ossification (Mimic) o Fragment from inferior C2 body
E
•..o
III
Rare but Important •
• Vertical dimension> horizontal
Accessory Ossicle
c:
« • Progressive Systemic Sclerosis o Asymptomatic, incidental finding
o Smooth margins, cortical-medullary
ESSENTIAL INFORMATION architecture
• Avulsion Fracture Anterior Arch Cl
Helpful Clues for Common Diagnoses o Hyperextension injury
• Calcium Pyrophosphate Deposition o Horizontally oriented fx anterior arch Cl
Disease o Avulsion longus colli muscles &
o Rarely symptomatic atlantoaxial ligament
o Flocculent mineralization within midline
o Soft tissue swelling
Cl-2 articulation • Stylohyoid Ligament Ossification (Mimic)
• Calcification speckled or linear, o On lateral view ligament may project
irregularly distributed anterior to arch Cl
o Associated soft tissue mass may be large & o Eagle-Barrett syndrome: Sore throat, pain
may compress spinal canal during swallowing
o Varying size cysts in odontoid process &
anterior arch Cl Helpful Clues for Rare Diagnoses
o May see chondrocalcinosis elsewhere • Progressive Systemic Sclerosis
including symphysis, knee o Cloud-like soft tissue calcification
• Not necessary to make diagnosis o Pain, stiffness, dysphagia, spine or nerve
root compression
Helpful Clues for Less Common Diagnoses o Paraspinallocation: Any site cervical,
• Hydroxyapatite Deposition Disease thoracic, lumbar spine
(HADD)
Calcium Pyrophosphate Deposition Hydroxyapatite Deposition Disease

Disease (HADD)
I Sagillal bone CT shows speckled & linear calcification

centered at the CI-] articulation. with associated
Axial bone a shows an amorphous calcific density •
with mild surrounding soft tissue edema in this patient
calcification of the occipitocervicalligaments Ell in this with hydroxyapatite deposition disease of the longus
patient with CPPD. collimuscle.
274
OSSIFICATION/CALCIFICATION ANTERIOR TO Cl »
:l
..•o
III
3
'<
llJ
Hydroxyapatite Deposition Disease III
III
(HADD) Hyperextension (Teardrop) Fracture <D
shows focal soft tissue -U
spine =
swelling in the upper cervical
and small
calcifications inferior to C 1
Cl
~
Cl
00
~.
:::J
and anterior to C2 EiIII Cl
indicative of longus colli
calcification. (Right) Sagittal
»
rr
:::J
NECT shows hyperextension o
teardrop (racture at the
anterior inferior margin of
3
Cl
the C2 body =. The ~

ro·
fracture fragment is slightly 00
distant to the arch of C 7.
Accessory Ossicle Avulsion Fracture Anterior Arch Cl

(Left) Axial NECT shows the
typical appearance of an
accessory ossicle of C 1 111
with a well-defined cortex
and internal trabecular bone.
shows longitudinal
atlanta-occipital dislocation
and C 7 fracture. There is
pre vertebral soft tissue
swelling and a transverse
fracture of the anterior arch
of C 7 with a visible fragment
inferior to the arch of C 1 EiIII.
Stylohyoid ligament Ossification

(Mimic) Progressive Systemic Sclerosis
shows an unusually thick
ossification of the stylohyoid
ligament •. Note its course
just anterior to the arch of
C/. (Right) Lateral
radiograph shows cloud-like
calcification surrounding the
C2 vertebral body and
posterior elements =.This
is a typical appearance of
progressive systemic
sclerosis, or scleroderma.
I
275
en
Q) PARAVERTEBRALOSSIFICATION AND CALCIFICATION
:e
ro
E
'-
o DIFFERENTIAL DIAGNOSIS • Vertebral Body Osteomyelitis, Pyogenic
C
.0 o Disc space destruction
« Common o Endplate sclerosis & fragmentation
ro • Post-Operative Fusion
c • Fragmentation may give appearance of
0-
en • Extruded Cement (Mimic) soft tissue mineralization/ossification
[ll
ro • Vertebral Body Osteomyelitis, Pyogenic o Irregular periosteal new bone formation
ll.
"'C
Less Common o Paravertebral ossification may be
C1l
VI • Psoriatic Arthritis component of healing process
III
lXl • Chronic Reactive Arthritis • Located at disc space
>- • Paraplegia • Progresses to mature bone
E
.•.
o
III
• Charcot, Neuropathic • May lead to disc ankylosis
C
« Rare but Important Helpful Clues for Less Common Diagnoses
• Tumoral Calcinosis • Psoriatic Arthritis
• Osteochondroma o Spondyloarthropathy may involve any
• Progressive Systemic Sclerosis segment of spine
• Osteoblastoma o Ranges from immature mineralization to
• Chondrosarcoma bulky mature bone
• Chordoma • May fuse with vertebral body & disc
• Vertebral Osteomyelitis, Granulomatous o More pronounced on the right; formation
• Osteosarcoma on the left possibly limited by aortic
• Fibrodysplasia Ossificans Progressiva pulsation
o Associated appendicular findings
• Enthesopathy, periosteal new bone
ESSENTIAL INFORMATION • Bilateral asymmetric erosive arthritis in
Key Differential Diagnosis Issues hands & feet
• Differential excludes syndesmophytes, • Sausage digits, phalangeal tuft resorption
anterior longitudinal ligament ossification, • Chronic Reactive Arthritis
& associated forms of ossification that are o Mimics psoriasis
more commonly seen anteriorly & closely • Cervical spine less common
adherent to spine • Foot involvement more common than
• Hint: Determine if associated findings upper extremity involvement
include abnormal disc space or abnormal • Paraplegia
vertebra or otherwise normal spine o Bulky paravertebral ossification mimics
psoriasis
o Other spinal changes
• Post-Operative Fusion
• Syndesmophyte-like ossification
o Posterior fusion
mimicking ankylosing spondylitis
• Initially just small osseous fragments
• Anterior longitudinal ligament
• Develops mature ossification with time;
ossification mimicking DISH
mayor may not -+ solid osseous union
• Neuropathic changes
• May extend from transverse process to
transverse process or across facet joints
o Mimics vertebral osteomyelitis
o Anterior (interbody) fusion
• Destruction, osseous debris,
• Usually confined to disc space malalignment more extensive with
• Graft material may extrude; initially neuropathic disease
small mineralized fragments, may
progress to mature bone Helpful Clues for Rare Diagnoses
• Extruded Cement (Mimic) • Tumoral Calcinosis
o Intravascular or within paraspinal muscles o Amorphous, cloud-like deposits of calcium
o Adjacent intravertebral cement, collapsed o Associated with hyperparathyroidism
vertebra
I
276
PARAVERTEBRALOSSIFICATION AND CALCIFICATION
• Other findings: Bone resorption; • Lobulated growth is characteristic

subchondral, subperiosteal, o Mesenchymal type
subligamentous, subtendinous, cortical • Women, 3rd & 4th decades
tunneling • May be purely soft tissue
o Associated with renal osteodystrophy • Chordoma
• Bone resorption of hyperparathyroidism o Any age, adults most common
• Ill-defined trabecula of osteomalacia o Sacral> clivus> remainder of spine
o Idiopathic form o Osseous destruction ± soft tissue mass
• Most common in African-American • Associated mineralization> 50%
males, 10-20 years old, familial • Vertebral Osteomyelitis, Granulomatous
• Osteochondroma o Single or multiple noncontiguous levels of
o Cortical-medullary continuity with involvement
vertebra • Subligamentous spread
o Any vertebra surface o Disc destruction late
• May cause cord compression o Endplate sclerosis may be minimal
• Progressive Systemic Sclerosis o Calcification within soft tissue abscesses
o Amorphous, cloud-like deposits • May be large & remote from disc space
o Few other spinal changes • Osteosarcoma
o Appendicular changes o Teens & young adults
• Osteolysis • 2nd peak older adults
• Soft tissue resorption of distal digits o Spectrum of appearance
• Erosive arthritis in hands & feet • Primarily lytic ± soft tissue mass; varying
• Osteoblastoma degrees of ossification within tumor,
o Any age, most frequent 10-30 years old may be minimal
o Expansile lytic lesion • Diffusely sclerotic ± heavily ossified soft
• Wide spectrum of internal calcification tissue component
or ossification • Fibrodysplasia Ossificans Progressiva
o Arises in posterior elements o Axial changes dominate
o Most common thoracic, lumbar spine o Begins in infancy
• ± Scoliosis, lesion on concavity o Progresses from proximal to distal
• Chondrosarcoma o Changes progress over time
o Osteolytic lesion with mineralization • Initial soft tissue swelling/nodules
• Conventional or mesenchymal type • Progress to large plaque-like foci of
• Mineralization stippled, arcs, whorls ossification
Extruded Cement (Mimic)
Axial T1WI M R shows extraosseous coffeelion

methacrylate (cement)" foffowine vertebroplasly.
of Axial NEeT shows destruction of the 15-51 disc space in
this patienl with pyogenic vertebral body osteomyelitis.
I
Ossific fragments. are seen in the anterior soft tissues
within a large paraspinal abscess EiI.
277
<II
Q) PARAVERTEBRAL OSSIFICATION AND CALCIFICATION
:E
ro
E
~
o
C
.0
« Chronic Reactive Arthritis Paraplegia
ro
c (Left) Anteroposterior
'6. radiograph shows a classic
<II
ro
~ presentation of chronic
ro reactive arthritis with
a.. abnormal sacroiliac joints
"t:l and bulky paraspinal
QI
<II ossification _ Psoriatic
ro
ell spondyloarthropathy has a
>- similar appearance. (tMSK
E Req). (Right) Lateral
•..ro
o radiograph shows significant
c subluxation and endplate
« destruction with osseous
debris at 2 adjacent levels
III in this paraplegic patient.
Though infection should be
considered, this process was
neuropathic (Charcot spine).
Charcot, Neuropathic Tumoral Calcinosis

shows severe vertebral body
destruction, centered on the
L2/3 disc space &
accompanied by endplate
sclerosis, and extensive
osseous debris around the
vertebrae aI. This is a
typical Charcot
(neuropathic) spine (Right)
Axial bone CT shows a
typical appearance of
tumoral calcinosis with large
calcificmass. associated
with posterior elements of
lumbar spine.
Osteochondroma Progressive Systemic Sclerosis

vertebral body exostosis ••
without suggestion of
degeneration. Note the
extension into the canal. This
benign neoplasm was highly
symptomatic. (Right) Lateral
radiograph shows cloud-like
calcification surrounding the
C2 vertebral body and
posterior elements •. This
is a typical appearance of
progressive systemic
sclerosis, or scleroderma.
I
278
PARAVERTEBRAL OSSIFICATION AND CALCIFICATION >
:J
...•
III
o
3
'<
OJ
III
VI
Osteoblastoma Chondrosarcoma (1)
radiograph shows a densely -0

Q)
ossified mass HI arising at ~
Q)
the T3 level on the left. The VI
mass proved to be an ~.
osteoblastoma arising in the
:J
Ql..
posterior elements. (Right)
Axial NECT shows a fairly
»
rr
:J
well-defined matrix arising o
from a lesion in the spinous
process =. While
3
Q)
osteoblastoma might be
strongly considered, this
proved to be
chondrosarcoma, arising in
an exostosis.
Chordoma Vertebral Osteomyelitis, Granulomatous

massive thoracic chordoma
with calcific matrix in the
paraspinal 50ft tissues III
and destruction of several
adjacent vertebral bodies
ElII. (Right) Axial NECT
shows thoracic spinal TB in a
young child with large
epidural and paraspinal
abscesses. Peripheral
mineralization is present and
involves both the intradural
and extradural portions of
the 50ft tissue mass III.
Osteosarcoma
sites of sclerotic dense bone
formation" in this patient
with osseous metastases
from a primary
osteosarcoma. A large
paravertebral ossified mass
ElII accompanies the largest
vertebral lesion. (Right)
shows mature ossification
within the soft tissues of the
back •. A similar
ossification was present in
the anterior thigh of this
patient with fibrodysplasia
ossificans progressiva.
I
279
E
'"
Q) LINEAR OSSIFICATION ALONG ANTERIOR SPINE
Cii
E
•...
o DIFFERENTIAL DIAGNOSIS o Spinal fusion & thin syndesmophytes
c
.n • Inflammatory Bowel Disease Arthritis
« Common o Spine findings identical to AS
ro
c • DISH
0..
• Aortic Calcification Helpful Clues for Less Common Diagnoses
'"ro.... • Ankylosing Spondylitis (AS) • Psoriatic Arthritis
ro
0..
• Inflammatory Bowel Disease Arthritis o Bulky paravertebral ossification
"t:l • Chronic Reactive Arthritis
Q)
VI Less Common o Spine findings identical to psoriasis
III
CO • Psoriatic Arthritis • Pyrophosphate Arthropathy
>- • Chronic Reactive Arthritis
E o Mineralization anterior annular fibers
-
o
III
C
«
(MAAF); disc normal or narrowed, favors
lumbar spine
• Hemochromatosis • Renal Osteodystrophy
• Juvenile Idiopathic Arthritis (Mimic) o 2° HPTH; Rugger Jersey spine
• Hyperparathyroidism (HPTH) • Hemochromatosis
• Complications of Retinoids o MAAF; arthritis with subchondral cysts
• Paraplegia • Juvenile Idiopathic Arthritis (Mimic)
Rare but Important o Hypoplastic discs mimic syndesmophytes;
• Sternoclavicular Hyperostosis (SAPHO) facet joint fusion
• Ochronosis (Alkaptonuria) • Hyperparathyroidism (HPTH)
• Osteomalacia, Hypophosphatemic o MAAF, bone resorption, calcific deposits
o ALL ossification, spinal osteophytes
ESSENTIAL INFORMATION • Paraplegia
Helpful Clues for Common Diagnoses o MAAF, ALL/paravertebral ossification
• DISH Helpful Clues for Rare Diagnoses
o Flowing anterior longitudinal ligament • Sternoclavicular Hyperostosis (SAPHO)
(ALL) ossification o Ossification ALL, cervical spine
o Closely adherent midvertebra, lucency at • Ochronosis (Alkaptonuria)
vertebra corner where loosely adherent o Syndesmophytes, spinal osteoporosis,
• Aortic Calcification discallinear mineralization
o Separate from disc • Osteomalacia, Hypophosphatemic
• Ankylosing Spondylitis (AS) o MAAF; t bone density, enthesopathy
DISH Aortic Calcification
I UJleral radiograph shows flowing

longitudinal ligament ossification •
Ihe anlerior
characteristic of
UJleral radiograph shows extensive calcificalion of the
aorta. At two levels the calcification is closely related to
DISH. Note how the ossificalion is tighlly adherent 10 the anteriordisc space" mimicking mineralization in
the mid~anter;or vertebral body cortex. the annulus fibrosus.
280
LINEAR OSSIFICATION ALONG ANTERIOR SPINE »
::l
...•
Ql
o
3
'<
OJ
Ql
Inflammatory Bowel Disease Arthritis III
Ankylosing Spondylitis (AS) It)
shows syndesmophyte -U
formation" throughout the ,
Q)
Q)
lumbar spine in this patient (f)
with ankylosing spondylitis. "2.
::l
The syndesmophytes are Q)
intimately related to the

vertebral body corners.
»
0-
::l
(Right) Lateral radiograph o
shows extensive cervical =3
ankylosis with thin Q)
syndesmophytes at multiple a:
CD
levels" in this patient with (f)
spondyloarthropathy of
inflammatory bowel disease.
Posterior fusion is related to
prior injury.
(Left) Sagittal bone CT shows

ankylosis of hypoplastic
vertebra and facet joints in
this patient with juvenile
idiopathic arthritis. The discs
are also hypoplastic,
producing an appearance
mimicking syndesmophytes
••. (Right) Sagittal bone CT
shows mineralization within
the anterior fibers of the
annulus fibrosus III
mimicking syndesmophytes
Complications of Retinoids Ochronosis (Alkaptonuria)

shows the productive
changes associated with
retinoiduse. that mimic
the anterior longitudinal
ligament ossification of
DISH. (Right) Lateral
findings of ochronosis with
extensive mineralization
within the discs and spinal
osteoporosis. Less apparent
is the thin mineralization in
the anterior annular fibers ••
that mimics syndesmophyte
formation.
I
281
Q)
a. BULLETSHAPED VERTEBRA/ANTERIORVERTEBRALBODY BEAKING
ro
.s:::
(f)
ro
~ DIFFERENTIAL DIAGNOSIS o Brachycephaly, abnormal facies
..Cl
Q) o Short stature, atlanto-axial instability,
t
Q)
Common developmental hip dysplasia
> • Achondroplasia
"Ql
III
III
• Down Syndrome (Trisomy 21)
aJ Less Common o Regional osteoporosis ± scoliosis
>- • Radiation-Induced Growth Deformities
E • Hypothyroidism (Congenital)
o
.•... • Hypothyroidism (Congenital) o Mental retardation, delayed growth, short
• Pseudoachondroplasia
«'"
r:: stature, stippled epiphyses
Rare but Important o Abnormal skull & face with thick
• Morquio Syndrome protruding tongue, delayed dentition
• Hurler Syndrome • Pseudoachondroplasia
o Rhizomelic dwarf
o CI-2 subluxation, accentuated lumbar
ESSENTIAL INFORMATION lordosis, early osteoarthritis
Key Differential Diagnosis Issues o Short thick tubular bones especially hands
• Bullet shape: Down, achondroplasia, & feet, metaphyseal excrescences
pseudoachondroplasia, hypothyroidism, Helpful Clues for Rare Diagnoses
Hurler, Morquio • Morquio Syndrome
• Anterior beaking: Achondroplasia, o Short stature, macrocephaly, coarse facial
radiation-induced, Hurler, Morquio features, widely spaced teeth
Helpful Clues for Common Diagnoses o Odontoid hypoplasia, increased lumbar
• Achondroplasia lordosis, bell chest, & paddle-shaped ribs
o Rhizomelic dwarf o Flared iliac wings, inferior tapering iliac
o Exaggerated lumbar lordosis, posterior bones, steep acetabuli, coxa valga
vertebral scalloping, narrow foramen • Hurler Syndrome
magnum, congenital spinal stenosis, o Mental retardation, short stature
decreased interpediculate distance o Coarse facial features, macrocephaly, &
o Squared iliac wings, narrow sciatic notch, other craniovertebral anomalies including
horizontal acetabular roof ]-shaped sella
o Trident hand, flared anterior ribs o Small iliac bones with inferior tapering,
• Down Syndrome (Trisomy 21) steep acetabuli, abnormal femoral heads
o Congenital heart disease, GI abnormalities o Thickened tubular bones, contractures
Achondroplasia
I Lateral radiograph shows bullel-shaped verlebrae al lhe

lumbosacral junction • and scalloping of lhe poslerior
Lateral radiograph shows poslerior verlebral scalloping
IElll hypoplasia of L1 & L2, and anlerior beaking •
vertebral cortices _ findings commonly seen in wilh focal kyphosis in lhis paUenl wilh achondroplasia.
patients wilh achondroplasia.
282
BULLET SHAPED VERTEBRA/ANTERIOR VERTEBRAL BODY BEAKING >
::l
..•o
III
3
'<
lJl
III
IJJ
Radiation-Induced Growth Deformities Pseudoachondroplasia tD
shows a hypoplaslic almost
bullet-shaped L1 • in a
<
tD
;:l.
child who was radiated 1 <ll
CT
year earlier for Wilms tumor. ~
Ql
Radialion of growing bone
(f)
slows or stops growth due to ::r
vascular damage. (Right) Cll
"0
Lateral radiograph shows <ll
very mild platyspondyly,
with mild anterior beaking
• in a patient with
pseudoachondroplasia.
Morquio Syndrome
shows a thoracolumbar
kyphosis, with a hypoplaslic
oval L 1 and central anterior
beaking • in this paliem
with Morquio syndrome.
shows classic example of
Morquio syndrome,
including dorsolumbar
gibbus with vertebral
beaking •.
Hurler Syndrome
shows inferior beaking ~ of
] vertebral bodies in this
patient with many classic
findings of Hurler syndrome.
shows typical skeletal
findings of dysostosis
multiplex, including vertebral
body beaking • in this
patient with Hurler
syndrome.
I
283
Q)
a. CONGENITAL & ACQUIRED CHILDHOOD PLATYSPONDYLY
ro
.<::
(f)
ro
~ DIFFERENTIAL DIAGNOSIS o Metaphyseal bands (lucent, dense, or
.0
Q) alternating), may involve vertebra
t
Q)
Common • Metastatic Disease
> • Trauma o Neuroblastoma, retinoblastoma, Wilms
"tl
OJ • Langerhans Cell Histiocytosis o ± Soft tissue mass, skeletal imaging
I/)
ltl • Leukemia nonspecific
co
>. • Metastatic Disease • Ewing Sarcoma
E • Ewing Sarcoma
-
o
ltl
C
<t:
Less Common
o Teens, young adults
o Solitary lesion
• Achondroplasia (Homozygous) o Permeative destruction, soft tissue mass
• Osteogenesis Imperfecta Helpful Clues for Less Common Diagnoses
• Pseudoachondroplasia • Achondroplasia (Homozygous)
• Mucopolysaccharidoses o Radiographically & clinically mimics
• Radiation-Induced thanatophoric dwarf
• Spondyloepiphyseal Dysplasia o Both parents have achondroplasia
Rare but Important o Diffuse collapse
• Complications of Bisphosphonates o Congenital presentation
• Homocystinuria • Osteogenesis Imperfecta
• Idiopathic Juvenile Osteoporosis o Generalized osteoporosis
• Cushing Disease o Solitary, multiple, or diffuse vertebra
• Thanatophoric Dwarf involved
• Metatropic Dwarf • Depends on severity of disease
• Kniest Dysplasia • Younger patients at presentation have
• Short Rib Polydactyly more extensive disease
• Hypophosphatasia • May be congenital
o Multiple fractures axial & appendicular
skeleton
ESSENTIAL INFORMATION o Congenital platyspondyly type IIA
Key Differential Diagnosis Issues o Micromelia, short ribs
• Platyspondyly: Generalized vertebral • Pseudo achondroplasia
collapse maintaining relatively parallel o Rhizomelic dwarf
endplates o Normal infancy, manifests age 2-3 years
• Differentiating features: Congenital o As child develops, mimics
presentation vs. childhood onset; diffuse spondyloepiphyseal dysplasia
collapse vs. solitary or multifocal collapse o Diffuse collapse develops during childhood
Helpful Clues for Common Diagnoses o Short stature, diffuse skeletal dysplasia
• Trauma o Coarse facial features
o Solitary or multifocal, history diagnostic o Diffuse collapse
o Any age o Congenital presentation
• Langerhans Cell Histiocytosis o Morquio, Hunter best known
o Childhood, thoracic spine mainly
• Mental retardation with Hunter
o Solitary or few vertebra involved
• Radiation-Induced
o May reconstitute during healing o Regional osteoporosis
• Leukemia o May affect only one side of vertebra
o Age 2-5 years
• ± Scoliosis
o Variable presentations
o May induce osteochondroma formation
• Generalized osteoporosis, diffuse collapse • Spondyloepiphyseal Dysplasia
• Focallesion(s) with permeative o Truncal dwarfism
destruction, periostitis, soft tissue mass; o Diffuse spine deformities
collapse solitary or multifocal o Delayed ossification long bone epiphyses
I
284
CONGENITAL & ACQUIRED CHILDHOOD PlATYSPONDYlY :I>
::::l
..•o
III
o Coxa vara consistent feature of variable • Thanatophoric Dwarf 3

'<
severity o Fatal, rhizomelic dwarf OJ
III
o Congenita: Congenital presentation • Micromelia, short ribs <II
(1)
o Tarda: Develops around puberty o Diffuse collapse a.

• Spine changes are not dominant feature o Congenital presentation <
(1)
o Telephone receiver femurs (bowing, ~

Helpful Clues for Rare Diagnoses <0
CT
metaphyseal flaring) ~
• Complications of Bisphosphonates III
o Used to treat conditions such osteogenesis

• Metatropic Dwarf (JJ
::r
o Metatropic: Changing III
imperfecta (01) -0
• Early life short limb, normal trunk <0
• See above for discussion of 01
o May cause bone weakening, lead to
• Later life short trunk with severe
fractures kyphoscoliosis
o Characteristic short long bones with
o Metaphyseal dense bands including
vertebral bodies dramatic metaphyseal flaring
o Diffuse collapse
• Homocystinuria
o Congenital presentation
o Nonspecific osteoporosis
o Scoliosis
• Kniest Dysplasia
o Short trunk, short limb, large joints
o Diffuse collapse develops in childhood
o Diffuse collapse develops in childhood
o Body habitus mimics Marfan
o Mental retardation
• Short Rib Polydactyly
o Lethal dwarfism
• Idiopathic Juvenile Osteoporosis
o Short ribs, micromelia, polydactyly
o Typically> 2 years
o Diffuse changes
o Axial & appendicular osteoporosis
o Congenital presentation
• Complicated by fractures
o Includes asphyxiating thoracic dystrophy
• Spine involvement solitary, multifocal,
diffuse Oeune) & Ellis-van Creveld
o May mimic osteogenesis imperfecta tarda
o Varying degrees of poor bone
• Cushing Disease
o Rare in children
mineralization
o Congenital (lethal)
o Produces generalized osteoporosis
• Solitary or multifocal collapse, especially • Diffuse collapse
o Variable degree & number collapsed
thoracic & lumbar spine
o May develop osteonecrosis
vertebra with later presentations
Langerhans Cell Histiocytosis
Lateral radiograph shows parual collapse of thoracic

vertebral body _ The endplates are intact as are the
Lateral radiograph shows typical presentauon
Langerhans cell histiocytosis with vertebra plana at C7
of
I
disc spaces and posterior elements. The appearance is _ Following treatment, this body partially
common in l.iJngerhans cell histiocytosis. reconstiluted its heigh/.
285
Q)
a. CONGENITAL & ACQUIRED CHILDHOOD PLATYSPONDYlY
ro
.r:
(/)
~
.0
Q)
t
Q)
leukemia Ewing Sarcoma
> Sagiual T1 C+ MR
(Left)
"0 shows the typical
CIl
Vl appearance of leukemic
III
al marrow infiltration with
>. height loss of varying degrees
•..Eo
III
r::
=
involving all vertebral bodies
Note the
contra5l~enhancement of all
ct the vertebral bodies in this
child. (Right) Anteroposterior
radiograph shows
=
asymmetric platyspondyly
with destruction of the
left pedicle in a 12 year old.
This proved to be early
destruction in Ewing
sarcoma.
Pseudoachondroplasia
rib, vertebral, and long bone
fractures in this fetus with
osteogenesis imperfecta,
type If. The arms and legs
are short due to angulation
and deformity resulting from
the fractures. (Right) Lateral
platyspondyly =
radiograph shows very mild
with mild
anterior beaking in this
patient with
pseudoachondrop~s~.
Mucopolysaccharidoses Radiation-Induced
shows classic example of
Morquaio syndrome, with
diffuse vertebral body
collapse, dorsolumbar
gibbus, and vertebral
beaking. (Right)
shows relative hypoplasia of
the left side of the T12, L1,
L2, and L3 vertebral bodies
_ creating an asymmetric
platyspondyly due to
radiation of a left Wilms
tumor. Note the clips from
the left nephrectomy.
I
286
CONGENITAL & ACQUIRED CHILDHOOD PLATYSPONDYLY :t>
.•o
:J
III
3
'<
III
III
Ul
<D
(Left) Sagittal T2WI MR Co
shows endplate irregularity
and diffuse platyspondyly
<
<D
;:l-
with rectangular-shaped <D
CT
vertebral bodies. There is a ~
OJ
generous bony spinal canal
(j)
dimension. This is the adult ::T
appearance of OJ
"D
spondyloepiphyseal (1)
dysplasia. (RighI) AP
osteopenia, gracile ribs, and
diffuse vertebral
compressions. Metaphyseal
dense bands are present.
This patient has osteogenesis
imperfecta and was treated
with bisphosphonates.

shows diffuse osteopenia
and mild generalized
platyspondyly. The findings
are nonspecific and, in this
case, due to homocyslinuria.
radiograph shows minimal
platyspondyly of T 12 _
The 11th ribs have been
resected as a surgical
approach for adrenalectomy
in this patient with Cushing
disease.
Thanatophoric Dwarf
shows short ribs _ and
classic platyspondyly ElII.
with the widened
intervertebral disc spaces
associated with many
dwarfisms, including
thanatophoric dwarfism.
shows a severe deficit in
bone formation. Diffuse
platyspondyly is present. The
cranium is particularly
notable for having no
ossification, except at the
base of skull, a clue to the
diagnosis of
hypophosphatasia.
I
287
Q)
0-
FISH (BICONCAVE) OR H-SHAPED VERTEBRA
ro
.r:
(f)
ro
~ DIFFERENTIAL DIAGNOSIS o Chronic medical diseases (exogenous) &
.D
Q) Cushing disease (endogenous)
t
Q)
Common • Paget Disease
> • Senile Osteoporosis (SOP) o Increased vertebral size, coarse trabecula,
"'0
Cll • Complications of Steroids increased density at vertebral margins
II)
• Paget Disease • Multiple Myeloma
'"
lXl
• Multiple Myeloma
>- o Generalized osteoporosis mimics SOP
..'"
E
o
c:
• Neoplasm
• Neoplasm
o Metastatic: Multilevel disease, variable
<t • Hyperparathyroidism (HPTH) destruction
• Osteomalacia o Primary: Ewing, lymphoma; collapse is
• Sickle Cell Anemia more common with other neoplasms
less Common • Renal Osteodystrophy
• Gaucher Disease o HPTH, osteomalacia, osteoporosis
• Osteogenesis Imperfecta • Hyperparathyroidism (HPTH)
• Thalassemia Major o Bone resorption weakens vertebra
• Osteomalacia
Rare but Important o Coarse, ill-defined trabecula
• Homocystinuria • Sickle Cell Anemia
o Osteoporosis, osteonecrosis, coarse
ESSENTIAL INFORMATION trabecula
Key Differential Diagnosis Issues Helpful Clues for less Common Diagnoses
• H-shape: Osteonecrosis producing central • Gaucher Disease
end plate collapse with sharp margins o Erlenmeyer flask deformity distal femur
o Sickle cell, Gaucher, thalassemia • Osteogenesis Imperfecta
• Biconcave: Structural weakening, disc o Bones thin & gracile or short & tubular
impresses upon & remodels vertebra o Osteoporosis, bowing, & deformities
o Any entity on list may be biconcave • Thalassemia Major
o Osteoporosis, Erlenmeyer flask deformities,
Helpful Clues for Common Diagnoses "hair on end" skull, rodent facies
• Senile Osteoporosis (SOP)
o Elderly individuals: Women> men Helpful Clues for Rare Diagnoses
• Complications of Steroids • Homocystinuria
o Nonspecific osteoporosis, scoliosis
Senile Osteoporosis (SOP) Senile Osteoporosis (SOP)
I Lateral radiograph shows collapse of T 12 vertebral body

in this patient with senile osteoporosis. Gas is present
Sagittal nWf MR shows biconcave
Ballooning of the T9-IO disc.
no vertebra.
is due to concave
within the body ••• consistent with pseudoarthrosis deformities of the adjacent endplates in this patient with
and intervertebral cleft senile osteoporosis.
288
FISH (BICONCAVE) OR H-SHAPED VERTEBRA
Complications of Steroids Paget Disease

shows multilevel biconcave
vertebra. in thispatient on
long term steroids. Note the
edema at TB ElIIl indicative
of active compression.
shows AP dimension
enlargement as well as
coarsened cortical and
trabecular bone in LJ, typical
of Paget disease _ The
vertebral height is diminished
relalive to adjacent vertebra
with mild concavity of each
endplate.
Neoplasm
shows diffuse osteoporosis
and compression fractures of
all the lumbar vertebrae _
No focal lesions are seen.
Biopsy was required to
establish a diagnosis of
multiple myeloma. (Right)
Sagillal STIR MR shows
multiple vertebral lesions.
with severe compression of
LJ ElIIl Diagnosis of
metastatic disease is
facilitated by the multiplicity
of lesions.
Sickle Cell Anemia Sickle Cell Anemia

shows a very abrupt loss of
height in the mid portion of
the vertebral body _ This
appearance ;s known as
"H-shaped" vertebral body,
as seen in this patient with
sickle cell anemia. (Right)
Coronal NECT shows
anteroposterior appearance
of "H-shaped" vertebral
bodies in this patient with
sickle cell anemia. The
appearance mimics the
changes seen on the lateral
view.
I
289
Ql
0.
SQUARING OF ONE OR MORE VERTEBRA
co
L
(fJ
co
~ DIFFERENTIAL DIAGNOSIS o Vertebra narrowed anterior to posterior
..c o Hypoplastic or fused disc
Ql
t
Ql
Common o ± Unilateral or bilateral posterior fusion
> • Anterior Cervical Discectomy & Fusion • Ankylosing Spondylitis (AS)
"0
Cll • Long-Standing Posterior Fusion o Most common at thoracolumbar junction
III
ro • Paget Disease o Romanus lesion (early): Corner erosion
al
>. • Block Vertebra (Congenital Fusion) o Shiny corner: 2° new bone at corner
E • Ankylosing Spondylitis (AS) o Normal size vertebral bodies
o
+-
ro Less Common o Associated findings: Anterior & posterior
c:
« • Inflammatory Bowel Disease Arthritis fusion, symmetric sacroiliac (SI) disease,
• Normal Variant enthesopathy, large joint arthritis
• Juvenile Idiopathic Arthritis Helpful Clues for Less Common Diagnoses
• Psoriatic Arthritis • Inflammatory Bowel Disease
• Chronic Reactive Arthritis o Radiographically identical to ankylosing
spondylitis, differentiate clinically
ESSENTIAL INFORMATION • Normal Variant: Absence of other features
• Juvenile Idiopathic Arthritis
Key Differential Diagnosis Issues o Cervical fusion common (anterior &
• Finding is only evident on lateral view posterior); generalized osteoporosis
• Hint: Vertebral size is a distinguishing o Other: Erosive arthritis, periostitis,
feature ballooned epiphyses; esp. knee & elbow
Helpful Clues for Common Diagnoses • Psoriatic Arthritis
• Anterior Cervical Discectomy & Fusion o Vertebral squaring uncommon, mimics AS
o Osseous-fusion across disc space o No spinal fusion, asymmetric SI arthritis
o Normal-sized vertebra o Associated findings
• Long-Standing Posterior Fusion • Enthesopathy, periosteal new bone

o Disc may mineralize or completely fuse • Bilateral asymmetric erosive arthritis
o Normal-sized vertebra hands & feet, sausage digits, tuft
• Paget Disease resorption
o Increased vertebral body size • Chronic Reactive Arthritis
• May involve posterior elements o Radiographically identical to psoriasis
o Thickened cortices, coarse trabecula • Less cervical spine involvement
• Block Vertebra (Congenital Fusion) • Foot involvement greater than hand
Long-Standing Posterior Fusion
I Sagittal T2WI MR shows solid C6-7 anterior fusion. Note

the normal concavity along the upper cervical vertebra
UJteral radiograph shows long-standing posterior spinal
fusion. The anterior vertebra body cortices assume a flat
_ The concavity is missing at the fused levels iii. contour III rather than the normal mild concavity.
290
SQUARING OF ONE OR MORE VERTEBRA »
.•o
:J
III
3
'<
OJ
III
VI
Paget Disease l1>
shows the classic 'lpicture <
C1>
frame" appearance of ;:l.
vertebral body Paget disease. C1>
CJ
With enlargement of the ~
Q)
body, the anterior concavity
is lost •. Note normal U>
::r
concavity in the adjacent Q)
-0
body for comparison HI. C1>
shows congenital fusion of
C3 and C4. Note the
relatively flat anterior
vertebra contours, especially
atO.

shows typical squaring of the
lumbar vertebral bodies ••
& diffuse disc calcification
(from long-standing
ankylosing spondylitis).
shows squared configuration
of anterior vertebral cortices.
The squaring is caused by
erosions beneath the anterior
longitudinal ligament. L2 also
shows the characteristic
"shiny corner II sign. due
to inflammatory reaction
seen in patients with
seronegative
spondyloarthropathy.
Normal Variant Juvenile Idiopathic Arthritis

shows squaring of several
vertebral bodies. with loss
of the normal prominent
corners and flattening of the
anterior cortex. Pagel disease
of L4 Ell also with squaring,
is an incidental finding in this
otherwise normal individual.
(Right) Sagittal T2WI MR
shows long and gracile
upper cervical vertebral
bodies that are of normal
height but thin in anterior
posterior direction due to
fusion from C2-C6 •.
I
291
en
c VERTEBRALBODY SCLEROSIS
o
"iii
Q)
--l
ro DIFFERENTIAL DIAGNOSIS o Reactive sclerosis to degenerative disc
~ disease
.n
t
Q)
Common o Endplate distribution, or triangular
Q)
> • Fracture Healing distribution in anterior vertebral body
"C • Schmorl Node • Intraosseous Hemangioma
C1l
en
ro
• Discogenic Sclerosis o Corduroy appearance: Thickened vertically
al • Intraosseous Hemangioma oriented struts
>- • Compression Fracture, Acute
E o Seen more often on MR than radiography
•...roo • Metastases, Blastic • Compression Fracture, Acute
c • Enostosis (Bone Island)
<I: o Superimposed trabecula creates sclerotic
• Vertebral Augmentation (Mimic) appearance
• Paget Disease o Height loss evident, may be along
• Osteomyelitis, Chronic end plate, diffuse or asymmetric
• Renal Osteodystrophy o Traumatic or insufficiency fracture
Less Common • Metastasis, Blastic
• Langerhans Cell Histiocytosis o Breast, prostate, lung, colon, stomach,
• Lymphoma bladder, uterus, rectum, thyroid, kidney,
• Fibrous Dysplasia carcinoid
• Enostosis (Bone Island)
Rare but Important
o Round or oblong (long axis vertical),
• Chordoma
brush-like margins, solitary or multiple
• Myelofibrosis
• Vertebral Augmentation (Mimic)
• Plasma Cell Myeloma
o Homogeneously dense cement within
• Osteopetrosis
collapsed or destroyed vertebra
• Osteosarcoma
• Paget Disease
• Ewing Sarcoma
o Picture frame
• Chondrosarcoma
o Increased vertebra size, thickened cortices
• Helmut Sclerosis
& trabecula
• Mastocytosis
• Osteomyelitis, Chronic
• Fluorosis
o Disc space destruction ± fragmentation
• Axial Osteomalacia
o Osteolytic foci may be evident
• Melorheostosis
o Periosteal new bone formation
• Tuberous Sclerosis
o Paras pinal abscess
ESSENTIAL INFORMATION o Rugger jersey spine: Thick sclerosis along
end plates
o Associated changes of
• Excludes conditions with diffuse polyostotic
hyperparathyroidism & osteomalacia
osteosclerosis unless limited to spine or
unusual appearance in spine Helpful Clues for Less Common Diagnoses
• Ivory vertebra (diffusely dense): Lymphoma, • Langerhans Cell Histiocytosis
Paget, blastic metastases, low grade o Increased density within vertebra plana
osteomyelitis o Protean manifestations: Varying types of
osteolytic lesions throughout skeleton
o Button sequestrum skull
• Fracture Healing
• Lymphoma
o Callus formation, may be seen with any
o Splenomegaly
fracture pattern
o Hodgkin> non-Hodgkin
• Schmorl Node
o Nucleus pulposus herniates through
o Spine involvement unusual, more
endplate, sclerotic margin; abuts endplate
common with polyostotic disease
• Discogenic Sclerosis
o Expansile lesion, ground-glass matrix
I
292
VERTEBRALBODY SCLEROSIS l>
..
~
~
o
o Teens & young adults, 2nd peak older 3
adults III
• Chordoma ~
o Spectrum
o Any age, adults most common
• Primary lytic lesion ± soft tissue mass,
'"a.
<ll
o Sacrum> clivus> rest of spine

variable degrees of mineralization <
<t>
o Osseous destruction ± soft tissue mass ::\.
• Diffusely sclerotic with extensively <t>
• Mineralization> 50% 0"
ossified soft tissue mass OJ
• Myelofibrosis
o Vertebra, pelvis, ribs, proximal long bones
• Ewing Sarcoma r
<t>
o Teens & young adults '!!.
• Sclerosis, especially endosteal; loss of o
o Diffuse vertebral body reactive sclerosis ± :J
corticomedullary distinction '"
soft tissue mass
• Endplate sclerosis = sandwich vertebra
• Chondrosarcoma
o Splenomegaly
o Expansile lytic lesion with flocculent
o Extra-medullary hematopoiesis
mineralization (arcs & whorls) ± soft tissue
o Presents in late middle-aged, elderly adults
mass, may see lobulated growth pattern
• Plasma Cell Myeloma
• Helmut Sclerosis
o Typically multiple osteolytic lesions
o Women in 40s, pain
• Sclerosis following fx or treatment
o Isolated hemispherical sclerosis in anterior
o Plasmacytoma
inferior lumbar vertebra
• Younger patients than multiple myeloma
• Normal disc space
• Rarer than myeloma, rarely sclerotic
• Mastocytosis
• Solitary, expansile lesion
o Axial ± appendicular involvement
o POEMS
o Focal or diffuse sclerosis
• Polyneuropathy, Organomegaly,
o Splenomegaly
Endocrinopathy, M proteins, Skin
changes • Fluorosis
o Spinal osteophytes, enthesopathy,
• Younger patients than multiple myeloma
ligament calcification, periosteal new bone
• Osteopetrosis
• Axial Osteomalacia
o Diffuse axial & appendicular sclerosis
o Spine involvement only, predominately
o Bone-within-bone appearance
cervical, coarse trabecula
o Endplate sclerosis = sandwich vertebra
o Primarily males
o Undertubulation of long bones, especially
• Tuberous Sclerosis
femurs
o Variable size osteosclerotic foci
• Osteosarcoma
Schmorl Node Discogenic Sclerosis
Coronal bone CT shaws mulUple Schmor/ nodes of

varying size _ There is variable sclerosis at the
I.iJteral radiograph shows triangular-shaped sclerosis
within the anterior vertebralbody. with adjacent disc
I
periphery of the nodes. space narrowing, a typical pattern of reactive sclerosis
associated with degenerative disc disease.
293
I/)
c VERTEBRAL BODY SClEROSIS
o
'r;;
Q)
-.J
III
~
.Q
Q)
1::: Intraosseous Hemangioma Compression Fracture, Acute
Q)
> (Left) Sagittal NECT shows

the classic honeycomb
"Ql
I/)
III
appearance of hemangioma
with thickened trabeculae,
In intact cortex, and focal/ow
>- attenuation between
E
-o
ro
c
<I:
trabeculae. (Right)
Anteroposterior 3D bone CT
shows compression fractures
at T4 & TS 11II. At TS
generalized height 1055 is
present, and the vertebra is
diffusely sclerotic, an
appearance consistent with
acute fracture.
Compression Fracture, Acute Metastases, Blastic

step-off depression of
superior endplate • and
sclerotic line due to
trabecular impaction 11II
following vertebral
compression fracture. (Right)
Sagittal bone CT shows
prostate metastases causing
uniformly dense L3 vertebral
body. and less extensive
dense metastases at adjacent
levels Ell.
Enostosis (Bone Island) Vertebral Augmentation (Mimic)

the characteristic dense
sclerosis that is oriented
along the long axis of the
vertebra with typical
irregular /I brush.Jjke"
margins of a bone island.
obtained following
vertebroplasty shows cement
filling a cleft within a
compressed vertebral body
=-
I
294
VERTEBRAL BODY SCLEROSIS
Paget Disease Osteomyelitis, Chronic

radiograph shows an "ivory"
L I vertebral body due to
Paget disease. The vertebra
;s enlarged with cortical
thickening, findings that are
a clue to the underlying
etiology. (Right) Sagittal
NECT shows marked
sclerosis of L3 and L4 bodies
with extensive endplate
irregularity and bone
destruction resulting from
chronic osteomyelitis. The
endplale destruction is the
clue that the abnormality
originated altha! site as
infection.
radiograph shows unusually
severe sclerosis and
thickening of the vertebral
endplates •• Severe
nephrocalcinosis. and
small left kidney are a clue to
the underlying renal disease
that produced this rugger
jersey spine. (Right) Lateral
radiograph shows unusually
severe sclerosis and
thickening of the vertebral
endplates" in this dramatic
case of rugger jersey spine in
a patient with renal
osteodystrophy.
shows vertebra plana with
diffuse sclerosis" in this
patient with Langerhans cell
histiocytosis. (Right) Axial
NECT in this patient with
lymphoma shows a single
sclerotic vertebral body and
paraspinal mass •.
Lymphoma is one of the
recognized causes of ivory
vertebra.
I
295
III
C VERTEBRAL BODY SCLEROSIS
o
';;;
Q)
..J
~
III
.0
Q)
t: Chordoma
Q)
> (Left) Coronal bone CT

"tl shows characteristic
Cll appearance of fibrous
III
III dysplasia with extensive
l:lI "ground-glass" vertebral
>. lesions EiII & associated lytic
•..Eo
III
lesions. Note expansion of
the skull base & clivus =-
C (Right) Sagittal NECT shows
« massive thoracic chordoma
with a large mediastinal mass
& scattered calcifications •.
The mass destroys the
anterior margin of several
upper thoracic vertebral
bodies. Note the sclerosis
within several of the vertebra
EiII.
Myelofibrosis Plasma Cell Myeloma

osteosclerosis predominantly
involving the medullary
space, without thickening of
the endosteal cortex. This is
typical of myelofibrosis,
which results from
replacement of the fatty
marrow with fibrous tissue.
shows small round lesions
too numerous to count,
either sclerotic or lytic with
sclerotic rings. This pattern is
a variant of the purely
sclerotic lesions seen in the
POEMS form of myeloma.
Osteopetrosis Osteopetrosis
typical example of dense
vertebral body in a patient
with osteopetrosis,
demonstrating diffuse bony
sclerosis. (Right) Lateral
radiograph shows
bone-in-bone appearance
that can be seen in
osteopetrosis •. The bones
are mildly diffusely sclerotic.
The bone-in-bone
appearance results from
failure of osteoclasts to
remodel vertebral bodies
during growth.
I
296
VERTEBRAL BODY SCLEROSIS
Osteosarcoma Ewing Sarcoma

(Left) Axial CECT shows
metastatic osteosarcoma
with an unusual appearance
of peripheral sclerosis with
central lucency _ Some of
this appearance may be due
to chemotherapy. (Right)
sclerotic lesion occupying
the body of S 1 •. An
un mineralized soft tissue
mass is present Ell. These
findings are typical for Ewing
sarcoma, with the scferosis
due to reactive bone
formation. The location in
the axial skeleton is not
unusual.
Chondrosarcoma
(Left) Sagittal NECT shows a
large expanded mass with
flocculent chondroid ("arcs
and whorfs") matrix
involving posterior elements
and right posterior vertebral
body" in this patient with
chondrosarcoma. (Right)
Lateral radiograph of the
thoracic spine shows a
classicivory vertebra.
with dense bone replacing
the entire body but no
change in size. Focal
sclerosis such as this is one
appearance round in
mastocytosis.
Fluorosis Melorheostosis
shows diffuse sclerosis. There
is thickening and
indistinctness of the
trabeculae. The findings
resulted from two years or
fluoride treatment (Right)
Coronal NECT shows dense
sclerosis that involves the
right side of the C2 and C3
vertebral bodies. The
dermatomal distribution is
characteristic of
melorheostosis.
I
297
(/)
c SPINAL OSTEOPHYTES
o
·w
Q)
...J
cu DIFFERENTIAL DIAGNOSIS o Solitary/multifocal: Trauma, infection,
~ neuropathic
..c
t
Q)
Common
Q)
• Spondylosis Deformans Helpful Clues for less Common Diagnoses
> • Seronegative SpondyIoarthropathy
"C • DISH (Mimic)
ell
(/) • Disc Disease (Mimic)
(Il
CO o Syndesmophytes in all forms
>. less Common o Psoriasis, chronic reactive arthritis
E • Seronegative Spondyloarthropathy (Mimic)
~
-
o
(Il
c
• Paralysis
• Spectrum: Syndesmophytes to bulky
paravertebral ossification
• Enthesopathy, periostitis, bilateral
• Sternoclavicular Hyperostosis/SAPHO asymmetric erosive arthritis hands &
Rare but Important feet, sausage digits, tuft resorption
• Hypoparathyroidism • Paralysis
• Acromegaly o Spectrum: Osteophytes, syndesmophytes,
• Ochronosis (Alkaptonuria) bulky paravertebral ossification
• Fluorosis • Complications of Retinoids
o Ligament ossification, especially spinal;
enthesopathy
ESSENTIAL INFORMATION • Sternoclavicular Hyperostosis/SAPHO
Key Differential Diagnosis Issues o Spectrum: Osteophytes, syndesmophytes,
• Osteophytes demonstrate cortical & bulky paravertebral ossification
medullary continuity with vertebral body Helpful Clues for Rare Diagnoses
Helpful Clues for Common Diagnoses • Hypoparathyroidism
• Spondylosis Deformans o Normal disc space, enthesopathy
o Independent of disc disease & facet • Acromegaly
arthritis o Posterior vertebral scalloping, t disc space
• DISH (Mimic) height, ossification mimics DISH
o Ossification anterior longitudinal ligament • Ochronosis (Alkaptonuria)
o Peripheral enthesopathy ± ossification o Linear disc mineralization & osteoporosis;
posterior longitudinal ligament osteophytes minimal
• Disc Disease • Fluorosis
o Disc space narrowing, endplate changes o Osteosclerosis, enthesopathy, tendon
o Multilevel or diffuse: Degenerative ossification
Spondylosis Deformans DISH (Mimic)
I I..]teral radiograph shows typical changes

deformans with osteophytes of varying sizes ••
of spondylosis
=
wteral radiograph shows anterior "flowing" osteophytes
over multiple levels in this patient with typical
without other changes. changes of 015/-1.
298
SPINAL OSTEOPHYTES »
::::l
...•
III
o
3
'<
Ol
III
Disc Disease VI
Disc Disease (I)
(Left) Sagittal T2Wf MR Co
shows severe disc
degeneration with loss of
<
CD
;:l-
disc height at every cervical CD
0-
level. Large anterior. and ~
smaller posterior osteophytes
are present. (Right) Axial
'"r-
CD
NEeT shows severe en
multilevel disc degeneration
o'
::::l
with loss of disc height, bony
en
eburnation, and vacuum
phenomenon at Ls-s1, LJ-4,
and L2-3, accompanied by
osteophytes •.
Seronegative Spondyloarthropathy Seronegative Spondyloarthropathy

(Mimic) (Mimic)
radiograph shows bulky,
asymmetric paravertebral
ossification" in the
thoracolumbar spine in this
patient with chronic reactive
arthritis. (Right) Sagittal bone
CT shows lower cervical
ankylosis in this patient with
ankylosing spondylitis Ell.
Somewhat prominent
syndesmophytes are present
in the upper cervical spine
_ Odontoid fraclure is
incidentally noted III a
result of minor trauma in this
patient who has severe
osteoporosis.
Complications of Retinoids Ochronosis (Alkaptonuria)

shows small osteophyte at
the anterosuperior margin of
LS • in this patient taking
relinoids. Such changes are
usually more prominent at
the thoracolumbar junction.
(Right) Laleral radiograph
shows classic appearance of
ochronosis (alkaptonuria)
-
with disc space narrowing &
disc mineralization. Note the
small anterior osteophyles
I
299
VI
c LESIONS ORIGINATING IN VERTEBRALBODY
.Q
VI
Q)
--'CIl DIFFERENTIAL DIAGNOSIS • Schmorl Node (Mimic)
~ o Often multiple, no posterior element
..0
t
Q)
Common involvement
Q)
> • Intraosseous Hemangioma o Cup-like lesion adjacent to end plate
"tl • Metastases defect, disc continuity into lesion, sclerotic
Q)
VI
III
• Schmorl Node (Mimic) rim; if acute has edema on MR
CO • Paget Disease • Paget Disease
>- • Multiple Myeloma (MM)
E o Typically solitary, may be multiple
•..
o
III
• Limbus Vertebra (Mimic) o Hint: Enlarged vertebra
s:: • Osteonecrosis • Thick cortices, coarsened irregular
« • Vertebral Body Osteomyelitis trabecula (picture frame vertebra)
• Lymphoma • May produce ivory vertebra
• Plasmacytoma • Multiple Myeloma (MM)
Less Common o Patients typically 40 years or older
• Giant Cell Tumor o Multiple vertebra, variable appearance
• Langerhans Cell Histiocytosis • Multiple lytic foci, variable size,
• Fibrous Dysplasia non-sclerotic margins
• Ewing Sarcoma • Innumerable tiny lesions
• Osteochondroma • Solitary lesion: Plasmacytoma
• Renal Osteodystrophy, Brown Tumor • Sclerotic lesions: POEMS syndrome
o Bone scan: Cold lesions or false negative
Rare but Important
• Limbus Vertebra (Mimic)
• Chondrosarcoma o Well-corticated bone fragment at vertebral
• Chordoma corner; anterosuperior most common
• Osteosarcoma o Matching defect in adjacent vertebra,
• Echinococcal Disease variable size with sclerotic margin
o If acute has bright marrow signal on MR,
ESSENTIAL INFORMATION increased uptake on bone scan
o No posterior element involvement
• Osteonecrosis
• List specifically excludes disc-centered o Difficult to see on radiographs
processes such as degenerative disease o MR: Serpiginous low signal rim & internal
• Unless stated, any lesion may extend into fat; posterior elements lesions rare, no soft
posterior elements tissue mass
• Most lesions have nonspecific appearance: o May have vertebral collapse
Lytic lesion that may be expansile, • H-shaped vertebra
geographic non-sclerotic margins ± soft • Ktimmel disease: Gas within cleft
tissue mass o Underlying medical condition such as
Helpful Clues for Common Diagnoses sickle cell, chronic steroid use
• Intraosseous Hemangioma • Vertebral Body Osteomyelitis
o Solitary or multiple o Typically destroyed intervertebral disc
o Rarely extends to posterior elements o Coccidiomycosis: Non-contiguous,
o Common on MR with characteristic intraosseous osteolytic foci, disc spared,
rounded hyperintense Tl lesion paraspinal abscesses, rib involvement
o Immature lesions have nonspecific, often o Tuberculosis: Non-contiguous vertebral
aggressive appearance lesions with anterior cortical destruction
o Corduroy vertebra: Coarse, vertically • Disc destruction late
oriented trabecula seen on CT & X-ray • Paraspinal masses may be extensive
• Metastases o No posterior element involvement, lesions
o Breast, lung, prostate, thyroid, kidney notexpansile
o Multiple lytic, blastic, or mixed lesions • Lymphoma
I
300
LESIONS ORIGINATING IN VERTEBRAL BODY ~
::l
••...•o
o Any age, frequently young adult o Hint: Corticomedullary continuity 3
'<
o Permeative destruction, soft tissue mass diagnostic CD
even without cortical destruction o Usually part of multiple hereditary ••
VI
C1l
o Variant: Ivory vertebra osteochondromas; evaluate knees to help Co
• Plasmacytoma establish diagnosis <

(1)
o Slightly younger patient than MM • Renal Osteodystrophy, Brown Tumor ;:+

(1)
rr
...,
o Lesion may be quite expansile o Other findings of renal osteodystrophy III
Helpful Clues for Less Common Diagnoses • Coarse ill-defined trabecula, bone r
(1)
resorption, soft tissue calcium deposits VI
• Giant Cell Tumor 0"
::l
o Adults: 25-40 years old Helpful Clues for Rare Diagnoses VI
o May present with vertebra plana • Chondrosarcoma

o Posterior element involvement unusual o Any age; typically adult
• Langerhans Cell Histiocytosis o Hint: Lobulated growth pattern,
o Children: 2-6 years old chondroid mineralization (flocculent or
o Thoracic spine most common arcs & whorls)
o Posterior element involvement rare • Chordoma
o Lymphadenopathy, soft tissue mass/edema o Any age, adults most common
o Hint: Vertebra plana common o Sacrum> clivus> remainder of spine
• May reconstitute during healing phase o Mineralization in 50%
• Fibrous Dysplasia • Osteosarcoma
o Child < 10 years old; lumbar> cervical o Teens & young adults, 2nd peak in older
o Vertebral involvement rare in monostotic adults; solitary or multiple
disease, common in polyostotic disease o Ranges from purely lytic to densely
o May have internal septations/striations sclerotic (ivory vertebra) ± soft tissue mass
o Hint: Ground-glass matrix characteristic with variable ossification
• Ewing Sarcoma • Echinococcal Disease
o Teens & young adults o Spine disease common in endemic areas,
o Solitary lesion, confined to vertebral body usually monostotic
o Permeative destruction, large soft tissue o Middle-aged & elderly adults, children rare
mass, often little cortical destruction o Septated osteolytic lesion ± soft tissue mass
o Variant: Ivory vertebra with calcification in cyst walls
• Osteochondroma o MR & CT: Multicystic lesion with primary
cyst & multiple daughter cysts
Intraosseous Hemangioma
Axial T'WI MR shows a hyperintense L4 vertebral

III without epidural expansion. The appearance is
lesion Axial NEeT shows the classic honeycomb appearance
of a hemangioma with thickened trabeculae, intact
I
characteristic for an intraosseous hemangioma. cortex, and focal/ow atlenua(jon between trabeculae.
301
II)
c LESIONS ORIGINATING IN VERTEBRAL BODY
o
'(i'j
Ql
--l
~
<Il
.0
Ql
1::
Ql
Metastases Metastases
> (Left) Sagittal NECT shows
"l:l
multiple blastic metastatic
Ql foci involving the thoracic
II)
CO and lumbar vertebral bodies
CD III. (Right) Sagiltal T1 WI MR
>- shows multiple focal areas of
-
<
E
o
CO
C
abnormal low signal due CO
diffuse metastases. There is
confluent involvement
upper thoracic bodies with
of
epidural extension and cord

compression _ along with
a pathologic lower thoracic
fracture with no bony
retropulsion Ell.
Schmorl Node (Mimic) Schmorl Node (Mimic)

(Left) Sagiltal bone CT shows
small lytic-appearing lesions
= within severa/thoracic
vertebral bodies. The lesions
have sclerotic margins and
abut the endplate, which is
absent. The appearance is
characteristic of Schmor!
nodes. (Right) Sagiltal T1 C+
MR shows a Schmorl node.
There is a large,
'Icup-shapedu depression =
within the superior vertebral
endplate, with sclerotic
margins and no adjacent
marrow edema. The disc
protrudes directly inco the
vertebral depression.
Paget Disease Paget Disease

radiograph shows an ivory
vertebra. Enlargement of the
vertebral body Ell. pedicles
• and transverse processes
11IIis key CO making the
diagnosis of Paget disease.
(Right) Sagiltal STIR MR
shows a typical appearance
ofPagetd~ease. The
vertebra is mildly enlarged in
anterior-posterior dimension
_ with slight height loss.
Enlargement of the spinous
process is also present •.
Coarsened trabecula are
another clue to diagnosis.
I
302
lESIONS ORIGINATING IN VERTEBRALBODY »
::l
..•
III
o
3
'<
III
III
Multiple Myeloma (MM) limbus Vertebra (Mimic) <II
lD
(Left) Sagittal T1 WI MR a.
shows typical MR
appearance of multiple
<
<1l
;:l.
myeloma, with innumerable <1l
ill-defined marrow nodules,
r::T
~
III
subcentimeter in size.
Schmorl nodes are also
r
<1l
present •. (Right) Lateral
radiograph shows limbus
'"::l
0'
fragments at both L4 and L5
•. At both levels, the
'"
f1divot" in the anterosuperior
vertebral body is larger than
the limbus fragment because
of concurrent Schmorl nodes
ElIlI.
Osteonecrosis
shows typical H-shaped
vertebra of sickle cell disease
•. The H-shape results from
collapse of the central
endplate due to
osteonecrosis. (Right)
Sagittal NECT shows multiple
focal areas of bone
destruction. with
preservation of the disc
spaces and minimal
prevertebraf soft tissue
involvement in this patient
with indolent infection
(coccidiomycosis).

ivory vertebra IIIlI without
clear destruction, resulting
from lymphoma. (Right)
Axial T1 C+ MR shows
marrow replacement
throughout the vertebral
body, extending into the
right neural arch ElIlI. There is
extension of the tumor into
the paraspinous 50ft tissues
anterior to the vertebral
body and into the epidural
space •. This pattern of
tumor spread is commonly
seen in lymphoma.
I
303
III
C lESIONS ORIGINATING IN VERTEBRAL BODY
o
.iij
Q)
-'
~
Cll
.0
Q)
t
Q)
Plasmacytoma Giant Cell Tumor
> (Left) Axial bone CT shows
't:l
Ql plasmacytoma, with a lytic
III
<1l lesion arising in the vertebral
!Xl body and mild expansion of
>- the lateral cortical margin 11III
E of the vertebra. (Right)
.•..o
<1l Lateral radiograph shows
C lesion with geographic
« non-sclerotic margins arising
in the. L 7 vertebral body 11III.
The lesion was subsequently
proven to be a giant cell
tumor.
Langerhans Cell Histiocytosis

shows vertebra plana 11III at
C7 in a child. This is a
common presentation of
Langerhans cell histiocytosis.
Note that the posterior
elements are not involved.
(Right) Coronal T2WI FS MR
shows central collapse of C3
11III, increased signal of C5
lilt and asymmetric
right-sided 50ft tissue edema
HI. Large soft tissue masses
are common during the early
phase of Langerhans cell
histiocytosis, but they regress
with evolution of lesions.
Fibrous Dysplasia Fibrous Dysplasia

radiograph shows a sharply
demarcated, slightly
expansile lytic lesion of the
T2 vertebral body 61. The
lesion has a ground-glass
appearance. The findings
suggest the diagnosis of
fibrous dysplasia. (Right)
Axial CECT shows lytic
lesions 11III within the
vertebra & posterior
elements with sharp margins,
sclerotic rims, & mild
expansion. They contain
amorphous ground-glass
matrix consistent with Fibrous
dysplasia.
I J
lO-l
lESIONS ORIGINATING IN VERTEBRAL BODY »
..
:J
Cl
o
3
'<
OJ
Cl
VI
Ewing Sarcoma Osteochondroma l1>
(Leh) Sagittal STIR MR C.
shows a lesion arising in the
L 1 vertebral body III in a
<
l1>
;:+
teenager. Posterior soft tissue <l>
rr
mass is present. The ~
OJ
appearance is consistent
r
with an aggressive process. <l>
VI
The patient's age indicates
that Ewing sarcoma must be
o'
:J
VI
considered. (RighI) Axial
bone CT shows a mature
osteochondroma arising from
the anterior cortex of the C2
vertebral body =.
Mineralization is present in
the cartilage cap EEl in this
skeletally mature individual.
Chondrosarcoma Chordoma
destructive vertebral body
lesion that leatures stippled
chondroid matrix III
extending into the
prevertebral tissues. The
features are characteristic of
chondrosarcoma. (RighI)
Axial T1 C+ FS MR shows a
large, diffusely enhancing
soft tissue mass. arisingin
the L4 vertebral body. The
lesion also crossed the disc
space to extend into the LS
vertebra. Such behavior is
typical, but not specific, for
chordoma.
Osteosarcoma
sites of sclerotic dense bone
formation, extending from
the bones into the adjacent
soft tissue, involving two
lumbarspine vertebra.
and the left pubic ramus 61
This patient has developed
osseous metastases from
osteosarcoma. (RighI)
complex, predominately
left-sided, multicystic mass
III involving bone and
adjacent soft tissue in this
patient with echinococcus
infection.
I
305
(/)
c lESIONS ORIGINATING IN POSTERIOR ElEMENTS
.Q
(/)
Q)
-'ro DIFFERENTIAL DIAGNOSIS Helpful Clues for less Common Diagnoses

L
.n
Q) Common • Pedicle Reactive Sclerosis
t
Q) o 2° abnormal contralateral pedicle:
> • Spondylolysis
• Metastases, Bone Marrow Spondylolysis most common
"0
Q)
VI • Acute Trauma • Osteoid Osteoma
ro o Under 30 years; M > F, any spinal level
In less Common
>. o Pain relieved by salicylates
E • Pedicle Reactive Sclerosis
•..o • Osteoid Osteoma
o Lytic lesion, central nidus, reactive
sclerosis (sclerosis less dramatic in spine)
'"
c
<l: • Aneurysmal Bone Cyst o Non-rotational scoliosis; lesion on
• Osteoblastoma concavity & generally < 1 cm in size
• Hypoplastic/Aplastic Pedicle o MR: Surrounding inflammatory response
Rare but Important • Aneurysmal Bone Cyst
• Brown Tumor o Any age, typically under 20 years, F > M
o Any spinal level, favors thoracic, lumbar
o ± Extension to adjacent bones, across disc
ESSENTIAL INFORMATION o Fluid-fluid levels common, not diagnostic
Key Differential Diagnosis Issues o MR: Blood products
• Hint: Most destructive lesions visualize as • Osteoblastoma

absent pedicle on AP view o Any age, especially 10-30 years: M > F
• Hint: Sclerotic pedicle should lead one to o Expansile lytic lesion
consider osteoid osteoma, blastic metastasis, • Wide spectrum of calcification or
or reactive sclerosis ossification ± soft tissue mass
o Most common thoracic, lumbar spine
Helpful Clues for Common Diagnoses • ± Scoliosis, lesion on concavity
• Spondylolysis • Hypoplastic/Aplastic Pedicle
o Best seen on lateral or oblique view
o Varying degrees of malformation
o Anterolisthesis vertebral body if bilateral
o ± Abnormal lamina
o Hint: Retrolisthesis of posterior arch
o Incidental finding when isolated
o Typically older patient Helpful Clues for Rare Diagnoses
o Hint: Usually not solitary lesion • Brown Tumor
• Acute Trauma o Primary or secondary hyperparathyroidism
o History definitive, variable mechanism o Lytic lesion ± mild expansion
Spondylolysis Metastases, Bone Marrow
I Sagillal bone CT shaws defect in pars interarticularis •

and grade 2 anterior displacement of 15 vertebral body
Axial NECT shaws hypervascular renal cell metastasis
• with a large soft tissue mass. The origin of the lesion
relative lo sacrum. is the pedicle.
306
LESIONS ORIGINATING IN POSTERIOR ELEMENTS »
-
::I
Ql
o
3
'<
OJ
Ql
VI
Acute Trauma Pedicle Reactive Sclerosis CIl
(Left) Lateralradiograph a.
shows typical case of <
hangman fracture co
::l-
demonstrating fracture co
between the vertebral body rr
~
III
and neural arch ••. (Right)
Axial NECT shows left r
CO
posterior element hypoplasia ~.
o
EiII and left pedicle aplasia :J
1lII. There is sclerosis of the en
compensatory enlarged right
pedicfe, which contains a
central horizontal lucency
from an insufficiency fracture
=.
Osteoid Osteoma Aneurysmal Bone Cyst

classic appearance of osteoid
osteoma with a sharply
demarcated lesion in the
neural arch" containing
bone matrix. Reactive
sclerosis is present around
the lesion EiII. (Right) Axial
T2WI MR shows a
multiloculated mass
containing multiple
fluid-fluid levels in this
aneurysmal bone cyst ••.
Mixed signal intensity reflects
the presence of blood
products.
Osteoblastoma Brown Tumor

radiograph shows an
expansile mass replacing the
right L5 pedicle" and
indistinct vertebral body
cortex resulting from
osteoblastoma. (Right) Axial
bone CT shows an expanded
lytic lesion within the
posterior elements of this
cervical vertebra". The
patient had a parathyroid
adenoma, and a Brown
tumor was proven at biopsy.
I
307
RIB NOTCHING, INFERIOR
"0
ell
DIFFERENTIAL DIAGNOSIS • Normal Variant
'"
ltl
al o Inferior rib often undulating/indistinct
:>. Common • Post-Operative
E
-o
ltl
t:
<l:
• Coarctation Aorta, Thoracic
• Normal Variant
• Post-Operative
o Thoracotomy rib resection/deformity
• Hyperparathyroidism (Mimic)
o Subperiosteal & endosteal bone resorption
• Hyperparathyroidism (Mimic) o Bone destruction by Brown tumors
• Neurofibromatosis • Neurofibromatosis
less Common o Pressure from intercostal neurofibromas
• Decreased Pulmonary Blood Flow o Dysplastic "twis·ted ribbon" ribs
• Congenital Heart Disease, Repaired Helpful Clues for less Common Diagnoses
• Subclavian Artery Obstruction • Decreased Pulmonary Blood Flow
• Low Aortic Obstruction o Notching from enlarged transpleural
• Thalassemia collateral vessels
• Arteriovenous Malformation o Congenital absence of pulmonary artery,
Rare but Important pulmonary stenosis, tetralogy of Fallot,
• Superior Vena Cava Obstruction Ebstein anomaly, emphysema
• Giant Cell Tumor (Mimic) • Congenital Heart Disease, Repaired
• Tuberous Sclerosis (Mimic) o Findings of Blalock-Taussig shunt or
cava-pulmonary anastomosis
o Often unilateral right-sided
ESSENTIAL INFORMATION • Subclavian Artery Obstruction
Key Differential Diagnosis Issues o Takayasu arteritis, arteriosclerosis
• Rib notching = localized erosion or thinning obliterans, Blalock-Taussig procedure,
thrombosis
• Low Aortic Obstruction
• Coarctation Aorta, Thoracic o Low thoracic or abdominal aorta
o Commonly involves 4th to 8th ribs
o Notching of lower ribs
• Tortuous, dilated intercostal arteries
• Thalassemia
o "Figure 3" sign = undulation in distal aortic
o Cortical erosion in posteromedial rib
arch at coarctation site o Unusual in widened rib
o Right unilateral notching if coarctation
• Arteriovenous Malformation
proximal to left subclavian artery origin o Involves intercostal or pulmonary vessels
o Bicuspid aortic valve in 25-50%
Coarctation Aorta, Thoracic Coarctation Aorta, Thoracic
I Posleroanterior radiograph shows lypical aorlic

coarclaUon rib nOlching • along the inferior surface of
Posleroanlerior radiograph shows typical aorlic
coarclalion rib nOlching • along che inferior surface of
lhe poslerior righl fifch rib. cheposterior left fourth and fiflh ribs.
308
RIB NOTCHING, INFERIOR >
::::l
...•
III
o
3
'<
[Jl
III
Coarctation Aorta, Thoracic Coarctation Aorta, Thoracic III
l1>
(Left) Posteroante,iOf Co
inferior rib notching =

radiograph shows left-sided
and
post-stenotic dilatation IIIil!I of
the descending aorta due to
coarctation. The aortic
contour abnormality is
referred to as the "(igure 3"
sign. (RighI) Posteroanterior
radiograph shows a typical
case of aortic coarctation
with bilateral inferior rib
notching=.
Post-Operative Hyperparathyroidism (Mimic)

radiograph shows scalloping
along the inferior border of
the right fourth rib 1IIil!I. This
was post-operative in origin.
Additional signs of surgical
intervention includes staples
in the middle lobe 1IIil!I.
radiograph shows bone
resorption along the inferior
second rib" mimickingrib
notching. This is caused by
hyperparathyroidism, seen as
a manifestation of renal
osteodystrophy. Note signs
of rickets in the humerus,
with slipped epiphysis.
Neurofibromatosis Giant Cell Tumor (Mimic)

radiograph shows inferior
scalloping. of the ribs
caused by pressure erosions
from intercostal
neurofibromas. (RighI) Axial
NEeT shows a lytic lesion IIIil!I
originating from and partially
destroying the rib.
Heterogeneous low density
favors either a giant cell
tumor containing fluid levels
or an aneurysmal bone cyst
containing a solid portion.
I
309
C/l
.0 RIB NOTCHING, SUPERIOR
i:r:
't:J
Cl>
l/l DIFFERENTIAL DIAGNOSIS Helpful Clues for Common Diagnoses
ns
Cll
Common • Hyperparathyroidism (Mimic)
>- o Subperiosteal & endosteal bone resorption
E • Normal Variant
•..ns
o
• Hyperparathyroidism (Mimic) • Unilateral predominance
c: o Bone destruction by Brown tumors
< • Systemic Lupus Erythematosus
• Rheumatoid Arthritis, Wheelchair • Systemic Lupus Erythematosus
• Progressive Systemic Sclerosis o Third to fifth rib superior border
• Rheumatoid Arthritis, Wheelchair
Less Common o Osteoporosis + scapular erosion into ribs
• Coarctation Aorta, Thoracic
• Neurofibromatosis Helpful Clues for Less Common Diagnoses
• Multiple Hereditary Exostosis (Mimic) • Coarctation Aorta, Thoracic
o Usually causes inferior rib notching
• Post-Operative
o Superior rib notching seen when
• Pressure Effect, Thoracic Drainage Tube
• Pressure Effect, Rib Retractor intercostal arteries markedly enlarge &
• Radiation Osteonecrosis erode the superior surface of adjacent rib
• Neurofibromatosis
Rare but Important o Pressure erosions from neurofibromas are
• Intercostal Muscle Atrophy usually inferior
• Paraplegia, Complications o Dysplastic "twisted ribbon" ribs
• Osteogenesis Imperfecta o Vertebral abnormalities
• Marfan Syndrome • Radiation Osteonecrosis
• Polio o Delayed alteration in bone remodeling
• Restrictive Lung Disease
• Thalassemia Helpful Clues for Rare Diagnoses
• Progeria • Osteogenesis Imperfecta
o Dysplastic rib rotation & curvature
• Marfan Syndrome
ESSENTIAL INFORMATION o Thin ribs with thin cortices
Key Differential Diagnosis Issues • Polio
o Thin ribs & atrophic intercostal muscles
• Rib notching = localized erosion or thinning
o Superior> inferior scalloping - "hourglass"
• Superior notching is less common than
inferior notching and is more likely to be shape
non-neurovascular in origin • Progeria
o Thin clavicles & ribs
I Anteroposterior radiograph shows resorption of the

superior rib cortex" which may be mistaken for rib
Posteroanterior radiograph shows subtle superior rib
notching III and an enlarged heart •• due to a
notching. pericardial effusion.
310
RIB NOTCHING, SUPERIOR »
::::l
...•
III
o
3
'<
OJ
III
III
Cl)
(Left) Posteroanterior C.
radiograph shows an
i/l-defined superior cortex of
the posterior mid-thoracic
ribs" The combination of
osteoporosis & constant
rubbing of the scapula
againsllhe rib cage results in
this pattern of resorption in
this rheumatoid arthritis
patient who uses a
wheelchair. (Right)
shows a ribbon rib on the
/I I,
left" which reflects an

osseous dysplasia seen in
neurofibromatosis.
Multiple Hereditary Exostosis (Mimic) Post-Operative

radiograph shows deformity
and notching of the superior
cortex of the ribs lID
adjacent to a scapular
exostosis in this patient with
multiple hereditary
exostoses. (Right)
Posteroanterior radiograph in
a patient with a previous left
thoracotomy shows a
resultant post-operative
deformity of the left third rib
_. The ascending aorta El!lI
is enlarged.
Radiation Osteonecrosis Paraplegia, Complications

radiograph shows deformity
of the superior rib borders
• in a patient with radiation
osteonecrosis. Note the
elevated hila 11II.The patient
had mantle radiation for
lymphoma. (Right)
shows unilateral superior rib
notching 11II in a
quadriplegic patient. This
erosion is likely due to
pressure from the scapula
combined with osteopenia
and muscle atrophy.
I
311
(/)
.D SOLITARY RIB LESION
a:
"0
Q)
(/) DIFFERENTIAL DIAGNOSIS o Lytic to ground-glass density on
ra radiograph
al
>- Common o Commonly polyostotic (but < 50%)
E • Fracture Healing Process
-o
ra
c:
<l:
• Fibrous Dysplasia (FD)
• Enchondroma
• Enchondroma
o Quoted as being most common benign rib
lesion in autopsy series
• Multiple Myeloma (MM) o Not frequently noted on chest radiograph:
• Metastatic Small lesion, chest rather than osseous
• Pancoast Tumor X-ray technique makes it difficult to see
• Osteomyelitis o Watch for chondroid matrix (punctate)
• Osteochondroma o Generally no geographic margin
Less Common • Multiple Myeloma (MM)
• Langerhans Cell Histiocytosis (LCH) o Usually multiple lytic lesions or diffuse
• Ewing Sarcoma infiltration seen only as osteopenia
o Rarely will find a single rib lesion, with
Rare but Important
other lesions elsewhere in skeleton
• Giant Cell Tumor (GCT)
• If expanded or bubbly, lesion is likely the
• Chondrosarcoma original plasmacytoma
• Askin Tumor • Metastatic
• Osteosarcoma o Generally polyostotic
• Cystic Angiomatosis o Occasional solitary metastasis is found in
rib
ESSENTIAL INFORMATION • Thyroid or renal cell most common
• Pancoast Tumor
o Tumor in lung apex, may have rib
• Many entities in the differential may be destruction
polyostotic lesions, even if only a single rib o Proximity to nerves & vessels leads to
lesion is seen in any specific case typical clinical symptoms
o FD, MM, metastases, LCH,
• Shoulder & arm pain
osteochondroma, cystic angiomatosis
• Horner syndrome
o Hint: Look for other skeletal lesions
• Osteomyelitis
• Age may be a differentiating factor o Lytic destructive rib lesion
o FD, LCH, Ewing sarcoma, Askin tumor,
• Usually wide zone of transition, not
GCT tend to be seen in younger patients geographic
than metastases or MM o Soft tissue mass is most frequently present
Helpful Clues for Common Diagnoses o Elicits pleural effusion
• Fracture Healing Process o Radiographic appearance may be
o During callus-producing phase, fracture indistinguishable from Ewing sarcoma or
may appear as a sclerotic metastasis Askin tumor
o Slightly mal aligned healed fracture may o MR with contrast usually will differentiate
appear as a slightly expanded lytic lesion, • Osteochondroma
but without geographic borders o Rib osteochondromas less frequent than
o Generally will see other fractures in on long bones
adjacent ribs, making the diagnosis o Rib osteochondromas often seen as part of
obvious multiple hereditary exostosis (MHE)
• Fibrous Dysplasia (FD) o Osteochondroma of rib arises as on long
o Most common solitary rib lesion in bone
teenager & young adult • Stalk in continuity with rib cortex
o Slightly expanded to bubbly; not • Marrow extending from rib into
aggressive osteochondroma
• Overlying cartilage cap
I
312
SOLITARY RIB LESION >
..
::l
III
o
a Because rib osteochondromas often project 3
intrathoracically, they may have the • Giant Cell Tumor (GCT)
CJ
III
appearance of lung nodules a Rare rib lesion
II>
Cl>
Co
• Hint: Watch for attaching stalk & a Lytic lesion, generally geographic but
osseous character of "nodule" ::u
rarely may be aggressive 0-
Il>
Helpful Clues for Less Common Diagnoses a Young to middle-aged adults
• Langerhans Cell Histiocytosis (LCH) a Characteristic MR features

a Frequently involve ribs, skull, flat bones of • Some low signal regions on T2
shoulder & pelvic girdle, long bones • May occasionally have fluid-fluid levels
a Frequently polyostotic • Chondrosarcoma
a Generally occur in a younger age group a May arise in enchondroma or at
(children, young teenagers) than the other costochondral junction of rib
listed lesions a Lytic, usually containing chondroid matrix
a Lytic lesion, ranging from geographic to a Generally low grade & not aggressive in
aggressive appearance
• Aggressive lesions may have cortical • Askin Tumor
breakthrough and soft tissue mass a Although rare, most common pleural
a May advance rapidly & be tumor in teenagers & young adults
indistinguishable by imaging from Ewing (especially females)
sarcoma a Primitive neuroectodermal tumor (PNET)
• Ewing Sarcoma arises in pleura or chest wall
a Aggressive lytic lesion a Involves rib 23-60% of time
• Cortical breakthrough, large soft tissue • Osteosarcoma
mass a Very rare lesion in rib
• Rib lesions often elicit a large pleural a Osteoid matrix, varying aggressiveness
effusion • Cystic Angiomatosis
a Proximal & flat bones such as ribs, pelvis, a One of the vascular tumors that may be
scapula generally involved in older age polyostotic
group; tubular bones in younger children a All may involve a rib; preference is lower
• Late teenage and young adults are the extremities
prime age group for Ewing of rib a Range of aggressiveness; cystic
a May appear polyostotic since osseous angiomatosis & hemangioma are generally
metastases are common the least aggressive
Fibrous Dysplasia (FDl
Anteroposterior radiograph shows a healed rib fracture

.:II. With slight offset, it may appear to be a slightly
Oblique radiograph shows an expanded, bubbly solitary
rib lesion B. In this young patient, FD is the most likely
I
expanded lytic lesion. Alternatively, during healing, it diagnosis. She had spine and humeral lesions, adding to
may appear sclerotic, mimicking metastatic disease. the probability, as well as a brachial plexopathy.
313
(/)
.0 SOLITARY RIB lESION
0::
'1:l
Q)
(/)
01
m
>- Enchondroma
E
•..
o
01
small region of chondroid
c: matrix within the first rib.
< a typical enchondroma.
These lesions are reportedly
common in ribs (autopsy
series) but infrequently
noted on chest X-rays.
(Right) Coronal STIR MR of
the right upper thorax shows
high signal in what proved to
be a solitary rib lesion _.
The MR survey showed
myeloma lesions in other
osseous structures. A single
rib involved in MM is
unusual; plasmacytoma
would be more frequent.
Metastatic Pancoast Tumor

an expanded solitary rib
lesion.:ll. While the lesion
does not appear highly
aggressive, it is important to
remember that chest X-ray
technique is suboptimal to
evaluate osseous structures.
This proved to be a solitary
kidney metastasis. (Right) PA
radiograph shows near
complete destruction of the
first rib El!lII (compare with
normal right side), with
associated apical lung mass
•. Pancoast tumors have
distinct clinical symptoms.
Osteomyelitis Osteochondroma
destruction of a solitary rib
•• with associated large soft
tissue mass Ell. While this
certainly could represent an
aggressive tumor such as
Ewing sarcoma, osteomyelitis
can have just as aggressive
an appearance. (Right)
"Iung nodule" which in fact
arises from the rib" The
lesion contains mature bone
and represents an
osteochondroma. The chest
X-ray technique is
suboptimal for evaluating the
matrix.
I
J1.j
SOLITARY RIB LESION :P
:l
...•
III
o
3
'<
III
III
III
langerhans Cell Histiocytosis (lCH) Ewing Sarcoma (1)
(Left) Axial CECT shows a Q.
lytic destructive lesion in the

rib of a 2 year old III. It was
<9.
rr
III
a solitary lesion and proved
to be LCH. Note that there is
a small associated soft tissue
mass. The age of the patient
should help suggest the
diagnosis. (Right)
shows destruction of a
solitary rib III in a 15year
old, along with a large soft
tissue mass and pleural
effusion HI. Ewing sarcoma
must be strongly considered
and proved to be the correct
diagnosis.
Giant Cell Tumor (GCT)

both a solid portion of the rib
lesion" and regions
containing fluid levels Ill.
The appearance is not
specific. Aneurysmal bone
cyst with a solid component
should be considered. Giant
cell tumor with fluid levels is
the final diagnosis. (Right)
5agittal CECTshows an
expanded rib end containing
a chondroid matrix HI. The
location adjacent to the
costochondral cartilage is
typical but not exclusive for
this tumor.
Askin Tumor
(Left) Axial CECTshows a
large pleural-based tumor
extending around the
hemithorax III in a young
adult with associated
destruction and reactive
change of the adjacent rib
Ill. The distribution and age
of the patient are typical of
Askin tumor; rib involvement
is variable. (Right) Axial
bone CT shows a rare low
grade intraosseous
osteosarcoma of the rib •.
Statistically, most rib lesions
containing matrix are
chondroid in nature, most
frequently enchondroma.
I
315
~
II)
SACROILIITIS, BILATERAL SYMMETRIC
Q)
0...
"0
CIl DIFFERENTIAL DIAGNOSIS o Eventual profound osteoporosis
II)
III
o Spine involvement: Tends to be
III Common continuous
>- • Ankylosing Spondylitis (AS)
E • Thin vertical syndesmophytes lead to
-«
o
III
c:
• Osteoarthritis (Mimic) (OA)
• DISH (Mimic)
body fusion
• Facets fuse as well, leads to bamboo spine
• Osteitis Condensans Ilii (Mimic) o Peripheral involvement: Large proximal
Less Common joints (hip, shoulder)
• Inflammatory Bowel Disease Arthritis (lED) o Male> > female; onset 2nd or 3rd decade
• Psoriatic Arthritis, Late (PSA) • Osteoarthritis (Mimic) (OA)
• Renal Osteodystrophy (Mimic) (Renal OD) o Purely productive; osteophytes tend to
bridge anteriorly at superior & inferior
Rare but Important
ends of synovial portion of SI joint
• Chronic Reactive Arthritis, Late (CRA) o May mimic sclerosis of sacroiliitis, but
• Rheumatoid Arthritis (RA) usually is easily differentiated
o May appear as a rounded region of
ESSENTIAL INFORMATION sclerosis overlying mid SI joint; may mimic
a sclerotic metastatic site
• DISH (Mimic)
• Sacroiliac (SI) joint inflammatory disease is o Purely productive, not an articular process
most frequently seen in • Iliolumbar ligaments located superior to
spondyloarthropathies SI joints may ossify & bridge
• Two spondyloarthropathies are particularly • Nonarticular superior portion of SI joint
noted for bilateral and symmetric may ossify & appear fused
involvement • Synovial (inferior) portion of SI joint not
o Hint: Bilateral symmetric sacroiliitis most
affected by DISH
frequently is due to ankylosing spondylitis, o Ossified superior portions of SI joints
inflammatory bowel disease spondylitis appear symmetric & may mimic end-stage
o Hint: Remember that
sacroiliitis
spondyloarthropathies that are usually • Should be easily differentiated since the
bilaterally asymmetric (PSA, CRA) may true SI joint is not involved
develop bilaterally symmetric disease at o Other axial features
some point • Ossification sacrotuberous or sacrospinal
• Purely productive diseases of the SI joints ligaments
may mimic the sclerosis of sacroiliitis • Bridging anterior osteophytes along
o OA, DISH, osteitis condensans ilii
spine, particularly thoracic
o Sclerosis is predominantly on iliac side • Osteitis Condensans Ilii (Mimic)
o No associated erosive change
o Sclerotic reactive osseous change on iliac
o Hint: Watch for location of sclerosis of SI
side of joint
joints to differentiate these mimics from • Usually, but not invariably, symmetric
true spondyloarthropathies & from one • Sclerosis may mimic the sclerosis seen in
another sacroiliitis
Helpful Clues for Common Diagnoses o Sclerosis is generally specific in appearance
• Ankylosing Spondylitis (AS) • Involves iliac side of joint, inferiorly
o Sacroiliitis begins with erosive change • Often triangular in shape
• Loss of distinctness of SI joint cortices o Not an articular process; joint is normal
• Erosions lead to widening of joints Helpful Clues for Less Common Diagnoses
• Usually bilaterally symmetric, but • Inflammatory Bowel Disease Arthritis
occasionally one side lags behind the (IBD)
other & they appear asymmetric o Similar in appearance but much less
o Eventual sclerosis and bilateral fusion
frequent than AS
I
316
SACROILIITIS, BILATERAL SYMMETRIC l>
..•o
j
III
o Sacroiliitis begins with erosive change o Sacroiliac joints may appear widened & 3
'<
• Loss of distinctness of SI joint cortices irregular OJ
III
• Erosions lead to widening of joints o Most frequently bilateral & symmetric 1/1
(t)
• Usually bilaterally symmetric, but o Not a true sacroiliitis, but rather a Co
occasionally one side lags behind the resorptive process \l

(t)
other & they appear asymmetric • Subchondral resorption on the iliac side ~
1/1
o Eventual sclerosis and bilateral fusion • With weight-bearing, resorbed bone
o Spine involvement: Tends to be collapses, resulting in apparent widening
continuous & erosive change
• Thin vertical syndesmophytes lead to o Differentiating features: Look for other
body fusion signs of renal 00 or hyperparathyroidism
• Facets fuse as well, leads to bamboo spine • Abnormal bone density
o Peripheral involvement: Large proximal • Other resorptive patterns: Subperiosteal,
joints (hip, shoulder) subligamentous, Brown tumors
o Watch for signs of IBD
• Staple lines from ileoanal pull-through • Chronic Reactive Arthritis, Late (CRA)
• Colostomy o Spondyloarthropathy in CRA generally
• Signs of steroid use bilateral but asymmetric
• Tubular, featureless bowel pattern of • May appear symmetric, especially in
colitis early or end-stage (bilateral fusion)
• Psoriatic Arthritis, Late (PSA) o Differentiating features of end-stage fused
o Spondyloarthropathy in PSA generally sacroiliitis of CRA from AS
bilateral but asymmetric • Normal bone density
• May appear symmetric, especially in • Character of spine involvement (bulky
early or end-stage (bilateral fusion) paravertebral osteophytes, skip regions)
o Differentiating features of end-stage fused
• Peripheral joint disease favors ankles &
sacroiliitis of PSA from AS feet, rather than large proximal joints
• Normal bone density • Clinical symptoms of urethritis & uveitis
• Character of spine involvement (bulky • Rheumatoid Arthritis (RA)
paravertebral osteophytes, skip regions) o RA relatively frequently affects SI joints
• Peripheral joint disease favors hands, • Erosions, generally bilaterally symmetric
feet, rather than large proximal joints o Though present, erosions generally not
• Skin disease large enough to be observed on imaging
• Renal Osteodystrophy (Mimic) (Renal 00)
Ankylosing Spondylitis (AS) Ankylosing Spondylitis (AS)
AP radiograph shows a "bowl-shaped" pelvis, typical of

advanced A5. Both 51 joints are completely &
AP radiograph shows A5 refatively early in the disease
process. The 51 joints show bilateral and symmetric
I
symmetrically fused •. Note also the prominent widening due Co erosions, as well as bilateral sclerosis
enthesopathy HI & the arthritic changes in the hips. _ Osteoporosis has not yet developed.
317
.>
II)
SACROILIITIS, BILATERAL SYMMETRIC
Qi
a.
"0
Gl
1Il
"'>.
al
Ankylosing Spondylitis (AS) Osteoarthritis (Mimic) (OA)
-"'
E (Left) AP radiograph shows
o bilaterally symmetric
sacroi!iitis which is
c: predominantlyerosive.
< with little productive change
at this point. The hips
bilaterally show minimal
productive change EllI in this
/8 year old male. (Right) AP
involving both sides of the 51
joints, bilaterally symmetric
_ The iliac side is more
prominently involved than
the sacral side. There is no
erosive change; this is
osteoarthritis.

complete & symmetric fusion
in the upper non-synovial
portions of the 51joints 1IlII.
The synovial portions of the
joints are normal ElIltypical
of DISH. Since the synovial
portions are not involved,
this is not a true sacroiliilis.
(Right) Axial bone CT shows
sclerosis of the iliac side of
the 51joints which is
bilaterally symmeTric ElIl The
sacral side is normal, as are
the joints themselves. Since
the joints are normal, this
form of sclerosis is a mimic
rather than a true sacroiliilis.
Inflammatory Bowel Disease Arthritis Inflammatory Bowel Disease Arthritis

(lBD) (IBD)
bilateral & symmetric mixed
erosive and productive
changes at the 51joints
There is no fusion. The left
=
hip shows productive
change" in this young
adult. The appearance is of
either AS or 180; clinical
information proved 180.
bilateral widening of the 51
joints due to erosions, with
minimal associated sclerosis
III. The barium outlines
findings of ulcerative colitis
III this patient has 180
spondyloarthropathy.
I
318
SACROILIITIS, BILATERAL SYMMETRIC :l>
-
::::l
III
o
3
'<
Inflammatory Bowel Disease Arthritis lJl
III
(IBD) Psoriatic Arthritis, Late (PSA) III
(l)
bilateral symmetric mixed

erosive & productive
sacroiliitis _ Staples are
seen outlining an ileoanal
pull-through in this patient
with IBO. Note also the left
hip AVN •• related to
steroid use for the bowel
disease. (RighI) AP
radiograph shows bilaterally
symmetric nearly fused 51
joints. in a patient with
psoriatic arthritis. Although
we generally think of P5A
being asymmetric, in
end-stage disease it will be
symmetric.
Renal Osteodystrophy (Mimic) (Renal Renal Osteodystrophy (Mimic) (Renal

OD) OD)
widened 51joints, bilaterally
symmetric. that could be
mistaken for sacroiliitis.
These are not true erosions
in this patient with renal
osteodystrophy but rather
regions of subchondral
resorption and collapse
along the iliac side. (RighI)
AP radiograph shows
bilateral severe widening of
the 51joints. in a child
with renal osteodystrophy.
This is resorption with
collapse rather than true
erosive disease. Note the
peritoneal dialysis catheter.
Chronic Reactive Arthritis, Late (CRA)

end-stage sacroiliitis with
complete fusion. which is
bilaterally symmetric. The
patient had CRA; earlier
sacroiliitis is usually bilateral
but asymmetric. (RighI) AP
fusion of the 5/ joints. in
end-stage CRA. The patient
also has erosive change in
the left hip ElII; the hip is
usually involved only late in
the process; foot and ankle
involvement is generally
most prominent.
I
319
'"
s SACROILIITIS, BILATERALASYMMETRIC
Q)
0..
"'C
Q) DIFFERENTIAL DIAGNOSIS o Consider sites & appearance of peripheral
II)
1tI
arthropathy in making diagnosis
al Common • Hand> foot; acral> proximal
>- • Psoriatic Arthritis (PSA) • Mixed erosive/productive
•..Eo
1tI
• Osteoarthritis (OA) (Mimic) • Sausage digit & periostitis
c: • Osteoarthritis (OA) (Mimic)
<l: Less Common
• Chronic Reactive Arthritis (CRA) o Not sacroiliitis, but bridging osteophyte is
• Ankylosing Spondylitis (AS) seen
• Inflammatory Bowel Disease (lBD) • Seen as sclerosis, often rounded, more
• Renal Osteodystrophy (Renal OD) (Mimic) often iliac than sacral side of joint
• Most prominent at margins of joint
Rare but Important
• Juvenile Idiopathic Arthritis OIA) Helpful Clues for Less Common Diagnoses
• Gout • Chronic Reactive Arthritis (CRA)
• Rheumatoid Arthritis (RA) o Identical SI joint & spine findings to PSA
o MUCH less frequent than PSA sacroiliitis
o Peripheral involvement: Foot/ankle> hand
ESSENTIAL INFORMATION • Ankylosing Spondylitis (AS)
Key Differential Diagnosis Issues o Generally bilateral symmetric sacroiliitis,
• Bilateral asymmetric sacroiliac (SI) disease but early in disease may be asymmetric
most frequently is seen in PSA & CRA o Osteoporotic; peripheral disease usually
• Other spondyloarthropathies that are has large proximal joints
generally bilaterally asymmetric may be • Inflammatory Bowel Disease (IBD)
asymmetric at some point in the process o Generally bilateral symmetric sacroiliitis,
o Hint: AS is much more prevalent than but early in disease may be asymmetric
either psoriatic or chronic reactive • Renal Osteodystrophy (Renal OD) (Mimic)
spondyloarthritis, so should be strongly o Subchondral resorption & collapse on iliac
considered with this appearance side may be asymmetric
Helpful Clues for Common Diagnoses Helpful Clues for Rare Diagnoses
• Psoriatic Arthritis (PSA) • Juvenile Idiopathic Arthritis (JIA), Gout,
o Spondyloarthritis is most frequently Rheumatoid Arthritis (RA)
bilateral & asymmetric o Involvement of SI joint may not be rare,
o Spine involvement: Bulky asymmetric but is rarely seen with imaging
paravertebral osteophytes, skip areas
Psoriatic Arthritis (PSA) Osteoarthritis (OA) (Mimic)
I AP radiograph shows bilateral erosive/productive

joint disease" that is mildly asymmetric, with greater
51
=-
AP radiograph shows a focal site of sclerosis at the
superior aspect of the right 51joint with minimal
widening on the left than the right. The patient also had sclerosis on the left E£I & normal Sf joints otherwise.
psoriatic arthritic changes in the hands. These represent OA with marginal osteophytes.
320
SACROILIITIS, BilATERAL ASYMMETRIC »
:J
...•
III
o
3
'<
tD
III
Osteoarthritis (OA) (Mimic) Chronic Reactive Arthritis (CRA) VI
(D
(Left) Axial bone CT of the C.
same patient confirms the \J
bridging osteophyte on the <1l
right" and sclerosis of OA 5
VI
on the left HI. These sites of
sclerosis tend to form at the
margins of the 51] and could
mimic spondyloarthropathy.
asymmetric 51 joint disease in
a patient with CRA. The left
joint shows far more erosive
change as well as sclerosis
•. compared with mild
erosion on the right HI.
8i1ate,al asymmetry is typical
ofCRA.
Chronic Reactive Arthritis (CRA) Ankylosing Spondylitis (AS)

bilateral but significantly
asymmetric 51 joint disease in
a patient with CRA. The left
Sf joint shows erosions &
sclerosis" while the right
shows only mild
deossification, or very early
erosions Ell. (Right) AP
erosive & scferotic change in
the left 51joint" and only
minimal deossification on the
right Ell. This patient has
early manifestations of AS;
with early disease, the
usually bilaterality of 51joints
may not be seen.
Renal Osteodystrophy (Renal 00)

Inflammatory Bowel Disease (IBD) (Mimic)
(Leh) AP radiograph in a
patient with 180 shows
bilateral advanced but
asymmetric sacroiliWs, left
Ell less severe than right •.
which is nearly fused. Even
in late disease, symmetry is
not always maintained.
right 51joint widening with
iliac sclerosis" typical of
the subchondral resorption &
collapse seen with renal 00.
The left 51joint shows less
prominent involvement.
Note the vas deferens
calcification" in this
diabetic.
I
321
.!!l SACROILIITIS, UNILATERAL
2:
OJ
Cl..
"tl
Ql DIFFERENTIAL DIAGNOSIS • If chronic, sclerotic reactive changes
VI
ttl
• Abscess in iliopsoas or gluteal muscles
m Common
>. Helpful Clues for Less Common Diagnoses
E • Septic Joint
• Psoriatic Arthritis (PSA), Early
•...ottl Less Common o PSA sacroiliitis is a bilateral & generally
r::
« • Psoriatic Arthritis (PSA), Early asymmetric process
• Ankylosing Spondylitis (AS), Early o Early in process, changes may be so subtle
• Chronic Reactive Arthritis (CRA), Early on one side that the more advanced side
• Osteoarthritis (OA) (Mimic) appears to mimic unilateral disease
Rare but Important o Other findings to help differentiate PSA
• Rheumatoid Arthritis (RA) • Peripheral mixed erosive/productive
• Gout disease in hands & feet; skin changes
• Ankylosing Spondylitis (AS), Early
o AS sacroiliitis is a bilateral & generally
ESSENTIAL INFORMATION symmetric process
Key Differential Diagnosis Issues o Early in process, changes may be so subtle
• Hint: True unilateral sacroiliitis must be on one side that the more advanced side
considered septic joint until proven appears to mimic unilateral disease
otherwise o Other findings to help differentiate AS
o Radiographic signs may be subtle • Large proximal joint arthritis
o Clinical signs may be misleading (buttock, • Chronic Reactive Arthritis (CRA), Early
groin, hip pain) o Like PSA, sacroiliitis is bilateral &
• Hint: Consider diagnosis of septic SI joint in asymmetric, but may appear to be

at-risk patients unilateral early in the process
o HIV-AIDS • Osteoarthritis (OA) (Mimic)
o Diabetic patients o Unilateral sclerosis of productive change
could mimic a unilateral sacroiliitis
• Septic Joint Helpful Clues for Rare Diagnoses
o Earliest changes • Rheumatoid Arthritis (RA)
• Effusion, deossification (lack of o Bilateral erosive disease & rarely visualized
distinctness) of subchondral cortex • Gout
o Later changes o Rare involvement; rarely visualized
• Erosions, widening of joint
I Axial T2WI MR shows fluid in /he right 51 joint III

without evidence of destruction of /he cortices. There is
Axial T2WI MR in /he same patient shows /he ante,ior
fluid collection, as well as extension posteriorly _ This
a fluid collection extending into /he iliacus _ This is a patient had HIV-AID5, making him more susceptible to
septic joint; /he left 51joint is normal. 51joint infection.
322
SACROlllITIS, UNILATERAL
Septic joint
(Leh) Oblique axial T I WI
MR shows low signal
abnormality involving both
sides of the left 51joint •.
Note that the abnormal
signal is centered on the
synovial portion of the joint.
It should not be mistaken for
stress fracture. (Right)
Oblique axial TI C+ F5 MR
high signal, again involving
both sides of the left 51joint
•. There is a small fluid
collection adjacent to the
joint" there is no
diagnosis to consider other
than septic joint.
Septic joint Septic joint

(Left) Axial STIR MR shows
high signal involving the
sacral ala as well as the iliac
wing, with fluid in the 51joint
•. There is a mass
extending from the joint
anteriorly, deviating the
iliacus. which is fluid
signal. (Right) Coronal T2WI
F5 MR in the same patient
confirms the abnormality
centered on the 51joint, with
unilateralsacroiliitis. and
extension of a soft tissue
abscess. This is a septic
hip in an HIV-AI05 patient
who presented with hip
pain.
Psoriatic Arthritis (PSAl, Early Ankylosing Spondylitis (AS), Early

normal left 51joint" but
abnormality on the right
side. There is sclerosis on the
iliac side" without
significant erosive change.
This early & apparently
unilateralsacroiliitis was seen
in a patient with P5A. (Right)
AP radiograph shows normal
width & appearance of the
left 51joint in a 74 year old
• but widening & erosions
on the right Ell This
represents very early and
unilateral sacroiliitis in a
teenager who proved to
have AS.
I
323
en
1: SYMPHYSIS PUBIS WITH PRODUCTIVE CHANGES/FUSION
Q)
0..
"'C
Ql DIFFERENTIAL DIAGNOSIS • DISH
VI
III o Bone proliferation at ligamentous
lD Common insertions
>- • Chronic Repetitive Trauma
E o Flowing ossification of 4 contiguous
-
o
III
c:
<l:
• Post-Traumatic Instability
• Fracture, Malunion (Mimic)
vertebral bodies
o Disc spaces preserved
• Septic Joint
• Osteoarthritis Helpful Clues for Less Common Diagnoses
• DISH • Ankylosing Spondylitis
o Symphysis pubis & sacroiliac joint erosion
• Stress Fracture, Adult (Mimic) leading to fusion
o Proliferative changes predominantly along
• Postpartum
• Post-Operative inferior pubic rami
Less Common o Erosion & sclerosis of symphysis pubis in
• Ankylosing Spondylitis primary hyperparathyroidism; rarely fuses
• Juvenile Idiopathic Arthritis alA) • Psoriatic Arthritis
• Rheumatoid Arthritis o Erosion & sclerosis with asymmetric
• Hyperparathyroidism sacroiliac joint involvement
• Psoriatic Arthritis • Osteitis Pubis, Late
• Osteitis Pubis, Late o End stage - spontaneous arthrodesis
Rare but Important Helpful Clues for Rare Diagnoses
• SAPHO • Complications of Fluoride
• Complications of Fluoride o Diffuse increased bone density
• Ochronosis (Alkaptonuria) o Ligamentous ossification: Paraspinal,
sacrotuberous, & iliolumbar in pelvis
o Bulky spinal osteophytes
Helpful Clues for Common Diagnoses o Symphysis pubis fusion
• Septic Joint o Disc spaces narrowed + marginal vertebral
o Irregular bone destruction body sclerosis
o Sclerosis is sign of healing o Disc calcification progresses to ossification
• Osteoarthritis • Intervertebral bridging can mimic
o Osteophytes & joint space narrowing ankylosing spondylitis
Septic Joint DISH
I Axial NEeT shows significant irregular deSlruction of the

pubic symphysis • CT was performed for biopsy
AnterofX>ster;or radiograph
ligament calcificalion.:I
shows sacrotuberous
as well as enthesopathy of the
guidance, which cultured Staphylococcus. ischial tuberosities Ell and sclerosis of pubic symphysis
III
324
SYMPHYSIS PUBIS WITH PRODUCTIVE CHANGES/FUSION »
:J
..•o
Dl
3
'<
1Il
Dl
tII
Stress Fracture, Adult (Mimic) Ankylosing Spondylitis (1)
(Left) Axial T7 WI MR shows a.
changes typical of -U
nondisplaced insufficiency CO
(ractures in the pelvis. Edema <"
(ji.
and fracture lines are seen
not only in the left pubic
ramus EiII but also in the
right pubic ramus lID. (Right)
shows solid bony fusion of
the symphysis pubis lIlI and
symmetric fusion of the
sacroiliac joints •.
Characteristic enthesopathic
changes are present along
the ischial tuberosities EiII.
Rheumatoid Arthritis Hyperparathyroidism

erosion of the symphysis
pubisllll. Note the typical
appearance of the hipsllll in
rheumatoid arthritis. There
are small erosions and
concentric joint space
narrowing without any
suggestion of productive
change. (Right)
shows that the sacroiliac
joints lID and symphysis
pubis" are fused,
consistent with the patient's
history of secondary
Ochronosis (Alkaptonuria)
radiograph shows irregular
sclerosis and fusion of the
symphysis pubis lIlI. This
reflecls chronic changes
from osteitis pubis. (Right)
shows fusion of the
symphysis pubis lIlI.
Changes in the spine
including disc calcification
and marked disc space
narrowing" along with
large marginal osteophytes,
are typical for ochronosis.
I
325
en SYMPHYSIS PUBIS, WIDENING
~
Q)
0..
"tl
Q) DIFFERENTIAL DIAGNOSIS • Pregnancy
en o Symphysis pubis mobility increases to 8-12
nl
al Common mm during last trimester of pregnancy
>- • Osteitis Pubis
E o Air in symphysis pubis is normal < 24
-
o
nl
c:
«
• Pregnancy
• Trauma, Pelvic Injury
hours postpartum
• Trauma, Pelvic Injury
• Stress Fracture, Malunion o Injury patterns include diastasis, straddle
• Chronic Repetitive Trauma fracture, intraarticular fracture,
• Septic Joint overlapping dislocation, and
less Common fracture-dislocations
• Metastasis, Osteolytic o Diastasis is most common injury
• Radiation Osteonecrosis o Widening> 10 mm in adult males or > 15
• Hyperparathyroidism (Mimic) mm in females, suggests instability
• Ankylosing Spondylitis, Early o Widening> 25 mm suggests associated
• Rheumatoid Arthritis, Early sacroiliac joint injury
• Achondroplasia • Stress Fracture, Malunion
• Chronic Reactive Arthritis o Insufficiency fractures of pubic bone are
more common than overuse stress
Rare but Important
fractures
• Langerhans Cell Histiocytosis o Typically these fractures are not
• Pycnodysostosis immobilized & thus prone to malunion
• Marfan Syndrome • Chronic Repetitive Trauma
• Ehlers-Danlos o Repetitive microtrauma leads to fatigue
• Chondrodysplasia Punctata fracture or ligamentous injury
• Hypophosphatasia o Widening, erosions, & sclerosis
• Prune Belly Syndrome (Eagle-Barrett)
• Septic Joint
• Cleidocranial Dysplasia o Moth-eaten destruction of bone
• Imperforate Anus o Pyogenic infection has rapid destruction
• Bladder Extrophy o Tuberculosis has more indolent course
• Urethral Duplication o Intravenous drug abuse increases risk of
• Hypospadias infection with unusual organisms
• Epispadius
• Spondyloepiphyseal Dysplasia Helpful Clues for less Common Diagnoses
• Dyggve-Melchior-Clausen Syndrome • Metastasis, Osteolytic
o Metastases are the most likely of any
tumor to involve both pubic bones
ESSENTIAL INFORMATION • Radiation Osteonecrosis
Key Differential Diagnosis Issues o Located in distribution of radiation port
• Normal symphysis pubis width varies with o Damage is related to radiation dose
age & gender • Hyperparathyroidism (Mimic)
o 10 mm wide in early childhood o Subchondral bone resorption causing
o 6 mm wide in early adulthood symmetric symphyseal widening
o 3 mm wide in middle to late adulthood o Osteopenia
o Females have greater symphysis mobility o Focal bone lesions in pelvis
than males • Ankylosing Spondylitis, Early
o Symphysis pubis less commonly involved
Helpful Clues for Common Diagnoses than sacroiliac joints
• Osteitis Pubis o Erosive changes early, fusion late
o Mild widening - osteolysis & erosions -
o Proliferative new bone at muscle
sclerosis attachments
o ± Periosteal reaction
• Rheumatoid Arthritis, Early
o Symphysis may fuse late in course
o Marginal erosions & osteopenia
I
326
SYMPHYSIS PUBIS, WIDENING >
.•o
:]
III
• Achondroplasia o Hip dysplasia 3

'<
o Champagne glass pelvis o Urogenital abnormalities [Jl
III
o Square iliac wings • Cleidocranial Dysplasia Ul
<II
o Narrow sciatic notch o Absent or delayed pubic bone ossification C.
-0
• Chronic Reactive Arthritis o Hypoplastic iliac wings <l>
o Erosions produce widening o Coxa vara or valga ~
Ul
o Other midline structure dysplasia:
Cranium, mandible, teeth, clavicles, neural
arches
o Well-defined border of lytic lesions
• Imperforate Anus
• Pycnodysostosis
o Widened symphysis
o Narrow ilia
• Bladder Extrophy
o Wide cranial sutures
o Pubic bones completely separated
o Generalized osteosclerosis
• Absent symphysis
o Distal phalangeal aplasia or resorption
o Laterally flared innominate bones
• Marfan Syndrome
• Posterolateral facing acetabula
o Protrusio acetabuli
o Midline anterior soft tissues unfused
o Kyphoscoliosis + spondylolisthesis
o Bladder mucosa exposed
o Sacral abnormalities
• Urethral Duplication
• Ehlers-Danlos
o Widened or completely separated pubis
o Pubic symphysis distraction during birth
o Heterotopic bone around hips
• Hypospadias
o Widened or completely separated pubis
o Lumbar platyspondyly
• Spondyloepiphyseal Dysplasia
• Chondrodysplasia Punctata
o Small iliac wings
o Punctate calcifications of epiphyses &
o Hypoplastic acetabular roof
spine
o Epiphyseal ossification delay
o Vertebral coronal clefts
• Dyggve-Melchior-Clausen Syndrome
o Shortened limbs
o Small iliac wings with lacy calcification of
iliac crests
o Skeletal ossification delay
o Wide public ramus & ischiopubic
o Thoracolumbar vertebral wedging
synchondrosis
• Prune Belly Syndrome (Eagle-Barrett)
o Wide sacroiliac joints
o Absent abdominal musculature
o Flat acetabular roof
o Flared iliac wings
Osteitis Pubis
Ant~roposterior radiograph shows a wide symphysis

pubiS • with iI/-defined borders. Note the marked
Anteroposterior radiograph shows a wide symphysis
pubis E!ll inferior displacement of the right hemipelvis
I
sclerosis IIIinvolving each side of the pubic bone. IIlIIl and widening of the right sacroiliac joint •.
327
(/)
"> SYMPHYSIS PUBIS, WIDENING

Qi
Cl.
'tl
Ql
(/)
to
!Xl
>- Stress Fracture, Malunion
E (Left) Radiograph outlet view
-o
to
c:
<l:
shows anterior to posterior
displacement through the
pelvic ring. The right
hemipelvis ;s minimally
displaced anteriorly HI and
the pubic symphysis is
widened ffi The outlet view
nicely demonstrates the
anterior sacroiliac joint
widening 11II and the normal
posterior aspect of the joint
11II. (Right) Anteroposterior
of the symphysis pubis 11II
due to malunion of a left
pubic bone stress
finsufficiency) fracture 11II.
Septic Joint Septic Joint

shows enhancement within
the osseous structures on
symphysis =-
both sides of the pubic
representing
osteomyelitis. There is also a
collection of fluid within the
widened symphysis HI
representing a septic joint.
(RighI) Axial NECT shows
gross destruction of the
symphysis pubis 11II giving it
a widened appearance, with
osseous destruction of both
the superior and inferior
pubic rami. CT was used for
needle aspiration guidance.
Metastasis, Osteolytic Ankylosing Spondylitis, Early

metastatic prostate
carcinoma foci in the right
pubic ramus" and left hip
611. These were osteolytic on
radiographs and caused a
widened appearance of the
symphysis pubis due to
adjacent bone destruction.
radiograph shows loss of
cortical definition and
mature enthesopathy
involving the ischial
tuberosities" Erosive
changes are mildly widening
the symphysis pubis 11II.
I
328
SYMPHYSIS PUBIS, WIDENING »
-
:l
III
o
3
'<
lJl
III
III
langerhans Cell Histiocytosis C1l
(Left) Anteroposterior c..
radiograph shows irregular -U
destruction of the leFtpubic (\)
bone. giving the <"

iii'
symphysis a widened
appearance. Bone
destruction extends into the
leFtsuperior pubic ramus •.
This child also had lytic skull
lesions. (Right)
demonstrates significantly
soFtened bones, showing
severe osteoporosis,
symphysis pubis diastasis ••
protrusio of the hips" and
bowing of the long bones E!lI
with fractures.
Cleidocranial Dysplasia Imperforate Anus

radiograph shows a midline
deFect at the pubic
symphysis III. The presence
of additional midline deFects
suggests cleidocranial
dysplasia (or dysostosis).
high-pressure colostogram
was performed to evaluate
imperforate anus and rectal
fistula prior to definitive
repair. /t shows (illing of the
distal rectal segment. From
the mucous fistula of the
c%stomy. A mildly widened
symphysis pubis" is a
common finding.
Imperforate Anus Spondyloepiphyseal Dysplasia

radiograph obtained in an
infant with imperforate anus
diagnosed at birth shows a
widened symphysis pubis III
and mildly dysmorphic
sacrum •. (Right)
shows a widened symphysis
pubis'" The epiphyses are
irregular and flattened •.
The spine was more
obviously abnormal, with
diffuse mild Flattening of the
vertebral bodies. The
combination of Findings
suggests spondyloepiphyseal
dysplasia.
I
329
.!!?
.2:
SUPRA-ACETABULARILIAC DESTRUCTION
Q)
a..
"0
ell DIFFERENTIAL DIAGNOSIS • Arthroplasty Loosening & Dislocation
III
<ll
o Lucency greater than 2 mm at the
aJ Common cement-bone or prosthesis-bone interface
>. • Subchondral Cyst
E of acetabular component of total hip
•..
o
<ll
• Metastases, Bone Marrow replacement
C • Arthroplasty Loosening & Dislocation o Evaluate multiple projections to assess for
<t
• Arthroplasty Component Wear/Particle component malposition or dislocation
Disease • Arthroplasty Component Wear/Particle
• Multiple Myeloma Disease
• Plasmacytoma o Polyethylene wear evident by progressive
• Osteomyelitis, Adult eccentric location of femoral component
• Radiation Osteonecrosis within the acetabular component
• Paget Disease o Periprosthetic lucency, as described above
• Ewing Sarcoma • Multiple Myeloma
Less Common o Multiple sharply demarcated lytic lesions
• Aneurysmal Bone Cyst o Intramedullary with endosteal scalloping
• Osteosarcoma o Lacks periosteal new bone formation
• Chondroblastoma o ± Soft tissue mass
• Hyperparathyroidism o Spine> ribs> femur> pelvis
• Fibrous Dysplasia • Plasmacytoma
• Fibrosarcoma o Solitary focus of myeloma
• Lymphoma o Larger & more expansile lesion than
• Angiosarcoma, Osseous multiple myeloma
• Hemophilia, Pseudotumor • Osteomyelitis, Adult
• Chondromyxoid Fibroma o Permeative bone destruction
• Giant Cell Tumor o Periosteal new bone
o Soft tissue abscess
Rare but Important
o Late surrounding sclerosis + sequestrum
• Syphilis, Secondary or Tertiary o More rapid bone destruction than tumor,
• Hemangiopericytoma, Osseous except for Langerhans cell histiocytosis
• Gaucher Disease • Radiation Osteonecrosis
o Ill-defined bone destruction ± fracture
ESSENTIAL INFORMATION o Lacks a soft tissue mass
o Latent period of at least one year before
Helpful Clues for Common Diagnoses bone changes are seen in pelvis
• Subchondral Cyst • Paget Disease
o Well-defined lytic lesion, often with
o Well-defined lytic lesions in active stage
sclerotic border o Enlarged bone with coarse trabeculae
o Most common cause is osteoarthritis
o Thickened iliopectineal line
• Associated findings of joint space o Acetabular protrusio
narrowing & osteophytes o Polyostotic in 70%
o Numerous less common causes include
o Pelvis> spine> skull
gout, PVNS, synovial • Ewing Sarcoma
osteochondromatosis, inflammatory o Osteolysis, cortical destruction, periosteal
arthropathy, & seronegative reaction, & soft tissue mass
spondyloarthropathy • Can mimic osteomyelitis
• Metastases, Bone Marrow o Aggressive periosteal new bone
o Well-defined lytic to ill-defined,
• Laminated, onion skin, sunburst, or "hair
permeative lesions on end"
o Breast, lung, & renal carcinoma metastases
o Lower skeletal involvement in 2/3 of cases
common • Femur> ilium> tibia
o Multiple lesions are usually evident
I
330
SUPRA-ACETABULARILIAC DESTRUCTION ~
::l
• Hemophilia, Pseudotumor
-
III
o
3
Helpful Clues for Less Common Diagnoses '<
o lntraosseous and subperiosteal bleeds lJl
• Aneurysmal Bone Cyst III
produce pressure erosion of bone (fl
nl
o Well-defined osteolysis with bone
o Soft tissue mass may extend into the Q.
expansion -u
iliopsoas and gluteal muscles
o Internal fluid-fluid levels <1l
:;:-
o ± Surrounding bone sclerosis
• Giant Cell Tumor (ii'
o Lytic metaphyseal lesion without sclerotic
• Osteosarcoma
border
o Mixed osteolytic & osteosclerotic lesion
• Bones around the acetabulum are
depending on subtype
metaphyseal and epiphyseal equivalents
o Aggressive periosteal reaction
o Cortical violation with soft tissue mass Helpful Clues for Rare Diagnoses
o Osteoid matrix present • Syphilis, Secondary or Tertiary
• Chondroblastoma o Secondary syphilis - irregular bone lysis
o Located around acetabulum in pelvis • Skull involvement is characteristic
• Epiphyseal equivalent o Tertiary syphilis - neuropathic changes
o Well-defined round to oval lytic lesion o Periostitis is common
with thin sclerotic rim • Hemangiopericytoma, Osseous
o Periosteal reaction in adjacent metaphysis o Lobulated lytic foci with honeycomb
or diaphysis appearance
• Hyperparathyroidism o Mild bone expansion
o Brown tumors in primary or secondary o Aggressive features include soft tissue
hyperparathyroidism mass, cortical destruction, ill-defined
o Well-defined lytic lesion ± bone expansion borders
o May undergo necrosis, producing a cyst o 10% of cases in innominate bone
• Fibrous Dysplasia • Gaucher Disease
o Hazy radiolucent, or ground-glass, lesions o Younger patients with generalized
± mild bone expansion osteopenia
o Usually polyostotic when pelvis is o Marrow infiltration causing cortical
involved scalloping can mimic metastasis, myeloma,
o Protrusio acetabula present or pseudotumor of hemophilia
• Lymphoma o Additional findings of abdominal
o Cancellous bone erosion early organomegaly, "H-shaped" vertebral
o Cortex destroyed late bodies, & femoral head avascular necrosis
Anteroposterior radiograph shows a large subchondral

cyst 11I:I present within the superior aspect of the
non-aggressive acetabular lesion =
shows a fairly
that distorts the
I
acetabulum. Note the joint space narrowing 1!IlI. normal trabecular pattern. This was a solitary breast
metastasis.
331
III
.S; SUPRA-ACETABULAR ILIAC DESTRUCTION
Qi
Cl.
"tl
Q)
III
'"
1Il
Disease
>.
E (Left) Coronal bone CT
-'"
o
c
<l:
shows acetabular lysis •.
Note that the distance
between the femoral head
and acetabular rim is less on
the superolateral side III
than the inferomedial side
Ell indicating wear of the
polyethylene liner. (Right)
Coronal TI WI MR shows the
multifocal presentation of
myeloma as hypoinlense
deposits" adjacent to the
normal bone marrow. This
has the appearance of
multiple "punched out" lytic
lesions on radiographs,
typical of myeloma.
radiograph shows a
well-defined, lytic bubbly
lesion III that occupies the
superior pubic ramus and
extends well into the
acetabulum. The lesion is
mildly expansile. This is a
plasmacytoma. (Right)
Coronal T1WI MR
demonstrates the extent of
the right hip infection •.
which destroys both
acetabular and femoral
bone. Antibiotic beads III
and surrounding 50ft tissue
edema EEl are also evident.
Paget Disease
overgrowth and trabecular
thickening of the pelvis and
femurs. The bones have a
mixed sclerotic and lytic III
appearance. Protrusio at the
hips III and femoral
deformity reflect bone
softening. (Right) Coronal
T2WI MR shows an
expansile lesion" involving
the superomedial
acetabulum. Multiple
loeulations contain fluid
intensity materiat and
fluid-fluid levels were seen
on axial images.
I
332
SUPRA-ACETABULAR ILIAC DESTRUCTION l>
-
~
'o"
3
'<
III
Osteosarcoma Hyperparathyroidism '"
III
(I)
radiograph shows a mixed -U
osteosclerotic and osteolytic CO
lesion" in the S.
(f)
supra-acetabular region.
There is an associated large
soft tissue mass lID that
contains osteoid matrix.
radiograph shows a
supra-acetabular lytic lesion
with indistinct borders.
and a similar femoral HI
lesion. The combination of
multiple lytic lesions with
cortical and trabecular
indistinctness is lypical of
Brown tumors.
Fibrosarcoma
lobulated lesion =
radiograph shows a large,
with a
scferotic border in the
supra-acetabular region. This
lesion has a faint
ground-glass appearance. A
similar lesion in the proximal
FemurlID produces a
shepherd's crook deformity.
radiograph shows severe and
rapid progression of bone
destruction" with an
obvious sort tissue mass
as well as pathologic
-=
fracture. This case is classic
for fibrosarcoma.
Lymphoma Giant Cell Tumor

highly permeative, inFiltrating
lesion involving the superior
acetabulum. and
extending into both the
superior pubic ramus lID and
ischium HI. This is a highly
aggressive lesion. (t MSK
radiograph shows an
extremely expansile lesion
• involving the leFt
acetabulum, inferior pubic
ramus, and ischium. There is
a narrow zone of transition.
Despite the degree of
expansion it does not appear
aggressive.
I
333
£
.gl
PROTRUSIO ACETABULI
£
I-
-0
C
DIFFERENTIAL DIAGNOSIS • Protrusio is more frequent in RA, but OA
ro
a. is so much more common than RA that,
I Common in absolute numbers, protrusio is more
"C
Q)
• Arthritis common in OA
VI
III
o Osteoarthritis • Axial or medial femoral head migration,
aJ o Rheumatoid Arthritis, Hip
>- joint space narrowing
E o Ankylosing Spondylitis • Normal mineralization; osteophytes
•...o
III
o Juvenile Idiopathic Arthritis alA) • May be asymmetric, unilateral
C
o Crystalline Arthropathy
« o Rheumatoid Arthritis, Hip
• Trauma .• Osteopenia, erosions of femoral head &
• Paget Disease acetabulum
Less Common • Axial femoral head migration; bilateral &
• Renal Osteodystrophy symmetrical joint space loss
• Septic Joint o Ankylosing Spondylitis
• Osseous Neoplasm • Axial femoral head migration with
uniform, symmetric joint space loss;
Rare but Important
femoral neck ring osteophytes
• Hint: Look at adjacent sacroiliac joints
• Otto Disease for erosion or fusion
o Juvenile Idiopathic Arthritis OIA)
• Osteomalacia
• Due to erosions & mechanical
• Rickets
remodeling from compressive forces
• Idiopathic Chondrolysis
• Periarticular osteopenia
o Crystalline Arthropathy
• Collagen Vascular Disorders
• Pyrophosphate arthropathy: Axial
• Osteogenesis Imperfecta
femoral head migration, osteophytes
• Hint: Look for rapid fragmentation &
destruction of both femoral head &
ESSENTIAL INFORMATION acetabulum with resultant protrusio
Key Differential Diagnosis Issues • Trauma
o Protrusio may result from
• Acetabular protrusion = intrapelvic bulging
• Acute trauma: Periacetabular fracture,
of acetabular wall, ± joint space loss
particularly quadrilateral plate
o Diagnosis of dramatic contour
• Late complications: Malalignment at
abnormalities (acetabular wall/femoral
time of healing; secondary osteoarthritis
head protruding into pelvis) are not
difficult • Post-operative complications: Hardware
failure due to loosening, infection, etc.
o Diagnosis of subtle or early changes may
o Underlying osteoporosis increases risk of
be challenging
protrusio development
o Hint: Acetabular line projecting medial to
• Paget Disease
ilioischialline is most reliable sign
o Patchy lytic, sclerotic pattern with relative
• Adults: Male> 3 mm; female> 6 mm
overgrowth of involved bone
• Children: Male> 1 mm; female> 3 mm
o Osteoarthritis changes with medial/axial
o Hint: Other methods are less accurate in
joint space loss & axial femoral head
evaluating subtle protrusio including
migration
center edge angle of Wiberg> 4S 0,
o Protrusio may result from inherently
teardrop "crossing"
weakened acetabular bone or associated
Helpful Clues for Common Diagnoses osteoarthritis
• Arthritis o Hint: Look for trabecular thickening,
o Osteoarthritis particularly along iliopectineal line
• Most common cause of protrusio
I
334
PROTRUSIO ACETABULI »
:J
..•o
III
o May be 1 due to adenoma, etc., or 2 due

0 0
3
Helpful Clues for Less Common Diagnoses '<
to renal failure CD
• Renal Osteodystrophy III
o Bone resorption is hallmark of disease III
o Osteomalacia combined with n>
o Diffuse osteopenia, Brown tumors, soft a.
hyperparathyroidism in chronic renal
tissue calcification I
-0'
failure
o Osteopenia with extensive bone resorption
• Osteomalacia III
:J
o Vitamin D production failure = 0.
o Soft tissue calcification, osteosclerosis, -I
periostitis, Brown tumors
osteomalacia =r
to'
o Rickets: Osteomalacia in child =r
• Septic Joint o Osteopenia with coarsened & indistinct
o Results in cartilage destruction; ±
trabeculae, Looser zones, acetabular
osteomyelitis with acetabular remodeling
remodeling
or destruction
• Idiopathic Chondrolysis
o Unilateral, rapid onset destruction;
o Monoarticular; acute onset occurring in
requires aspiration for diagnosis
adolescent females; no history of trauma
• Osseous Neoplasm
o Rapid cartilage loss/joint space narrowing
o Metastases & myeloma most common
with subchondral erosion, osteoporosis
o Replacement/destruction of quadrilateral
o Mimics inflammatory arthritis, septic
plate leads to protrusio
arthritis; requires aspiration to exclude
o Protrusio may be late complication of
infection
pelvic radiation therapy & osteonecrosis
Helpful Clues for Rare Diagnoses o Defective bone mineralization similar to
• Sickle Cell Anemia osteomalacia
o Marrow hyperplasia may contribute to o Protrusio due to abnormal bone; ±
bone weakness & remodeling from associated pyrophosphate arthropathy
compressive forces across hip • Collagen Vascular Disorders
• Otto Disease o Marfan syndrome, Ehlers-Danlos
o Primary protrusio acetabuli • Osteogenesis Imperfecta
o Due to abnormal triradiate cartilage o Defective collagen matrix synthesis &
development mineralization
o Familial; female> male • Fibrous Dysplasia
o Bilateral, symmetric, normal joint space in o Lytic expansile lesion(s) with ground-glass
early stages progressing to osteoarthritis matrix; abnormally weak bone allows
• Hyperparathyroidism deformity with weight-bearing
Anteroposterior radiograph shows acetabular medial

wall HI projecting> 3 mm
medial to ilioischialline IIlI
Anteroposterior radiograph shows prolrusio HI due to
osteoarthritis with medial femoral head migration & joint
I
in this male with mild secondary OA due to trauma. space loss 1IlI. Acetabular & femoral osteophytes lID
Note heterotopic ossification near acetabular rim III. are seen with subchondral sclerosis~.
335
.r:
.!2> PROTRUSIO ACETABULI
.r:
t-
1:)
c
Ol
0.
J:
Rheumatoid Arthritis, Hip Ankylosing Spondylitis
"tl
ell (Leh) Anleroposterior
VI radiograph shows
'"
aJ rheumatoid arthritis with
>- bilateral, symmetric joint
E narrowing III & axial femoral
-'"
o
c
<l:
head migration with small
erosions but no osteophytes.
Note diffuse osteopenia &
mild protrusio EilI. (Right)
shows bilateral hip joint
space narrowing & erosion
III with protrusio acetabuli
on the right EilI. The bilateral
sacroiliac fusion ~ confirms
ankylosing spondylitis.
Juvenile Idiopathic Arthritis OIA) Trauma

radiograph shows classic j/A
in a 22 yo Female with severe
bilateral femoral head
erosion 11:I as well as erosive
acetabular remodeling,
protrusio El!l & diffuse
osteopenia. (Right) Axial
NEeT shows left hip
prolrusio from a
comminuted acetabular
fracture ~ The right hip
demonstrates a mild
protrusio EilI from
osteoarthritis, characterized
by joint space narrowing,
subchondral cysts" &
osteophytic ridging III.
Trauma
radiograph shows secondary
osteoarthritis. & protrusio
HI from comminuted
acetabular fracture treated
with multiple plates & screws
that are loose, with screws
III projecting into the pelvic
soft tissues. (Right)
shows Paget disease with
marked thickening of cortical
& trabecular bone. as well
as disuse osteoporosis,
Despite the apparenl
thickening, the bone is weak
& protrusio EilI results.
I
JJ6
:>
PROTRUSIO ACETABULI
..
:l
III
o
3
'<
OJ
III
VI
Renal Osteodystrophy to
(Left) Posteroanterior a.
radiograph shows residua I
from renal osteodystrophy
with bone resorption of 2° "::J
Q)
hyperparathyroidism & a.
osteomalacia resulting in a -I
::r
shepherd crook deformity
<0
IllIl & protrusio ElII. (Right) ::r
Coronal reformation NECT
shows extensive (emoral
head. & acetabular
destruction E±I with a large
joint effusion ail & protrusio
ElII in this patient with septic
arthritis/osteomyelitis.
Osseous Neoplasm Otto Disease

radiograph shows protrusio
HI due to metastasis from
lung adenocarcinoma. Note
the permeative lytic
acetabular lesion =:I while
the femoral head is normal.
protrusio ElII of Otto disease
in this young woman whose
mother had similar signs &
symptoms at age 41.
Secondary osteoarthritis
often develops over time, but
the primary failure is in
triradiate cartilage
development.
osteopenia, protrusio •. &
disordered bone formation.
There is widening of the
zone of provisional
ossification at the femoral
head metaphysis. (Right)
shows diffuse expansile lytic
lesions. throughout pelvis
& femora with ground-glass
matrix typical of fibrous
dysplasia with marked
deformity of femoral necks &
bilateral protrusio EiIl
I
337
.c
.Ql COXA MAGNA DEFORMITY
.c
r-
"0
c DIFFERENTIAL DIAGNOSIS • Subtle DDH does not show coxa magna,
CIl
a. but seen as ~ center-edge angle of Wiberg
I Common o Hint: Shallow acetabulum distinguishes
"tl
(l)
• Developmental Dysplasia Hip (DDH) coxa magna of DDH from other etiologies
III
CIl
al
less Common of coxa magna
>. • Slipped Capital Femoral Epiphysis (SCFE) Helpful Clues for less Common Diagnoses
-
«
E
o
CIl
c
Rare but Important
• Septic Hip
• Slipped Capital Femoral Epiphysis (SCFE)
o Femoral capital epiphysis slips medially &
posteriorly
• Hip/Femur Trauma • As head slips, appears short & broad, on
a short & broad neck
o Most frequently occurs 8-14 years of age
ESSENTIAL INFORMATION o Hint: Position of femoral head on neck &
Key Differential Diagnosis Issues a normal acetabulum distinguish coxa
• Coxa magna: Short broad femoral head magna of SCFE from other etiologies
sitting on a short broad femoral neck • Legg-Calve-Perthes (LCP)
o Results in limb length discrepancy o Avascular necrosis femoral head in a child,
o Relatively proximal displacement of generally 4-8 years of age
greater & lesser trochanters o Flattening of head leads to coxa magna
• Coxa magna is secondary to an insult to deformity
femoral head or epiphysis o Hint: Head remains centered on femoral
neck & acetabulum is normal,
distinguishing this etiology of coxa magna
• Developmental Dysplasia Hip (DDH) from others
o Lack of coverage of femoral head during
development due to deficient acetabulum Helpful Clues for Rare Diagnoses
o Without coverage, head cannot develop • Septic Hip
spherical shape o Chronic hip infection during childhood
• Head becomes short, broad • Hyperemia results in overgrowth of
• With head & neck shortening, limb femoral head & neck
becomes short, with proximal • Hip/Femur Trauma
displacement of both trochanters o Resorption/impaction of neck or
o Congenital abnormality malalignment mimics coxa magna
• Severe DDH develops coxa magna o Salter fracture with early fusion
Developmental Dysplasia Hip (DDH) Slipped Capital Femoral Epiphysis (SCFE)
I AP radiograph shows right DOH. Note short broad

head. & neck, compared with normal left side. Coxa
AP radiograph shows SCFE, with medial & posterior
femoral head slip _ This results in the appearance of a
magna is due to DOH, with shallow acetabulum seen short broad femoral head; the neck also appears broad.
_ resulting in decrease in femoral head coverage. Note the lateral femoral neck is not covered by head.
338
COXA MAGNA DEFORMITY >
..•o
j
III
3
'<
[II
III

'a."
CIl
(Iattened & dense femoral I

capital epiphysis typical of 1:)
LCP. This is already chronic Ql
;:)
disease, & morphologic a.
change of short broad head -l
& neck is seen in its early
::T
to
form. (tMSK Req). (Right) ::T
AP radiograph in same
patient 12 years later shows
typical coxa magna
deformity. Head is not
medially displaced to suggest
SCFf, & acetabulum is
normal, ruling out DOH.
Even without prior X-ray, this
should be diagnosed as coxa
magna due to LCP.
Legg-Calve-Perthes (LCP) Septic Hip

(Leh) Coronal T2WI FS MR
shows old LCp, with the
short broad femoral head"
on a shortened femoral neck,
resulting in a coxa magna
deformity. This has resulted
in a significant labral tear HI
& early arthritic change.
radiograph shows an
enlarged, short femoral
capital femoral epiphysis
with broadening & slight
=-
shortening of the femoral
neck. This 12 year old had a
septic hip treated 9 months
earlier. The growth deformity
results from hyperemia.
Hip/Femur Trauma Hip/Femur Trauma

an old subcapital fracrure
treated with pins. The
fracture has impacted, with
resorption of much of the
neck. & backing out of
the pins •. This results in
the appearance of a short
femoral head on a short
broad neck, similar to a coxa
magna deformity. (Right) AP
radiograph shows enlarged
femoral head with early
fusion. & subsequent limb
shortening in a teenager. This
coxa magna deformity
resulted from Saller II
fracture.
I
339
.r::c
.Q>
HIP lABRAl TEARS, ETIOLOGY
.r::c
I-
-0
C
ro DIFFERENTIAL DIAGNOSIS • DDH results in several abnormalities that
Q. can result in impingement & subsequent
I Common labral tears
-0
(I)
• Degenerative o Hint: DDH morphologic abnormalities can
/J)
o Osteoarthritis (OA) be very subtle, and must be carefully
'"
CO • Femoral Acetabular Impingement, sought out
>-
-E
o
«'"
c
CAM-Type
o Lateral Femoral Neck "Bump"
o Elliptical Femoral Head Morphology
• May make diagnosis on routine MR, but MR
arthrograph increases specificity &
confidence
• Femoral Acetabular Impingement, o Consider traction on hip during
Pincer-Type arthrography to better visualize cartilage
o Retroverted Acetabulum • Note that different morphologic
• Hip Dysplasia (DDH) abnormalities resulting in CAM or pincer
o Acetabular Dysplasia FAlor DDH may be more or less common;
o Coxa Valga hence, examples of FAI and DDH are found
Less Common in "common", "less common", and "rare" lists
• Femoral Acetabular Impingement, Helpful Clues for Common Diagnoses
CAM-Type • Osteoarthritis (OA)
o Slipped Femoral Capital Epiphysis (SCFE) o OA is most common abnormality of hip
o Legg-Perthes, Coxa Magna o Cartilage damage in weight-bearing region
o Femoral Neck Fracture, Malunited o Advanced disease usually results in
• Femoral Acetabular Impingement, superolateral subluxation of femoral head
Pincer-Type • Shear stress may result in labral tear
o Hip Protrusio, Secondary o Though labral & cartilage damage are
o Otto Disease common, advanced imaging generally not
o Ossification of Acetabular Rim utilized for OA
o Overcorrection Osteotomy for DDH • Salvage or arthroplasty situation rather
Rare but Important than surgical reconstruction
• Hip Dysplasia • Lateral Femoral Neck "Bump"
o Reduced Femoral Anteversion o Etiology of the bump unknown
o ! Cutback at femoral head/neck junction
o Conflict between bump & labrum when
ESSENTIAL INFORMATION hip in flexion, internal rotation,
Key Differential Diagnosis Issues adduction: "Cam" mechanism of FAI
• Labral tears likely are common in OA, but o Cartilage damage earlier than labrum
are rarely specifically imaged o Labral injury is often detachment
• Cartilage damage is as important as labral • Elliptical Femoral Head Morphology
damage, but more difficult to accurately o Functions the same as the lateral femoral
diagnose neck bump
• Femoral acetabular impingement (FAI) is an • ! Cutback at femoral head/neck junction
important etiology of labral tears • "Cam" mechanism of FAI
o Hint: Important to diagnose morphologic • Retroverted Acetabulum
abnormalities early in order to avoid early o Acetabulum is generally anteverted
damage and development of osteoarthritis o Usually only the cranial portion is
at a young age retroverted in FAI
• Impingement has been separated into "cain" • Seen as crossover sign of anterior rim
and "pincer" types, based on different hip overlapping posterior rim on X-ray
morphologies & etiologies • Directly visualized on axial MR or CT
o Hint: There is often overlap between "cam" o - Focal acetabular rim overcoverage
and "pincer" types, with contributions of • "Pincer" mechanism of FAI

both in an individual • Labral tear> detachment
I
340
HIP LABRAL TEARS, ETIOLOGY »
:J
...•
III
o
• Acetabular Dysplasia o Impaction of femoral neck fx may shorten 3
'<
o Acetabular coverage of head may be neck & I femoral head/neck cutback OJ
III
deficient either laterally or anteriorly a May result in "cam" type of FAI
• Abnormal lateral coverage if center-edge • Hip Protrusio, Secondary
'0-"
en
angle of Wiberg < 25° o Many secondary causes of hip protrusio I

"0
• Abnormal anterior coverage seen on false • Rheumatoid arthritis, Paget disease, or OJ
:J
profile view; vertical-center angle < 25° renal osteodystrophy C.
-1
o DDH also frequently has cranial acetabular • Acetabular fx that heals in protrusio ::r
US·
retroversion o ~ Relative over-coverage by acetabular rim ::r
o Labrum frequently hypertrophied • "Pincer" type of FAI
• Shear stress on hypertrophied labrum • Otto Disease
makes it at high risk for tear o Hereditary type of OA, resulting from
o Watch for morphologic changes from abnormal fusion of triradiate cartilage
childhood acetabular surgery o Primary protrusio of hip ~ relative
• Gives hint of diagnosis overcoverage of head by acetabular rim
• May have overcoverage anteriorly • "Pincer" type of FAI
• Coxa Valga • Ossification of Acetabular Rim
o Form of DDH with decreased femoral o Anterosuperior acetabular rim may become
neck/shaft angle overgrown & hyperossified
o Associated with pulvinar hypertrophy & o ~ Relative overcoverage of femoral head
labral tear • "Pincer" type of FAI
Helpful Clues for Less Common Diagnoses • Overcorrection Osteotomy for DDH
o Periacetabular osteotomy to improve
• Slipped Femoral Capital Epiphysis (SCFE)
o SCFE: Head slips medially & posteriorly
femoral head coverage in DDH may result
o ~ Coxa magna deformity with decreased a
in overcoverage, especially anteriorly
angle & femoral head/neck offset • Iatrogenic acetabular retroversion
o Acts as a "cam" type of FAI, with same
• "Pincer" type of FAI
association of labral & cartilage injury Helpful Clues for Rare Diagnoses
• Legg-Perthes, Coxa Magna • Reduced Femoral Anteversion
o Short broad femoral head & neck resulting o Femoral head/neck is generally anteverted
from childhood AVN ~ "cam" type of FAI o If retroverted, increased shear stress on
• Femoral Neck Fracture, Malunited posterior labrum, increasing risk for tear
lateral Femoral Neck "Bump"
=.
Coronal T1WI F5 MR arthrogram shows osteoarthritis
with osteophytes lit cartilage loss and a detached
AP radiograph shows a lateral remoral neck "bump" =
causing cam type impingement; note the lack or normal
I
labrum 11II. OA is the most common etiology or cutback at the remoral head/neck junction. This is the
cartilage & labral damage but is rarely imaged with MR. most common type or remoral acetabular impingement.
341
.<::
.Ql HIP LABRAL TEARS, ETIOLOGY
.<::
I-
"0
C
'a" .
I
Elliptical Femoral Head Morphology
1:l (Left) AP radiograph shows
Ql
VI an elliptical morphology of
CIl
lJl the femoral head, with small
>- lateral femoral neck bump
..
E
o
CIl
C
_ There is no femoral
head/neck cutback. This
appearance has been likened
< to a pistol, also called pistol
grip deformity. (Right)
Coronal TlWI FS MR
patient shows the elliptical
head morphology, along
with a complex labral tear
=. This was a young adult
with early onset of hip pain
related to femoral acetabular
impingement

acetabular retroversion. The
anterior acetabular rim =
crosses over the posterior rim
•• superiorly (crossover
sign). This results in focal
relative overcoverage by the
anterosuperior acetabular
rim which contributes to the
pincer type of femoral
acetabular impingement.
(Right) Axial TI WI FS MR
arthrogram on the same
patient shows the
retroversion of the anterior
acetabularrim. relativeto
the posterior E!!l confirming
the retroverted acetabulum.
Retroverted Acetabulum Acetabular Dysplasia

(Left) Sagittal TI WI FS MR
patient shows the large labral
tear. associated with the
acetabular retroversion &
subsequent femoral
acetabular impingement.
radiograph shows a normal
right hip but shallow
acetabulum on the left. The
center·edge angle of Wiberg
on the left is less than 25°,
indicating acetabular
dysplasia. With this
abnormality, the labrum
becomes hypertrophied and
is at significant risk for tear.
I
342
HIP LABRAL TEARS, ETIOLOGY »
:J
...•
Ql
o
3
'<
lD
Ql
t/l
Acetabular Dysplasia Acetabular Dysplasia <l>
(Left) Coronal T1 WI FS MR a.
arthrogram of the same I
patient shows the shallow
acetabulum. that does not ":J
OJ
cover the femoral head. The a.
labrum is hypertrophied, and -i
there is an extensive lear ••.
::T
<6.
which continued over a ::T
significant distance. (Right)
Axial TlWI FS MR
arthrogram of the same
patient shows a
hypertrophied ligamentum
teres •. This and a
hypertrophied pulvinar
occupy medial joint space in
patients with DOH.
Slipped Femoral Capital Epiphysis (SCFEl

straightening of the femoral
neck, termed coxa valga.
There is no acetabular
dysplasia, but coxa valga is a
form of DOH. It may result
in femoral acetabular
impingement and
labral/cartilage damage.
an old SCFE,pinned during
childhood. The medial slip of
the femoral head results in
lack of normal femoral
head/neck cutback" or a
form of femoral neck bump.
This results in cam-type FAI.
legg-Perthes, Coxa Magna Femoral Neck Fracture, Malunited

shows a coxa magna
deformity Ell with normal
acetabular coverage and no
evidence of SCFE. This
deformed head & neck is
due to Legg-perthes, and
puts the labrum at risk for a
cam-type of impingement
and tear" (RighI) AP
radiograph shows subcapital
fracture which was pinned
but impacted, developing a
varus deformity. This results
in lack of femoral head/neck
cutback & lateral bump III.
This alignment may result in
cam-type FAI.
I
343
.c HIP LABRAL TEARS, ETIOLOGY
.~
.c
I-
"0
c::
ro
a.
:r: Hip Protrusio, Secondary Otto Disease
"
Q)
VI
protrusio of the right hip.
'"
CO (due to old acetabular
>. fracture) compared to a
E normal left hip. This results
-'"
o
c::
<l:
in relative overcoverage
the right femoral head &
neck B resulting in a
of
pincer-type of FAI. Labral

tear was found at surgery.
prolrusio acetabulae •.
which was bilateral &
hereditary. This is Otto
disease, which results in
pincer type impingement
and early OA, including
labral and cartilage damage.
excessive ossification of the
acetabular rim = that can
cause a pincer-type of FAI.
Note there is also a lateral
femoral bump III
contributing to a earn
impingement. These often
coexist. (Right) Coronal
TI WI FS MR arthrogram
shows the overgrown
acetabular rim to be
fragmented III The femoral
neck bump is seen as well
1Iiil. Both contributed to the
labral tear and cartilage
damage found at surgery.

excess ossification of the
acetabular rim _ along
with a lateral femoral neck
bump 1Iiil. This patient is
highly symptomatic; one
must alert the surgeon to the
combined pincer & earn
mechanisms. (RighI) Coronal
TlWI FS MR arthrogram on
overgrown ossification of the
acetabular rim E!lI and
confirms the {emoral bump
1Iiil. The combined
impingement mechanisms
resulted in severe labral and
cartilage damage III
I
~44
HIP lABRAl TEARS, ETIOLOGY l>
:J
...•
III
o
3
'<
!Xl
III
Overcorrection Osteotomy for DOH Overcorrection Osteotomy for DOH t/I
III
(Left) AP radio8faph shows a.
left hip DOH, with coxa I
magna deformity. The
patient had a Salter opening ":J
Q)
wedge osteotomy of the a.

acetabulum to increase -I
coverage of the left femoral
::T
<5.
head 1lIl. This results in ::T
acetabular retroversion (note
the crossover sign) &
pincer-type FAI. (Right) AP
radiograph during
arthrogram shows subtle
DOH, with an abnormally
small center-edge angle of
Wiberg. Additionally, there is
evidence of prior surgery to
deepen the acetabulum 1lIl.
Overcorrection Osteotomy for DOH Overcorrection Osteotomy for DOH

(Left) Coronal Tl WI FS MR
patient shows DOH with
shallow acetabulum, as
expected. As is frequently
seen in DOH, the labrum is
hypertrophied and has an
extensive tear" (Right)
Sagillal TlWI FS MR
arthrogram from the same
study shows that the
acetabulum has been
overcorrected. While it did
not sufficiently cover the
femoral head laterally, it has
too much anterior coverage,
creating retroversion •.
Note the associated tear •.
Reduced Femoral Anteversion Reduced Femoral Anteversion

retroversion of the femoral
neck". Normally the
femoral head and neck are
anteverted. This unusual
form of dysplasia results in
abnormal force on the
posterior labrum. (Right)
Sagillal TlWI FS MR
patient shows a large
posterior labraltear __
associated with the
retroversion of the femoral
neck.
I
345
OJ
Ql ENLARGEMENT OF INTERCONDYLAR NOTCH DISTAL FEMUR
-l
~
Ql
:: • Hyperemia, epiphysis overgrowth, notch
o
-l
"0 widening, minimal erosion or cysts
C
ell
Common initially
Ql
Ql
• Post-Operative (Notchplasty) • Late disease mimics hemophilia
c • Hemophilia: MSK Complications
~ o Rheumatoid arthritis
'0 • Inflammatory Arthritis • Profound osteopenia, erosions, bilateral
Ql
I/)
Ol Less Common Helpful Clues for Less Common Diagnoses
al
>. • Pigmented Villonodular Synovitis (PVNS) • Pigmented Villonodular Synovitis (PVNS)
E • Septic Joint o Nodular soft tissue masses, ± ~ SI on all
-
o
Ol
c:
<l:
Rare but Important sequences due to hemosiderin
• Septic Joint
• Gout I
• Synovial Osteochondromatosis o More common with indolent

• Hemangioma, Synovial non-pyogenic infection (e.g.,
• Inherited Skeletal Disorders mycobacterium, fungal)
o Monoarticular, poorly defined erosions,
effusion, juxtaarticular osteopenia, gradual
ESSENTIAL INFORMATION joint space loss
• Intercondylar notch widening, remodeling • Gout
due to abnormal bone growth, hyperemia, o Sharp erosions, effusion, tophi
surgical intervention • Synovial Osteochondromatosis
Helpful Clues for Common Diagnoses o Multiple intraarticular bodies ± ossification
• Post-Operative (Notchplasty) o Rare pressure erosions may mimic notch
o Notch osteoplasty of lateral wall & roof to widening

limit impingement in ACL reconstruction • Hemangioma, Synovial
• Hemophilia: MSK Complication o Phleboliths, serpentine vascular tangle of
o Chronic hyperemia ...•femoral epiphyseal vessels, may be diffuse or localized
overgrowth & notch widening, • Inherited Skeletal Disorders
accentuated by flexion of knee o Mucopolysaccharidoses
o Osteopenia, intraosseous cysts, radiodense o Dysplasia epiphysealis hemimelica

joint effusion o Engelmann disease (Engelmann-Camurati)
• Inflammatory Arthritis o Klippel-Trenaunay-Weber syndrome
o Juvenile idiopathic arthritis o Kasabach-Merritt syndrome
Post-Operative (Notchplasty)
I AP radiograph shows an ACL reconstruction with

interference screws HI in place to secure the
Coronal PO FSEMR shows the lateral wall portion of a
notchplasty •• performed to limit osseous impingement
bone-patellar tendon·bone graft. A notchplasty •• of the reconstructed ACL Bl
widens the notch to reduce impingement on the graft.
346
ENLARGEMENT OF INTERCONDYLAR NOTCH DISTAL FEMUR :l>
::J
..•o
III
3
'<
OJ
III
VI
Hemophilia: MSK Complications Inflammatory Arthritis (t)
(Left) AP radiograph shows a.
femoral condylar overgrowth A
with widened notch •. ::J
(l)
Significant erosions ~ & (l)
subchondral cysts EiIl as III

::J
seen in this young male with Cl.
hemophilia, may mimic r
o
juvenile idiopathic arthritis. ~
(l)
(Right) AP radiograph shows ~
severe juvenile idiopathic r
(l)
arthritis with profound co
osteopenia, femoral
epiphyseal overgrowth EiIl
notch widening" early
growth plate closure, and
marked joint space loss with
accompanying erosions ffi
Pigmented Villonodular Synovitis (PVNS)

(Left) Axial PO F5f F5 MR
shows multiple ~ 51masses
Ell of pigmented viflonodular
synovitis, mechanically
eroding the femoral condyles
and widening the
intercondylar notch ••.
(Right) Coronal bone CT
reformation shows erosive
notch widening. from
gouty tophi Ell in this 88
year old man with
longstanding tophaceous
gout.

both intraarticuJar • and
conglomerate eXlraarticular
Ell synovial
osteochondromatosis, with
widening of the
intracondylar notch IIIl due
to pressure erosion. (Right)
severe erosive change in the
tibia. secondary to an
intraarticuJar synovial
hemangioma. The bowed
Blumensaat line ~ indicates
that there is also focal
erosion of the intercondylar
notch.
I
347
PATElLAR LYTIC LESIONS
~
Q)
;;:
o DIFFERENTIAL DIAGNOSIS o Cysts may be large, mimicking lytic lesion
~
"0 • Generally in tibia rather than femur or
C
C1l
Common patella
Q)
Q)
• Subchondral Cyst, Osteoarthritis • Watch for osteophytes & other cysts
C
~ • Subchondral Cyst, Pyrophosphate • Subchondral Cyst, Pyrophosphate
"0 Arthropathy Arthropathy
Cll
I/)
C1l
• Gout o Pyrophosphate arthropathy develops
III • Hyperparathyroidism, Brown Tumor (HPTH) particularly large cysts
>-
E Less Common • Generally in tibia rather than femur or
•..
o
C1l • Amyloid Deposition patella
c • Watch for chondrocalcinosis,
« • Chondroblastoma (CB)
• Giant Cell Tumor (GCT) prominence of patellofemoral disease
• Paget Disease • Gout
• Pigmented ViIlonodular Synovitis (PVNS) o Lytic, often well-defined lesion
• Unicameral Bone Cyst (UBC) o Often associated disease such as end-stage
• Aneurysmal Bone Cyst (ABC) renal disease (ESRD)
• Metastases, Bone Marrow • With ESRD, lytic lesions may be due to
• Dorsal Defect of Patella (Mimic) gout, amyloid deposition, or Brown
• Osteomyelitis tumor
o MR inhomogeneous low T2 signal;
Rare but Important
enhances with contrast
• Langerhans Cell Histiocytosis (LCH)
• Vascular Tumors (HPTH)
• Lymphoma o Radiographic appearance depends on stage
• Osteoblastoma • Active stage: Lytic, often well-defined
• Osteosarcoma • Healing stage: Various degrees of
ossification in lesion; may be entirely
ESSENTIAL INFORMATION hyperossified
o MR inhomogeneous low T2 signal; may
enhance with contrast
• Patellar tumor distribution published by o Often has associated ESRDfindings
Kransdorf
• Abnormal bone density, disordered
o Benign: 38% chondroblastoma, 19% GCT, trabeculae
others: UBC, hemangioma, exostosis, • Quadriceps tendon rupture
osteoblastoma
o Malignant: Lymphoma> Helpful Clues for Less Common Diagnoses
hemangioendothelioma • Amyloid Deposition
• Patellar tumor distribution published by o Often secondary (ESRD, myeloma,
Mercuri rheumatoid arthritis)
o Benign: 33% GCT, 16% chondroblastoma, o Lytic, well-defined lesion
others: Enchondroma, ABC, osteoid o MR inhomogeneous low T2 signal;
osteoma, osteoblastoma, hemangioma enhances with contrast
o Malignant: Osteosarcoma> lymphoma> o Watch for thickening of tendons, soft
hemangioendothelioma tissue deposits with same MR
• Some arthritides result in prominent characteristics
subchondral cyst formation; may mimic • Chondroblastoma (CB)
lytic lesion o Lytic, well-marginated lesion
o In correct age group, may be more likely o MR: Lobulated high T2 signal, typical of
diagnosis than neoplasm cartilage
o Typically seen in skeletally immature or
young adult patient
• Subchondral Cyst, Osteoarthritis • Giant Cell Tumor (GCT)
I
348
PATELLAR LYTIC LESIONS :l>
:J
..•o
Ql
o Lytic lesion; may not have sclerotic margin 3

o MR: Inhomogeneous high T2 signal lD
• Langerhans Cell Histiocytosis (LCH) Ql
(patchy low signal within); enhances with o Lytic lesion .
l/l
(1)
contrast o May be well-defined or more aggressive

Co
• Pigmented ViIlonodular Synovitis (PVNS) A

o Nonspecific on MR :J
CD
o Common in knee CD
o May be polyostotic III
o Nodular or diffuse low signal material :J
o Either indolent or extremely rapid growth 0.
within synovium o Generally seen in child or young teenager r
o
o May develop erosions or large subchondral :E
• Vascular Tumors ct>
cysts ~
o Range from benign to malignant r
• More frequent in femur or tibia than o Benign: Hemangioma
ct>
<0
patella • Coarsened trabeculae, well-defined lesion
• Unicameral Bone Cyst (UBC) o Indeterminate: Hemangioendothelioma,
o Lytic, well-marginated lesion hemangiopericytoma
o Fluid signal on MR
• May appear non-aggressive or aggressive
o Generally in skeletally immature patients;
o Malignant: Angiosarcoma
rare in adults o Vascular tumors often are located within
• Aneurysmal Bone Cyst (ABC) fatty stroma; demonstrated on MR
o Lytic, well-marginated lesion o Often polyostotic
o MR: Fluid-fluid levels in most cases
• Lower extremity favored
• Lymphoma
o Rare patellar involvement
o Malignant tumors involving patella rare
• Dorsal Defect of Patella (Mimic) o Of these, lymphoma is one of the two
o Lytic, round lesion in upper outer
more frequent lesions
quadrant of patella
• Osteoblastoma
o Located on articular surface
o Rare benign bone-forming tumor
o Overlying cartilage is intact
o Extremely rare location
• Osteomyelitis o ± Osteoid formation
o Lytic, often serpiginous lesion
• Osteosarcoma
o Direct inoculation likely; watch for foreign o Common tumor but extremely rare
body or tracking ulcer/air location; aggressive lesion
o Effusion
o May be lytic, but generally has immature
o Reactive edema in Hoffa fat pad
osteoid matrix
o MR: Enhancing rim with contrast
Subchondral Cyst, Pyrophosphate

Arthropathy
Lateral radiograph shows a subchondral cyst. along

with prominent osteophyte formation & cartilage los5.
Lateral radiograph shows an ill-defined subchondral cyst
• wiUlin the patella, along with erosive changes. The
I
The combination is typical of osteoarthritis. Cysts are AP view showed chondrocalcinosis. Cysts may be large
more common in the femur/tibia than patella in OA. in pyrophosphate arthropathy, especially in the libia. 349
Ol
Q) PATELLAR LYTIC LESIONS
..J
~
Q)
;;:
o
..J
"0
C
<Il Gout
Q)
Q) (Leh) Lateralradiograph
C shows a large lytic lesion
~ within the patella. with
"0 no signs of arthritic change.
Ql
This is a 20 year old with
'"
nl
III end-stage renal disease; the
>. lesion proved to be gout at
E
-
biopsy. (Right) Lateral
o radiograph shows a lytic
nl lesion. without other
c:
< distinct changes of arthritis in
the knee. However, the
patient had more classic
evidence of gout involving
the hands. This lesion
improved with treatment for
gout.
Hyperparathyroidism, Brown Tumor Hyperparathyroidism, Brown Tumor

(HPTH) (HPTH)
shows a lytic lesion in the
patella" as well as the
distal femur HI in this
patient with end-stage renal
disease. (Right) Axial T2WI
MR in the same patient
shows both the patellar"
and femoral HI lesions to be
inhomogeneously low signal.
In this renal patient, this
could represent Brown
tumors; gout, or amyloid
deposits. With treatment of
the underlying disease, these
lesions hyperossified, proving
that they were Brown
tumors.
Amyloid Deposition Giant Cell Tumor (GCT)

shows lytic lesions in the
patella" and proximal
femur" in a patient with
end-stage renal disease.
Biopsy proved amyloid, but
there is nothing on imaging
to distinguish it from gout or
Brown tumors. (Right)
lytic lesion within the patella
•. It is nonspecific in
appearance,
well-marginated, and
without matrix. Since there is
no effusion, either
chondroblastoma or GeT
should be suspected.
I
350
PATElLAR LYTIC LESIONS »
::::l
..•o
Ql
3
'<
to
Ql
t/I
Giant Cell Tumor (GCT) lD
(Left) Sagittal TlWIFS MR of C.
the patient shown in the ;:>\
previous image demonstrates ::::l
<ll
the lesion to be <ll
inhomogeneously high OJ
::::l
signal, containing patchy 0-
areas of low signal III. This r
o
is a typical T2 appearance :1i'
<ll
for giant cell tumor. (Right) ~
Lateral radiograph shows a r
<ll
lytic lesion with (Q
pseudotrabeculations. The
patient is middle-aged, so it
;s surprising that this lesion
proved to be a unicameral
bone cyst at biopsy. GCT or
cartilage tumor would be
more likely in this age group.
Dorsal Defect of Patella (Mimic) Dorsal Defect of Patella (Mimic)

radiograph shows a round
lytic" lesion" occupying the
upper outer quadrant of the
patella _ (Right) Lateral
patient confirms the lytic
lesion is within the patella
_ The location is typical of
dorsal defect of the patella,
which is a normal va';ant. If
MR were performed, it
would show normal cartilage
overlying this lesion.
(Left) Sagittal T2WI FSEMR

shows a fluid signal lesion
within the patella. with
adjacent blooming low signal
metal artifact Ill; this
suggests penetrating foreign
body. There is edema in
Hoffa fat pad Ell
substantiating the diagnosis
of osteomyelitis, proven
Staphylococcus. (Right)
Axial T2WI FS MR shows
pathologic fracture through a
large lesion in the patella.
The appearance is
nonspecific, and biopsy
showed a rare lesion for the
patella: LCH.
I
351
OJ
Q) TIBIAL BOWING
-I
~
Q)
~ Diaphyseal fractures may malunite

o
-I
DIFFERENTIAL DIAGNOSIS o
"0 • Anterior or posterior bowing may be
C
Cll
Common compensated by hinge joints
Q)
Q)
• Physiologic (knee/ankle)
~
C
• Fracture Malunion • Medial or lateral bowing> S° cannot be
"C • Paget Disease compensated
Ql
VI • Hyperparathyroidism/Renal 00 • Paget Disease
<ll
al • Rickets o Tibia is common location
>- • Blount Disease
E o Unlike other long bones, lesion may
o
.•... originate at diaphysis of tibia
<ll Less Common
C
• Fibrous Dysplasia (FD) o Anterior cortical origin is common; with
<l:
• Neurofibromatosis overgrowth, develops anterior bowing
o Watch for abrupt sclerotic line at margin
Rare but Important
with normal bone ("blade of grass")
• Congenital Pseudoarthrosis • Hyperparathyroidism/Renal OD
• Osteogenesis Imperfecta o Resorption of bone results in weakening
• Adamantinoma o Incomplete insufficiency fractures result in
• Osteofibrous Dysplasia bowing, especially of tibia & femur
• Tertiary Syphilis
• Rickets
• Hypophosphatasia o Poor mineralization of bone - weakening
• Oilier Disease o Insufficiency fractures attempt to heal by
• Maffucci Syndrome laying down osteoid, which in turn is not
• Metaphyseal Chondrodysplasia properly mineralized
• Turner Syndrome (Mimic) • - Looser zone (wide, non-healing.fx line)
o Bowing at fracture sites, anterior or lateral
ESSENTIAL INFORMATION • Blount Disease
o Abnormal vertical orientation of physis at
Key Differential Diagnosis Issues medial tibia - abnormal tilt & growth
• Tibial bowing is generally anterior abnormality of medial tibial condyle
o Normal slight anterior bowing is
• - Varus bowing at proximal tibia
accentuated when bearing weight on o Frequently bilateral
abnormal bone
• Lateral bowing most frequently due to Helpful Clues for Less Common Diagnoses
o Physiologic causes • Fibrous Dysplasia (FD)
o Abnormalities of the medial physis o Common process which results in mild
• Fracture malunion expansion & thinning of endosteum

o Most frequently arises in central diaphysis,
• Blount disease
• Turner syndrome but in tibia, may be based in cortex
• Rickets • Cortical fibrous dysplasia frequently
• Hypophosphatasia results in bowing, usually anteriorly
• Neurofibromatosis may lead to tibial bowing • Neurofibromatosis
in any direction o Dysplasia of bone
• Several sites may be affected, but of the
Helpful Clues for Common Diagnoses tubular bones, tibia is most frequent
• Physiologic o Dysplastic bone is fragile & develops
o Tibial bowing (varus, bowlegged) common
incomplete fractures, usually transverse
in infants o Continued weight bearing - deformities
o Mild bowing may persist into adulthood
• Healed incomplete fracture may result in
• Fracture Malunion bowing, in any direction
o Salter III or IV at the proximal tibia with
• Completed fracture may develop
cessation of medial growth & continued pseudarthrosis, with attenuated ends at
lateral growth - proximal varus bowing fracture site and no callus formation
I
352
TIBIAL BOWING »
::::l
..•o
OJ
o 50% of tibial pseudoarthroses associated o Rare anterior tibial lesion that may cause 3
'<
with neurofibromatosis bowing (lytic or with osteoid matrix) lD
OJ
Helpful Clues for Rare Diagnoses • Tertiary Syphilis VI

It)
o Mixed lytic & sclerotic; expanded with c.
• Congenital Pseudoarthrosis
anterior bowing A
::::l
o Anterior or anterolateral tibiofibular CD
o Termed "saber shin"; may not be easily CD
bowing at birth Q)
distinguished from chronic osteomyelitis ::::l
o Progresses to fracture within 2 years 0-
or Paget disease r
o Fracture develops fibrous union or o
pseudarthrosis • Hypophosphatasia :E
CD
o Similar appearance to rickets: Osteoporotic ~
• Smoothly tapered bone at fracture site r
with bowed bones & widened physes CD
o Cannot be differentiated from <C
pseudarthrosis of neurofibromatosis • Ollier Disease

o Metaphyseal dysplasia results in growth
without clinical information
abnormality; bowing is uncommon
o Congenita: Short, broad tubular bones
• Maffucci Syndrome
o Same as Oilier disease, plus soft tissue
• Bowing results from multiple
intrauterine fractures hemangiomas
o Tarda form: Either thin, gracile tubular
• Metaphyseal Chondrodysplasia
o Heterogeneous group of dysplasias
bones or normal tubulation
• Osteoporosis & multiple incomplete involving metaphyses
fractures with weight bearing - bowing • Enlarged, widened, cupped metaphysis
appears similar to rickets
• Adamantinoma
o Schmid type particularly shows genu
o ~are les!o.n that occurs nearly exclusively
In the tIbIa (usually anterior tibial cortex) varum & tibial bowing
o Over time, may develop bowing, most
• Turner Syndrome (Mimic)
o Hypoplasia medial tibial metaphysis; may
frequently anteriorly
o Lytic lesion ranges from nonaggressive to
have compensatory overgrowth of medial
moderately aggressive femoral condyle
o Results in mild varus deformity; mimics
o Differential is cortical fibrous dysplasia &
osteofibrous dysplasia; imaging does not Blount disease, but medial physis is not
differentiate the 3 entities vertical (as in Blount)
~nter~p?sterior :adiographshows clinicalbowing or the

right IIb,a resulting from medial tibial condylar fracture
~teral .radiograph shows anterior bowing of the
diaphYSIS Hl with associated cortical thickening &
I
with depression and malunion
progress to early osteoarthritis.
=. If untreated, this will mixed lytic/sclerotic density: Note the sharp border with
normal bone. typical of Paget disease.
353
TIBIAL BOWING
~
<I>
3
o
-.J
-0
c
ell
<I> (Left) Lateral radiograph
<I>
c shows anterior bowing of the
~ femur" & posterior bowing
-0 of the tibia Ell in a patient
Q)
III with renal osteodystrophy,
I1l
al now being treated. Note the
>. ossified Brown tumors.
-
E
o
I1l
c
«
shows osteoporosis
is a fracture with wide

with
thickened trabeculae. There
lucency, termed a Looser

zone _ anterior tibial
bowing is occurring at this
site of particularly fragile
bone. Findings are classic for
rickets.
Fibrous Dysplasia (FD)

radiograph shows
underdevelopment of medial
tibial metaphysis resulting
physis =
from vertical orientation
Final result is a
severe varus deformity of the
of
knee due to acute bowing of

the proximal tibia. (Right)
lesion occupying the
mid-tibia. Though fibrous
dysplasia is generally a
central process, it may be
cortically based in the tibia
=
and often results in tibial
bowing
Neurofibromatosis Neurofibromatosis
radiograph shows dysplastic
bone of the tibia, with
incomplete transverse
fractures that are resistant to
normal healing _ With
continued weight bearing,
the tibia bows laterally.
lateral bowing" in bone
that otherwise appears
normal. The tibia is the most
frequently involved long
bone in the dysplastic
process seen with
neurofibromatosis.
I
354
TIBIAL BOWING :t>
::::I
...•
III
o
3
'<
ll:J
III
III
(l)
radiograph shows complete A
fracture through the ::::I
<1l
mid-tibia and fibula at the <1l
junction of the mid and distal OJ
::::I
1/3 of the diaphyses". The C.
fracture margins are r
o
smoothly tapered, without :E
callus. This appearance is <1l
~
classic for congenital r
<1l
pseudoarthrosis. (Right) to
shows a gracile tibia & fibula
with medial bowing" and
hypertrophic callus bridging
them in a patient with typical
osteogenesis imperfecta
tarda.
Adamantinoma Osteofibrous Dysplasia

lesion of the anterior tibia in
a child" with associated
anterior tibial bowing. This
lesion is most suggestive of
either adamantinoma or
cortical FD; former was
proven. ItMSK Req). (Right)
cortically based lytic lesion
in the anterior tibia =
with
mild assodated anterior
bowing. This proved to be
osteofibrous dysplasia,
though adamantinoma or FD
might be considered. It MSK
Req).
Turner Syndrome (Mimic)

shows enlargement and
anterior bowing of the
diaphysis of the tibia, with
mixed lytic & sclerotic
density. This is a typical
"saber shin" deformity of
tertiary syphilis. (Right)
shows mild hypoplasia of the
medial tibial metaphysis ••
resulting in slight tibial
bowing. This, along with the
associated small
excrescence, is seen in
Turner syndrome.
I
355
Ol
Q)
FLUID COLLECTIONS ABOUT THE KNEE
--'~
Q)
3: o At site of rupture, may dissect through

--'
"0
adjacent tissues, giving an infiltrative
C
CIl
Common appearance
Q)
Q)
• Popliteal Cyst o Follow "lesion" to origin where it will
C
~ • Popliteal Cyst, Ruptured appear more cystic
"t:l • Meniscal Cyst • Meniscal Cyst
Q)
Vl • Synovitis, Knee o Associated with meniscal tear
III
lD • Hematoma • lateral meniscal cyst: Most frequently
>- • Patellar (Anterior) Bursitis anterolateral
-
E
o
III
C
<t:
• Mucoid Degeneration, Cruciate Ligament
• Medial Bursitis, Pes Anserine
• Medial Bursitis, Collateral Ligament
• Medial meniscal cyst: May arise from any
portion of meniscus & may dissect away
from site of tear
• Gastrocnemius Strain • Synovitis, Knee
• Popliteus Myotendinous Injury o Low signal enhancing material lining
• Intercondylar Notch Cyst synovium; effusion
• Ganglion, Knee • Hematoma
• Iliotibial Bursitis o MR signal characteristics of blood
• Soft Tissue Abscess products, depending on age of injury
Less Common o Frequently found within the prepatellar
• Bursitis Surrounding Osteochondroma bursa

• Infectious Bursitis • Patellar (Anterior) Bursitis
• Semimembranosus Bursitis o Fluid interposed between subcutaneous
• Proximal Tibio-Fibular Joint Synovial tissues and patella or inferior patellar

Processes tendon
• Popliteal Artery Aneurysm • Mucoid Degeneration, Cruciate Ligament
o May involve anterior cruciate (ACl),
Rare but Important posterior cruciate (PCl), or both
• Synovial Osteochondromatosis within a o High signal separating fibers from one
Bursa another, with fibers continuing through;
• Pigmented Villonodular Synovitis within a ligament may appear enlarged overall
Bursa • Medial Bursitis, Pes Anserine
o Bursa surrounding fibers of pes (sartorius,
ESSENTIAL INFORMATION gracilis, semitendinosus)
o Approach to insertion: Wraps from
Key Differential Diagnosis Issues posteromedial above knee to anteromedial
• Bursae: Suprapatellar, prepatellar, superficial location below knee joint
infra patellar, deep infrapatellar, anserine, • Medial Bursitis, Collateral Ligament
MCL, semimembranosus-MCl, iliotibial, o Bursa is normally present between deep
lCL-biceps and superficial fibers
o Isolated suprapatellar bursa (by
• Gastrocnemius Strain
non-perforated plica) may mimic a cyst o Strain most frequently located in proximal
• Hint: Analysis of location often leads to calf rather than at knee
correct diagnosis o May occur at gastrocnemius origin
Helpful Clues for Common Diagnoses • High signal in fibers at femoral origin
• Popliteal Cyst • ± Edema in adjacent bone
o Located in • Popliteus Myotendinous Injury
semimembranosus/gastrocnemius bursa o Popliteus injury most frequent at
o Connects to knee joint, but thin myotendinous junction, posterior to knee
connecting neck may be difficult to o May present with large fluid collection
visualize surrounding fibers
• Popliteal Cyst, Ruptured • Intercondylar Notch Cyst
I
356
flUID COllECTIONS ABOUT THE KNEE :J>
:J
...•
III
o
o Cyst may split ACL or PCL or arise o Adjacent edema 3
'<
between them o Thick enhancing rim on MR OJ
III
o Fluid collection with adjacent • Semimembranosus Bursitis VI
CD
normal-appearing cruciate fibers o U-shaped fluid collection surrounding the Co
• Ganglion, Knee anterior, medial, & posterior portions of :A

:J
CO
o Intraarticular ganglia: Usually arise from semimembranosus tendon near its tibial CO
cruciate ligament; sometimes in Hoffa fat insertion Q)
:J
0-
pad • Proximal Tibio-Fibular Joint Synovial r
o Insertional cysts (tibial insertions of Processes o
~
cruciates & menisci) common o 15% of proximal tibiofibular joints co
~
r
• Iliotibial Bursitis connect with knee joint co
co
o Bursitis arising secondary to friction of o Synovial joint; at risk for synovial process
iliotibial band against lateral femoral o Posterolateral location is diagnostic
epicondylar prominence • Popliteal Artery Aneurysm
o Fluid collection adjacent to lateral femoral o Round mass in path of popliteal artery
condyle, associated with iliotibial (IT) o Lamellated appearance due to
band • Mural thrombus
o ± Adjacent marrow edema & IT band • Differing rates of blood flow
thickening Helpful Clues for Rare Diagnoses
• Soft Tissue Abscess • Synovial Osteochondromatosis within a
o Fluid-filled mass; enhancing rim on MR
Bursa
o Watch for adjacent periosteal reaction
o Remember that bursae may develop
&/or osteomyelitis
synovial processes, just as joints
Helpful Clues for less Common Diagnoses o Multiple round bodies, all of similar size
• Bursitis Surrounding Osteochondroma • Generally visible as calcified/ossified
o Osteochondromas are particularly bodies on X-ray; occasionally lucent
common around knee • Pigmented Villonodular Synovitis within
o With mechanical trauma, may develop an a Bursa
overlying bursa o Rarely arises within a bursa
o Watch for stalk of exostosis projecting into o MR characteristics typical for PVNS
fluid collection • Inhomogeneous low T2 signal
• Infectious Bursitis • "Blooms" on gradient echo due to
o Bursitis with irregular margins hemosiderin
Popliteal Cyst Popliteal Cyst, Ruptured
Axial T2WI FS MR shows a large popliteal cyst, located

in the expected position of the semimembranosus
Axial PO FSf FS MR shows high signal located
the gastrocnemius & semimembranosus muscles •.
between
I
gastrocnemius bursa. These may dissect far proximally There is not a mass-like configuration. A poplileal cyst
or distally, may become bilobed, or may coneain debris. can appear infiltrative at the point of rupture.
357
Ol
Ql flUID COLLECTIONS ABOUT THE KNEE
-'•...
Ql
;:
o
-'
"0
C
m Meniscal Cyst Meniscal Cyst
Ql
Ql
(Left)Sagittal T2' CRE MR
C shows a large multi/obulated
~ cyst Ell located anteriorly to,
"tl and arising from, a
Q)
III degenerated anterior horn
en'" lateral meniscus" The
>- patient is a gymnast; such
-E
o
m
c
<t
injuries are common in this
population. (Right) Coronal
T2WI MR shows a large
multi/obulated cyst arising
from a meniscal tear of the
medial meniscus. The cyst is
distorting the pes anserinus
tendons Ell. Medial
meniscus cysts Frequently
dissect far from the original
meniscal tear.
Synovitis. Knee Hematoma

(Left)Sagittal T1 C+ FS MR
shows a huge popliteal cyst
containing mildly enhancing
synovitis •. The erosive and
edematous changes in the
bone help confirm the
underlying diagnosis of
rheumatoid arthritis. (Right)
Sagittal PO FSEMR shows an
intermediate signal intensity
fluid collection within the
prepatellar bursa" typical
of hematoma. There is
associated elevation of the
tibial apophysis Ell and
metaphyseal fracture" in
this Salter II injury.
Mucoid Degeneration, Cruciate

ligament
(Left) Axial PO FSEFS MR
shows fluid within the
pre-patellar bursa.
resulting from direct trauma;
note also the contusion in
the vastusmedialis. in this
patient who "caught" a
medicine ball with his knee.
shows a cystic structure
within the posterior cruciate
ligament _ displacing
fibers that are otherwise
intact. This is the typical
appearance of mucoid
degeneration of a cruciate
ligament.
I
358
flUID COLLECTIONS ABOUT THE KNEE >
::l
...•
Ql
o
3
'<
Mucoid Degeneration, Cruciate [lJ
Ql
Ligament Medial Bursitis, Pes Anserine rn
<D
(Leh) Axial PO FSEFS MR Cl.
shows fluid signal within the A
anterior crudale ligament ::J
CD
that displaces fibers that are CD
Q)
otherwise intact'" Thisis a ::J
typical appearance of a.
mucoid degeneration. The r
o
normal posterior cruciate :E
ligament is seen as well Ell. CD
~
(Right) Sagittal T2WI FS MR r
CD
located far medially shows CO
fluid surrounding the
tendons of the pes anserinus
IIlI as they approach their
insertion site.
Medial Bursitis, Pes Anserine Medial Bursitis, Collateral Ligament

(Leh) Axial PO FSEMR
shows fluid surrounding the
pes anserinustendons.
(sartorius, gracilis,
semitendinosus) as they
approach their insertion on
the anteromedial portion of
the tibial metaphysis. (Right)
Coronal PO FSEFS MR
shows a variant case of
medial bursitis involving an
adventitial bursa overlying
the medial femoral condyle.
There is a calcific density"
surrounded by inflammation
that is clearly within the
medial collateral bursa rather
than the pes anserine bursa.
(Leh) Sagittal PO FSEFS MR

shows a low grade partial
thickness strain at the medial
gastrocnemius origin, with
increased signal and
thickening at the muscle
origin" & adjacent edema
1m. (Right) Coronal T2WI
MR located far posterior in
the knee shows increased
fluid at the
musculotendinous junction
of the popliteus ••
(popliteus tendon seen
proximally Ell and muscle
seen distally 1mJ, typical of
injury.
I
359
Ol
Ql
FLUID COLLECTIONS ABOUT THE KNEE
-J
•...
Ql
~
o
-J
"0
C
ro
Ql (Left) Sagittal T2WI FS MR
Ql
c shows increased fluid
~ surrounding the
"0 musculotendinous junction
CII
Ul of the popliteus. in a
III
en patient with posterolateral
>. corner injury. Edema in the
E fabella EiII indicates
-o
III
C
<t
fabellofibular ligament injury.
Edema in the anterior
III suggests hyperextension
tibia
injury. (Right) Sagittal T2WI

MR shows normal fibers of
the ACL EiIIthat are split by
an intercondylar notch cyst.
The fibers do not appear
degenerated. These cysts
may be symptomatic.
Ganglion, Knee Iliotibial Bursitis

(Left) Axial T2WI FS MR
shows a small
teardrop-shaped ganglion III
arising anterior to the distal
fibers of the anterior crudate
ligament Ell. The ligament
appeared intact in this case,
but such ganglia are often
related to prior partial
cruciate ligament tear.
(RighI) Axial PO FSf FS MR
shows fluid. interposed
between
band = a normal iliotibial
and prominence of
the lateral femoral condyle
EiII. This is the typical site of
friction, resulting in iliotibial
band syndrome.
Soft Tissue Abscess Bursitis Surrounding Osteochondroma

fLeft) Sagittal T2WI MR
shows a high signal complex
mass posterior to the knee
Ell. There is adjacent
osseous destruction •.
Contrast imaging proved this
to be an abscess which has
progressed to osteomyelitis.
shows a bursa EiII
surrounding an
osteochondroma. of the
proximal tibia. Trauma to an
osteochondroma may result
in development o( such a
bursa, which may cfinically
mimic degeneration to
chondrosarcoma.
I
360
flUID COllECTIONS ABOUT THE KNEE l>
-
::J
III
o
3
'<
CJ
III
Infectious Bursitis Semimembranosus Bursitis VI
<ll
(Leh) Sagittal T I C+ Fs MR Co
shows irregular thick
enhancing
collection"
rim about a
within the
fluid '"
::l
<1>
<1>
pre-patellar bursa. There is III
::l
surrounding edema; this c-
represents infectious bursitis. o
o
(Right) Axial T2WI MR :E
<1>
shows fluid" surrounding ~
the semimembranosus o
<1>
tendon •. indicating (Q
semimembranosus bursitis.
The configuration of the fluid
is typically U-shaped in this
entity.
Proximal Tibio-Fibular Joint Synovial

Processes
shows multiple loose bodies
•. The bodies are within
the proximal tibiofibular joint
(note the fibula ffi. It is
important to remember that
this is a synovial joint, which
may develop any articular
process. (Right) Axial T1WI
Fs MR shows a lamellated
mass" in the popliteal
fossa of the knee. This mass
is in the expected location of
the popliteal artery. Signal
characteristics are due to
mural thrombus and blood
flow of varying speed and
turbulence.
Synovial Osteochondromatosis within a Pigmented Villonodular Synovitis within

Bursa a Bursa
(Left) Axial PO Fsf Fs MR
shows innumerable small
bodies located within a large
fluid collection EiII which
surrounds the popliteal
musculotendinous junction.
This is synovial
chondromalosis, extending
from the knee through the
popliteal hiatus. (Right)
Coronal T1 C+ Fs MR shows
a mass containing low signal
elements" which proved
to be PVNs within the pes
anserinus bursa. Remember
that bursae may develop
many of the same processes
as synovial joints.
I
361
OJ
OJ POPLITEAL MASS, EXTRAARTlCUlAR
-'~
OJ
>:a DIFFERENTIAL DIAGNOSIS o Cyst may appear complex, containing
-'
"0 nodular densities, especially along lining
C
co Common o Watch for osseous erosions
OJ
OJ
• Popliteal Cyst o Watch for similar appearance of synovitis
C
~ • Popliteal Cyst, Ruptured in suprapatellar bursa
'tl • Popliteal Cyst, Synovitis • Pigmented Villonodular Synovitis (PVNS)
Q)
Vl • Pigmented Villonodular Synovitis (PVNS) (Mimic)
ra
CO (Mimic) o PVNS occasionally appears as a focal mass
>. • Osteosarcoma, Conventional o If mass is located posteriorly in joint, it
-
E
o
ell
s::
<
• Osteosarcoma, Parosteal
• Synovial Sarcoma
• Benign Peripheral Nerve Sheath Tumor
may mimic extraarticular popliteal mass
• Watch for overlying capsule to define
intraarticular position
(BPNST) o Usually inhomogeneously low signal on
• Lymph Node (Mimic) T2 MR; enhances
• Soft Tissue Abscess • "Blooms" on gradient echo imaging due
less Common to hemosiderin deposition
• Gastrocnemius Muscle Variant • Osteosarcoma, Conventional
• Hemangioma, Soft Tissue o Most common malignant osseous tumor in
• Popliteal Artery Aneurysm 1st two decades

• Malignant Peripheral Nerve Sheath Tumor o Distal femoral metaphysis is one of most
(MPNST) common locations
• Semimembranosus Bursa • If cortical breakthrough is posterior, soft
tissue mass may present as a popliteal
Rare but Important mass
• Synovial Osteochondromatosis, o Watch for permeative osseous destruction
Extraarticular & amorphous osteoid formation
ESSENTIAL INFORMATION o Surface osteosarcoma occurring in 2nd &
3rd decades
Key Differential Diagnosis Issues o Most common location is distal femoral
• Hint: Carefully identify nerves, vessels, & metaphysis
normal musculature to help identify o Fairly mature osteoid extends from cortical
etiology of popliteal mass bone
Helpful Clues for Common Diagnoses • More mature centrally than peripherally
• Popliteal Cyst • Commonly involves intramedullary
o Simple fluid collection within bone as well
semimembranosus/gastrocnemius bursa • Synovial Sarcoma
o Connects with joint, though thin o Relatively common sarcoma in young
connecting neck may not be visible adults
o When large, may dissect far proximally or o Most frequent in lower extremity,
distally especially around knee
• Popliteal Cyst, Ruptured • Almost never intraarticular
o Routine popliteal cyst that ruptures o May contain dystrophic calcification
o At ruptured site, fluid is not contained • Benign Peripheral Nerve Sheath Tumor
• Dissects through tissues (BPNST)
• Identify by tracking it back to o Popliteal mass when sciatic, tibial, or
semimembranosus/gastrocnemius bursa peroneal nerves involved
• Popliteal Cyst, Synovitis o Target sign (central low signal on T2
o Popliteal cyst in classic location of imaging) is frequent but nonspecific
semimembranosus/gastrocnemius bursa o Watch for elongated shape with associated
nerve
I
362
POPLITEAL MASS, EXTRAARTICULAR »
::l
...•
III
o
• Lymph Node (Mimic) • Malignant Peripheral Nerve Sheath Tumor 3
'<
o Generally multiple nodes (MPNST) OJ
III
o May have fatty tissue in hilum o Associated with sciatic, tibial, or peroneal III
C1>
• Soft Tissue Abscess nerves in popliteal fossa C.
o Enhancing rim about fluid collection o May have target sign on T2 imaging (as A
:::>
CD
o Watch for adjacent osteomyelitis & does BPNST) CD
o Often seen in association with
Q)
reactive bone formation :::>
0-
Helpful Clues for Less Common Diagnoses neurofibromatosis r
o
• Watch for dominant mass & multiple :E
• Gastrocnemius Muscle Variant CD
smaller masses associated with nerve ~
o Aberrant origin of a portion of r
tissue CD
gastrocnemius <0
• Usually lateral head arising from medial • Semimembranosus Bursa

o U-shaped fluid collection surrounding
femoral condyle
semimembranosus tendon near its tibial
o Forms a sling around popliteal vessels
o Rarely presents as a mass; not symmetric to
insertion
o Does not extend up between
opposite limb on palpation
semimembranosus and gastrocnemius, so
o More frequently presents with claudication
should not be mistaken for popliteal cyst
o Most frequently is an incidental finding
• Hemangioma, Soft Tissue Helpful Clues for Rare Diagnoses
o May occur in popliteal fossa • Synovial Osteochondromatosis,
o When located as intramuscular mass (in Extraarticular
gastrocnemius), symptoms are of calf o Multiple round bodies
spasm o Generally calcified or ossified; may be
o Watch for tortuous vessels within fatty confirmed on radiograph
stroma • Occasionally no matrix within bodies, so
• Popliteal Artery Aneurysm seen only on MR
o Aneurysm presents as round mass, in path o Knee is common location
of popliteal artery o Generally contained within joint space
o Lamellated appearance due to o Rarely becomes more aggressive, extending
• Walled-off thrombus from joint into surrounding soft tissues
• Different rates of blood flow through • Invades muscle, fascial planes, bursae
aneurysm
Axial T2WI MR shows a typical popliteal cyst [;8

located within the semimembranosus-gastrocnemius
Axial PO FS MR shows uncontained mass-like fluid _
dissecting within the semimembranosus/gastrocnemius
I
bursa, with a neck extending towards the joint space bursa within the popliteal fossa. A ruptured popliteal
_. Large cysrs may dissect far proximally or distally. cyst appears infiltrative at the point of rupture.
363
Ol
CIl POPLITEAL MASS, EXTRAARTICUlAR
...J
~
CIl
~
o
...J
-0 Pigmented Villonodular Synovitis (PVNS)
C
<II (Mimic)
CIl (Left) Axial TZWI FS MR
CIl
C shows a complex popliteal
~ cyst arising between the
"tl displaced semimembranosus
CIl
III BI & gastrocnemius 11III
ns tendons. There is synovitis
III
>- within the cyst and joint; the
-E
o
ns
c
oCt
patiene has rheumatoid
arthritis. (Right) Sagittal PO
FSE MR shows a mass
posterior to the cruciate
ligaments 1IIiI. Low signal
persisted in T2 & eRE
imaging, & this proved to be
PVNS, which may appear
mass-like. It is a mimic;
however, as it is actually
intraarticular.
Osteosarcoma, Conventional Osteosarcoma, Parosteal

shows a large popliteal fossa
50ft tissuemass. in a
teenaged patient, along with
lytic permeative destruction
within the metaphysis Ill.
This appearance is typical of
a lytic osteosarcoma. (Right)
large popliteal mass that
contains inhomogeneous
areas of low signa/lllil. The
mass extends from the
posterior surface of the
femur, & there is invasion of
the adjacent femoral
metaphysis. This is typical
parosteal as.
Benign Peripheral Nerve Sheath Tumor

(BPNST)
shows a large
inhomogeneous mass within
the popliteal fossa _ The
extraarlicular location in the
lower extremity, in a young
adult, should make one
strongly consider the
diagnosis of synovial
sarcoma. (Right) Sagittal
T1 WI MR shows a large
inhomogeneous mass within
the popliteal fossa" with a
"tail" of nerve extending
from it Bl The location and
associated nerve makes the
diagnosis of PNST; this
proved to be a schwannoma.
I
364
POPLITEAL MASS, EXTRAARTICULAR »
-
::::l
Dl
o
3
'<
[ll
Dl
<II
Soft Tissue Abscess Hemangioma, Soft Tissue <ll
(Left) Sagittal T1 C+ MR C.
shows a thick enhancing rim A
surrounding an abscess HI ::::l
(1)
in the popliteal fossa. There (1)
is adjacent osseous III

::::l
destruction _. This patient C.
had been camping in the r
o
western U.S. desert and :E
(1)
acquired a Yersinia pestis ~
infection. (Right) Axial T2WI r
(1)
MR shows tortuous vessels <C
within an intramuscular
hemangioma" This
presented as a popliteal
mass. It also resulted in calf
muscle spasm.
Malignant Peripheral Nerve Sheath

Popliteal Artery Aneurysm Tumor (MPNST)
shows a mass at the
expected location of the
popliteal artery m. The
lamellated appearance is due
to mural thrombus in this
aneurysm, as well as differing
rates of blood flow. (Right)
Axial T2WI MR shows a large
inhomogeneous popliteal
fossa mass" as well as
adjacent smaller masses
within the neurovascular
bundle 11II. This patient has
neurofibromatosis; the
dominant mass is an MPNST.
Synovial Osteochondromatosis,
Semimembranosus Bursa Extraarticular
a typical U-shaped fluid
collection "that surrounds
the semimembranosus
tendon just prior to its
insertion on the posterior
tibia. This is in an
extraarticular position.
(Right) Sagittal T1 C+ FS MR
shows large extraarticular
popliteal masses that contain
calcified bodies Ell. Similar
masses are seen
intraarticularly" This
palientha5synov~1
osteochondromatosis, which
may rarely extend into an
extraarticular location.
I
36S
Cl
(l) ALTERATIONS IN MENISCAL SIZE
-'~
(l)
;;: • Morphology of posterior horn tends to
-'
"0 be abnormal, with popliteal hiatus and
C
CO
Common popliteus tendon more prominent
(l)
(l)
• Enlarged, Medial (MM) or Lateral (LM) • Diagnosis most often suggested when
C
~ o Discoid Meniscus sagittal plane shows body of meniscus
"0 o Lateral Meniscal Bucket-Handle Tear with over more than 3 images (bow-tie)
Q)
III Flipped Fragment (Mimic) • Confirmed on coronal or axial imaging
l'll
ell • Diminutive Meniscus o Generally diagnosed at a younger age than
>- o Post-Operative Meniscus Change routine traumatic meniscal injury
E
-
o
l'll
C
o Meniscal Bucket-Handle Tear
o Meniscal Degeneration
o Enlarged meniscus is at t risk for tear
o Hint: If a portion of the meniscus appears
< o Meniscal Extrusion (Mimic) too wide from peripheral to central,
Less Common consider discoid meniscus
• Enlarged Meniscus • Lateral Meniscal Bucket-Handle Tear with
o Chondrocalcinosis Flipped Fragment (Mimic)
o Meniscal Ossicle o Vertical tear continuing over a significant
o Intrameniscal Cyst longitudinal extent that detaches at either
o Meniscal Flounce (Mimic) anterior or posterior end
o Ligament Merging with LM (Mimic) o Detached end of meniscus, often with a
• Diminutive Meniscus large amount of meniscal tissue, may flip
o Small Anterior Root, MM (Mimic) over the opposite end of meniscus
• Flipped meniscal fragment generally is
Rare but Important superimposed on native anterior horn,
• lntraarticular Air (Mimic) making it appear to be double in size (t
height from superior to inferior)
ESSENTIAL INFORMATION • Flipped fragment may be obliquely
superimposed (t in size both height &
Key Differential Diagnosis Issues width)
• Menisci have typical normal size & • Flip from torn posterior horn,
morphology superimposed over native anterior horn
o Posterior horn is largest portion of medial is more frequent than anterior horn
meniscus (long triangle) fragment over posterior horn
o Anterior horn shorter than posterior, but • This pattern of tear with flipped
body is shortest (small equilateral triangle) fragment is more frequent in lateral
o Lateral meniscus is symmetric in size meniscus than true bucket handle
through all portions • True bucket-handle tear is more frequent
• Either enlargement or diminution of in MM than is flipped fragment
meniscus indicates pathology, with few o Hint: If one portion of meniscus appears!
exceptions & another portion appears t (height or
Helpful Clues for Common Diagnoses width), consider flipped fragment
• Discoid Meniscus • Post-Operative Meniscus Change
o Enlarged meniscus from peripheral to o Results in smaller meniscus in the portion
central free edge that was trimmed
• In axial plane, assumes more of a discoid o Free edge often blunt; may have adjacent
than C-shaped outline cartilage defect
• May be partial, making the diagnosis o May continue to show abnormal signal
more difficult within meniscus, extending to free edge
• Lateral more frequently involved than o Hint: If considering diagnosis of
medial post-operative change for an abnormally
• Occasionally involves both MM & LM small meniscus, watch for linear fibrotic
changes in Hoffa fat pad from arthroscope
I
366
ALTERATIONS IN MENISCAL SIZE ~
::l
...•
Ql
o
• Meniscal Bucket-Handle Tear o Chondrocalcinosis generally appears low 3
'<
o Vertical longitudinal tear that remains signal on all sequences, but infrequently lJl
Ql
intact at anterior & posterior horns, with may be high signal III
CD
fragment flipped centrally into • High signal may be solid or speckled Co
intercondylar notch • High signal may be mistaken for A

::J
o Results in diminutive meniscus degenerative tear <1l
<1l
throughout nearly its entire extent o Hint: When meniscus appears enlarged in III
::J
C.
o Bucket-handle tear seen in medial height, particularly with central high r
meniscus more frequently than lateral signal, consider chondrocalcinosis o
:E
o Hint: If entire meniscus appears small, do • May confirm on radiograph ...,
<1l
r
not assume it is post-operative; look for • Meniscal Ossicle <1l
<0
meniscal tissue in intercondylar notch o Intraarticular osseous structure, usually
• Meniscal Degeneration MM posterior horn, causes t in meniscal
o Degeneration may result in tears at free size
edge of meniscus which detach o Follows MR bone signal; confirm on X-ray
o Involved portion of meniscus appears to • Intrameniscal Cyst
have a blunt edge, without necessarily o Cystic signal within meniscus - size t
having increased signal of a tear • Meniscal Flounce (Mimic)
o Hint: With this pattern, search for free o Positionally dependent wavy appearance
intraarticular meniscal fragments of "extra" meniscal tissue
• Meniscal Extrusion (Mimic) • Ligament Merging with LM (Mimic)
o With severe degenerative change, & o Meniscofemoral or transverse ligaments
especially with radial tears, a portion of merging with posterior or anterior horns,
meniscus may be extruded beyond joint respectively, may mimic focal t in size
line; meniscus appears small • Small Anterior Root, MM (Mimic)
o Anterior horn medial meniscus may be
• Chondrocalcinosis small & have variable attachments
o Extensive meniscal chondrocalcinosis may
(anterior to joint line, transverse ligament)
result in enlargement of meniscus Helpful Clues for Rare Diagnoses
• Enlargement usually in height, rarely • Intraarticular Air (Mimic)
enlarged from periphery to free edge o Intraarticular air appears as low signal that
blooms on GRE imaging; adjacent
meniscus may appear enlarged
Discoid Meniscus Discoid Meniscus
Sagittal PO FSE MR located just medial

intercondylar notch shows a continuous "bowtie"
to the Coronal T2WI FS MR shows enlargement of both the
body of medial meniscus •• and body of lateral
I
meniscus, with lxxiy stjlf in evidence" This indicates meniscus Ell. This was confirmed on sagittal imaging.
an abnormally large body, termed discoid meniscus. Lateral discoid is more frequently seen than medial.
367
Ol
Q) ALTERATIONS IN MENISCAL SIZE
....J
~
Q)
;:
o
....J
"0 lateral Meniscal Bucket-Handle Tear lateral Meniscal Bucket-Handle Tear
C
ell with Flipped Fragment (Mimic) with Fli ped Fragment (Mimic)
Q)
=
Q)
C shows an apparently
~ enlarged anterior horn
"0
Q)
l/l
'"
al
=
but small torn posterior horn
of the lateral meniscus.
This is a longitudinal vertical
>- tear of the posterior horn
E and body, flipped over the
-'"
o
c
<l:
anterior horn, mim;cking
enlargement. (Right) Sagittal
PO FSEMR shows an
unusual flipped body
fragment which doubles the
size of both the anterior &
posterior horns. The flipped
fragments. are
superimposed on the native
meniscus HI.
Post-Operative Meniscus Change Meniscal Bucket-Handle Tear

shows a blunt & irregular
posterior horn •• with
adjacent cartilage damage
E!il Though a degenerative
lear may result in meniscal
blunting, this appearance is
more frequently seen
following arthroscopic repair.
(Right) Coronal T2Wf FS MR
shows a small, blunt body of
medial meniscus" Whileit
is possible for this to be a
degenerative tear, one must
look for the displaced
fragment E!il generally in the
intercondylar notch. This is a
bucket-handle tear
Chondrocalcinosis
(Left) Sagittal PO FSE FS MR
shows an enlarged anterior
horn containing speckled
high signal •. The signal
might be mistaken for
meniscal degeneration, but
the enlargement should
make one consider other
etiologies. (Right) Lateral
patient shows
chondrocalcinosis •.
Though meniseal
chondrocalcinosis is
generally dark or not seen on
MR, it rarely will exhibit high
signal and cause
enla,sement of the meniscus.
I
l61l
ALTERATIONS IN MENISCAL SIZE :r>
:J
III
r+
o
3
'<
[II
III
Meniscal Ossicle Meniscal Ossicle VI
(l)
(Left) Sagiltal PO FSEMR Co
shows a body with signal ;>\
identical to bone occupying :J
CD
the posterior horn medial CD
Q)
meniscus III causing mild
:J
enlargement o( that 0-
structure. The signal r
o
followed that of bone on all :;;
CD
sequences and is typical of -,
meniseal ossicle. (Right) r
CD
Lateral radiograph of the <0
same knee confirms the
ossicle ilia. Its location in the
posterior horn of the medial
meniscus is typical; it
generally results in meniscal
enlargement & degeneration.
Intrameniscal Cyst Meniscal Flounce (Mimic)

(Left) Sagiltal PO FSEMR
shows an enlarged anterior
horn of the lateral meniscus.
The enlargement results from
a distended intrameniscal
cyst 1IlI. (Right) Sagiltal PO
FSE MR shows a meniscal
flounce __ a single meniscal
fold along the free edge that
is a normal variant. It is not
associated with a meniscal
tear. The appearance is
typical and does not
represent true meniscal
enlargement.
ligament Merging with lM (Mimic) Intraarticular Air (Mimic)

(Left) Sagittal PO FSEMR of
two adjacent images through
the lateral compartment
shows a large transverse
ligament •• merging with
the anterior horn •. Once
fully merged, it gives the
appearance of an enlarged
anterior horn. (Right) Sagittal
T2' CRE MR shows an
apparently irregularly
enlarged posterior horn
medial meniscus •. This is
a gradient echo image,
which allows lib/Doming" of
either meta/ or air. In this
case, the radiograph showed
a focus of inlraarticu/ar air.
I
369
Ol
<D GENU VALGUM (KNOCK KNEES)
....J
~
<D
3:
o
....J
DIFFERENTIAL DIAGNOSIS I I ESSENTIAL INFORMATION
D
C
C1l
Common Key Differential Diagnosis Issues
<D
<D
• Idiopathic • Genu valgum: 2 measurements
C
• Arthritis a Angle described by line bisecting distal
:.::
"'C • Physeal Fractures femur & line bisecting proximal tibia
C1l
VI • Renal Osteodystrophy (Renal OD) (normal angle 6° ± 2°; valgus> 8°)
Cll
al • Rickets a Mechanical axis: Line drawn from center
>- • Osteomyelitis of femoral head to center of tibial plafond
E
•..o
Cll
Less Common • Should fall through middle of knee
c • Consider joint-related abnormalities
<l: • Fibrous Dysplasia
a Arthritis, differentially affecting lateral
• Osteochondromatosis
compartment cartilage (RA > OA)
• Fluorosis
a Morphologic abnormalities of epiphyses,
• Homocystinuria
resulting in relatively larger medial femoral
condyle or flat lateral femoral condyle
• Multiple Epiphyseal Dysplasia
• Spondyloepiphyseal dysplasia, multiple
• Trevor Fairbank (Dysplasia Epiphysealis epiphyseal dysplasia, Trevor Fairbank,
Hemimelica) etc.
• Consider abnormalities differentially
affecting lateral physis
• Oilier Disease
a Early bony bridging laterally following
Salter fracture or osteomyelitis
a Differential radiation to lateral portion of
Rare but Important knee prior to skeletal maturation
• Vitamin C Deficiency • Consider osseous abnormalities resulting in
• Pseudoachondroplasia dysmorphic change in metaphysis/diaphyses
• Chondroectodermal Dysplasia (Ellis-van -+ bowing of femur or tibia
Creveld) a Not a true genu valgus deformity, but
• Spondyloepimetaphyseal Dysplasia mimics one clinically
• Chondrodysplasia Punctata a Renal OD, rickets, hypophosphatasia,
• Cleidocranial Dysplasia fibrous dysplasia, osteochondromatosis,
• Pyle Dysplasia osteogenesis imperfecta, Ollier disease, etc.
Arthritis
I AP radiograph shows osteopenia, uniform cartilage loss,

and a valgus deformity. Note the medial-lateral
AP radiograph shows a femoral bowing deformity Ell
which in turn mimics genu valgum clinically. There is
translation of the tibia, indicating ligamentous instability. patchy increased density in the bones, as well as ossified
The findings are typical of rheumatoid arthritis. brown tumors. in this treated renal 00.
370
GENU VALGUM (KNOCK KNEES) ~
..
;,
III
o
3
'<
CD
III
tIl
<II
(Left) AP radiograph shows Q.
bilateral genu valgus. There A

is widening of the provisional ;,
ct>
zone of calcification III with ct>
Q)
impaction and fraying of the ;,
metaphyses, contributing to 0-
the deformity in this patient r
o
with nutritional rickets. :E
(Right) Coronal T2WI MR ct>
~
shows a focus of r
ct>
osteomyelitis within the (Q
metaphysis of the lateral

femoral condyle. crossing
the physis. With healing, a
bony bar will form, inhibiting
growth. Continued medial
growth will result in genu
valgum. (tMSK Req).

focus of polyostotic fibrous
dysplasia in the femur III
that, with weight bearing,
has resulted in a focal medial
bowing. This bowing
clinically mimics a valgus
deformity of the knee.
sessile osteochondromas.
lining the femoral
metaphyses. These, along
with hip exostoses, result in
mechanical abnormalities
promoting early osteoarthritis
Ell centered in the lateral
compartment and a resulting
valgus deformity.

Hemimelica)
enlarged, flattened, slightly
dysmorphic epiphyses in a
patient with a mild form of
spondyloepiphyseal
dysplasia. The morphologic
abnormalities can result in
abnormal alignment (genu
valgum) and early
osteoarthritis. (Right) AP
radiograph shows lobulated
cartilage attached to the
medial femoral condyle.
an example of Trevor
Fairbank disease. With
weight bearing, this forces
the knee into a genu valgum
position. (tMSK Req).
I
371
Ol
Q) GENU VARUM (BOW LEG DEFORMITY)
--'~
Q)
~ o Joint-related abnormalities (arthritis,

--'
"0 morphologic abnormalities of epiphyses)
C
CIl
Common o Abnormalities differentially affecting
Q)
Q)
• Physiologic Bowing medial physis (trauma, osteomyelitis,
c • Arthritis
~ Blount disease, radiation, Turner)
"0 • Physeal Fractures o Abnormalities resulting in bowing of
Q)
<Il • Blount Disease femur/tibia, mimicking genu varum (renal
'"
aJ • Renal Osteodystrophy (Renal 00) 00, 01, osteochondromatosis, Ollier, etc.)
>-
E Less Common Helpful Clues for Common Diagnoses
-
o
«'"
c
• Osteogenesis Imperfecta (01)
• Osteomyelitis
• Physiologic Bowing
o Seen in infants; occasionally persists
• Charcot, Neuropathic • Arthritis
• Osteochondromatosis o Osteoarthritis (OA) most frequently affects
• Achondroplasia medial compartment, resulting in varus
• Spondyloepiphyseal Dysplasia • Physeal Fractures
• Multiple Epiphyseal Dysplasia o Salter fx (usually III or IV) of medial
Rare but Important femoral or tibial condyle - early bony
• Turner Syndrome (Mimic) bridging medially - genu varum
• Mucopolysaccharidoses • Blount Disease
• Ollier Disease o Vertical & irregular medial tibial growth
• Lead Poisoning plate - undergrowth of medial tibial

• Hypochondroplasia condyle (beaking) - varus
• Fluorosis Helpful Clues for Less Common Diagnoses
• Hypophosphatemic Rickets (X-Linked) • Osteogenesis Imperfecta (01)
• Metaphyseal Chondrodysplasia o Congenita form has short, bowed femora
• Radiation-Induced Growth Deformities & tibia, giving exaggerated bowed leg
ESSENTIAL INFORMATION o Any epiphyseal dysplasia may have larger
lateral femoral condyle, resulting in varus
• Genu varum = < 4° valgus, or mechanical
axis falling lateral to mid-knee • Turner Syndrome (Mimic)
o Underdevelopment & flattening medial
• General categories resulting in genu varum
tibial metaphysis; may mimic Blount dz
Arthritis Physeal Fractures
I AP radiograph shows differential

medial compartment •.
narrowing
resulting in genu varum.
of the
medial tibial epiphysis, physis, & metaphysis =.
AP radiograph shows a Salter IV fracture crossing the
There
Normal bone density, sclerosis of the sulxhondral is mild depression of the fragment. Healing occurred in
bone, & mild osteophyte formation are all typical of OA. this position. resulting in a varus deformity.
372
GENU VARUM (BOW LEG DEFORMITY) ~
::J
...•
III
o
3
'<
OJ
III
Osteogenesis Imperfecta (01) VI
Blount Disease 11l
(Leh) Coronal PO FSf FS MR Co
shows typical case o( Blount A
disease or tibial vara, with a ::J
11l
vertically oriented irregular ro
medial tibial growth plate OJ
::J
lID. This results in a beak-like Co
appearance o( the proximal r
o
tibial metaphysis Eill (Right) :E
Anteroposterior radiograph ro
~
shows OJ congenita, with r
ro
short, broad, & bowed <0
tubular bones of the lower
extremity IIll. The bowing of
the tibia & femur typically is
in a lateral direction,
resulting in a clinical
appearance of genu varum.

abnormalities at (emoral &
tibial epiphyses, with early
tibial physis =-
bony bridging at the medial
With
continued growth laterally, a
genu varum deformity
develops. The underlying
cause in this case was
meningococcemia. (Right)
AP radiograph shows
destruction of the joint,
predominantly medially III
resulting in genu varum.
Note the bony debris
dissecting down fascia/tissue
planes. in thispatient with
tabes-related Charcot joint.
Achondroplasia
short tubular bones of the
lower extremity, with broad
dysmorphic metaphyses. The
abnormal growth at the
metaphyses often results in
genu varum in patients with
achondroplasia. (Right) AP
radiograph shows relative
underdevelopment and
flattening of the medial tibial
metaphysis" in Turner
syndrome. There is some
compensatory overgrowth of
Ell but varus deformity may
occur. This may mimic
Blount disease.
I
373
Q)
:;;: ACHILLES TENDON THICKENING/ENLARGEMENT
c
<{
""0
C
C1l DIFFERENTIAL DIAGNOSIS o Seen with degenerative tendinopathy,
oo Common
inflammatory or seronegative arthritis
LL • Haglund Syndrome
""0 • Tendinosis/Tear o Enlarged posterosuperior calcaneal process,
Q)
Ul • Retrocalcaneal Bursitis retrocalcaneal bursitis, Achilles tendinosis
Ol
III • Haglund Syndrome o Aggravated by tight shoes = "pump bump"
>.
-
E
o
Ol
C
<{
Less Common
• Post-surgical Thickening
• Arthritis
Helpful Clues for Less Common
• Post -surgical Thickening
o Marked thickening with extensive
Diagnoses
Rare but Important intrasubstance increased Sl typical in

• Xanthoma (Fibroxanthoma) repaired tendon
• Accessory Soleus (Mimic) o Failed repair marked by extensive fiber
• Neoplasm disruption
• Arthritis
o Inflammatory arthritis: Osteopenia,
ESSENTIAL INFORMATION retrocalcaneal bursitis, erosions
Helpful Clues for Common Diagnoses o Seronegative spondyloarthropathies: ±
• Tendinosis/Tear Osteopenia, mixed erosive-productive
o Tendon thickening ± increased Sl arthritis, periostitis
o Most common 2-6 cm proximal to o Gout: Tophaceous calcific deposition
insertion Helpful Clues for Rare Diagnoses
o Results in rounding of normal crescentic • Xanthoma (Fibroxanthoma)
tendon in axial plane o Thickened tendon with speckled
o lntrasubstance, partial & complete tears = t intermediate Sl due to lipid deposition in
Sl on T2 hyperlipoproteinemia
o ± Peritendinous edema & retrocalcaneal • Accessory Soleus (Mimic)
bursitis o Located anteromedial to Achilles tendon,
• Retrocalcaneal Bursitis obscuring Kager fat pad; intermediate Sl =
o Inflammation/swelling of bursa between muscle
calcaneus & tendon • Neoplasm
o Typically t Sl (T2) due to bursal effusion ± o Rare reports of pigmented villonodular
synovial hypertrophy synovitis, lymphoma, chondrosarcoma,
fibroma
Tendinosis/Tear Tendinosis/Tear
I Sagittal PO FSE FS MR shows intermediate SI tendon

thickening Ell 4- S cm proximal to tendon insertion,
Sagittal PO FSEFS MR shows complete Achilles tendon
tear Ell at the musculotendinous juncUon with fiber
represenUng Achilles tendinosis. Note adjacent 50ft retracUon leaving a 2.5 em gap. The more distal tendon
tissue edema. & Kager fat pad edema •. is markedly thickened •.
374
ACHILLESTENDON THICKENING/ENLARGEMENT »
..
:l
III
o
3
'<
OJ
III
VI
Retrocalcaneal Bursitis (1)
(Left) Sagittal PO FSf FS MR a.
shows retrocalcaneal bursitis TI
with intermediate & t SI due o
to synovial hypertrophy Ell ~
III
& effusion" respectively. :l
Note the adjacent a.
heterogeneity & thickening »
:l
of tendinosis _ (Right) ~
(l)
Sagittal T2WI FS MR shows a
prominent posterosuperior
calcaneal "bump" with mild
marrow edema. &
retrocalcaneal bursitis Ell.
There is a partial tear of the
thickened Achilles tendon
•. The combination is
typical of Haglund
syndrome.
Post-surgical Thickening Arthritis

shows an intact Achilles
tendon debridement & repair
with diffuse intermediate
thickening Ell & post-surgical
change in the adjacent soft
tissues" including small
foci of micrometallic debris
•• (Right) Sagittal bone CT
reformation shows Achilles
tendon thickening IlIII with
periostitis" & enthesitis Ell
in this middle-aged man with
Xanthoma (Fibroxanthoma) Accessory Soleus (Mimic)

shows a diffuse Achilles
tendon mass Ell with slightly
heterogeneous ~ Sian all
sequences, typical of a
xanthoFibroma. This patient
has hypercholesterolemia.
shows an accessory soleus
muscle" extending to the
medial posterior calcaneal
tubercle. This normal variant
may present as a "thickened
Achilles tendon" but in fact
is a separate structure. Note
the normal SI of muscle
throughout.
I
375
Q)
CALCANEAL EROSIONS, POSTERIOR TUBERCLE
32
c I I
<l:
"0
C
DIFFERENTIAL DIAGNOSIS o Inflammatory arthritis may be axial &/or
<Il I peripheral
oo Common
LL • Axial: Spondyloarthropathy,.generally
"tl
• Rheumatoid Arthritis (RA) with bilaterally asymmetric sacroiliitis
Ql
II) • Chronic Reactive Arthritis (CRA) • Peripheral: Foot/ankle most frequently
n:I
al • Psoriatic Arthritis (PSA) involved
>. o Arthritis is mixed erosive & productive;
E Less Common
-
o
n:I
C
<l:
• Inflammatory Bowel Disease Arthritis (IBD)
either may predominate
• Digits may show sausage swelling &
• Haglund Syndrome periostitis
• Achilles Tendinitis o Hint: Calcaneal involvement is thought to
• Plantar Fasciitis be the hallmark of CRA

• Osteomyelitis • CRA is relatively rare process, but
calcaneal involvement is frequent if one
Rare but Important has the disease
• Gout • Psoriatic Arthritis (PSA)
• Repair of Achilles Tendon (Mimic) o Relatively common inflammatory arthritis
• Juvenile Idiopathic Arthritis alA) o Arthritis may occur prior to development
of skin lesions
ESSENTIAL INFORMATION o May be axial &/or peripheral
• Axial: Spondyloarthropathy, generally
Key Differential Diagnosis Issues with bilaterally asymmetric sacroiliitis
• Classic calcaneal erosive disease is CRA • Peripheral: Hand most frequently
o CRA much less prevalent relative to other
involved, though foot/ankle may be as
inflammatory arthritides that may well
occasionally affect the calcaneus o Arthritis is mixed erosive & productive,
o Hint: Remember that RA eroding the
with either predominating
calcaneus may actually be more common • Digits may show sausage swelling &
than CRA periostitis
• Hint: Watch for osteoporosis o Hint: PSAmay involve calcaneus, but not
o Present in RA, AS, & JIA
as frequently as CRA
o Present focally with local inflammatory
change (Achilles bursitis & early Helpful Clues for Less Common Diagnoses
inflammatory arthritis) • Ankylosing Spondylitis (AS)
• Hint: Location of other erosions is an o Most common of the spondyloarthritides
important parameter (bilaterally symmetric sacroiliitis)

o Does not often involve foot/ankle
Helpful Clues for Common Diagnoses • Generally involves large proximal joints
• Rheumatoid Arthritis (RA) (hip, shoulder)
o Most common inflammatory arthritis o Advanced disease (generally not treated)
o Purely erosive process; osteoporotic may involve peripheral joints, including
o Foot disease more prevalent than is
ankle & calcaneus
commonly thought o Mixed erosive/productive
• MTP (especially 5th) o Osteoporosis
• Ankle, including posterior calcaneus • Inflammatory Bowel Disease Arthritis
o Hint: Purely erosive change in
(IBD)
osteoporotic posterior calcaneus results o Similar appearance to AS, with symmetric
from RA more frequently than CRA & bilateral sacroiliitis
• Chronic Reactive Arthritis (CRA) o Generally involves proximal large joints
o Combined syndrome of uveitis, urethritis (hip, shoulder)
(cervicitis), & inflammatory arthritis o Rarely involves peripheral joints &
calcaneus
I
376
CALCANEAL EROSIONS, POSTERIOR TUBERCLE
• Haglund Syndrome • Hematogenous spread

a "Pump bump" • Direct inoculation
a Prominent posterior calcaneal osseous & o Direct inoculation in adults, particularly
bursal projection diabetics with heel ulceration
a Thickening of Achilles tendon at insertion a Destructive change, but usually not at
a Achilles bursitis typical location for true erosive disease
a True erosive change of posterior calcaneus
is rare, but deossification may occur,
related to bursal inflammation • Gout
a Tibiotalar involvement may extend as
• Achilles Tendinitis juxtaarticular involvement of posterior
a Most often occurs at the
calcaneus
musculotendinous junction, well above a Scalloped erosive change on posterior
posterior calcaneal tubercle
tubercle with associated soft tissue mass
a Occasionally may occur more distally
• Mass may be dense (tophus) or even
• Thickening & signal abnormality within subtly calcified
tendon • Repair of Achilles Tendon (Mimic)
• Elicits pre-Achilles bursitis a Tunnel or direct attachment of
• Does not cause true erosion, but adjacent reconstruction into posterior tubercle
inflammation may result in posterior
• One technique is to loop flexor hallucis
calcaneal cortical deossification
tendon through tunnel & attach to
• Plantar Fasciitis residual Achilles fibers
a Thickening, increased signal intensity of a Site of tunnel or attachment may cause a
plantar fascia
defect in posterior calcaneus mimicking an
a Usually at plantar aponeurosis insertion on
erosion
plantar aspect posterior calcaneal tubercle
a Generally there is an associated plantar
a Ankle involvement in JIA is generally
spur tibiotalar destructive change, similar to
a May have edema within adjacent bone
that of hemophilic arthropathy
a Inflammatory changes may result in a Rare true erosive change in posterior
deossification of bone, though generally calcaneal tubercle
not true erosion
• Osteomyelitis
a Calcaneal metaphysis & apophysis are
typical locations for infection in child
Lateral radiograph shows extensive erosive disease at the

posterior tubercle III. The bones are osteopenic for age
Lateral radiograph shows focal osteopenia and a
dot-dash cortical pattern III typical of early erosive
I
& gender, and there is no productive change. Prominent change. This patient has convincing RA at other sites;
MTP erosions help make the diagnosis of RA. later erosive change in the calcaneus is not uncommon.
377
Q)
:>< CALCANEAL EROSIONSr POSTERIOR TUBERCLE
c
<l:
"0
C
<tl
(5
o
u.. Chronic Reactive Arthritis (CRA)
"0 (Left) Lateral radiograph
Ql shows normal bone density,
Ul
<tl very large erosions _ and
III mild productive change
>- adjacent to the erosions. The
E
-o
III
C
<l:
patient was a young male
with urethritis; this is eRA.
shows mild erosive change at
the posterior calcaneus III
with surrounding more
prominent fluffy productive
change Ill. This pattern of
periostitis in the calcaneus ;s
typical of CRA, though less
frequently could be seen
with psoriatic arthritis.

shows an erosion. with
mild periostitis III as well as
a heel spur. Though this
could represent the changes
of CRA, in this case the
diagnosis is PSA; the patient
had skin changes as well as
arthritis involving the hand.
shows posterior calcaneal
deossification & early erosion
III along with severe
erosions in the Chopart joints
III & subtalar fusion. This
patient had long-standing
AS, not treated with
medication.

(lBO) Haglund Syndrome
shows inflammatory change
at the posterior calcaneus.
and an early erosion Ill. The
more inferior osseous density
is ossification of the
calcaneal apophysis. This is
IBO arthritis in a 10 year old
child who had 3 months of
diarrhea. (Right) Sagittal
T1WI MR shows an osseous
bump ~ at the posterior
tubercle with thickened
overlying Achilles Ell typical
of Haglund syndrome. There
is fluid distending the
pre-Achilles bursa and
adjacent deossification IlIl.
I
l7/l
CALCANEAL EROSIONS, POSTERIOR TUBERClE :l>
:J
..•o
Gl
3
'<
OJ
Gl
VI
Achilles Tendinitis Plantar Fasciitis C1l
Sagittal PO FSE FS MR Co
(Leh)
shows high signal of Achilles ,.,o
tendinitis.
~
with adjacent
distended pre-Achilles bursa
There is mild calcaneal
edema at the insertion.
-
o
Q)
:J
a.
that may be seen as
:l>
:J
deossification on radiograph.
(Right) Sagittal STIR MR
'"CO
shows thickening & high
=
signal in the plantar fascia
with surrounding soft
tissue edema •. There is
edema within the calcaneus
EiII that may eventually
develop into a plantar spur;
at this point, it may appear
as deossification on X-ray.
Osteomyelitis
shows erosive and
destructive change in the
metaphysis of the calcaneus
as well as the apophysis _
This is typical of, and proved
to be, osteomyelitis. (Right)
severe erosive destructive
change at the posterior
calcaneus, along with air in
the soft tissues _ This is
advanced osteomyelitis in a
diabetic patient.
Repair of Achilles Tendon (Mimic)

shows a dense 50ft tissue
mass. with erosions of the
posterior talus. and
calcaneus Ia. This proved to
be gout in a young woman
with end-stage renal disease.
shows the looped flexor
hal/ucis tendon interposition
• for an Achilles tendon
repair (which has failed).
There is an associated
surgical defect in the
superior aspect of the
posterior calcaneus li'8 that
might be mistaken for an
erosion.
I
379
(l)
3< RETROCAlCANEAl BURSITIS

c:
«
"0
c:
C1l DIFFERENTIAL DIAGNOSIS • Inflammatory Arthritis
oo o Rheumatoid & juvenile idiopathic arthritis
LL
Common o Diffuse osteopenia, erosion of
'1:l
• Achilles Tendon Tear & Tendinopathy posterosuperior calcaneus from synovial
Q)
II) • Haglund Deformity inflammation; joint space loss & erosions
C1l
10 • Inflammatory Arthritis in hindfoot joints
>-
E less Common Helpful Clues for less Common Diagnoses
-
o
C1l
c:
«
• Gout
• Seronegative Spondyloarthropathy
• Gout
o Discrete, marginated erosions; ± soft tissue
• Calcaneal Fractures tophi
• Osteomyelitis • Seronegative Spondyloarthropathy
Rare but Important o Psoriatic, chronic reactive, ankylosing
• Sever Disease (Calcaneal Apophysitis) spondylitis & inflammatory bowel disease
arthritis
o Posterosuperior calcaneus erosions, soft
ESSENTIAL INFORMATION tissue thickening, periosteal reaction
Key Differential Diagnosis Issues ("whiskering") near tendon insertions
• Inflammation of deep Achilles bursa • Calcaneal Fractures
interposed between Achilles tendon & o Consider this diagnosis when evaluating
posterior calcaneal tubercle bone & soft tissue edema on MR; fractures
• May have f Sl from bursal effusion &/or may be less evident on MR than
synovial hypertrophy (intermediate Sl) radiography/CT
• May be unilateral or bilateral depending on • Osteomyelitis
etiology o Soft tissue swelling, cortical loss, marrow
edema, ± abscess
• Achilles Tendon Tear & Tendinopathy Helpful Clues for Rare Diagnoses
o Tendon thickening with intrasubstance • Sever Disease (Calcaneal Apophysitis)
signal; ± bursal thickening, effusion o Calcaneal apophysitis: Inflammation of
• Haglund Deformity apophysis in active boys 10-13 years

o Also known as "pump bump"; related to o Sclerotic calcaneal apophysis with
wearing tight shoes with closed back associated pain; marrow edema with intact
o Prominent posterosuperior calcaneal cortical surfaces
tubercle (squaring or enthesophyte)
I Sagillal T2WI F5 MR shows Achilles tendon thickening

III with associated retrocalcaneal bursitis •. Note the
Sagittal bone CT reformation shows marked
prominence of the posterosuperior calcaneal tubercle
prominent posterior calcaneal tubercle Ell resulting in •• typical of Haglund deformity.
"pump bump".
380
RETROCAlCANEAl BURSITIS »
-
:l
Ql
o
3
'<
llJ
Ql
VI
<1l
(Leh) Lateral radiograph a.
shows diffuse osteopenia & -n
multiple small posterior o
ca/caneal erosions III in this
~
Q)
patient with rheumatoid :l
arthritis. Note the marked
a.
tibiotalar joint space »
:l
narrowing EEl & absence of 2:5:
<1l
reparative bone. (Right)
posterior calcaneal erosions
IIlI with 50ft tissue swelling
of the reuoea/caneal bursa
Ell in this patient with
psoriatic arthritis. Note the
large tibiotalar joint effusion
=
(Leh) Sagillal bone CT
reformation shows
retrocalcaneal bursitis HI
with a mixed
erosive-productive
arthropathy in this 40 year
old man with chronic
reactive arthritis. Note the
"whiskering". of
reparative bone. (Right)
Sagittal STIR MR shows the
=
reuoea/caneal
accompanying a
bursal effusion
calcaneal fracture IlIIthat

runs perpendicular to the
main trabecular struts with
surrounding marrow edema.
Osteomyelitis Sever Disease (Calcaneal Apophysitis)

(Leh) Sagittal T1 C+ MR
shows intense calcaneal
marrow edema Ell with a
small fluid collection IlII in
apophysis as well as 50ft
tissue swelling & bursitis
in this biopsy proven
=
osteomyelitis. (RighI) Sagittal
T2WI FS MR shows
inflammation with ca/caneal
apophyseal & metaphyseal
edema EEl with
retrocalcaneal bursitis III as
well as subcutaneous edema
IlII but no discrete fluid
collection. The apophysis is
sclerotic on radiograph (not
shown).
I
381
Q)
:;;:; SOFT TISSUE MASS IN THE FOOT
c::
«
"0
c::
ctl DIFFERENTIAL DIAGNOSIS o Complete tendon tear with minimal
"0 diastasis: t SI in tear defect
o
LL
Common o Tenosynovitis: Distended t SI in sheath, ±
"'C • Bursitis tendon abnormality
Q)
Ifl • Tendon, Injury • Plantar Fasciitis
III
!Xl • Plantar Fasciitis o Thickening fascia (usually medial band); ±
>- • Ganglion Cyst plantar fat pad edema, calcaneal marrow
E
•..o
III
• Plantar Fibroma edema
c: • Morton Neuroma o May lead to rupture
« • Gouty Tophus • Ganglion Cyst
• Lipoma, Soft Tissue o Thin-walled discrete fluid collection, ±
LessCommon multiseptate, often near joint line
• Charcot, Neuropathic • Plantar Fibroma
• Hemangioma, Soft Tissue o Single or multiple nodular thickenings
• Soft Tissue Abscess arising from plantar fascia
• Giant Cell Tumor Tendon Sheath o Intermediate to ~ SI on all sequences, ±
• Pigmented Villonodular Synovitis (PVNS) enhancement
• Glomus Tumor • Morton Neuroma
o Nodule plantar to intermetatarsal
Rare but Important ligament; intermediate Tl SI, ~T2 SI, ±
• Rheumatoid Nodule enhancement
• Xanthoma (Fibroxanthoma) o May be associated with intermetatarsal
• Aneurysm bursitis
• Accessory Muscle • Gouty Tophus
• Soft Tissue Neoplasms o Soft tissue nodular calcification, ~ SI (T1 &
• Granuloma Annulare T2); osseous erosions, predilection for
• Tumoral (Idiopathic) Calcinosis Lisfranc, MTP joints
• Macrodystrophia Lipomatosa • Lipoma, Soft Tissue
• Skin & Subcutaneous Lesions o SI similar to subcutaneous fat; may have
associated calcification, ossification,
ESSENTIAL INFORMATION hemorrhage, or fibrosis
Key Differential Diagnosis Issues Helpful Clues for LessCommon Diagnoses
• While radiographs demonstrate the osseous • Charcot, Neuropathic
changes, MR is the imaging tool of choice o Mimics soft tissue mass due to marked
for soft tissue evaluation joint distension, dissolution, destruction,

disorganization, dislocation
Helpful Clues for Common Diagnoses • Hemangioma, Soft Tissue
• Bursitis o ~ SI (Tl) mass with interdigitating fat;
o Inflammation of space interposed between
striated or septated t SI (T2); ± phleboliths
muscle, tendon, skin, & adjacent bone • Soft Tissue Abscess
o Retrocalcaneal: Between calcaneus &
o Look for sinus tract, foreign body implant
Achilles o Fluid collection with thickened, irregular
o Intermetatarsal: Between 2 metatarsal
walls; ± surrounding soft tissue edema
heads, dorsal to intermetatarsalligament • Giant Cell Tumor Tendon Sheath
o Adventitious: Plantar fat pad near o Intermediate to ~ SI (Tl & T2) mass
metatarsal head (1st & 5th, most associated with tendon, + enhancement; ±
commonly); often with accompanying calcification
fibrosis • Pigmented Villonodular Synovitis (PVNS)
• Tendon, Injury o Intermediate to ~ SI (Tl & T2) mass; ~ SI on
o Tendinopathy/partial intra substance tear: GRE due to hemosiderin; ± calcification; +
Intermediate to t SI in tendon enhancement; erodes adjacent bones
I
382
SOFT TISSUE MASS IN THE FOOT ~
:l
..•o
Ql
• Glomus Tumor o Ill-defined, intermediate to ! Sl nodule 3

'<
o Well-defined, t Sl (T2/STIR), intense with enhancement OJ
Ql
enhancement • Tumoral (Idiopathic) Calcinosis
o Tumor of neuromyoarterial glomus of nail o Lobular calcification in muscles & soft
'c."
(I)
bed tissues; heterogeneous! Sl due to

calcification intermixed with edema,
"
o
~
Helpful Clues for Rare Diagnoses III
fibrosis :l
• Rheumatoid Nodule C.
o More common in African Americans J>
o Subcutaneous nodule with homogeneous ! :l
• Macrodystrophia Lipomatosa """
Sl, peripheral enhancement; adjacent joint
o Macrodactyly associated with neural
en
erosions
fibrolipoma; osseous/soft tissue
• Xanthoma (Fibroxanthoma)
o Seen in hypercholesterolemia; ! Sl (Tl & overgrowth
o Look for nerve enlargement
T2) masses within tendons, speckled in
appearance • Skin & Subcutaneous Lesions
o Plantar warts, epidermal inclusion cyst
• Aneurysm
o Look for vessel of origin, may be saccular Other Essential Information
or fusiform; flow voids • Differential considerations may be further
• Accessory Muscle subdivided by anatomic location
o Soleus, flexor digitorum accessorius o Forefoot
longus, peroneocalcaneus intern us, • Morton neuroma, intermetatarsal
tibiocalcaneus internus bursitis, adventitious bursitis,
• Soft Tissue Neoplasms rheumatoid nodule, gout, glomus tumor
o Benign: Lipoma, hemangioma, nerve o Plantar fascia
sheath tumor, soft tissue chondroma, • Fasciitis, fascial rupture, plantar
desmoid type fibromatosis fibromatosis, soft tissue abscess, foreign
o Malignant: Fibrosarcoma, body
dermatofibrosarcoma protuberans, clear o Retrocalcaneal palpable mass
cell sarcoma, malignant fibrous • Retrocalcaneal bursitis, Achilles
histiocytoma, synovial sarcoma, tendinopathy, xanthoma, accessory
leiomyosarcoma, Kaposi sarcoma, muscle
chondrosarcoma, rhabdomyosarcoma
• Granuloma Annulare
Bursitis Bursitis
Sagittal STIR MR shows retroca/caneal bursitis (t 51

fluid) III accompanying Achilles tendinosis/partial
Coronal PO Fsf Fs MR shows a slightly nodular fluid
collection III interposed between Jrd & 4th metatarsal
I
inLrasubSlance lear with striated intermediate 5/ • in heads dorsal to the intermetatarsal ligament, typical of
the tendon. intermetatarsal bursitis.
383
Q)
:i1
SOFT TISSUE MASS IN THE FOOT
c
<t:
"0
C
ro
oo
u..
"t:l (Left) Coronal TI WI MR
Q)
shows a focal uniform • 51
VJ
mass EiIII under the 5th
'"
CD metatarsal head that is
>. palpable & relatively
-'"
E
o
c
<t:
painless. The adjacent
metatarsal is normal. (Right)
Coronal PO FSf FS MR
shows the same soft tissue
mass with slightly
heterogeneous t 51 in the
patient with an adventitious
bursa lEI & fibrosis EiIII. This
benign subcutaneous bursitis
is biopsy proven.
(Left) Sagittal PO FSf FS MR

shows an ankle mass Ell
anterior to the talus.
Thickening & intermediate 51
• represent an anterior
tibialis tendinosis/partial tear
with a small amount of
tenosynovitis lEI. (Right)
Sagittal PO FSf FS MR shows
a normal flexor hallucis
longus tendon ~ with a
distended tendon sheath EiIII
osteoarthritis & tenosynovitis.
Note the degenerative
subchondral cyst ••.
(Left) Sagittal STIR MR

shows plantar fat pad" &
muscle edema lEI with
complete plantar plate
rupture ~ 15 mm distal to
calcaneal origin EiIII of fascia.
shows medial plantar fascial
band thickening" just
distal to the calcaneal origin
with mild adjacent plantar
fat pad edema EiIII.
I
184
SOFT TISSUE MASS IN THE FOOT
Ganglion Cyst Plantar Fibroma

(Left) Coronal PO FSf FS MR
shows a thin-walled
multiseptate ganglion ••
that arises lateral to the 1st
metatarsal head & tracks to
the dorsal subcutaneous so(t
tissues. (Right) Sagittal PO
FSf FS MR shows a small
intermediate signal nodule
E!III arising in the planter
(ascia, typical o( a plantar
fibroma. In addition, there is
a small but iII-de(ined so(t
tissue ganglion" arising
(rom the arthritic 1st
tarsometatarsal joint •.
Morton Neuroma Morton Neuroma

shows a slightly
dumbbell-shaped nodule E!III
arising between the 3rd &
4th metatarsal heads plantar
to the intermetatarsal
ligament and extending into
the plantar so(t tissue. (Right)
Coronal T1 C+ FS MR shows
heterogeneous enhancement
E!III o( the same lesion,
typical of a Morton neuroma,
which ;s a perineural Fibrosis
o( a plantar digital nerve,
resulting in entrapment of
the nerve itself.
Gouty Tophus lipoma, Soft Tissue

shows a large soft tissue
mass. low signal
intensity, which remained
largely low Sian T2
weighted imaging. The lesion
is destructive but involves
the 1st MTP joint. It proved
to be gout. (Right) Coronal
T1WI MR shows a dumbbell
shaped t 51mass" similar
to the adjacent
subcutaneous fat. This
encapsulated lipoma results
in a widened intermetatarsal
space.
I
385
Q)
:i: SOFT TISSUE MASS IN THE FOOT
c
~
"0
C
co
oo
u..
"0 (Left) Sagillal T1 WI MR
Q)
shows the typical destruction
IJl
l'll of a Charcot joint with
lD talonavicular dislocation _
>- There is joint effusion ••
E
•...o
l'll
filled with ossific debris.
this patient with diabetes.
in
C
The large distended and
~ disrupted joints may present
as a soft tissue mass. (Right)
Coronal T2WI FS MR shows
a mass composed of t 51
tubular structures. with
interdigitating fat 0 51on fat
suppression sequence) __
displacing the flexor
digitorum tendons. &
infiltrating the muscle belly.
(Left) Sagillal T1WI FS MR

shows a plantar mass in a
young girl with a history of a
toothpick puncture wound 2
months earlier with
incomplete removal. There is
subsequent abscess.
formation around the
retained foreign body_
(Right) Sagittal PO FSf FS
MR shows a focal
subcutaneous fluid collection
EiII & sinus tract. to a
deeper fluid collection with a
thickened, irregular wall.
in this patient with diabetes.
Giant Cell Tumor Tendon Sheath Pigmented Villonodular Synovitis (PVNS)

shows an intermediate 51
mass. withinthe anterior
tibialis tendon sheath EiII
d~p~cmgthetendon. Th~
giant cell tumor of tendon
sheath enhanced uniformly
(not shown). (Right) Sagittal
T2WI MR shows a large,
predominantly low signal
intensity mass within the
ankle joint _ which
produces an anterior foot
mass. Since it is
intraarticuJar, the low signal
should be suggestive of
either PVNS or gout; the
former was proven.
I
186
SOFT TISSUE MASS IN THE FOOT l>
:]
...•
Dl
o
3
'<
OJ
Dl
Xanthoma (Fibroxanthoma) VI
Glomus Tumor CD
(Leh) Coronal TI WI FS MR Co
shows an intensely TI
enhancing nodule. in the o
tip of the nailbed. There was ~
Q)
subtle erosion of the distal :J
Cl.
phalanx on initial radiograph
(not shown). (Right) Axial »
:J
T1WI MR shows ~
CD
xanthofibromatosis of
Achilles tendon Ell with
slightly heterogeneous low
signal. There are similar
findings in the posterior tibial
tendon. in this patient
with hype/cholesterolemia.
Accessory Muscle Soft Tissue Neoplasms

(Leh) Axial PO FSEMR
shows a palpable, painless
mass _ (isointense to
muscle) that originates from
the tibia anterior to soleus &
inserts on the superior
calcaneus, typical of an
accessory soleus. (Right)
Sagittal T2WI MR shows the
multiple lobulate, t Silesian
• destroying the tarsals &
invading the adjacent soft
tissues. This aggressive lesion
is a chondrosarcoma.
radiograph shows a normal
hind & midfoot, as well as
normal 4th & Sth rays _
However, there is giantism of
both the soft tissues & bones
of 1st three digits Ell typical
of macrodystrophia
lipomatosa. (Right) Sagittal
TI WI MR shows an elliptical
epidermal mass. that is ~
SI & corresponds to a slightly
flattened nodule with a small
central petechiae, typical of
a plantar wart.
I
387
~ TALAR BEAK
-'<c
<{
-0
C
ctl DIFFERENTIAL DIAGNOSIS • Hypertrophied Talar Ridge
(5 o Same location as talar ridge
o Common o Subjectively enlarged talar ridge, but no
LL
-0 • Talar Ridge specific size to delineate normal from
CIl
IJl • Hypertrophied Talar Ridge hypertrophied
III
lD • Osteophyte o Key finding: Bony ridge is located
>- proximal to the talar head articular surface
E Less Common
•...o
III
• Tarsal Coalition with an intervening normal segment
C o Seen in athletic patients or patients with
<l:
diffuse enthesopathy
ESSENTIAL INFORMATION • Osteophyte
Key Differential Diagnosis Issues o Located along cartilage margins
• Osseous excrescence located along the dorsal • Proximally at ankle with associated
surface of the talus anterior tibial osteophytes
• Location & size of bony outgrowth is most • Distally at talonavicular joint with
important for diagnosis associated joint space narrowing
• a.k.a., talar spur, talar lip, or talar crest o Degenerative or post-traumatic finding
• Best demonstrated on lateral radiographs & Helpful Clues for Less Common Diagnoses
sagittal MR or CT • Tarsal Coalition
Helpful Clues for Common Diagnoses o Anteriorly directed, triangular outgrowth
• Talar Ridge extending from the talar ridge to, or near,
o Located 7-14 mm from trochlear surface the level of the talar head articular surface
o Several millimeters high o May be extreme hypertrophy of talar ridge
o Straight to convex configuration o Look for osseous or fibrous union of the
• Sloped along proximal border talus & calcaneus or calcaneus & navicular
• More acute angle along distal border o Secondary signs of coalition include the
o Normal ridge of bone at junction of "C-sign" & non-visualization of the
• Ankle joint capsule subtalar joint middle facet
• Talonavicular ligament
• Anterior talofibular ligament SELECTED REFERENCES
o Largest along lateral border
1. Resnick D: Talar ridges, osteophytes, and beaks: a
o Normal, flat portion of talus between talar radiologic commentary. Radiology. 151(2):329-32, 1984
ridge & talar head articular surface
I Sagittal NECT shows a normal talar ridge. along the

dorsum of the talus. Note the shorl, flat segment.
Sagittal NECT shows a normal talar ridge. located
proximal to the talar head articular surface. This patient
between the ridge and articularsurface. also had an unrelated but extensively comminuted
calcaneus fracture HI.
388
TALAR BEAK »
:J
...•
Ql
o
3
'<
OJ
Ql
VI
C1l
(Left) Sagittal TI WI FS MR Co
shows hypertrophy. of the "Tl
normal talar ridge. This is o
likely caused, at least in part, ~
OJ
by traction from a thickened :J
Q.
talonavicular ligament. in
this athletic patient. (Right) »
:J
Sagittal NECT shows a
hypertrophied talar ridge •.
'"
m
The location of the
excrescence proximal to the
talar head articular surface,
with a short intervening
normalsegment. is
typical. This patient had a CT
to characterize the
comminuted distal tibial
fracture EiII.

shows a talar osteophyte 11II
that extends all the way to
the articular surface. Note
a/so the talonavicular joint
space narrowing" and
mild osteophyte formation
HI on the navicular side of
the joint. (Right) Sagittal
NECT shows a proximally
located dorsal talar
osteophyte IIiI along the
articular margin of the
anterior ankle joint This is
secondary to degenerative
changes, as seen by an
associated small anterior
tibial osteophyte •.
Tarsal Coalition Tarsal Coalition

shows a large talar beak ••
due to talocalcaneal
coalition. Notice that the
talar dome is rounded, as is
the medial aspect of the
tibial plafond, producing the
"C-sign" EiII. The normal
lucency of the subtalar joint
middle facet. is obscured.
(Right) Sagittal NEeT shows
a small talar beak. in a
patient with talocalcaneal
coalition. Solid bone bridges
the subtalar joint middle
facet. and partially fuses
the subtalar joint posterior
facet EiII
I
389
:>2
<1l
TARSALCYSTIC/LYTICLESIONS
c
<l:
"0
C
C1l DIFFERENTIAL DIAGNOSIS • Surrounding sclerotic bone
oo Common
• Preferential involvement of pressure
LL portion of joint
"0 • Subchondral Cyst o Gout
CIl
Vl o Osteoarthritis • Oval erosions with overhanging edges
C'O
o Gout
[JJ • Preserved joint spaces
>. o Rheumatoid Arthritis
E • Normal mineralization
.•..o o Juvenile Idiopathic Arthritis alA) • Soft tissue tophi
C'O
c: o Pyrophosphate Arthropathy o Rheumatoid Arthritis
<l:
o Amyloid Deposition • Inflammatory erosions located in
o Pigmented Villonodular Synovitis (PVNS) juxtaarticular regions
• Intraosseous Ganglion • Lack sclerotic border
• lntraosseous Lipoma • Joint space narrowing with osteoporosis
• Osteomyelitis • Lytic lesions may also be due to
• Charcot, Neuropathic secondary osteoarthritis
• Osteonecrosis o Pyrophosphate Arthropathy
Less Common • Large, widespread lesions
• Osteochondral Lesion of the Talus • Surrounding sclerotic bone
• Hemophilia, Pseudotumor • Joint space narrowing with bone collapse
• Unicameral Bone Cyst (UBC) o Amyloid Deposition
• Aneurysmal Bone Cyst • Intraosseous amyloid collections have
• Giant Cell Tumor variable appearance on MR
• Enchondroma • May show communication with articular
• Ewing Sarcoma surface
• Hyperparathyroidism/Renal Osteodystrophy, • History of hemodialysis is common
Brown Tumor o Pigmented Villonodular Synovitis
• Chondroblastoma (PVNS)
• Chondrosarcoma • Blooming signal of soft tissue masses on
• Soft Tissue Tumor, Locally Invasive gradient echo MR sequences
• Silicone-Induced Synovitis • Intraosseous Ganglion
o Single lesion with sclerotic border
Rare but Important
o ± Soft tissue mass
• Metastases, Bone Marrow • Intraosseous Lipoma
• Multiple Myeloma o Typical location in mid-calcaneus
• Paget Disease o Fat content can be confirmed with CT
• Osteosarcoma, Telangiectatic o ± Central calcification or fluid
• Angiosarcoma, Osseous • Osteomyelitis
• Hemangioendothelioma, Osseous o Osteopenia
• Sarcoidosis o Ill-defined bone erosion
o Soft tissue abscess
ESSENTIAL INFORMATION o Sinus tract
o ± Sequestrum
• Subchondral Cyst o Bone collapse & fragmentation
o a.k.a., synovial cyst, geode, pseudocyst
o Joint disorganization & debris
o Rounded radiolucent lesion near bone
o Can be difficult to differentiate from
surface osteomyelitis
o Signal intensity on MR varies with cyst
• Osteonecrosis
content: Fluid, gas, fibrous, adipose, o Single or multiple lesions
myxoid, or proteinaceous material o Weight-bearing area of joint
o Osteoarthritis
o Bone collapse & fragmentation
• Joint space narrowing
I
390
TARSAL CYSTIC/lYTIC LESIONS »

a Onset months to years after placement of
-
:l
Ql
o
3
'<
silicone joint prosthesis III
• Hemophilia, Pseudotumor Ql
a Normal surrounding bone mineralization VI
a Subchondral bone erosion, joint space CIl
helps exclude osteomyelitis Co
narrowing, osteopenia, & soft tissue masses
from hemorrhage Helpful Clues for Rare Diagnoses "o!a-
a Calcaneus: 1 of 3 most common sites of • Metastases, Bone Marrow ll)
OJ
hemophiliac pseudotumor a History of colon, genitourinary, or lung 0-
• Giant Cell Tumor malignancy in adults »

OJ
a Eccentric, expansile lytic lesion in a History of neuroblastoma, '"en

epiphysis rhabdomyosarcoma, or clear cell renal
a Lacks sclerotic border carcinoma in children
a ± Soft tissue mass • Multiple Myeloma
• Ewing Sarcoma a Lytic lesions with well-defined margins
a Lytic or sclerotic lesion with cortical a Faint sclerotic rim is rare
breakthrough • Paget Disease
a Classic onion-skin periosteal reaction is a Osteolytic lesion with blade of grass or
rare in foot flame shape
• Chondroblastoma a Disease progression includes coarsened
a Epiphyseal or apophyseal lytic lesion with trabeculae, cortical thickening, bone
sclerotic border & chondroid matrix enlargement, & sclerosis
• Chondrosarcoma • Osteosarcoma, Telangiectatic
a Lytic lesion with chondroid matrix a Fluid-fluid levels
a Endosteal scalloping or cortical a ± Aggressive periosteal reaction
breakthrough • Angiosarcoma, Osseous
a ± Soft tissue mass a Clustered, multicentric lytic lesions
• Soft Tissue Tumor, Locally Invasive a l1l-defined borders
a Soft tissue mass not centered in bone • Hemangioendothelioma, Osseous
a Signs of extrinsic mass effect, such as a Similar but less aggressive appearance than
scalloping, in addition to invasion angiosarcoma
a Bone invasion favors synovial sarcoma, a May have faint sclerotic borders
clear cell sarcoma, or epithelioid sarcoma • Sarcoidosis
• Silicone-Induced Synovitis a Punched-out round to oval lytic lesions
a Well-defined periprosthetic lytic lesions a Honeycomb or lattice trabeculae
Gout
Anteroposterior radiograph shows marked lytic erosion

IIlI of the larsals and melalarsals. Overhanging edges
Coronal NECT shows a focal lytic lesion in the talus IIlI
wilh a subtle overhanging edge 1IlI.An additiona/lesion
I
• and calcified soft tissue lophiHl are Iypical of goul. in the fibula HI supports the diagnosis of gout.
391
Q)
32 TARSAL CYSTIC/LYTIC LESIONS
c
<l:
"0
C
III
oo
U. Rheumatoid Arthritis
"0 (Left)Axial T1WI MR shows
Ql
III
periarticularerosions.
ro involving the metatarsal
ell heads. The bones were
>. osteopenic on radiographs.
E
-
o
ro
c
<l:
This is typical for rheumatoid
arthritis. (Righi) Lateral
joint space narrowing at the
tibiotalar joint and a
moderate joint effusion •.
A few small ossifications in
the effusion are likely
intraarticuJar osteochondral
bodies. Subchondral cystic
changes. involve both the
talus and tibia.
Pigmented Villonodular Synovitis (PVNS) Pigmented Villonodular Synovitis (PVNS)

radiograph shows 2 lytic
lesions •• in the 1st
metatarsal head. The smooth
borders of the lesions suggest
extrinsic erosion of the bone.
This was due to pigmented
villonodular synovitis of the
1st metatarsophalangeal
joint. (Right) Sagittal T1WI
MR shows multiple
isointense lesions" eroding
the calcaneus and cuboid
bones. There is an
intraarticular soft tissue mass
IllIa extending from the region
of the anterior and middle
facet of the subtalar joint.
Intraosseous lipoma Osteomyelitis

shows an oval, sharply
demarcated~ radiolucent
lesion. in the middle
portion of the calcaneus. The
lesion has a central focus of
calcification Ell. Fat content
of the lesion was confirmed
with computed tomography.
radiograph shows osteopenia
and a focal, ill-defined
erosion involving the tibial
side of the 3rd metatarsal
III An infectious etiology is
also suggested by the prior
amputation of the 3rd digit
1llIa.
I
192
TARSAL CYSTIC/LYTIC LESIONS
shows a fluid collection
located between the 3rd and
=
4th digits at the level of the
MTP joints. This collection
communicates with the joint
via a small sinus tract Ell.
Bone enhancement favors
septic arthritis and
osteomyelitis. (Right) Sagittal
TI WI MR shows irregular
destruction of the talus
and intraarlicular 50ft tissue
=
IlIIIl which extends
posteriorly in the joint space.
These findings were due to
an indolent fungal infection.
Osteomyelitis Charcot, Neuropathic

shows a typical case of
osteomyelitis. There is a focal
erosion Ell and abnormal
signal. involving the
calcaneus and calcaneal
apophysis, with extension
into the adjacent 50ft tissues.
Biopsy confirmed infection.
radiograph shows a
neuropathic deformity of the
midfoot with collapse,
fragmentation, dislocations,
and cystic changes III.
There are amputations.
through the 1st metatarsal
and 3rd toe.
Osteochondral lesion of the Talus Hemophilia, Pseudotumor

(Left) Sagittal TI WI FS MR
arthrogram shows an
osteochondral lesion III
involving the medial tafar
dome. fntraarticularly
administeredcontrast.
extends into the
osteochondral lesion,
suggesting instability. fRight)
lytic expanded lesions III in
the calcaneus. The cfinical
history is key. This represents
a pseudotumor, resulting
from repealed intraosseous
bleeds in a young man with
hemophilia.
I
393
Q)
32 TARSAL CYSTIc/LYTIC LESIONS
c
«
"0
c
<Il
oo
u.. Unicameral Bone Cyst (UBC) Unicameral Bone Cyst (UBC)
't:l (Left) Lateral radiograph
Q) shows a lytic lesion IIIin the
Vl
III calcaneal neck. The
1XI calcaneus ;s one of the most
>. common locations of UBC ;n
•..oE
III
adults. A paucity of
trabeculae in this region, as
C an anatomic variant, can
« mimic a bone cyst. (Right)
Sagittal T I C+ FS MR shows
an ovoid lesion IIIin the
mid calcaneus. The lesion
followed fluid signal intensity
on all MR imaging
sequences. UBC typically
shows mild peripheral
enhancement. without
central enhancement.
Aneurysmal Bone Cyst Aneurysmal Bone Cyst

aneurysmal bone cyst III
involving the base of the first
metatarsal. Note the thin,
intact cortex surrounding the
expanded portion of the
lesion. (Right) Sagittal T1WI
MR shows an eccentrically
located lesion IIIin the base
01 the 1st metatarsal. Note
the intact surrounding cortex
III. These findings in this
location suggest ABC,
unicameral bone cyst, and
possibly giant cell tumor as a
potential diagnoses.
Chondroblastoma Chondrosarcoma
(Left) Coronal oblique CECT
shows a lytic lesion with
geographic borders III
involving the right talus. The
lesion has a faintly sclerotic
border and internal
chondroid matrix EiIl
suggestive of a
chondroblastoma. (Right)
multiple lytic lesions _
which cause frank
destruction of most of the
tarsal bones and metatarsal
bases. These aggressive
lesions have an associated
soft tissue mass •.
I
394
TARSAL CYSTIc/LYTIC LESIONS :>
::::J
...•
III
o
3
'<
OJ
III
III
Silicone-Induced Synovitis Metastases, Bone Marrow <l>
radiograph shows lucency in
the distal first metatarsal
and great toe proximal
= "
o
~
Q)
phalanx 11II. This patient with :J
rheumatoid arthritis had a a.
1st MTP joint replacement :>
:J
and a silicone prosthesis.
Prosthesis failure has led to a
'"
iD
granulomatous reaction
eroding bone. (Right) Sagittal
medial
=
T1 WI MR shows a low signal
mass destroying the
cuneiform bone.
Cortical disruption and a
subtle soft tissue mass are
present. This was due to lytic
metastatic breast carcinoma.

(Left) Coronal NECT shows a
large, aggressive-appearing
lytic lesion 11II involving
multiple bones of the
hindfoot. Metastases below
the elbow or knee are
unusual; however. the
diagnosis in this case was
metastatic adenocarcinoma.
(Right) Axial T I WI MR
shows a focal low signal
lesion III involving the 3rd
metatarsal. This lesion was
lytic on radiographs. A
pathologic fracture is faintly
visible as a nondisplaced low
signal line 11II. Myeloma was
proven on biopsy.
Angiosarcoma, Osseous
shows an abnormal talus ffi
On radiographs the
appearance was of mixed
sclerosis and lucency. The
MR best demonstrates the
cortical and trabecular
thickening with mild bone
enlargement, typical of Paget
disease. (Right) Sagittal T I WI
MR shows an extensive caSE
of polyostotic osseous
angiosarcoma. Multiple
(oca" aggressive destructive
lesions II involve, to some
extent, nearly every bone of
the right foot and ankle.
I
395
PART II
Image Based
Radiograph/Cl, Osseous
Radiograph/Cl, Soft lissue
MR, Osseous
MR, Soft lissue
MR, Joint
Ultrasound
Nuclear Medicine
CI)
:::J POLYOSTOTIC LESIONS, ADULT
o
OJ
CI)
CI)
o DIFFERENTIAL DIAGNOSIS Helpful Clues for Common Diagnoses
1-"
-
U
.r::
0-
ro
~
Common
o Bone islands may be multiple without
Q) • Metastases, Bone Marrow having a pattern that suggests
.Q
"0 • Multiple Myeloma osteopoikilosis
ro o Bone islands are densely & uniformly
0:: • Paget Disease
"0 • Fibrous Dysplasia, Polyostotic sclerotic, differentiating them from some
Q)
II) less densely sclerotic metastases
III • Bone Infarcts
llJ o Metastases tend to be axial or shoulder
• Brown Tumor: HPTH/Renal OD
Q)
girdle/proximal humerus &
Cl
III • Enchondromas
E pelvis/proximal femora; bone islands less
• Osteochondroma, Multiple Hereditary
location -specific
Exostosis
o If questions remain, MR or PET/CT may
• Ewing Sarcoma, Metastatic
indicate inactivity of bone islands vs.
• Leukemia
activity of sclerotic metastases
• Lymphoma, Multifocal
• Caveat: This is not always reliable with
Less Common the latter
• Osteomyelitis • Multiple Myeloma
• Angiosarcoma, Osseous o Vast majority are lytic, punched out
• Hemangiopericytoma, Osseous lesions or else diffusely osteopenic
• Hemangioendothelioma, Osseous o Those presenting with osteopenia +
• Cystic Angiomatosis gammopathy are best evaluated by MR
• Tuberculosis survey
• Bacillary Angiomatosis o There may be a dominant lesion
• Sarcoidosis (plasmacytoma), with multiple smaller
• Oilier Disease lytic lesions
• Osteoma o Distribution is heavily axial (including
• Maffucci Syndrome skull), shoulder girdle/humerus, &
• Osteosarcoma, Metastatic pelvis/proximal femora
Rare but Important • Fibrous Dysplasia, Polyostotic
o New lesions do not generally develop in
• Mastocytosis
• Giant Cell Tumor, Skull or Phalanges adults
o May see residual lesions which developed
during childhood
ESSENTIAL INFORMATION o Hint: Watch for residual deformities
Key Differential Diagnosis Issues (Shepherd's Crook, bowing, protrusio of

• Long list, with wide spectrum of lesions hips) & expanded bone
ranging from benign, "leave me alone" • Brown Tumor: HPTH/Renal OD
o Location not specific; may be axial or
(don't further image) to aggressive
nonspecific lesions appendicular; often noted in digits
o Watch for abnormal bone density which is
• List can be modified into shorter, more
helpful lists (see "alternative differential always present
o Watch for bone resorption patterns
approaches")
• Even with this lengthy list, knowing that a (subperiosteal, subligamentous,
lesion is polyostotic helps to limit subchondral, tuft)
differential considerations & is extremely o Watch for indications of dialysis (such as
useful central catheter, peritoneal catheter,
o MR survey, PET/CT, or bone scans are shunt)
o Watch for clips in neck region of
useful in identifying polyostotic nature of
disease & thus limiting differential parathyroids
• Ewing Sarcoma, Metastatic
II
2
POLYOSTOTIC LESIONS, ADULT
o Young adults, with primary more likely in o Multiple lesions with either prominent
proximal flat bone than long bone trabeculae or cystic appearance
o Primary lesion will be larger, more o Expand slowly but significantly over time
aggressive in appearance ;u
Alternative Differential Approaches III
0-
o Ewing sarcoma is more likely to cr
• Consider subdividing the list into 2 which <0
metastasize to bone than other bone are easier to handle "'
III
sarcomas; equal likelihood of metastases to o Polyostotic lesions which are easily
"0
:T
bone & lung identified by imaging (when their o
.--1
o Osteosarcoma less frequent in adult
population, metastasizes to lung & local
appearance is classic) o
lymph nodes more frequently than bone
• Paget disease '"CD'"
• Fibrous dysplasia o
c
• Leukemia • Bone infarcts '"
o Focal lesions rare on X-ray; hint:
• Enchondromas
Osteoporosis inappropriate for age/gender • Osteochondromas, multiple hereditary
o Diagnosis & tumor burden determined by
exostoses
MR which shows infiltrative pattern
• Sarcoidosis
o Given normal radiographs, MR differential
• Ollier disease
is myeloma & multifocallymphoma
• Osteoma
• Lymphoma, Multifocal • Maffucci syndrome
o Lymphoma usually is monostotic in
o Polyostotic lesions which have a
adults, but often polyostotic in children moderately to severely aggressive
o Hint: Serpiginous pattern on MR suggests
appearance but are otherwise nonspecific
the diagnosis; otherwise infiltrative • Metastases, bone marrow (including
Helpful Clues for Less Common Diagnoses primary bone sarcomas)
• Vascular Tumors • Multiple myeloma
o No imaging discrimination between • Brown tumor:
angiosarcoma, hemangiopericytoma, Hyperparathyroi dism/ renal
hemangioendothelioma osteodystrophy
o Hint: Vascular tumors favor lower • Leukemia
extremity locations; polyostotic lytic • Lymphoma, multifocal
lesions predominantly involving lower • Vascular tumors
extremities should raise this consideration • Osteomyelitis (including TB)
• Cystic Angiomatosis
Enostosis (Bone Island) Metastases, Bone Marrow
AP radiograph shows multiple scleroUc lesions restricted

to the left iNac wing m. These were stable over a 4 year
Axial CECT shows multiple sclerotic bone lesions lEI
scattered throughout the pelvis. They were extensively
II
period and represent multiple bone islands. At initial seen in the entire axial skeleton; the primary was
presentation, one might consider sclerotic metastases. non-small eel/lung adenocarcinoma.
3
'"o::> POLYOSTOTIC LESIONS, ADULT
Q)
o'"'"
r-:-
-
u
.c
C-
ro
~ (Left) Lateralradiograph
Multiple Myeloma
OJ shows multiple "punched

.2 out lytic lesions. of different
"ro
0::
sizes. There is no sclerotic
border. This appearance is
1::l typical of multiple myeloma.
C1l
& the skull is a favorite
'"ro
CO
location. (Right) Coronal
C1l
STIR MR in a patient with
Cl normal radiographs &
l\l
gammopathy shows a lesion
E
in the clavicle ElII and
another, larger, lesion in the
sternum". Myeloma may
appear as osteopenia
without {ocal lesions on
radiograph; MR survey helps
determine tumor burden.
Paget Disease
shows a mixed lytic/sclerotic
lesion in a thoracic vertebra
Ill. The alert radiologist will
recognize slight enlargement
of the body and suggest
Paget disease. (Right)
Posteroanterior bone scan of
the same patient, distallo
the thoracic lesion shows an
additional Ls lesion as well
as uptake extending along
the ilioischialline of the right
hemipelvis &8 and
involvement of the right hip.
This distribution is classic,
and confirms the diagnosis.
Bone Infarcts
shows multiple lesions, both
lytic" & ground-glass" in
the left hemipelvis. there is
no aggressive feature, and
fibrous dysplasia is the only
reasonable diagnosis to
consider. (Right) Axial T1WI
MR shows multiple
serpiginous bone infarcts,
paralleling the bone outline
••. When this is the
presentation (rather than a
subtle density change
without serpiginous outline),
the diagnosis is secure.
II
4
POLYOSTOTIC LESIONS, ADULT 3
III
(Q
CD
tD
III
l/I
CD
a.
Enchondromas
(Left) AP radiograph shows a ;0
Ql
supraacetabular lesion with C-
indistinct borders _ & a o'
<0
femoral neck lesion with ~
Ql
distinct borders EiIl The -0
::T
bone density is abnormal &
trabeculae indistinct,
o
.-;
suggesting metabolic disease.
o
l/I
l/I
shows multiple lytic lesions, CD
some containing chondroid o
C
matrix". Each is a typical l/I
enchondroma. The patient

had no other lesions to
suggest Oilier disease; she
had multiple enchondromas
but not multiple
enchondromacosis.
Osteochondroma, Multiple Hereditary Osteochondroma, Multiple Hereditary

Exostosis Exostosis
(Leh) Axial NECT shows an
exophytic osteochondroma
••. It might be easy to
overlook the additional small
sessife osteochondromas at
the iliac spines 1IIIl. (Right)
Axial NECT more distally in
the same patient shows a
portion of the exophytic
osteochondroma" as well
as multiple small sessile
osteochondromas draped
along the iliac wings EiIl It is
important not to overlook
these; multiple hereditary
exostosis carries a different
prognosis than solitary
exostosis.
Ewing Sarcoma, Metastatic

aggressive permeative lytic
lesion of the scapula" with
cortical breakthrough & 50ft
tissue mass. This lesion in a
flat bone of a 21 year old is
typical of Ewing sarcoma.
(Right) Bone scan obtained
;n the same patient is part of
the workup, looking for
osseous metastases.
Unfortunately, there were
several, scattered throughout
the skeleton. Chest CT at the
same selling showed no lung
metastases.
II
5
'"o::l POLYOSTOTIC LESIONS, ADULT
Q)
o'"'"
~
-
t)
.c
a.
ro
~ (Left) Axial TI C+ FS MR
leukemia lymphoma. Multifocal
Ol shows enhancement of all

.Q the imaged osseous
"0
ro structures, indicating diffuse
0:: marrow infiltration.
"'"ro
Ql
Radiographs were normal,
can be the case with
as
infiltrative disease. Biopsy

al
Ql
proved leukemia. (Right)
en Coronal STIR MR shows
'E" multiple lesions in both
femora in this 60 year old.
Additionally, lesions were
seen throughout the axial
skeleton. This proved to be
mu'tifoca"ymphoma, an
unusual presentation of
lymphoma in the adult.
Osteomyelitis Angiosarcoma, Osseous

shows a septic joint with
superinfection of both the
humerusand radius. in a
patient with rheumatoid
arthritis. Polyostotic
osteomyelitis in adults tends
to be in contiguous bones,
unlike the child. (Right)
Sagittal TlWI MR shows
multiple lesions involving the
ankle and foot •. Vascular
tumor should be considered
with polyostotic lesions,
particularly of the lower
extremities. This proved to
be angiosarcoma.
Hemangioendothelioma, Osseous Cystic Angiomatosis

shows lytic lesions of the
talus and calcaneus •.
These moderately aggressive
lesions are typical of vascular
tumors, but otherwise
nonspecific. Biopsy showed
hemangioendothelioma.
significant expansion of the
pubic rami" which has
occurred over at feast 2
decades. The patient had
other lower extremity
cystic'appearing lesions. The
slow growth is typical of this
benign vascular multicentric
lesion.
II
6
POLYOSTOTIC lESIONS, ADULT 3
III
(0
ll)
lXJ
III
III
ll)
0-
Tuberculosis Tuberculosis
(Leh) Oblique radiograph ::0
Q)
shows a moderately 0-
aggressivelesion. with o'
(0
cortical breakthrough. This is
,
Q)
a nonspecific appearance. 1:l
::J'
radiograph coned from a
o
.-1
chest image of the same
patient shows a lytic lesion
o
III
III
of the rib •. The patient C1l
had complete white-out of o
C
the left lung, with III
mediastinal shift 10 the right.

The combination of chest
findings plus multiple lytic
osseous lesions is typical for
TB.
Sarcoidosis Sarcoidosis
shows multiple tiny lesions
scattered throughout the
humeral head/neck •.
These showed high signal on
fluid sensitive sequences.
There were also lesions of
similar size in the muscles.
These are sarcoid
granulomas. (Right) Oblique
lacy lytic lesions of the
phalanges. which are
seen in osseous sarcoidosis.

(Left) Sagiltal T2WI FS MR
shows multiple lobulated
high signal cartilaginous
lesions. There is one lesion
which is expanded
significantly •. Radiographs
showed chondroid matrix;
this is Oilier disease. (Right)
shows multiple lytic lesions
with chondroid matrix.
Additionally. there is a soft
tissue mass containing
phleboliths •. the
combination yields a
diagnosis of Maffucci
syndrome. ft MSK Req).
II
7
rJl
:J POLYOSTOTIC LESIONS, CHILD
o
Q)
rJl
rJl
o DIFFERENTIAL DIAGNOSIS a Both are cortically-based and
l- metadiaphyseal
-
t)
.r::
c.
ctl
~
Common
• Fibroxanthoma (Non-Ossifying Fibroma)
• Fibrous Dysplasia, Polyostotic
a Lesion may have different appearance in
Cl
o • Fibrous Dysplasia, Polyostotic different locations
"0
ctl
• Langerhans Cell Histiocytosis (LCH) • Skull: Sclerotic
0::: • Osteomyelitis, Pediatric • Pelvis: Bubbly, lytic
"C
Ql
• Osteochondroma, Multiple Hereditary • Long bones: Generally central,
1I)
III Exostosis metadiaphyseal, mildly expanded, with
OJ
Ql
• Leukemia variable homogeneous ground-glass
Cl
III • Ewing Sarcoma, Metastatic density
E • Metastases, Bone Marrow • Langerhans Cell Histiocytosis (LCH)
Less Common a Lesions may be lytic, geographic, &
• Lymphoma, Multifocal non aggressive
• Osteosarcoma, Metastatic a Lesions may also be extremely aggressive
• Hyperparathyroidism/Renal Osteodystrophy, in appearance: Permeative, cortical
Brown Tumor breakthrough, soft tissue mass, periosteal
• Melorheostosis reaction, with rapid growth
a Hint: Skull lesions may have beveled edge
Rare but Important appearance due to differential involvement
• Oilier Disease of inner & outer tables
• Maffucci Syndrome • Osteomyelitis, Pediatric
• Chronic Recurrent Multifocal Osteomyelitis a Hematogenous spread usually results in
• Sarcoidosis metaphyseal sites
• Trevor Fairbank a Osteomyelitis can appear extremely
aggressive, with permeative change &
ESSENTIAL INFORMATION cortical breakthrough with soft tissue
mass: May not be distinguishable from
Key Differential Diagnosis Issues aggressive tumor
• Polyostotic nature of a lesion can narrow the a Sickle cell patients at risk for multifocal
differential substantially & is a highly osseous infection; higher predilection for
valuable characteristic Salmonella
a Information regarding multiple sites can
• Osteochondroma, Multiple Hereditary
be gained by bone scan, PET/CT, or clinical Exostosis
exam a Not a difficult diagnosis if exophytic
• Lesions listed above range from benign (cauliflower) lesions are present
(leave me alone) lesions, through "Aunt a May have only sessile exostoses at the
Minnie" lesions, through highly aggressive metaphyses which can give the appearance
lesions of a dysplasia; diagnosis often missed
a It is most reasonable to have an alternative
• Leukemia
approach to sort these out a Diffuse marrow infiltration may result in
Helpful Clues for Common Diagnoses appearance of osteopenia, easily
• Fibroxanthoma (Non-Ossifying Fibroma) overlooked
a Benign fibrous cortical defects (same a Metaphyseal lucent bands may highlight
histologically as NOF, but smaller) are the degree of osteopenia
often multiple in children a MR shows the extent of the abnormalities
a Non-ossifying fibroma is not commonly • Ewing Sarcoma, Metastatic
multiple, except in patients with a Primary lesion usually highly aggressive:
neurofibromatosis Lytic, permeative, cortical breakthrough,
a Both have same natural history of healing large soft tissue mass
II
8
POLYOSTOTIC LESIONS, CHILD 3
III
lJ:l
<ll
o May have extensive reactive bone • Polyostotic lesions which are usually to
III
formation, giving the appearance of monomelic III
<ll
osteoid, with potential confusion with o Fibrous dysplasia (generally unilateral) Q.
osteosarcoma o Melorheostosis ;0
Ql
Q.
• Reactive bone formation restricted to o Oilier disease 0'
bone, does not extend into soft tissue o Trevor Fairbank ,
<0
Ql
mass (as it does in osteosarcoma) o Maffucci syndrome '0
:J
o Most common sarcoma to have osseous • Polyostotic lesions with an intermediately ()
_--i
metastases; lung & osseous metastases aggressive appearance
o Fibrous dysplasia: Generally central, poorly
o
present with equal frequency III
III
<ll
Helpful Clues for Less Common Diagnoses marginated, but geographic o
C
o Langerhans cell histiocytosis: Appearance III
• Lymphoma, Multifocal
ranges from nonaggressive geographic to
o 50% of childhood bone lymphoma is
extremely aggressive permeative
polyostotic (much less frequent in adults)
o Hyperparathyroidism/renal
o Lesions highly aggressive: Permeative,
osteodystrophy, Brown tumor: Generally
cortical breakthrough with soft tissue mass
the lesion is geographic, but surrounding
o Generally lytic, but may have reactive
bone abnormal in density & trabecular
sclerosis within osseous lesion
o In same differential as Ewing sarcoma with
pattern
metastases, multifocal osteomyelitis, LCH, • Polyostotic lesions with an aggressive
appearance: These can be indistinguishable
& metastases
from one another by imaging!
Alternative Differential Approaches o Langerhans cell histiocytosis: Range in
• "Aunt Minnie" lesions can generally be appearance from nonaggressive to highly
identified immediately aggressive
o Fibroxanthoma (non-ossifying o Osteomyelitis
fibroma)/benign fibrous cortical defect o Leukemia
o Osteochondroma (multiple hereditary o Ewing sarcoma, metastatic
exostoses): Remember they can be sessile & o Metastases, bone marrow
resemble a metaphyseal dysplasia o Lymphoma, multifocal
o Melorheostosis o Osteosarcoma, metastatic
o Sarcoidosis (when lacy appearance is o Chronic recurrent multifocal osteomyelitis
obvious)
o Trevor Fairbank
Fibroxanthoma (Non-Ossifying Fibroma)
Anteroposterior radiograph shows a smalllyUc cortical

lesion" (benign fibrous cortical defect! and a scleroUc
Oblique radiograph (same paUent) shows a lytic
cortically based lesion; this is another non-ossifying
II
healing non-ossifying fibroma EiIl The two lesions have fibroma, but one which is still active in this child. These
the same histology, & the natural history is to heal. images show the 3 expected appearances of this lesion.
9
IJ)
:::J POLYOSTOTIC LESIONS, CHILD
o
Q)
IJ)
IJ)
o
t-""
-
u
.r:
0-
III
•... (Left) Anteroposterior
Cl radiograph shows mixed lytic
.2 and sclerotic lesion involving
"0
III the meta diaphysis of the
c::: femur, tibia, & fibula. The
"1:l lesions are central &
Q)
IJ) nonaggressive, typical of
l\l fibrous dysplasia. (RighI)
10
Q)
Cl shows the mildly expanded
l\l
and sclerotic, otherwise
E featureless "ground-glass"
appearance of fibrous
diaphysis =
dysplasia in the tibial
with lytic talar
lesion. in this teenager
with polyostotic fibrous
dysplasia.
Langerhans Cell Histiocytosis (LCH) Langerhans Cell Histiocytosis (LCH)

radiograph shows a
geographic lytic lesion of the
femoral neck 1ilI. This is
compatible with a diagnosis
of Langerhans cell
histiocytosis (LCH). (RighI)
Lateralradiograph (same
child) shows multiple skull
lesions. These lesions have a
more aggressive appearance,
and in fact grew quite
rapidly. The polyostotic and
relatively geographic
appearance overall makes
the diagnosis of LCH highly
probable, proven in this
case.
Osteomyelitis, Pediatric Osteomyelitis, Pediatric

radiograph shows lytic
lesions within the metaphysis
IilI which have an aggressive
appearance. (RighI) Lateral
radiograph of the
contralateral heel in the
image, at the same setting,
shows lytic lesions within
both the metaphysis and
apophysis 1ilI. The
metaphyseal location makes
hematogenous spread of
osteomyelitis the most likely
diagnosis, proven here.
II
10
Ql
ee
<D
to
Ql
CIl
Osteochondroma, Multiple Hereditary <D
Co
Exostosis leukemia
(Left) Anteroposterior ;lJ
OJ
radiograph shows sessile 0-
osteochondromas along the 0'
ee
~
medial femoral metaphyses OJ
• in this teenager. Note the
subluxation of the right "::J"o
femoral head 1IIIl; this was -I
proven to be an intraarUcular
exostosis. (Right) AP
o
CIl
CIl
radiograph shows diffuse <D
osteopenia & metaphyseal o
c:
lucent lines EilI in this child. CIl
He also had mild

compression fractures in the
spine. Leukemia may present
as diffuse osteopenia rather
than (oea/lesions, as in this
case.
Ewing Sarcoma, Metastatic Ewing Sarcoma, Metastatic

shows faint permeative
change and sclerosis within
the proximal tibia lIlI in a
teenager. The lesion is 50
subtle as to be easily missed;
this makes it aggressive. With
the reactive sclerosis, Ewing
sarcoma is highly probable.
(Right) Anteroposterior bone
scan of the same patient as
previous image, shows the
tibial lesion, with extended
uptake lIlI. However, there
is also a lesion within the
contralateral fibula E!lI; the
diagnosis is Ewing sarcoma
with osseous metastasis.
Metastases, Bone Marrow lymphoma, Multifocal

multiple lesions in a child
lIlI. These are metaphyseal,
suggesting hematogenous
spread. The major differential
;s multifocal osteomyelitis &
metastases; the primary was
medulloblastoma (note the
VP shunt). (Right) Axial STIR
MR shows polyostotic lesions
involving the iliac wings &
sacrum in this child. A
=
serpiginous pattern is seen
which is typical. 50% of
children developing
lymphoma of bone present
with polyostotic lesions.
II
11
'":::lo POLYOSTOTIC LESIONS, CHILD
Ql
o'"'"
r:
t) Hyperparathyroidism/Renal
:<:a. Osteosarcoma, Metastatic Osteodystrophy, Brown Tumor
~
Ol radiograph shows multiple
.Q osseous sites of amorphous
"0
ro bone lormation III within
a:: the spine and pelvis in a
"tl teenager whose lelt hip was
Ql
III disarticulated 1 year earlier
III
for osteosarcoma (note the
tlI
Ql
recurrence in the
en acetabulum ElIIi. (Right)
III
E shows severe renal
osteodystrophy in a teenager
with end stage renal disease.
Besides the subperiosteal
and tuft resorption, there are
multiple lytic lesions, Brown
tumors •.
Melorheostosis Melorheostosis
sclerotic endosteal bone
extending down the femur
•• with what has been
termed a f1dripping candle
wax" appearance. This is
typical melorheostosis, a
sclerosing dysplasia. (Right)
Oblique radiograph (same
patient as previous image)
shows linear as well as
punctate regions of sclerosis
•. in a sclerotomal pattern.
The lesions are restricted to
one extremity (monomelic).
Oilier Disease Oilier Disease

shows multiple lytic lesions
in the hand" some with
prominent expansion. These
do not have distinct cartilage
matrix, but nonetheless are
typical lor multiple
enchondromatosis. (Right)
AP radiograph shows a lytic
metaphysis, with laintly seen
linear striations III. No
distinct matrix is seen.
Remember that the lesions in
Oilier disease olten do not
have the same appearance
as solitary enchondromas.
II
12
Ql
(Q
lTl
lD
Ql
VI
lTl
Q.
Maffucci Syndrome
(Left) Lateral radiograph Al
OJ
shows the linear striations a.
within a lytic metaphyseal o'
co
lesion Ell; note the proximal ~
OJ
fibula is abnormal as well. -0
::r
The findings are typical of
multiple enchondromatasis.
o~
radiograph (same patient as
o
en
en
previous image) shows a CD
lytic lesion in the proximal o
c
humerus; as well as VI
phleboliths in the adjacent

50ft tissues. these change
the diagnosis ta Maffucci
syndrome. Note: Patient is
undergoing limb lengthening.
(tMSK Req).
(Leh) Coronal TlWI FS MR

shows signal abnormalities in
the sacrum" iliac wing
•• and ischium Ell. There is
no soft tissue mass. The
patient had chronic pain for
1 year but normal
radiograph & no
constitutional symptoms.
radiograph shows the lacy
lytic lesion. typical of
sarcoidosis of the hands and
feet. This teen-age patient
had lesions in her fOOl as
well, and massive pulmonary
fibrosis.
Trevor Fairbank Trevor Fairbank

bone formation in the ankle
•. Other radiographs
demonstrate this to be
inlraarlicular and allached to
the talus. This represents an
intraarticular exostosis, or
Trevor disease. (Right)
of the hip in the same patient
as previous image, shows
abnormal ossi(;cation arising
from the acetabulum •. It is
not uncommon for Trevor
disease to be polyarticular; it
is monomelic.
II
13
en
::> SOLITARYGEOGRAPHIC LYTICLESIONS
o
OJ
en
en
o DIFFERENTIAL DIAGNOSIS o Need not have matrix
f- Most common lesion of the phalanx
-
o
U Common
.<: o Well-defined and may be mildly expansile
0-
ro
~
• Subchondral Cyst • Metastases, Bone Marrow
Ol
.Q
• Enchondroma o Lack of multiplicity & aggressive features
"0
ro • Metastases, Bone Marrow does not exclude metastatic disease
0:: • Fibroxanthoma (Non-Ossifying Fibroma) • Fibroxanthoma (Non-Ossifying Fibroma)
"tl
Ql
• Plasmacytoma o Cortically based, lobulated lesion with
VI
III • Unicameral Bone Cyst (UBC) narrow zone of transition
a:l • Giant Cell Tumor (GCT)
Ql o No aggressive features
OJ
III • Aneurysmal Bone Cyst (ABC) • Plasmacytoma
E • Fibrous Dysplasia o Solitary myeloma lesion
• Chondrosarcoma o Lytic & bubbly, often with cortical
• Langerhans Cell Histiocytosis breakthrough
• Chondroblastoma o Usually lacks a large soft tissue mass
• Osteomyelitis • Unicameral Bone Cyst (UBC)
Less Common o Associated fallen fragment sign
• Arthroplasty Component Wear/Particle • Giant Cell Tumor (GCT)
Disease o Metaphyseal lesion extending to
• Amyloid Deposition subchondral region of bone
• lntraosseous Lipoma o Lacks sclerotic margin
• Paget Disease • Aneurysmal Bone Cyst (ABC)
• Pyrophosphate Arthropathy o Expansile eccentric lesion, intact cortex
• Renal Osteodystrophy • Fibrous Dysplasia
• Osteosarcoma, Telangiectatic o Classic well-demarcated lesion with
• Osteosarcoma, Conventional "ground-glass" attenuation
o Pelvic lesions particularly may be lytic
Rare but Important
• Chondrosarcoma
• Adamantinoma o Cortical thinning or thickening; low grade
• Chondromyxoid Fibroma lesion may appear non-aggressive; no
• Tertiary Syphilis matrix necessary
• Sarcoidosis • Langerhans Cell Histiocytosis
• Hemophilia: Pseudotumor o Elicits periosteal reaction near the lesion
• Chondroblastoma
• Benign Peripheral Nerve Sheath Tumor o Epiphyseal lesion with sclerotic border
• Gout o Often with associated periosteal reaction
• Pigmented Villonodular Synovitis (PVNS) along the metaphysis
• Osteomyelitis
ESSENTIAL INFORMATION o Well-defined foci of osteomyelitis are
typically due to tuberculosis or fungi
• Less host reaction & bone destruction
• Lucent lesion with narrow zone of transition than Staphylococcus osteomyelitis
o May be due to intraosseous lesion or
erosion of lesion into bone Helpful Clues for Less Common Diagnoses
Helpful Clues for Common Diagnoses Disease
• Subchondral Cyst o Location in bone adjacent to joint
o Location around synovial joints
replacement
o Associated findings of subchondral
o Associated findings of polyethylene wear:
sclerosis, marginal osteophytes, joint space Narrowing or asymmetry of the liner
narrowing
• Amyloid Deposition
• Enchondroma o Erosion of amyloid deposits into bone
II
14
SOLITARY GEOGRAPHIC LYTIC LESIONS 3
III
lC
CD
o Patients with end stage renal disease & o Anterior tibial metadiaphysis llJ
III
multiple myeloma o Multilobulated, expansile lesion VI
CD
• Intraosseous Lipoma o Associated cortical breakthrough and soft a.
o Location in long bone metaphysis and tissue mass ;;0
III
calcaneus most common a.
• Chondromyxoid Fibroma o'
<0
o Presence of fat and central calcification o Multilobulated expansile lesion without ~
III
differentiates from normal variant or cortical breakthrough "0
::T
solitary bone cyst • Hemophilia: Pseudotumor o
_-i
• Paget Disease o Pseudotumor can have significant
o Osteoporosis circumscripta of skull destruction without a permeative pattern
o
VI
VI
• Typical location in frontal & occipital CD
• Osteofibrous Dysplasia o
c::
regions o Similar to adamantinoma & VI
o Associated findings of widened diploic chondromyxoid fibroma; tibial cortex

space & traversed suture lines • Benign Peripheral Nerve Sheath Tumor
• Pyrophosphate Arthropathy o Well-differentiated nerve sheath tissue
o May result in very large subchondral cysts mass
o Associated finding of chondrocalcinosis o May erode into the adjacent bone
• Renal Osteodystrophy o Rare intraosseous tumors occur
o Lytic lesions in patients with end stage predominantly in the mandible
renal disease include Brown tumors, • Gout
amyloid and gout o Masses of crystal deposition typically cause
o Subchondral location of these lesions can juxtaarticular erosions of bone
simulate an erosion or subchondral cyst o Depending on the imaging plane on
• Osteosarcoma, Telangiectatic radiographs, erosions can mimic
o Can have less permeative appearance than intraosseous lesions
conventional osteosarcoma • Alternatively sodium urate crystals can
o Associated finding of fluid-fluid levels form masses within subchondral bone
• Osteosarcoma, Conventional o Large erosions can cause significant bone
o Highly aggressive appearance typical destruction, simulating tumor
• Geographic appearance is uncommon • Pigmented Villonodular Synovitis (PVNS)
except in low grade intraosseous variety o Intraarticular, nodular masses with
Helpful Clues for Rare Diagnoses blooming signal on gradient echo MR

o Masses erode adjacent bone, similar to
• Adamantinoma
gout
Subchondral Cyst Enchondroma
Anteroposterior radiograph shows cartilage loss in the

weight-bearing area of the hip, femoral neck marginal
AP radiograph shows a lytic lesion in metaphysis •.
An enchondroma need not contain radiographically
II
osteophytes and a large subchondral cyst .::II in the visible chondroid mauix. Without matrix, differential
acetabulum, due to osteoarthritis. includes SBC, GeT, & ABC. ItMSK Req).
15
(J)
::l SOLITARY GEOGRAPHIC LYTIC LESIONS
o
Ql
(J)
(J)
o
t-
-
t)
~
a.
ro (Left) AP radiograph shows
'-
Ol an expanded lytic lesion ••
.Q in the region of the
1:)
ro acetabulum, which normally
a:: has a lucentlriangle. A
"'0 solitary lytic lesion in a
Ql
(J) woman should always lead
co to consideration of
10
metastatic breast cancer.
CI>
Cl (Right) AP radiograph shows
co a geographic lytic lesion ••
E
in the meta diaphysis of a
skeletally immature patient.
Laleral view (not shown)
shows il is cortically based,
non-aggressive and has a
narrow zone of transition.
lesion =
radiograph shows a bubbly
occupying the
superior pubic ramus and
extending well into the
acetabulum. In a patient
over 50 years of age,
metastatic disease or
myeloma should be
considered first. (Right)
shows a lytic lesion III with
sclerotic borders and thinned
cortices. This case a/so
shows the fallen fragment
sign. due to a fracture
fragment within the ffuid of
the lesion. rt MSK Req).
Aneurysmal Bone Cyst (ABC)

an eccentric metaphyseal
lytic lesion" extending to
the end of bone. The lesion
is geographic, with a narrow
zone of transition but no
sclerotic margin. This
appearance and location is
classic for giant cell tumor.
radiograph shows an
eccentric, expanded lytic
lesion III with intact cortex
in a teenager. An MR
demonstrated fluid levels
typical for an aneurysmal
bone cyst.
II
16
Ql
to
<ll
III
Ql
VI
<ll
Co
Chondrosarcoma
(Left) Anteroposterior ::0
Ql
radiograph shows a bubbly c-
expansile lesion _ without o·
<Cl
aggressive features. Bubbly ~
Ql
lytic non-aggressive pelvis
lesions are typical of fibrous "o:T
dysplasia. (Right) AP .-1
radiograph shows a
completely lytic lesion in the
o
VI
VI
pelvis EiIl with a pathologic CD
fracture through the superior o
c:
acetabulum. It is important VI
to remember that
chondrosarcoma need not
show radiographic evidence
of chondroid matrix.
Langerhans Cell Histiocytosis Chondroblastoma

lytic geographic lesion" in
the proximal humeral
metaphysis with periosteal
reaction HI. In this location
and young age group,
Langerhans cell histiocytosis,
infection, and metastatic
neuroblastoma should be
considered. (Right) AP
epiphyseal lesion •• without
significant chondroid matrix.
There is dense periosteal
reaction in metaphysis HI.
These findings are classic for
chondroblastoma. (t MSK
Req).

Osteomyelitis Disease
well-defined lesion" with
50ft tissue swelling Ell and
no periosteal reaction. This
suggests a slower process
than is usually seen with
bacterial osteomyelitis,
Blastomycosis was the
infecting agent. (Right)
acetabular lysislD from
particle disease. Note the
offset of the femoral head in
the cup on the superolateral
side" compared with the
inferomedial side EiIl
indicating polyethylene
wear.
II
17
VI
:J SOLITARY GEOGRAPHIC lYTIC lESIONS
o
Ql
VI
VI
o
r-:-
u
:ca. Amyloid Deposition
'"
~
Ol shows a humeral head
.Q erosion •. Rotator cu(f
""0
tendons are thick &
'"
a:: uniformly low in signal Ell.
"t:l Biopsy confirmed amyloid
Ql
VI deposition in this patient
III with end stage renal disease.
a:l (tMSK Req). (Right) Lateral
Ql
Cl radiograph shows a lucent
III
lesion" containinga
E
central calcific density Ell.
Lytic calcanea/lesions in this
location usually represent
normal variant, bone cyst, or
lipoma; a central calcific
density confirmed lipoma.
Paget Disease
shows a geographic lytic
region in the occiput _ The
skull shows a diffusely
widened diploic space Ell
Osteoporosis circumscripta is
an earfy destructive phase of
Paget disease of the skull.
radiograph shows
osteophyte formation,
cartilage narrowing, and a
large lytic lesion in the
medial tibial plateau •.
Chondrocalcinosis IIIl/eads
one to consider the diagnosis
of pyrophosphate
arthropathy.

shows diffuse mottled
density in the bones due to
bone infarcts Ell and a lytic
lesion of the anterior distal
femoral metaphysis. due
to a Brown tumor in this
patient with end stage renal
disease. (RighI) Oblique
lesion with fairfy geographic
borders. extending to the
end of the bone. Cortical
breakthrough and soft tissue
mass were subtle findings.
Telangiectatic osteosarcoma
is not as permeative as
classic osteosarcoma.
II
18
Ql
to
(t)
OJ
Ql
<II
(t)
C.
Adamantinoma Chondromyxoid Fibroma
(Left) Anteroposterior ;;0
Cll
radiograph shows an C.
expansile lytic lesion IIlI with o
CO
sclerotic margins. Cortical ~
Cll
destruction and a soft tissue
mass were visible with CT, "::T()
suggesting the diagnosis of .--1
adamantinoma. (Right)
o
<II
<II
shows an eccentric, C1l
expansiJe, lytic lesion _ in o
C
the tibial meta diaphysis, <II
without cortical
breakthrough. The large size
is unusual (or a
chondromyxoid fibroma.
(tMSK Req).
Hemophilia: Pseudotumor
expanded lytic lesion" of
the right iliac wing. This is
typical of pseudotumor;
despite the extensive
destructive change, there is
no permeative pattern.
lesion" in the proximal
tibial diaphysis with cortical
breakthrough" anteriorly.
The differential diagnosis
includes chondromyxoid
fibroma, osteofibrous
dysplasia, and
adamantinoma.
Benign Peripheral Nerve Sheath Tumor

lesion in the capitellum ••
Peripheral nerve sheath
tumors may excavate the
cortex of adjacent bone, but
{rank bone invasion such as
was proven in this case is
distinctly uncommon. (Right)
large erosion or lytic lesion
within the patella ••. Biopsy
proved gout in this patient
with end stage renal disease.
II
19
VJ
::J SCLEROTIC BONE lESION, SOLITARY
o
OJ
VJ
VJ
o DIFFERENTIAL DIAGNOSIS o Low signal on all MR sequences,
I- non-enhancing
o Common
::cCl. • Stress or Insufficiency Fracture
• Enostosis (Bone Island) o Best clue is linear pattern of sclerosis;
~
<ll
OJ
o • Stress or Insufficiency Fracture fracture line may be obscured by healing
"0
<ll
• Fibroxanthoma (Non-Ossifying Fibroma) callus
0::: • Bone Infarct o Fracture line seen well on Tl MR; may be
"0
C1I
• Enchondroma obscured on fluid sensitive sequences
''""
al
• Osteoma • Fibroxanthoma (Non-Ossifying Fibroma)
C1I
• Osteoid Osteoma o Cortically based, metadiaphyseal; location
Cl • Osteosarcoma, Conventional is best clue
'"
E • Intraosseous Lipoma o Natural history is for the lytic lesion to
• Metastases, Bone Marrow heal; it often appears mildly sclerotic prior
less Common to development of normal trabecular
• Paget Disease pattern
• Cement & Bone Fillers • Bone Infarct
• Ewing Sarcoma o Metaphyseal, metadiaphyseal, or
• Osteosarcoma, Parosteal subchondral
• Osteosarcoma, Periosteal o When dystrophic calcification is present,
• Lymphoma, Hodgkin Disease may be focal or serpiginous; serpiginous

• Fibrous Dysplasia, Skull Base pattern is fairly specific
• Liposclerosing Myxofibrous Tumor • Enchondroma
• Osteitis Condensans of Clavicle o Metaphyseal, metadiaphyseal
o Best clue: Usually contains chondroid
Rare but Important matrix: Punctate densities, C's & ]'S
• Sarcoidosis • Osteoma
• Mastocytosis o Homogeneously densely sclerotic,
featureless, like bone island
ESSENTIAL INFORMATION o Best clue: Usually calvarial or within
paranasal sinuses
Key Differential Diagnosis Issues o May see on long bones in patients with
• Differential for solitary sclerotic bone lesion polyposis syndrome; appearance may be
is wide similar to melorheostosis
o Ranges from malignant to "leave me alone"
• Osteoid Osteoma
lesions o May have central sclerotic nidus within
o Important to differentiate; may depend on
lytic lesion
clinical factors or, finally, biopsy o In long bone, nidus is cortically-based
• Location may be an important • Surrounding sclerosis in diaphyseal
differentiating factor lesion may obscure nidus
o Some of the lesions are site specific • May be difficult to differentiate from
o Most are site-preferred healing stress fracture by radiograph
• It is crucial to differentiate type of sclerosis if • CT or MR differentiates the two
possible • Osteosarcoma, Conventional
o If matrix, osteoid vs. chondroid
o Eccentric, metaphyseal
o Dystrophic or reactive sclerosis o Best clue: Subtle, amorphous osteoid
Helpful Clues for Common Diagnoses matrix is formed in bone & soft tissue
• Enostosis (Bone Island) mass; immature & appears aggressive
o Sub-centimeter to giant (10 cm); most o Other aggressive features: Periosteal
frequently metaphyseal reaction, permeative bone destruction, soft
o Homogeneously sclerotic, featureless, with tissue mass
edges "fading" into normal bone
II
20
SClEROTIC BONE LESION, SOLITARY 3
III
(C
CD
o Tumor osteoid is more mature bone than III
Helpful Clues for Less Common Diagnoses III
conventional osteosarcoma VI
• Paget Disease o Zoning of tumor bone formation: More
CD
a.
o Rarely appears purely sclerotic; lytic active ;0
mature centrally, less mature peripherally Ql
component generally present a.
• Osteosarcoma, Periosteal O·
o Watch for active edge of lesion
o Surface lesion, no marrow involvement ...•
(C
(blade-of-grass) Ql
"0
o Metadiaphyseal ~
o Usually originates at one end of long bone,
advancing away from subchondral bone
o Tumor osteoid is more mature than C'i
.-f
conventional osteosarcoma, but less than
• Cement & Bone Fillers o
o Generally seen within a geographic
parosteal '"'"
CD
o Often scallops underlying cortex o
(curetted) lesion c
• Fibrous Dysplasia, Skull Base
o Cement: Homogeneous sclerosis:
o Dense homogeneous bone: May be slightly
'"
Featureless
o Bone graft: Either structural (large piece of
ground-glass & less densely sclerotic than
bone) or multiple small pieces, often osteoma
o Density is different from the mild ground
squared
glass appearance in long bones or lytic
• Ewing Sarcoma
o Lesion itself is lytic & highly permeative,
bubbly fibrous dysplasia of pelvis
o Involved bone is usually enlarged, as in all
with aggressive periosteal reaction & soft
tissue mass cases of fibrous dysplasia
o May elicit tremendous reactive bone
• Liposclerosing Myxofibrous Tumor
o Location specific: Neck of femur
formation
o Geographic; variably sclerotic or mixed
• Reactive bone may simulate tumor
osteoid, but it is contained entirely lytic/sclerotic
within the bone • Osteitis Condensans of Clavicle
o Proximal clavicular sclerosis, without soft
• No bone formation within soft tissue
mass; differentiates from osteosarcoma tissue mass or manubrial abnormality
• Osteosarcoma, Parosteal Helpful Clues for Rare Diagnoses
o L?cation is constant: Metadiaphyseal, • Sarcoidosis
distal femur> proximal tibia> proximal o Rarely may present as focal sclerotic bone:
femur> proximal humerus Dense, inhomogeneous
o Surface lesion, but usually involves some • Mastocytosis
marrow o Focal sclerotic presentation rare
Enostosis (Bone Island)
Axial NEeT shows a solitary densely sclerotic lesion.

Note that the edge of the lesion is not completely
Anteroposterior radiograph shows a patient who is
oSleopenic & has a knee arthroplasty, putting her at risk
II
geographiC: but rather somewhat spiculated, fading out for insuffiCIency fracture. Note the subtle linear pattern
mlo the adlacent normal bone. This is Iypical. of the sclerotic lesion" confirming fracture.
21
III
::> SCLEROTIC BONE LESION, SOLITARY
o
Q)
III
III
o
r-:
()
:c
0.
Fibroxanthoma (Non-Ossifying Fibroma) Bone Infarct
ro (Left) Anteroposterior
~
Ol radiograph shows a cortically
.Q based elongated
"0
ro metaphyseal lesion which is
0: mildly sclerotic HI This is a
"t:l fibroxanthoma, undergoing
Q)
III the natural course of healing
'"
ell
Q)
with sclerosis. These lesions
are common. (Right) Lateral
Cl radiograph shows an
'"
E irregularly·shaped densely
sclerotic metaphyseal lesion
•. It has a somewhat
serpiginous pattern, which is
characteristic although not a
required feature of bone
infarct.
Enchondroma Osteoma
radiograph shows a
metaphyseal lesion
containing punctate sclerotic
densities •. There is no
sclerotic margin, though the
lesion has a geographic
appearance. This chondroid
lesion is a classic
enchondroma. (Right) Axial
NECT shows a densely
sclerotic, rather featureless
lesion of the cranium •.
typical of osteoma. These
hamartomas are usually
located in a paranasal sinus
or the calvarium.
Osteoid Osteoma Osteoid Osteoma

(Left) Coronal bone CT
shows a densely sclerotic
nidus located centrally
within a lytic lesion •.
Lesion was intensely hot on
bone scan, & was extremely
painful. The appearance &
clinical presentation is
typical of osteoid osteoma.
cortically based lesion •.
Osteoid osteoma of the
tubular bones may elicit so
much reactive bone
formation that it obscures the
lytic nidus. This nidus is seen
by MR or CT. rt MSK Req).
II
22
SClEROTIC BONE LESION, SOLITARY 3
Ql
to
lD
lJl
Ql
III
lD
Osteosarcoma, Conventional 0.
Osteosarcoma, Conventional
(Leh) Anteroposterior ;U
Q)
radiograph shows dense C-
osteoid formation within a o'
permeative lesion of the ..,
(Q
Q)
humerus Ea. There is a wide "0
::T
zone of transition & soft
tissue mass, as well as an
o
-i
ossified lymph node
metastasis •. (Right) o
III
III
Anteroposterior radiograph <1>
shows amorphous osteoid o
C
formation within the bone, III
with cortical breakthrough

and osteoid formation within
a large 50ft tissue mass •.
The presence of immature
osteoid confirms the
diagnosis of osteosarcoma.
Intraosseous Lipoma Metastases, Bone Marrow

lesion in the central
calcaneus" containing a
central sclerotic nidus=-
Location & appearance are
pathognomonic for
intraosseous lipoma. It MSK
shows an amorphous
sclerotic lesion occupying
the lesser trochanter _
Although lesion fades off into
normal bone, as is seen in a
bone island, the destructive
change at medial border
helps secure dx of metastatic
prostate carcinoma.
Paget Disease
focus in the subchondral
bone _ However, there is
an additional clue; there is
an adjacent lytic region,
demarcated by a sharp
"blade of grass" Ell making
the diagnosis of Paget
disease. (Right) AP
radiograph shows an isolated
densely sclerotic phalanx •.
The bone is expanded, with
thickened trabeculae. There
is no destructive change.
Findings are typical of Paget
disease, despite the
somewhat unusual location.
II
23
III
~ SClEROTIC BONE LESION, SOLITARY
o
Q)
III
III
o
r:
-
t)
.r:
a.
ro
~ (Leh) AP radiograph shows
Cement & Bone Fillers
Ol cement III placed following

.Q curettage for giant cell tumor
"0
ro (GCT). The cement has a
IY smooth, homogeneous
"t:l appearance, & should not be
Ql
III mistaken for a
ro matrix-producing tumor.
In Note local recurrence of the
Ql
Cl lytic GCT III. (Right) AP
ro radiograph shows bone
E
chips .:I placed following
curellage of a GCT. Some of
the chips are squared,
suggesting they are not
matrix, but iatrogenic. There
is a tumor recurrence _
Ewing Sarcoma
dense sclerosis of the
epiphysis .:I in a child. Axial
imaging demonstrated a 50ft
tissue mass and permeative
lytic lesion in the metaphysis,
typical of Ewing sarcoma.
Remember that this disease
can elicit tremendous
osseous reaction. (Right)
Axial NECT shows a sclerotic
lesion occupying a portion of
57 in a child _ This could
represent either osteoid
formation in osteosarcoma,
or reactive bone in Ewing
sarcoma; the laller was
proven.
Osteosarcoma, Parosteal
shows a sclerotic surface
lesion arising at the posterior
distal metaphysis .:I. Axial
imaging confirmed the
surface origin and zoning
pattern diagnostic of
paroslea/osteosarcoma.
radiograph shows fairly
mature osteoid matrix arising
from the surface of the tibial
meta diaphysis _ Axial
imaging is important to
confirm the pattern of bone
formation and lack of
marrow involvement.
II
24
SCLEROTIC BONE lESION, SOLITARY 3
III
CO
C\l
III
III
VI
C\l
C.
Fibrous Dysplasia, Skull Base
(Left) Lateral radiograph ;0
OJ
shows a sclerotic lesion in C.
the vertebral body __ 0'
demonstrated to be Hodgkin ...
CO
OJ
disease. This process is most -0
::r
frequently sclerotic; primary
lymphoma of bone may be
o
.-1
lytic or mixed. (Right) Axial
bone CT shows dense
o
VI
VI
"ground-glass" sclerosis of CIl
the maxilla and skull base o
c
_. The bones are VI
expanded. The lesion is not

as sclerotic as with an
osteoma. This is a typical
appearance of fibrous
dysplasia in this location.
Osteitis Condensans of Clavicle

radiograph shows a
well-marginated sclerotic
lesion located in the femoral
neck __ This case of LSMFT
is predominantly sclerotic;
others are mixed
lytic-sclerotic. Location is a
prime factor in considering
the diagnosis. fRight) Axial
NECT shows sclerosis of the
distal clavicle __ compared
with the normal left side _.
The adjoining manubrium
was normal, eliminating
infection as a possibility. The
lesion was stable over 1 year.
Sarcoidosis
radiograph shows a
homogeneous dense
sclerotic lesion within the
femoral head (trocar present
for biopsy). Rarely, osseous
sarcoid may present as a
sclerotic lesion. (Right)
shows a densely sclerotic,
enlarged diaphysis of the
clavicle __ The patient had
Gf and skin symptoms which
led to the diagnosis of
mastocytosis, biopsy proven.
II
25
(/)
:J SCLEROTIC BONE LESIONS, MULTIPLE
o
Ql
(/)
(/)
o DIFFERENTIAL DIAGNOSIS • Lung metastases are more frequently

I- lytic, but sclerotic mets are seen in
-
U
~
c.
co
L
Common
• Metastatic, Breast
non-small cell lung cancer
• Hint: Expect to see common diseases
Ol
o • Metastatic, Prostate with uncommon appearances
"0
CO
• Metastatic, Lung o Location of metastases: Axial, shoulder
cr: • Multiple Healing Rib Fractures (Mimic) girdle, pelvis, proximal humeri & femora
"C
CIl
• Paget Disease o Compared with bone islands, at least some
(/)
• Enostosis (Bone Island) lesions should enhance on MR or appear
'"
CO
• Bone Infarct active on PET CT
CIl
en • Brown Tumors, Healing • Multiple Healing Rib Fractures (Mimic)
'"
E • Fibrous Dysplasia, Skull o Healing may be bulky & round, obscure
• Metastatic, Osteosarcoma the fracture line, & mimic sclerotic lesions
• Metastatic, Medulloblastoma o Hint: Generally multiple & in a linear
• Fibroxanthoma (NOF), Healing pattern in adjacent ribs
• Melorheostosis • Paget Disease
• Osteopoikilosis o Usually the pattern is mixed lytic &
Less Common sclerotic, but mature Paget disease may
• Osteoma result in homogeneous sclerosis
• Renal Osteodystrophy, Neostosis o Hint: Location in long bones (end of bone,
• Hyperparathyroidism (Mimic) extending to subchondral surface, with
• Hyperparathyroidism, Treated abrupt cut-off adjacent to normal bone)
• Metastatic, Lymphoma o Hint: Enlargement of bone
• Metastatic, Carcinoid o Skull pattern of round "cotton wool"
sclerotic foci is classic; foci appear "fuzzier"
Rare but Important at margin than sclerotic metastases
• Sarcoidosis • Enostosis (Bone Island)
• Mastocytosis o May have several foci, scattered without a
• POEMS pattern to suggest osteopoikilosis
• Tuberous Sclerosis o Characteristics are same as solitary bone
island, dense sclerosis, fading at edges
ESSENTIAL INFORMATION o Inactive lesion on MR or PET CT
• Bone Infarct
Key Differential Diagnosis Issues o Different patterns; some easy to diagnose
• Diagnosis ranges from malignant • Most difficult: Patchy but homogeneous
(metastases) to benign, to "leave me alone" sclerosis, most often in femoral or
lesions (bone islands) humeral head: Early AVN, particularly in
• Clues which may help differentiate sickle cell patients
o Patient age
• Diffuse increased density: Often
o Clinical information, esp. known primary
overlooked, but not confused with
tumors or metabolic bone disease sclerotic bone lesions; most often in
o Specific location of lesions
sickle cell patients
• If necessary, MR or PET CT may differentiate • Serpiginous dystrophic calcification,
active lesions (such as metastases) from usually metaphyseal: Rarely may be
inactive lesions (such as bone islands) confused with enchondroma, but not
Helpful Clues for Common Diagnoses other sclerotic bone lesions
• Sclerotic Metastases • Fibrous Dysplasia, Skull
o Most common: Breast, prostate o Fibrous dysplasia usually has different
o Less common: Lung, Hodgkin disease, manifestations in different parts of body
lymphoma, carcinoid, medulloblastoma, o Skull: Sclerotic foci (base of skull most
osteosarcoma, transitional cell, GI tumors frequent, but may involve cranium)
II
26
SCLEROTIC BONE LESIONS, MUlTIPLE 3
III
10
CIl
o Sclerotic foci in the skull may be • Bowed bones, protrusio hips aJ

III
homogeneously dense, or may be slightly • Evidence of dialysis (central line, Ul
CIl
less dense than an osteoma, tending peritoneal catheter, shunt) Q.
• Hyperparathyroidism (Mimic) ;:0

towards a "ground-glass" opacity Q)
Co
o Hint: Enlarged bone, polyostotic in 50% o a.k.a. HPTH, active: Generally osteopenic, o'
10
• Fibroxanthoma (NOF), Healing in skull may develop a trabecular ~
Q)
o May occasionally be multiple, especially in resorptive pattern which leaves punctate "0
~
patients with neurofibromatosis sclerotic foci ("salt & pepper" skull) ()
.-1
o Natural history is to heal in (sclerosis - • Hyperparathyroidism, Treated
normal trabeculation) o HPTH & ROD, healing: New bone is
o
Ul
(J)
CIl
o Hint: Location is cortical & metaphyseal formed which may appear patchy, often o
c:
• Melorheostosis along with periosteal new bone (J)
o Hint: Watch for pattern of involvement o HPTH & ROD, healing: New bone fills in
• Linear, endosteal or periosteal, Brown tumors, often appearing
monomelic hyperossified (distinct, round sclerotic
• Osteopoikilosis foci); these may remain sclerotic or
o Metaphyseal, round eventually develop normal trabeculae
Helpful Clues for Less Common Diagnoses Helpful Clues for Rare Diagnoses
• Osteoma • Sarcoidosis
o Multiple in polyposis syndromes o Rare osseous manifestation: Sclerotic foci
• Renal Osteodystrophy, Neostosis o Hint: Skin involvement highly likely;
o Renal osteodystrophy (ROD) may show pulmonary involvement less likely
focal sclerosis of bone, at various stages of • Mastocytosis
disease, with various etiologies o Rarely may develop sclerotic bone foci
• ROD, active: Generally osteopenic, but o Hint: Clinical manifestations of skin rash,
osteoblast activation may result in episodic vomiting & diarrhea
superimposed generalized sclerosis; foci • POEMS
may be seen (Rugger jersey spine) o Homogeneous sclerotic or sclerotic rim
• ROD, treated: New bone formation o Clinical: Peripheral neuropathy,
o Hint: Watch for other manifestations organomegaly, endocrinopathy, skin
• Resorptive processes: Subperiosteal, manifestations
subligamentous, subchondral
• Soft tissue calcification
Metastatic, Breast Metastatic, Prostate
Anteroposterior radiograph shows multiple sclerotic (as

well as lytic) lesions in this young woman with
Coronal bone CT shows multiple sclerotic lesions
scattered through the axial skeleton & pelvis _ There
II
pathologic fx. The presence of axillary clips helps secure are clips in the pelvis from inguinal node dissection; this
the diagnosis of metastatic breast cancer. (tMSK Req). is sclerotic metastatic prostate cancer.
27
VJ
:J SCLEROTIC BONE LESIONS, MULTIPLE
o
Ql
VJ
VJ
o
t--'"
-
l)
.c
a.
ro
~ (Leh) Sagittal MIP shows
Metastatic, Lung Multiple Healing Rib Fractures (Mimic)
Cl diffuse small sclerotic

.Q metastases scattered
"0
ro throughout the vertebrae
c:: and sternum _ The
"0 primary lung cancer
Gl
VJ (non-small cell) is seen on
III
the same image Ell. (RighI)
al
Gl
PA radiograph shows
Cl multiple sclerotic" lesions II of
III
the ribs III. These sclerotic
E foci are aligned in a linear
fashion, making it clear that
they are healing rib fractures
rather than metastases in this
patient who happens also to
have a primary cancer.
Paget Disease Paget Disease

and enlargement of both the
clavicle. and axillary
border of the scapula Ell.
Both of these lesions are
mature sclerotic foci of Paget
disease. (RighI) Lateral
rounded, rather
fuzzy-appearing sclerotic
lesions, along with
generalized thickening of the
cranium. This is the "cotton
wool" appearance typically
seen in late Paget disease of
the skull.
Bone Infarct Brown Tumors, Healing

sclerotic foci_
representing the relative
sclerosis of bone infarcts in a
patient with sickle cell
anemia. The contralateral hip
showed collapse, indicating
a higher grade of AVN.
sclerotic lesions throughout
the pelvis of a young man.
The patient is on dialysis for
end stage renal disease, and
these are healed Brown
tumors.
II
28
SClEROTIC BONE LESIONS, MULTIPLE 3
III
to
(1)
OJ
III
VI
(1)
Co
Fibrous Dysplasia, Skull Metastatic, Osteosarcoma
(Left) Axial bone CT shows ::0
OJ
,ight maxilla,y &, pte'ygoid c.
replacement by ground-glass o'
to
sclerosis __ typical of ~
OJ
fibrous dysplasia of the skull.
Note the bones are enlarged. "o::T
50% of skull lesions in .-;
fibrous dysplasia are
polyostotic. (Right)
o
Anteroposterior radiograph '"'"
CD
shows amorphous bone o
c:
formation in two vertebral VI
bodies, left iliac wing, &, left

pubis, all sites of metastasis
from osteosarcoma. Note the
disarticulated left hip,
treatment for the primary I
year earlier.
Metastatic, Medulloblastoma
shows sclerotic ulnar lesion
with prominent sunburst
type of periosteal reaction
III This child had
medulloblastoma; osseous
metastases may be lytic,
sclerotic, or mixed. (Right)
shows multiple cortically
based nonossifying fibromas,
in the sclerotic phase of
healing III. This is the
natural history of these
lesions, and they generally
eventually acquire normal
trabeculation. The patient
had neurofibromatosis.
Melorheostosis Osteopoikilosis
radiograph shows linear as
well as rounded sclerotic
densities which were
confined to the left
extremity. This is
meJorheostosis, one of the
sclerosing dysplasias. (Right)
Axial NECT shows multiple
small rounded sclerotic
densities. If MR were
performed, they would be
low signal on all sequences.
When bone islands are
clustered in the metaphyses
like this, it is termed
osteopoikilosis.
II
29
'"o::l SClEROTIC BONE LESIONS, MULTIPLE
Ql
'"'"
o
t-="
()
:<:0- Osteoma
~
OJ radiograph shows multiple
.2 osteomas arising from the
"0
ro cortex of the femur" The
a:: patient had similar lesions on
'1:l the contralateral femur.
Q)
'"'"
!Xl
shows osteoma of the
Q)
mandible. in the same
OJ patient as previous image.
'E" Multiple osteomas may be
seen in patients with
polyposis, termed Gardner
syndrome.
Renal Osteodystrophy, Neostosis Hyperparathyroidism (Mimic)

radiograph shows
generalized bone sclerosis,
plus sclerotic osseous
excrescences" This is
neostosis, which may occur
with effective treatment of
end stage renal disease.
(Right) Lateral radiograph of
the skull shows the "salt &
pepper" pattern of
trabecular resorption in
hyperparathyroidism. The
appearance is of multiple
round sclerotic lesions, but it
is due to resorption around
residual bone.

shows several smudgy areas
of sclerosis. within bones
which show generalized
increased density. This
patient had a
parathyroidectomy for
intractable
hyperparathyroidism, and
the sclerosis shows healing of
bone. (Right) AP radiograph
shows a sclerotic aggressive
lesion in the metadiaphysis
of a child. This is a case of
polyostotic lymphoma; 50%
of childhood bone
lymphoma presents with
multiple lesions.
II
30
SClEROTIC BONE LESIONS, MUlTIPLE 3
~
to
(1)
OJ
~
VI
(1)
C.
Metastatic, Carcinoid Sarcoidosis
(Left) Axial bone CT shows ;0
Ql
two of the multiple densely C.
sclerotic lesions in this o·
(C
patient with known ~Ql
carcinoid. The lesions are -0
::r
typical of the osseous
metastases in this disease .
o
•-1
radiograph shows two sites
o
U>
U>
of osseous sclerosis •• <1l
without other features, in a o
c
patient with sarcoidosis. U>
Sarcoid occasionally presents

with sclerotic bone lesions,
as in this case, but more
frequently the lesions are
lytic.

shows an ivory vertebral
body, without enlargement
or other distinguishing
features. There was another
sclerotic focus in the lumbar
spine. Mastocytosis may
present with sclerotic
osseous lesions. (Right)
shows multiple sclerotic
lesions, some rather
confluent to give the
appearance of generalized
sclerosis in this patient with
mastocytosis. It MSK Req).
POEMS
radiograph shows one large
and several subcentimeter
round sclerotic skull lesions
111. Metastatic disease
should certainly be
considered, but this proved
to be POEMS, or sclerotic
myeloma. (Right)
shows a mixture of multiple
sclerotic lesions, and others
which are lytic with a
sclerotic rim. This is one
manifestation of POEMS, the
rare sclerosing myeloma.
(tMSK Req).
II
31
en SClEROTIC lESION WITH CENTRAL lUCENCY
:::l
o
Q)
en
en
o DIFFERENTIAL DIAGNOSIS • Fracture line not always evident
f- o Typical location in tibia and metatarsals
u Common
:cn. o Pain worsened by activity
ro • Osteoid Osteoma • Paget Disease
~
0>
o • Fibroxanthoma (Non-Ossifying Fibroma) o Cortical thickening with bone
"0
ro
• Stress Fracture, Adult enlargement is typical
cr: • Paget Disease o Mixed sclerotic and lytic lesions
"tl
Ql
• Bone Infarct • Reparative phase
en
l\l less Common • More common than purely sclerotic
III
Ql • Chronic Osteomyelitis phase
Cl
l\l
• Enchondroma o Sclerotic phase causes uniform areas of
E increased density
• Loose Bodies (Mimic)
• "Cotton wool" skull
Rare but Important
• "Ivory" vertebral body
• Osteoblastoma • Bone Infarct
• Langerhans Cell Histiocytosis o Dense bone in the medullary space
• POEMS o Serpiginous or "smoke up the chimney"
• Tertiary Syphilis outline with lucent center
o Proximal or distal long bones
ESSENTIAL INFORMATION • Metaphyseal most common
• Can extend to subchondral plate
Helpful Clues for Common Diagnoses o Associated with steroids, alcohol use +
• Osteoid Osteoma numerous other disease states
o Highly vascular nidus of osteoid tissue
(lucency) surrounded by reactive bone Helpful Clues for less Common Diagnoses
(sclerosis) • Chronic Osteomyelitis
• Intracortical, intramedullary or o Mixed osteosclerotic and osteolytic lesions
subperiosteal with periosteal reaction
• Less reactive bone when intraarticular o Solitary lesion with sequestrum is classic
(femoral neck) than when located in o Can have multiple lesions
diaphyseal cortex o Metaphyseal or diaphyseal location

• Nidus can calcify o Cortical thickening, periosteal new bone
o > 50% in tibia and femur • Enchondroma
o 90% of cases age < 25 years o Lytic lesion with chondroid matrix
• Fibroxanthoma (Non-Ossifying Fibroma) • Located in medullary cavity
o Eccentric, parallel to long axis of bone • Single or multiple lesions
o Ovoid or lobulated lesion • Expansile without cortical breech or
• Greater than 2 cm periosteal reaction, excluding pathologic
• Sclerotic medullary margin fracture
o Metaphyses of lower extremities most • Epiphyses spared when skeletally
common immature
o Spontaneous healing of lesions o Pattern of matrix can outline central
• Sclerosis varies based on stage of healing lucency

• Tends to progress peripheral to central o Can mimic a bone infarct when heavily
• Healed lesions may persist as regions of calcified

sclerosis or develop normal trabeculation o 50% in tubular bones of hand
• Stress Fracture, Adult • Proximal phalanges

o Appearance dependent on location and • Mid to distal metacarpals
duration of injury o Transformation to chondrosarcoma is rare
o Localized cortical thickening of tubular • Loose Bodies (Mimic)
bones o Osteochondral fragments
• Periosteal reaction along shaft o Vary in number and size
II
32
SClEROTIC lESION WITH CENTRAL LUCENCY 3
QI
to
n>
• Synovial osteochondromatosis = o Healing lesions can appear similar to ell
QI
numerous loose bodies due to synovial fibrous dysplasia fIl
n>
metaplasia a.
• POEMS
o Distribution limited to extent of joint o Polyneuropathy, Organomegaly, ;;0
Ql
Endocrinopathy, M protein, Skin changes a.

space' o·
CO
• Can be mobile or fixed to synovium o Solitary or multiple lesions ~
Ql
o Ossified ± central lucency o At ligamentous attachment sites, lesions <l
:T
• Solidly ossified loose bodies projected appear as fluffy, spiculated hyperostosis o
.--1
over other bones on radiographs can o Multiple lesions in a similar location to
artifactually simulate sclerotic lesion standard lytic myeloma show sclerosis ±
o
fIl
fIl
with lucent center central lucency n>
o
c
o May have accelerated arthritis due to • Tertiary Syphilis fIl
associated prior injury or impingement o Osteitis and osteomyelitis from Treponema

pallidum spirochetes
o Skull involvement = lucency or sclerosis of
• Osteoblastoma
outer table, relatively preserved inner table
o Large osteoid osteoma, > 1.5 to 2 cm
o > 50% involve vertebral body posterior
• Worm-eaten appearance on CT
o Gummatous destruction of bone with
elements
o Can have central lucency or calcification
periosteal reaction and sclerosis is seen late
o Majority show cortical expansion and
in disease
reactive sclerosis Alternative Differential Approaches
o Unlikely to spontaneously regress as • Sclerotic lesion with central lucency hich is
osteoid osteomas may solitary
• Langerhans Cell Histiocytosis o Osteoid osteoma, stress fracture, ch onic
o Abnormal proliferation of Langerhans cell osteomyelitis, enchondroma,
histiocytes in reticuloendothelial system osteoblastoma, secondary syphilis
o Single or multiple lesions, rapid growth • Sclerotic lesions with central lucency which
o Predilection for skull, mandible, ribs, may be either solitary or multiple
femur, pelvis, spine o Fibroxanthoma (non-ossifying fibroma),
o Lesion is generally lytic Paget disease, bone infarct, loose body,
o Healing lesion may develop peripheral Langerhans cell histiocytosis, POEMS
sclerosis, giving the appearance of a • Sclerotic lesions with central lucency which
sclerotic lesion with central lucency are generally multiple: POEMS, Paget disease
Lateral radiograph demonstrates a markedly thickened,

sclerotic anterior tibial cortex Ell Within this oblong
Oblique radiograph shows two metaphyseal, cortically
based lesions which are scferotic with a centra/lucency
II
region of sclerosis, there is a focal lucency III. This _ These are partially healed nonossifying fibromas,
lucency represents the osteoid osteoma nidus. sclerosing from the periphery.
III
~ SCLEROTIC lESION WITH CENTRAL lUCENCY
o
Q)
III
III
o
t-"
-
C)
.r:
a.
<0 (Left) Axial bone CT shows
Stress Fracture, Adult Stress Fracture, Adult
'-
Ol periosteal bone formation
.Q with focus of lucency"
"0
<0 This lucency continued
0::: longitudinally down the
"t:l femur, consistent with a
C1I
III stress fracture. Note: Osteoid
"'
al
C1I
osteoma, stress fracture &
osteomyelitis can be
Ol indistinguishable on a single
"'E axial CT image. (Right)
Coronal bone CT (same
patient as previous) shows
central longitudinal lucency
of the stress fracture ffi
surrounded by thick cortex.
This reconstruction helps
define the stress fracture.
radiograph shows a linear
lucency" surrounded by
sclerosis. One does not
usually visualize a stress
fracture this distinctly, but
this runner refused to rest his
leg. (Right) Lateral
vertebral body with central
lucency •. This is the mixed
phase of Paget disease, not
as advanced as the classic
II picture frame"; a bone scan
indicated the patient had
two other lesions as well.
Bone Infarct Chronic Osteomyelitis

(Left) Axial NECT of both
proximal tibias show
serpiginous dystrophic
calcification, with central
lucency, typical of bone
infarcts •. (Right) Axial
NECT is suboptimal, since it
was obtained using soft
tissue technique. However, it
shows a focal lucency ••
with sequestrum in the
thickened, sclerotic tibial
cortex" in thispatient with
chronic osteomyelitis. Also
note inflammatory stranding
in the adjacent subcutaneous
fat.
II
34
SClEROTIC LESION WITH CENTRAL LUCENCY 3Dl
10
<tl
D:l
Dl
l/I
<tl
Co
Enchondroma
(Leh) Lateral radiograph ::0
III
shows a ring-like sclerotic C-
lesion, with apparent central o·
<C
lucency •. The sclerosis is ~III
chondroid matrix; "0
::r
occasionally the matrix is
arranged such that there is
o
.-1
central non-ca/c;{jed
cartilage. (Right) Sagittal PO
o
l/I
l/I
FSEFS MR (same patient as <1>
previous image) shows the o
C
low signal ring of calcified l/I
chondroid matrix'" being

surrounded by lobular
cartilage in this classic
enchondroma~ incidentally
noted on MR.
Loose Bodies (Mimic) Osteoblastoma

(LehJ Anteroposterior
radiograph of the left hip
shows a sclerotic lesion with
central lucency • projected
over the femoral head. On
cross sectional imaging, the
density was shown to
represent a loose body.
(Right) Axial NECT shows
mild expansion of the
sacrum by a peripherally
sclerotic lesion" with
central lucency • and
osteoid matrix. The presence
of osteoid matrix favors
osteoblastoma over
aneurysmal bone cyst or
chordoma.
POEMS
lesion in the ischium with
centra/lucency _
Langerhans cell histiocytosis
normally is lytic, but this
patient was treated with low
dose radiation, and the
sclerosis indicates healing.
lytic lesions with sclerotic
rims'" along with purely
sclerotic lesions. This is a
variant appearance of
POEMS, or sclerosing
myeloma. (tMSK Req).
II
35
en SEQUESTRATION
:J
o
<1l
en
en
o DIFFERENTIAL DIAGNOSIS o Prominent smooth surrounding sclerosis is
I- typical unless lesion is intraarticular
-
o
J::
Cl.
~
Common
o Geographic lesions
en • Osteoid Osteoma (Mimic) o Lack sclerotic border
.Q
-0
ro • Langerhans Cell Histiocytosis o May contain button sequestrum (especially
a: • Lymphoma skull)
-0
<1l Less Common o Polyostotic in about 25% of cases
II)
l\l
• Fibrosarcoma • Polyostotic lesions may be less aggressive
II)
<1l • Malignant Fibrous Histiocytoma, Bone • Lymphoma
Cl
l\l • Metastases, Bone Marrow o Permeative destruction of bone with
E sequestrum in 11%
• Removed Hardware
• Bisphosphonate-Related Osteonecrosis o Disproportionally large soft tissue mass
• Intraosseous Hemangioma (Mimic) • Intact bone cortex; may be thickened
• Charcot, Neuropathic o Metaphysis or diaphysis of long, tubular
bones, with pelvis second most common
Rare but Important
• Pseudohypoparathyroidism Helpful Clues for Less Common Diagnoses
• Chordoma • Fibrosarcoma
• Tertiary Syphilis o Relatively uncommon diagnosis that
• Vascular Channel commonly has a sequestrum related to
residual bone fragment
o Eccentric, metaphyseal location typical
ESSENTIAL INFORMATION o Expands marrow space with endosteal
Key Differential Diagnosis Issues scalloping

• Classically, sequestrum refers to o Can appear similar to osteomyelitis
devascularized bone surrounded by purulent • Malignant Fibrous Histiocytoma, Bone
material o Metaphysis of long bones
• Lytic lesions with radiodense foci can have o Similar radiographic appearance to
similar appearance to true sequestra on fibrosarcoma
radiographs & CT • Sequestrum less common in this entity
o Calcific densities due to residual bone than seen in fibrosarcoma
fragments • Residual calcification of infarct may
o Calcification from chondroid matrix mimic sequestrum
o Dystrophic calcification o Can simulate osteomyelitis
o Ossification • Metastases, Bone Marrow

o Nidus of residual bone in lytic lesion
Helpful Clues for Common Diagnoses o Metastatic lesions are typically multiple
• Chronic Osteomyelitis and varying in size
o True sequestrum of necrotic bone o Can be seen with any primary malignancy
surrounded by viable infectious material producing lytic metastases
• Seen in subacute to chronic osteomyelitis • Breast carcinoma most commonly have
o Poorly defined lytic lesion with cortical button sequestra
destruction o Cortical destruction and soft tissue mass
o Enhancement of surrounding tissue are associated findings
o Periosteal reaction common
• Removed Hardware
o Sinus tracts develop to extrude the o Lucent region from prior instrumentation
sequestrum o Central dystrophic calcification along tract
• Osteoid Osteoma (Mimic) • Alternatively, infection along tract
o Typically a well-defined lytic lesion with o Typical pattern of pin, screw or rod holes
surrounding sclerosis with evidence of prior trauma or surgical
o Can have calcification of the central nidus intervention
II
36
SEQU ESTRATlON 3
III
~
(1)
• Bisphosphonate-Related Osteonecrosis o Short fourth & fifth metacarpals/tarsals III

III
o Poorly circumscribed, mixed sclerotic and o Calcification in basal ganglia & dentate III
(1)
lytic lesion in mandible or maxilla nuclei Q.
o Lacks periosteal reaction or soft tissue mass o Pseudo-pseudohypoparathyroidism has ::0

Ql
Q.
(differentiate from osteomyelitis, same radiographic appearance o·
metastases) • Chordoma ,
<0
Ql
• Intraosseous Hemangioma (Mimic) o Midline axial skeletal lesions from "0
;j
o Well-circumscribed lytic lesion without notochord remnants ()

.-i
periosteal reaction/cortical breakthrough o May be very large at presentation,
o Coarse vertical trabeculae can simulate especially in sacrum
o
III
III
punctate bone sequestra on axial imaging o Bone destruction with soft tissue extension
(1)
o
C
o Common location in vertebral body o lntratumoral calcification = residual bone III
• Uncommonly extend into pedicles, as fragments

metastases frequently do • Tertiary Syphilis
• Charcot, Neuropathic o Neuropathic joint disease
o "Six D's" o Late neurosyphilis = tabes dorsalis
• Normal bone density • Predilection for hip, knee & ankle
• Joint distention • Vascular Channel
• Destruction of joint or cartilage o Intraosseous vascular loop surrounds an
• Deformity island of normal bone
• Debris (may mimic sequestrum) .a Tubular nature is evident on axial imaging
• Dislocation Alternative Differential Approaches
o Location suggests etiology
• Button Sequestrum in Skull
• Shoulder = syringomyelia o Langerhans cell histiocytosis
• Spine = cord injury, diabetes, syphilis o Metastases
• Hip = alcohol, syphilis o Hemangioma
• Knee = insensitivity to pain, steroid o Meningioma
injection, syphilis o Epidermoid or dermoid cyst
• Foot & ankle = diabetes o Osteomyelitis
Helpful Clues for Rare Diagnoses o Radiation necrosis
• Pseudohypoparathyroidism o Osteonecrosis of craniotomy sites
o Multiple lytic lesions with button o Burr hole
sequestra, especially in skull o Pseudohypoparathyroidism
Chronic Osteomyelitis
Anteroposterior radiograph shows an ova/lytic lesion

•• with cenlIal density. representing a sequestrum,
Axial bone CT shows a sharply demarcated lesion in the
neural arch" containing bone matrix and surrounding
II
plus prominent periosteal reaction Ell and marrow reactive sclerosis. Lesions with central ossification or
osseous reactive bone, typical of osteomyelitis. calcification. can mimic a sequestrum.
37
1IJ
:J SEQUESTRATION
o
Ql
1IJ
1IJ
o
r-:
-
()
.r:
a.
ro
~ (Left) Anteroposterior
langerhans Cell Histiocytosis lymphoma
Ol radiograph shows multiple

.2 calvarial lesions" with
1:)
ro beveled edges. It is not
0:: pathognomonic for
1:) Langerhans cell histiocytosis
Ql
1IJ but is typical and is a useful
ltI finding when present.
en Sequestra 11II are common.
Ql
en (Right) Lateral radiograph
ltI
shows a permeative lesion
E involving the diaphysis of the
femur with cortical
thickening posteriorly 11:I
and scalloped endosteum
anteriorly Ell. A sequestrum
III favors primary bone
lymphoma.
Fibrosarcoma Malignant Fibrous Histiocytoma, Bone

destructive lytic lesion 11:I
involving both sides of the
pubic symphysis. There is no
matrix, but internal residual
bone fragments III mimic
sequestra. (Right) Lateral
lesion III arising in the
central diaphysis. There is a
wide zone of transition,
cortical breakthrough, host
reaction, and a small
sequestrum III. These
findings are not specific
beyond appearing
aggressive.

(Left) Axial NECT shows a
predominately lytic mass
involving the vertebral body
•• and left facet & lamina of
0. This has the typical
"soap bubble" appearance
of metastatic thyroid
carcinoma. Residual internal
bone trabeculae. mimic
sequestra. (Right) Axial bone
CT shows a lytic lung
carcinoma metastasis III in
the distal femur. Small foci of
calcificationin the lesion.
represent residual bone
fragments rather than matrix,
and appear as sequestra.
II
38
SEQUESTRATION 3
Ql
lC
nl
l:D
Ql
III
nl
Q.
Removed Hardware Bisphosphonate-Related Osteonecrosis
Ql
radiograph shows an old thin Q.
pin tract. which has o'

CO
widened into a round lytic "'
Ql
lesion with central sclerosis "0
:::r
•. The central sclerosis is a
sequestrum in this pin tract
o
.-1
infection. (Right) Axial NEeT
o
=
shows a mixed sclerotic and
lytic mandibular lesion,
at the site of a recent tooth
en
en
<ll
o
c:
extraction. Note the cortical III
loss EiiI and sequestrum ISI

in the defect, typical for
mandibular osteonecrosis in
a patient taking long-term IV
bisphosphonates.
Intraosseous Hemangioma (Mimic) Charcot, Neuropathic

typical hemangioma
characteristics of a
well-circumscribed lytic
lesion. with sparse, even,
thickened trabeculae ISI
mimicking sequestra. (Right)
Axial bone CT shows chronic
LS vertebral body fracture
•• with exuberant
osteophytes and bone
debris. Destruction and
debris is also centered
around the facet joints EiiI.
Bone destruction and debris
• mimics chronic
osteomyelitis with sequestra.
Pseudo hypoparathyroidism Chordoma

shows multiple calvarial lytic
lesions" suggestive of
multiple myeloma. However,
many of these lytic lesions
contain radiodense "button"
sequestra III and the skull is
thickened ElIl which is not
expected in myeloma and
suggests the true diagnosis.
(RighI) Axial CECT
demonstrates complete
destruction of the clivus ElIl
There is no significant
calcified matrix with the bulk
of the lesion but small bony
I'sequeslra" (retained
fragments) are present"
II
39
(/)
:J TARGET LESIONS OF BONE
o
Q)
(/)
(/)
o DIFFERENTIAL DIAGNOSIS • Chronic Osteomyelitis
-
I-
U
~
c.
~
Common
• Osteoid Osteoma
o Sequestrum of devitalized bone
surrounded by infectious material
produces target appearance
en • Intraosseous Lipoma
o o Poorly defined lytic lesion with marked
is
C1l
• Pinhole Sequestra enhancement of surrounding tissues
0:: • Chronic Osteomyelitis o Associated findings of periosteal reaction,
"C
Ql • Fracture Healing Process sinus tract, skin ulceration
VI
• Cement & Bone Fillers, Normal o Appearance is not pathognomonic for
'"
llJ
• Cement & Bone Fillers, Complications
Ql infection, as malignancy can have an
en
Less Common identical appearance
E'"
• Metastases, Bone Marrow • Fracture Healing Process
• Liposclerosing Myxofibrous Tumor o Irregular endosteal bone healing or
• Bone Infarct irregular external bone callus may
• Enchondroma surround bone fragments
• Chondroblastoma • Cement & Bone Fillers, Normal
• Chondrosarcoma o Can have a normal halo of lucency at
• Arthroplasty Loosening & Dislocation cement-bone interface
(Mimic) o Lucency will remain stable relative to
• Chordoma immediate postoperative images
• Pseudo hypoparathyroidism • Cement & Bone Fillers, Complications
o Tumor recurrence along border of
Rare but Important
curettage & cement packing
• Dermoid Cyst, Skull o Lucency at cement-bone interface
• Aneurysmal Bone Cyst progresses from postoperative appearance
ESSENTIAL INFORMATION • Metastases, Bone Marrow
Key Differential Diagnosis Issues o Breast metastases are most likely to have
• Lytic lesion of bone with central central bone fragments
radiodensity from any cause (calcification, o Osteosarcoma" metastases produce osteoid
ossification, bone fragment) o Metastases in various stages of both
• Location & associated findings most helpful healing and progression may have
for differentiation alternating regions of lucency & sclerosis
o Associated findings of soft tissue mass,
cortical destruction, additional lesions of
• Osteoid Osteoma varying size
o Classic: Lucent central nidus within bone
• Liposclerosing Myxofibrous Tumor
cortex may itself have central calcification o Classic location in proximal metadiaphysis
o Surrounding reactive bone sclerosis
of femur
• Intraosseous Lipoma o Lytic lesion containing fat & calcification,
o Well-defined lytic lesion containing fat
confirm with CT
o Typical location in the calcaneus
o Sclerotic border, no aggressive features
o Presence of central calcification
• Bone Infarct
differentiates from normal area of bone o Dense medullary bone in metaphyses of
with paucity of trabeculae long bones
• Pinhole Sequestra o Tends to have serpiginous borders, rather
o After removal of pins, screws and rods,
than smooth target appearance
central area can calcify
o No cortical destruction, soft tissue mass, or
o Infection along a hardware tract may
cortical breakthrough unless malignant
produce a bone sequestrum centrally transformation
within the pin track
• Enchondroma
II
40
TARGET lESIONS OF BONE 3
Cll
to
~
o Central chondroid matrix in medullary o Uncommon entity but common central tll
Cll
lytic lesion (cortical lesions less common) calcification of the multiple lytic lesions VI
~
Associated findings of short metacarpals & C.
o Typical location in hands o
o Associated findings of bone expansion or metatarsals and basal ganglia & dentate ;0
Q)
c.
pathologic fracture when occurring in nuclei calcification o·
to
~
small tubular bones Helpful Clues for Rare Diagnoses Q)
• Chondroblastoma
o Focal lytic lesion with internal chondroid
• Dermoid Cyst, Skull ":T()
o Well-defined lytic lesion containing _-i
matrix occurring at end of bone in mature skin & fat o
skeletally immature patient o Predilection for sutures & diploic region
VI
VI
ell
o Associated findings of thin sclerotic o
o No enhancement C
border, geographic bone destruction & • Aneurysmal Bone Cyst
VI
periosteal reaction in metaphysis, distant o Expansile lytic lesion, central regions of

from epiphyseal lesion dystrophic calcification may rarely be seen
• Chondrosarcoma o Associated findings of fluid-fluid levels,
o lll-defined, destructive lytic lesion with
sclerotic border, septations & intact cortex,
chondroid matrix unless pathologic fracture
o Associated findings of endosteal scalloping
or cortical breakthrough, ring & arc Alternative Differential Approaches
calcification; non-mineralized • Reverse target lesions of bone
cartilaginous tumor hypodense to muscle o Sclerotic bone lesion with lucent center
• Arthroplasty Loosening & Dislocation • Osteoid osteoma
(Mimic) • Fibroxanthoma (non-ossifying fibroma)
o Component failure with migration of • Stress fracture
portions of prosthesis within joint • Paget disease
o Lucency from particle disease rarely has • Bone infarct
central calcification or bone fragments • Chronic osteomyelitis
• Chordoma • Enchondroma
o Midline lytic lesion containing residual • Loose bodies
osseous fragments • Osteoblastoma
• Sacral chordomas more likely to have • Langerhans cell histiocytosis
target appearance than vertebral lesions • POEMS
• Pseudohypoparathyroidism • Tertiary syphilis
Osteoid Osteoma Intraosseous Lipoma
Axial NECT shows a classic osteoid osteoma in the

femoral neck. II demonstrates the lyric lesion within the
Lateral radiograph shows a lytic calcaneal lesion Ell
with a central sclerotic nidus _. Although this region
II
or
anterior cortex
nidus sitting within the lesion =.
the femoral neck, with a sclerotic
ItMSK Req).
often is relatively lucent because of normal trabecular
pattern. this is a true geographic lesion. ItMSK Req).
41
VI
::J TARGET lESIONS OF BONE
o
Ql
VI
VI
o
t--="
-
u
L
0-
ro
Pinhole Sequestra Chronic Osteomyelitis
Ol radiograph demonstrates an
.2 old, thin, pin tracl" which
"ro
a::
has widened into a round
lytic lesion with central
'tl sclerosis HI. The central
Ql
VI scleros;s is a sequestrum in
'"
al
this pin tract infection.
(Right) Laleral radiograph
Ql
Ol shows a region of irregular
'" lucency HI surrounding a
E
more sclerotic piece of bone
•. This is a focus of
osteomyelitis with a
sequestrum seen centrally.
(tMSK Req).
Cement & Bone FillerSr Complications Metastases, Bone Marrow

chips IIa which have been
placed fol/owing curetlage of
a giant cel/ tumor. Residual
or recurrent tumor is seen at
the periphery IIa causing an
eccentric target sign. (Right)
Axial CECT shows metastatic
osteosarcoma = to the
sacrum and ilium. The sacral
lesion has a target
appearance due to lhe
formation of osteoid matrix.
Liposderosing Myxofibrous Tumor Bone Infarct

lesion in the intercondylar
region of the femoral neck
with geographic borders and
central sclerotic matrix Ell.
Additional/y, fal is presenl
wilhin the lesion" These
have rare malignant
transformation. (Right) Axial
NECT shows a bone infarct
IIa in the right tibia wilh a
target appearance. A bone
infarct in the lefl tibia shows
corlical breakthrough Ell
due to degeneration into a
malignant fibrous
histiocytoma.
II
<12
TARGET lESIONS OF BONE 3
III
lC
CD
lD
III
l/I
CD
Q.
Enchondroma Chondroblastoma
(Left) AP radiograph shows a ;u
Q)
small, expansile, lytic lesion C-
=
with a small central density
that resembles a target.
This case is unusual;
o·
...
(Q
Q)
"0
::r
enchondromas are more
commonly located in the
o-;
medullary space than in the
cortex. (Right) AP radiograph
o
CIl
CIl
shows a lytic lesion in the CD
epiphysis HI containing o
c
small foci of calcific matrix CIl
•. There is prominent
dense periosteal reaction in
the metaphyseal region 11II
giving an overall appearance
of chondroblastoma. rt MSK
Req).
Arthroplasty loosening & Dislocation

(Mimic)
radiograph shows a
pathologic fracture I!llll
through a large lytic lesion
= containing dense central
matrix iii. This expansile
lesion has thinned the cortex
suggesting it was originally
slow growing but cortical
breakthrough indicates more
recent increased activity.
radiograph shows a rounded
the patella =
density located superior to
representing
dissociation of the metal
backing from the patellar
button.
Chordoma Pseudo hypoparathyroidism

(Left) Axial CECT shows a
large lytic lesion ••
destroying the majority of the
sacrum and extending into
the adjacent 50ft tissues Eill
Amorphous intra tumoral
calcification II has a target
appearance and is due to
bone destruction. (Right)
multiple lytic lesions of the
skull ••• some of which
contain central sclerosis HI
giving a target appearance.
When seen in the skull, this
central calcification is termed
button sequestra.
II
43
<J)
:J MATRIX-CONTAINING BONE LESIONS
o
(l)
<J)
<J)
o DIFFERENTIAL DIAGNOSIS • If a portion of lesion shows less
1-- organization of matrix, termed
-
U
.r::
a.
ro
~
Common
• Enchondroma
"snowstorm", it is more aggressive
o Mixed osteoid and chondroid elements
Ol
.Q
• Bone Infarct • No discernible separate elements; gives
"0
ro • Osteochondroma smooth opaque ground-glass appearance
0::: • Fibrous Dysplasia • No trabeculae seen
'0
CI) • Osteosarcoma, Conventional o Dystrophic calcification (matrix mimic)
IJ)
ctl • Osteoid Osteoma • Often globular, but may be serpiginous;
CO
CI)
• Chondrosarcoma, Conventional generally denser than bone
Cl
ctl • Fibroxanthoma (Non-Ossifying Fibroma), • Hint: Use the degree of aggressiveness of the
E Healing underlying lesion as a differentiating factor
• Fracture Callus Formation, Early between benign and malignant lesions
• Intraosseous Lipoma Helpful Clues for Common Diagnoses
• Malignant Fibrous Histiocytoma, Bone • Enchondroma
o Conventional
• Osteosarcoma, Periosteal • Ranges from dense punctate matrix to
• Liposclerosing Myxofibrous Tumor (LSMFT) fine, subtle matrix or entirely lytic
• Small bones of hand/foot or
Less Common metaphysis/metadiaphysis tubular bones
• Radiation-Induced Sarcoma • Appears geographic because of matrix,
• Paget Degeneration to Osteosarcoma but no sclerotic margin or true
• Osteoblastoma demarcating structure
• Chondroblastoma o Oilier Disease
• Chondromyxoid Fibroma • May be typical enchondroma, or may
• Oilier Disease have striated appearance in metaphyses
• Maffucci Syndrome • Generally monomelic; short extremity
o Maffucci Syndrome
ESSENTIAL INFORMATION • Same as Oilier, + soft tissue hemangioma

• Bone Infarct
Key Differential Diagnosis Issues o May be lytic, but often develops
• For the purpose of this topic, differential dystrophic calcification
diagnosis excludes hamartomatous bone o Classic pattern of serpiginous dense Ca++
formation (enostosis, osteoma) o May assume other forms difficult to
• Hint: Differentiate by the type and degree of differentiate from enchondroma
aggressiveness of matrix • Osteochondroma
o Bone-producing (osteoid) o Must have normal bone marrow and
• Aggressive: Amorphous, immature bone; cortex extending into excrescence
barely visible density, less dense than o May have chondroid matrix in the more
normal bone peripheral portions
• Less aggressive: More dense osteoid, • Fibrous Dysplasia
forming recognizable bone, sometimes o May have calcification of small spicules of
with trabeculae (more mature) osteoid and chondroid
• Less aggressive tumor bone formation • Leads to the ground-glass appearanc,e of
may have a zoning pattern: More mature smooth increased density without
bone centrally, less mature peripherally trabeculation
o Cartilage-producing (chondroid) o Density of ground-glass component varies
• Punctate matrix, often denser than bone • Depends on amount of calcified osteoid
• Described as "C's & arcs", ring-like and chondroid
• Therefore not surprising to see different
densities, even in same patient
II
44
MATRIX-CONTAINING BONE LESIONS 3
III
CO
<1>
• Osteosarcoma, Conventional Alternative Differential Approaches tD
III
o Aggressive tumor osteoid, amorphous &
• Divide into types of matrix and degrees of '"
<1>
Co
immature; may be quite subtle aggressiveness of matrix ;:0
o Secondary: Most frequently degeneration o Osteoid, aggressive Q)
a.
of Paget or radiated bone; Tumor osteoid is • Conventional osteosarcoma o·
CO
immature, aggressive, and amorphous ~
• Fracture callus, early Q)
"0
• Osteosarcoma, Parosteal • Radiation or Paget-induced osteosarcoma ::T
o Mature osteoid, often containing
o Osteoid, less aggressive
C'i
.--i
trabeculae • Parosteal osteosarcoma o
o Zoning of lesion with more mature bone
• Osteoid osteoma '"'"
l1>
centrally than peripherally • Osteoblastoma o
c
• Osteosarcoma, Periosteal • Fibroxanthoma, healing '"
o Intermediate grade of maturation of
• Periosteal osteosarcoma
osteoid; may be spiculated o Chondroid
• Chondrosarcoma, Conventional • Enchondroma, including OIlier and
o When matrix is present, it is chondroid
Maffucci
o High grade lesion: Chondroid matrix in
• Osteochondroma
obvious soft tissue mass • Chondrosarcoma
o May not be able to differentiate low grade
• Periosteal chondroma
central chondrosarcoma & enchondroma • Chondroblastoma
• Malignant Fibrous Histiocytoma, Bone • Chondromyxoid fibroma
o Degeneration of bone infarct may -+ MFH
o Ground-glass (mixed osteoid/chondroid)
o Dystrophic calcification of infarct is seen,
• Fibrous dysplasia
often with lytic destructive change arising • Liposclerosing myxofibrous tumor
in a portion of it o Dystrophic calcification
• Fracture Callus Formation, Early • Bone infarct
o Early callus is amorphous osteoid
• lntraosseous lipoma
• Same appearance as tumor osteoid • Malignant fibrous histiocytoma, arising
radiographically & histologically in infarct
o Generally can see fracture and avoid
confusion; osteopenic bone or pathologic
fractures are potentially difficult
Enchondroma
Lateral,adiograph shows the punctate matrix =:I which

is typical of chondroid. There is minor endosteal
scalloping Ell. Note that the lesion has no sclerotic
matrix =
AP radiograph shows minimal punctate chondroid
in a lypical enchondroma which was
discovered incidentally on MR. Note the lesion is not
II
margin. The appearance ;s typical of enchondroma. geographic and has no defined margin; this is expected.
45
(J)
:> MATRIX-CONTAINING BONE LESIONS
o
Q)
(J)
(J)
o
~
-
()
.c
a.
ro
~ (Left) Lateralradiograph
Bone Infarct Bone Infarct
Ol shows the serpiginous

o pattern of dystrophic
'6
ro calcification in two sites of
a:: bone infarct _ This is a
"tl typical, though not required
Q)
(J) pattern for an infarct. (Right)
tV Lateralradiograph shows a
CD
Q)
small site of punctate density
Cl •• in the tibia which could
tV
represent either chondroid
E matrix inan enchondroma or
dystrophic calcification in a
bone infarct The more
serpiginous pattern of infarct
in the femur HI makes the
diagnosis of bone·;nfarcts.
Osteochondroma Osteochondroma
(Left)Lateralradiograph
shows punctate regions of
chondroid matrix" within
the cartilaginous cap of an
osteochondroma, with
normal bone in the stalk ~
Matrix may be seen in
osteochondroma without
implying chondrosarcoma.
shows chondroid matrix
within the peripheral portion
III of this exostosis, but
clearly normal bone extends
from the posterior tibial
metaphysis into the stalk of
the exostosis itself HI.
(tMSK Req).
radiograph shows the rather
featureless increased density
"ground-glass" =.
which has been termed
typical of
fibrous dysplasia in tubular
bones. Note the absence of
normal trabeculae. (Right)
AxmlNECTshowsthe
smooth increased density of
ground-glass matrix HI at a
site of fibrous dysplasia in a
different patient. There is a
lesion =-
lytic focus in an adjacent
Fibrous dysplasia
often shows features of both.
II
46
MATRIX-CONTAINING BONE lESIONS

shows the amorphous,
(eatureless density o(
immature osteoid III within
the bone as well as soft
tissue mass in this patient
with osteosarcoma. The less
the matrix appears to be
distinctly bone, the more
aggressive it is. (Right) AP
radiograph shows regions of
very dense tumor bone
formation. mixed with
areas that are less dense Ell
in this advanced tumor.
Despite areas of density, the
matrix is all amorphous and
typical of osteosarcoma.
Osteoid Osteoma Chondrosarcoma, Conventional

(Left) Axial NEeT shows a
round lytic lesion containing
a focus of calcification ffi
buried within densely
sclerotic cortex •. There is
an adjacent nutrient vessel
~ The radiograph only
showed the dense reactive
sclerosis. (t MSK Req).
"snowstorm" appearance of
punctate chondroid matrix
III of a chondrosarcoma,
arising from an underlying
osteochondroma Ell which
has better organized
chondroid matrix.
Fibroxanthoma (Non-Ossifying Fibroma),

Healing Fracture Callus Formation, Early
shows two NOF lesions,
both undergoing the natural
process of healing. The
new bone formation contains
trabeculae and does not
have the amorphous
appearance of tumor bone.
fibrous dysplasia. The
mid-humeral lesion which is
more expanded, with matrix,
and pathologic fracture Ell is
concerning for sarcomatous
transformation; biopsy
showed healing fracture
callus.
II
47
<f)
:J MATRIX-CONTAINING BONE LESIONS
o
OJ
<f)
<f)
o
t-='
-
()
.r:
a.
ro
~ (Left) AP radiograph shows a
Osteosarcoma, Parosteal
Ol large osteoid-producing
Q lesion appearing to wrap
1:)
ro around tibial metaphysis ••.
0:: Note: Matrix is not
"0 amorphous, but well-defined
OJ
<f) ElIl typical of the less
aggressive parosteal variety.
'"
!Xl
Q)
Cl shows a well-defined lytic
ro lesion in the mid calcaneus
E E!:I containing dense
calcification'" The location
and appearance are typical
for intraosseous lipoma. The
calcification is not required
for the diagnosis. (t MSK
Req).
Malignant Fibrous Histiocytoma, Bone

aggressive lesion Ell
associated with a serpiginous
calcific density typical of
bone infarct". MFH may
arise secondary to bone
infarct; watch for a change
in character of the lesion.
radiograph shows matrix of
indeterminate type arising
from the surface of bone ••.
This is a periosteal
(juxtacortica/) chondroma;
the matrix may appear
osseous or chondroid; it is a
surface lesion.

Osteosarcoma, Periosteal (lSMFT)
fairly mature appearing
osteoid matrix within a lesion
bone =-
arising from the surface of
which proved to
be periosteal osteosarcoma.
The malrix in this lesion
occasionally appears a bit
more aggressive than this.
an intertrochanteric lesion
which is geographic and
contains both fat and a
ground glass matrix ••.
LSMFT usually contains a
mixture of lipomatous,
fibrous, myxomatous, and
osteoid matrix.
II
48
MATRIX-CONTAINING BONE LESIONS 3
III
to
tl>
Dl
III
t/I
tl>
Q.
Radiation-Induced Sarcoma
(Left) Y view radiograph ;0
Q)
shows a farge soft tissue Q.
mass arising from a o

permeative lesion of the ...•
<C
Q)
body of scapula. The bone 1:l
::r
and 50ft tissue mass contains
an amorphous osteoid =. o
•-1
This ;s a radiation-induced
osteosarcoma. (Right) Lateral
o
t/I
t/I
radiograph shows destructive <1>
change and expansion of the o
C
sacrum, with osteoid matrix t/I
replacing the entire bone =.

Individuals with longstanding
and diFFusePaget disease are
at risk for degeneration to
sarcoma.
Osteoblastoma Chondroblastoma
shows an expanded lesion of
C2 spinous process which
contains fairly mature
appearing osteoid matrix =.
OsteoblaslOma need not
contain matrix, but this
appearance and location are
classic. (tMSK Req). (Right)
Axial NECT shows a mostly
lytic, eccentric lesion of the
epiphysis which contains a
small amount of chondroid
matrix HI. This was a
skeletally immature patient,
and the appearance is classic
For chondroblaslOma.
Chondromyxoid Fibroma Oilier Disease

(Left) Axial CECT shows an
unusual appearance for
chondromyxoid fibroma. It is
in an unusual location, has
central necrosis, and a small
amount of chondroid matrix.
CMF most frequently arises
in the proximal tibia. (Right)
Lateral radiograph shows an
abnormally short ulna,
dislocated proximal radius,
and ulnar metaphyseal lesion
containing chondroid matrix
•. This is a case of Oilier
disease; the metaphyseal
lesions more frequently
appear striated.
II
49
fJ)
~ BENIGN OSSEOUS lESIONS THAT CAN APPEAR AGGRESSIVE
o
<l)
fJ)
fJ)
o DIFFERENTIAL DIAGNOSIS • Lytic, permeative pattern

I- • Periosteal reaction, marrow and soft
U Common
:;:: tissue edema
0-
ro • Osteomyelitis, Adult • Hint: Soft tissue fat planes tend to be
~
OJ
o • Osteomyelitis, Pediatric obliterated with infection, but displaced
"0
ro
• Langerhans Cell Histiocytosis (LCH) with tumor
0:: • Arthroplasty Wear/Particle Disease • Marrow and soft tissue abscess
"'C
CIl
• Hyperparathyroidism, Brown Tumor differentiate osteomyelitis from tumor
fJ)
<tl • Insufficiency Fracture (Mimic) • Reminder: Tumor necrosis may mimic
III
CIl
• Stress Fracture, Metatarsal (Mimic) abscess; be critical in assessment
Cl • Radiation Osteonecrosis
<tl o Chronic recurrent multifocal osteomyelitis
E • Giant Cell Tumor may have completely normal radiograph;
• Aneurysmal Bone Cyst biopsy required to differentiate from round
• Disuse Osteoporosis cell tumor
• Paget Disease • Langerhans Cell Histiocytosis (LCH)
• Enchondroma, Phalanx o Often geographic, but may also appear
• Fibrous Dysplasia lytic & permeative
• Garden IV Subcapital Fracture (Mimic) o May have soft tissue mass; imaging may be
less Common indistinguishable from malignant tumor
• Fibroxanthoma (Non-Ossifying Fibroma) such as Ewing sarcoma or lymphoma
• Hemangioma, Spine o Hint: Beveled edge in skull lesions
• Osteoblastoma (differential destruction of inner & outer
• Chronic Recurrent Multifocal Osteomyelitis tables) suggests LCH
• Charcot, Neuropathic o Hint: LCH may show much more rapid
destruction than sarcoma; this may be a
Rare but Important differentiating factor
• Pseudotumor of Hemophilia • Arthroplasty Wear/Particle Disease
• Hemangiopericytoma, Osseous o Lysis from particle disease usually
• Hemangioendothelioma, Osseous geographic but may appear aggressive
• Rapidly Destructive Osteoarthritis of Hip o Age: High risk for metastases or myeloma,
• Massive Osteolysis of Gorham which also must be considered
o Hint: Watch for sources of particles
ESSENTIAL INFORMATION (component wear, bead shedding, bone or
cement debris) to suggest associated
Key Differential Diagnosis Issues particle disease
• Many of these entities do not behave at all • Hyperparathyroidism, Brown Tumor
in an aggressive fashion, so the imaging can o Lytic lesion virtually always associated
be more confounding than helpful with other signs of HPTH
• Hint: Always consider both osteomyelitis • Abnormal bone density (osteopenic or
and Langerhans cell histiocytosis when in mixed), generalized pattern
the "small, round, blue cell" differential • Osseous resorption patterns:
oLe., when considering Ewing sarcoma, Subperiosteal, subchondral
leukemia, lymphoma • Stress or Insufficiency Fracture
• Certain traumatic entities may appear o Hint: These tend to be site-specific; search
aggressive; these are usually site-specific: for fracture line when "lesion" involves
Sacral alar insufficiency, subcapital hip sacral ala, pubic ramus, subcapital femoral
insufficiency, and metatarsal stress fractures neck, metatarsals
Helpful Clues for Common Diagnoses o Hint: Fracture line often obscured,
• Osteomyelitis, Adult or Pediatric particularly by edema in fluid-sensitive
o Active osteomyelitis, especially bacterial, sequences; search carefully for fracture
may show significant bone destruction line, which may be on only a single image
II
50
BENIGN OSSEOUS LESIONS THAT CAN APPEAR AGGRESSIVE 3
III
(Q
<Il
o Metatarsal fractures • Radiation Osteonecrosis to
III
• Particularly prone to having surrounding o Mixed lytic and sclerotic pattern may VI
<Il
soft tissue (as well as marrow) edema; appear aggressive Q.
appears aggressive on fluid sequences or o Abnormal bone at risk for fx, osteomyelitis ;U
Ql
Q.
post-contrast MR o Hint: Watch for radiation port-like ,5"
(Q
• Hint: Always look at radiograph before distribution of osseous abnormalities ~
Ql
suggesting tumor in a metatarsal o Since there is a primary tumor, differential
o Sacral insufficiency fractures includes metastatic disease; MR may be
"o~
_-i
• Pattern of bilateral vertical abnormality required to evaluate for soft tissue mass
is most suggestive o Differential also includes
o
VI
VI
• Edema can obscure fracture line & even radiation-induced sarcoma; watch for (\)
o
c
vertical pattern; may be confusing if tumor osteoid or more aggressive regions VI
unilateral • Giant Cell Tumor

• Radiographs generally not helpful since o Benign GCT may appear and behave
fracture line rarely seen; trabeculae aggressively, with cortical destruction &
appear smudged soft tissue mass
o Pubic ramus insufficiency fractures o Usually there is a suggestion of moderately
• Often do not heal well, particularly in slow growth (expanded bone prior to
elderly osteoporotic patient cortical breakthrough)
• Constant motion at fracture site results o Subchondral location suggests diagnosis
in appearance of a lytic destructive • Aneurysmal Bone Cyst
lesion, particularly on MR o ABC may be so significantly expanded that
• Radiograph usually shows fracture, but surrounding cortex is no longer visible
itself may be confusing due to o Fluid levels within lesion are suggestive,
mechanical destruction of bone but not pathognomonic
o Garden IV sub capital fracture o Remember that ABC may be solid, which
• Rotation of fragments and varus may confound the issue
alignment results in an apparent lytic o Hint: If there is anything of concern about
lesion at fracture site suspected ABC lesion (focally wide zone of
• Hint: Be aware and expect this transition, nodularity within regions of
appearance; should not require a fluid), consider telangiectatic osteosarcoma
work-up for underlying tumor; MR is • Alert pathologist to carefully examine all
confounded by the hematoma and submitted tissue; lesion is easily missed
granulation tissue of fracture healing
Lateral radiograph shows no distinct osseous lesion, but

obliteration of fat planes posteriorfy=. Osteomyelitis
Axial T2WI MR shows high signal within the bone _
with surrounding 50ft tissue mass HI Osteomyelitis
II
can be 50 highly permeative that no distinct lesion may frequently results in adjacent abscesses in the 50ft
be seen. It therefore appears aggressive. ItMSK Req). tissues; contrast differentiates abscess from tumor.
51
'":>o BENIGN OSSEOUS LESIONS THAT CAN APPEAR AGGRESSIVE
Q)
o'"'"
t--""
()
:<:a. Osteomyelitis, Pediatric
ro (Leh) Oblique radiograph
~
OJ shows dramatic permeative
.Q lytic destruction of the radius
"0
ro •• in this child. Periosteal
0:: reaction & soft tissue mass is
"0 present. Differential includes
Q)
aggressive tumor such as
'"
III
CD
Ewing sarcoma. (Right)
Sagittal T1 C+ MR in the
GI
OJ same case, shows diffuse
III
enhancement of the radius
E E!lI. There is an abscess.
but also so much reactive
change in the soft tissues that
it might be mistaken for soft
tissue tumor mass with
necrosis. Biopsy proved
Staphylococcal infection.

shows an aggressive
permeative lytic lesion of the
mid diaphysis with
prominent periosteal
reaction". LCH may
present either as a
geographic lesion, or with an
aggressive appearance as
seen here. (Right) Axial PO
FSEMR shows destructive
change of the acetabulum
•. along with a large soft
tissue mass. LCH may be
surprisingly rapidly
destructive, mimicking a
malignant tumor.
radiograph shows a large,
lytic, somewhat permeative
acetabulum. The offset of
the femoral head in the cup
indicates polyethylene wear,
resulting in massive
osteolysis. (Right) AP
delineated lytic lesion in the
humeral diaphysis. While
this appears moderately
aggressive, the correct
diagnosis of Brown tumor is
secured by the abnormal
bone density & resorption of
the distal clavicle ••.
II
52
BENIGN OSSEOUS LESIONS THAT CAN APPEAR AGGRESSIVE 3
III
(0
<D
OJ
III
VI
<D
Co
Insufficiency Fracture (Mimic) Stress Fracture, Metatarsal (Mimic)
(Left) Axial STIR MR shows ::0
III
diffuse high signal in both Co
sacral ala •. The actual O·
(0
fracture lines of insufficiency ~
III
fractures may be obscured -0
::T
by fluid sensitive sequences,
and are usually not seen on
o-l
radiographs. (Right) Coronal
TI C+ FS MR shows high
o
VI
fJ)
signal within the marrow" CI>
with an apparent o
c
circumferential" mass" HI fJ)
mimicking tumor. Stress

fracture elicits edema within
marrow as well as in the
adjacent soft tissues.
Misdiagnosis of tumor occurs
surprisingly often.
Radiation Osteonecrosis
moderately aggressive mixed
lyUc and sclerotic bone in a
square "port-like"
configuration. The rest of the
skeleton was normal. The
patient had axillary node
radiation for breast cancer.
Radiation osteonecrosis can
be difficult to differentiate
from metastases. (Right)
giant cell tumor which is 50
expanded that the cortex is
no longer seen" Despite
the appearance, this proved
to be a benign giant cell
tumor.

shows a lytic lesion
occupying the distal femur,
with a fairly wide zone of
transition" The lesion has
expanded into a farge 50ft
tissue mass _ with an
extremely thin cortical rim.
This proved to be
aneurysmal bone cyst.
such severe osteoporosis that
it has a moth-eaten
appearance" distal to a
fracturenonunion" This
osteoporosis can be rather
focal, related to fracture
hyperemia & disuse.
II
53
f/l
:> BENIGN OSSEOUS LESIONS THAT CAN APPEAR AGGRESSIVE
o
Q)
f/l
f/l
o
1-"
-
U
.<::
a.
Paget Disease Enchondroma, Phalanx
Ol shows osteoporosis
.Q circumscripta IElIl the lytic
"0
ro phase of Paget disease in the
0:: skull. The early lytic phase,
"0 or even the mixed
Q)
f/l lytic/sclerotic disordered
nl bone phase may appear
lD
Q)
aggressive. (Right) Lateral
Ol radiograph shows significant
nl
expansion, with severe
E cortical thinning and
chondroid matrix.
Enchondroma may appear
more aggressive in the
phalanges than in more
proximal locations, yet
behave in a benign manner.
Garden IV Subcapital Fracture (Mimic)

extensive fibrous dysplasia,
but focal expansion, cortical
break, & central matrix.
Concern is for degeneration
to sarcoma (extremely rare)
vs. the proven diagnosis,
pathologic fracture. (Right)
shows a displaced subcapital
fracture. The angulation and
rotation, combined with
osteoporosis, results in the
appearance of a lytic lesion
in the femoral neck ••
mimicking underlying
pathology.

lytic expanded somewhat
aggressive lesion in the fibula
• It is important to
remember that NOr, when it
arises in small bones like the
fibula, may appear central
and more aggressive than
usual. (Right) Sagittal T2WI
MR shows hemangioma
within a vertebral body"
extending to the posterior
elements IElIl & expanding
into a large epidural mass
•••. Occasionally this degree
of aggressiveness is seen in
hemangioma.
II
54
BENIGN OSSEOUS lESIONS THAT CAN APPEAR AGGRESSIVE 3
III
to
(l)
Ol
III
VI
Chronic Recurrent Multifocal (l)
C.
Osteomyelitis
(Left) Lateral ,adiog,aph ::0
OJ
shows a mixed lytic and C.
sclerotic lesion in the o
to
~
vertebral body, with OJ
destruction of the posterior "0
:::T
cortex _ Ra,ely an
osteoblastoma will show this
o
.-1
degree of agg,essiveness.
o
VI
VI
shows high signal in the CI>
sacral ala _ & iliac wing o
c
1m. The radiograph was en
normal; this is worrisome for
highly permeative lesions.
The differential for multifocal
osteomyelitis includes Ewing,
leukemia, & lymphoma.
Charcot, Neuropathic Pseudotumor of Hel110philia

dislocation & destruction of
the humeral head. There is
osseous debris within a
distended joint _. A
shoulder Charcot joint can
be so destructive that, with
the debris, it is mistaken for
shows expansile lytic lesion
of the iliac wing, with
fracture through the
acetabulum by the femoral
head. This appears
destructive; however, the
margination is sclerotic,
typical of pseudotumor.
Hemangioendothelioma, Osseous
shows a moderately
aggressive osseous lesion _
There were additional
osseous lesions raising the
concern for a vascular
tumor. Hemangiopericytoma
has a spectrum ranging from
benign to malignant. (RighI)
PA radiograph shows a
highly destructive lesion of
the 2nd metacarpal. The
appearance is nonspecific.
Biopsy proved
hemangioendothelioma,
which has an appearance &
behavior ranging from
benign to malignant.
II
55
II)
METASTASES TO BONE
"Q)
o
II)
II)
o DIFFERENTIAL DIAGNOSIS • Sclerotic healing
r-: • Sclerotic or lytic progression
()
:ca. Common • Radiation osteonecrosis
ro
~
• Breast Carcinoma
Q)
• Lung Carcinoma Helpful Clues for Common Diagnoses
.Q
-0 • Prostate Carcinoma • Breast Carcinoma
ro
a::: • Renal Cell Carcinoma (Hypernephroma) o Lytic or sclerotic lesions
o May contain button sequestra, especially
'tl
Q) • Thyroid Carcinoma
II) in skull
ltl
In Less Common o Normal skull thickness differentiates
Q)
Q) • Lymphoma extensive metastases from Paget disease
ltl
E • Leukemia • Lung Carcinoma
• Osteosarcoma o Typically lytic lesions, but can be sclerotic
• Neuroblastoma (esp. small cell lung carcinoma)
• Ewing Sarcoma o Majority of lytic metastases to the hands &
• Malignant Melanoma feet are from lung primary
• Gastrointestinal Carcinoma • Prostate Carcinoma
• Medulloblastoma o Sclerotic lesions typical but can be lytic
• Carcinoid • Homogeneously dense vertebral body,
• Wilms Tumor "ivory vertebra"
• Testicular Carcinoma • Lack of bone enlargement differentiates
Rare but Important from Paget disease
• Retinoblastoma o Can produce long, solitary expansile rib
• Adrenal Carcinoma lesions
• Squamous Cell Carcinoma o Diffuse skeletal involvement results in
• Cervical Carcinoma "super scan" pattern on bone scan
• Uterine Carcinoma • Renal Cell Carcinoma (Hypernephroma)
• Hepatoma o Expansile, poorly demarcated osteolytic
• Transitional Cell Carcinoma lesions
• Fibrosarcoma • "Soap bubble" appearance
o Tremendously vascular metastases make
biopsy dangerous; consider embolization
ESSENTIAL INFORMATION first
Key Differential Diagnosis Issues o Can contain fat, producing false negative
• Demographics drop out on opposed phase MR imaging
o Metastases are far more common than • Image kidneys if multiple bone lesions
primary bone tumors (25:1) are identified on MR and are shown to
o 80% of skeletal metastases are due to lung, contain microscopic fat
breast, prostate, and kidney carcinomas • Thyroid Carcinoma
o 50% of all patients with cancer will o Expansile, poorly demarcated osteolytic
eventually develop skeletal metastases lesions
• Skeletal distribution o Often solitary and highly vascular
o Predilection for regions containing red o Similar imaging appearance to renal cell
marrow: Skull, spine, ribs, pelvis, humeri, carcinoma metastases
femora Helpful Clues for Less Common Diagnoses
• Typical appearance • Lymphoma
o Single or multiple lesions of varying sizes o Oval, lytic lesions
o Joint spaces & intervertebral disks o Can be faintly sclerotic
preserved o Extensive permeative lesions in Burkitt
o Periosteal reaction rare lymphoma
o Density of lesions can change with o Sclerotic lesions with Hodgkin lymphoma
response or lack of response to therapy and histiocytic lymphoma
II
56
METASTASES TO BONE 3
III
CO
• Ivory vertebral body with Hodgkin o Lytic lesions, can be large & solitary 'l"Jl
III
lymphoma • Transitional Cell Carcinoma VI
• Leukemia o Sclerotic lesions '"

a.
o Moth eaten bone destruction

;0
• Fibrosarcoma III
a.
o Sub-epiphyseal rarefaction o Lytic lesions originating from soft tissue or O·
bone primary co
~
o Transverse radiolucent metaphyseal bands III
-0
o "Sunburst" appearance in skull
Alternative Differential Approaches ::T
• Osteosarcoma • Lytic metastases to bone
o
.-1
o Metastases ossify, including soft tissue
o Non small cell lung carcinoma o
deposits o Renal cell carcinoma
VI
VI
CD
• Neuroblastoma o Breast carcinoma o
c
o Similar to leukemia VI
o Thyroid carcinoma
• Ewing Sarcoma o Gastrointestinal carcinoma
o Ill-defined, lytic lesions
o Neuroblastoma
o May become confluent
• Blastic metastases to bone
• Malignant Melanoma o Prostate carcinoma
o Lytic or faintly sclerotic lesions
o Breast carcinoma
• Gastrointestinal Carcinoma o Transitional cell carcinoma
o Lytic or sclerotic lesions
o Gastrointestinal carcinoma
• Sclerotic more common with gastric o Small cell lung carcinoma
carcinoma and carcinoid o Medulloblastoma
• Medulloblastoma o Any carcinoma
o Mixed lytic and sclerotic lesions
• Metastases in children
o Most common in children
o Neuroblastoma
o Cerebrospinal metastases before bone
o Leukemia
Helpful Clues for Rare Diagnoses o Lymphoma
• Squamous Cell Carcinoma o Medulloblastoma
o Nodal involvement usually seen before o Ewing sarcoma
lytic bone lesion o Wilms tumor
• Cervical & Uterine Carcinoma
o Lytic lesions from hematogenous spread or
direct extension to bone
• Hepatoma
Breast Carcinoma lung Carcinoma
AP radiograph shows mixed sclerotic & lytic metastases

• in the ribs & shoulder, with pathologic fraclUre _
Axial CECT shows multiple sclerotic lesions. in the
pelvis. Additional imaging identified a primary non-small
II
Axillary clips suggest lymph node dissection & thus cell lung carcinoma. Metastatic lung carcinoma
metastatic breast carcinoma. It MSK Req). metastases are typically lytic but can be sclerotic.
57
en METASTASES TO BONE
::l
o
Q)
en
en
o
~
-
()
~
0-
ro
<-
Lung Carcinoma Prostate Carcinoma
Ol radiograph demonstrates a
.2 small cortically-based lesion
"ro
0::
•. Few cortically-based
lesions are seen in older
1:1 patients, & metastases must
Q)
CIl be suspected. Lung & breast
III are the most frequent
CO
Q)
primaries causing
Ol cortically-based lesions.
III
(tMSK Req). (Right) Axial
E
bone CT shows multiple
prostate carcinoma
metastases" Even though
sclerotic metastases can
appear more dense than
cortical bone, these lesions
have an increased risk for fx.
Prostate Carcinoma
shows diffuse sclerosis
involving all the ribs,
vertebral bodies, and
posterior elements. The
bones are normal in size.
This remarkably
homogeneous osseous
replacement is metastatic
prostate disease. (Right)
demonstrates a severely
destructive, lytic, and
expanded lesion III This
was a solitary lesion. It is
important to consider
metastatic kidney or thyroid
disease in older patients.
Thyroid Carcinoma Lymphoma

radiograph shows an avulsed
lesser trochanter" with
lucency extending into the
subtrochanteric region Ia. A
lesser trochanteric avulsion
in an adult is pathologic until
proven otherwise. (Right)
Axial bone CT demonstrates
vague sclerosis in a lesion.
identified on PET/CT. Since
the bone marrow is the
"organ" involved in this
patient's primary disease,
return of the disease, even in
a different bone, is more
accurately termed a
recurrence.
II
58
METASTASES TO BONE 3
III
(C
(1)
llJ
III
'a."
(1)
Osteosarcoma Neuroblastoma
(Left) Axial CECT shows a ;0
Q)
metastasis with osteoid C-
matrix Ell The central o·
<C
lucency may be due to ~
Q)
response to chemotherapy. "0
:::T
Osteosarcoma metastases
are typically ossified. (Right)
o
-l
shows vertebral plana of L 1
o
(f)
(f)
11:I with preservation of <1>
posterior elements, but o
c
(f)
complete flattening of the
body. In addition, there is a
paraspinous mass. as well
calcifications in the mass
superior to the right kidney
EilI representing the primary
tumor.
Malignant Melanoma Medulloblastoma

sclerotic lesion with vague
central lucency • There
were additional metastases
to the liver, peritoneum,
spleen and thoracic spine.
Bone metastases from
melanoma are typically lytic
or faintly sclerotic. (Right)
with prominent periosteal
reaction in the ulna •.
These metastases may have
either a lytic, sclerotic, or
mixed appearance.
Hepatoma Fibrosarcoma
large destructive mass.
obliterating the proximal
humerus. A thin rim of
residual bone is present
anteriorfy III. Hepatocellular
metastases to bone are
typically lytic. Most patients
have nonosseous metastatic
sites identified before skeletal
metastases develop. (Right)
Axial bone CT shows vague
medullary sclerosis and
endosteal scalloping III. The
patient had a paravertebral
50ft tissue mass as well as
other osseous lesions, any of
which could be the primary.
II
59
(/)
:J GENERALIZED INCREASED BONE DENSITY, ADULT
o
Q)
(/)
(/)
o DIFFERENTIAL DIAGNOSIS a Begins focally but can become diffuse over

f-
()
time
:ca.. Common a Mixed lytic-sclerotic pattern depending on
ro
~
• Metastases, Bone Marrow phase; sclerotic in late phase
Ol
.Q
• Renal Osteodystrophy, Healed a Thickened, coarsened, disorganized
-0
ro • Sickle Cell Anemia: MSK Complications trabeculae & bone overgrowth
0::: • Paget Disease a "Picture frame" vertebra due to peripheral
"0
CIl • Myelofibrosis sclerosis with central lucency
(/)
III
ell Less Common • Myelofibrosis
CIl • Radiation Osteonecrosis (Mimic) a Axial osteosclerosis with uniform density,
Cl
III
• Gaucher Disease cortical thickening, endosteal sclerosis
E a Hepatosplenomegaly, extramedullary
hematopoiesis
Rare but Important
a May have secondary gout
• Hypertrophic Osteoarthropathy (Mimic)
• Hypoparathyroidism Helpful Clues for Less Common Diagnoses
• Mastocytosis • Radiation Osteonecrosis (Mimic)
• Osteopetrosis a Due to osteonecrosis, dystrophic
• Pycnodysostosis calcification &/or insufficiency fractures
• Engelmann Disease (Engelmann-Camurati) with hypertrophic callus formation
(Mimic) a Look for sharp transition of abnormal to
• Erdheim-Chester normal bone defining the radiation port

• POEMS • Gaucher Disease
a Marrow packing results in bone expansion
with thinned cortices; Erlenmeyer flask
ESSENTIAL INFORMATION deformities (undertubulation)
Key Differential Diagnosis Issues a Density due to mixed lytic/sclerotic
• Increased density may be related to altered pattern with endosteal bone formation
osteogenesis or overlying periosteal new resulting in bone-within-bone appearance
bone a Osteonecrosis with dystrophic calcification
may contribute to density
• Metastases, Bone Marrow a Ranges from trabecular coarsening to
a Breast & prostate most common
uniform sclerosis; ± periosteal reaction
metastases to progress to diffuse a Involves axial> appendicular skeleton
involvement a Ligament calcification, particularly in
a Bone scintigraphic superscan with intense
sacrospinous ligaments
diffuse bone uptake & minimal renal
activity Helpful Clues for Rare Diagnoses
• Renal Osteodystrophy, Healed • Hypertrophic Osteoarthropathy (Mimic)
a Increased density results from excessive a Skin thickening, paw-like hands & feet
a 1 Pachydermoperiostosis: Inherited
0
osteoid, subperiosteal new bone, &/or -
healing resorption • Shaggy periostitis; involves all segments

a "Rugger jersey" spine results from endplate tubular bones
sclerosis a 2 0
Secondary hypertrophic
-
• Sickle Cell Anemia: MSK Complications osteoarthropathy: Related most frequently

a Bone infarctions with dystrophic to pulmonary or congenital heart disease
calcification; periostitis in children • Painful, smooth periostitis; involves
a Normally contoured bones with no tubular bones except epiphyses
cortical destruction • Hypoparathyroidism
• Paget Disease a Characterized by hypocalcemia &
neuromuscular signs & symptoms
II
60
GENERALIZED INCREASED BONE DENSITY, ADULT 3
III
CO
C1l
o Osteosclerosis may be focal or generalized; o Syndrome: Polyneuropathy, tll
III
increased density along iliac crests, Organomegaly, Endrocrinopathy, M 1Il
C1l
vertebral margins, metaphyseal bands proteins, Skin changes Co
o Calcification of ligaments (esp. o Affects axial skeleton (spine & pelvis) ;:0
Q)
C-
paraspinous), tendons, soft tissues o Diffuse sclerosis seen in about 3% of O
CO
• Mastocytosis patients with plasma cell myeloma Ql
o Diffuse or focal; ± osteolysis
o Tends to be homogeneous in axial skeleton
Alternative Differential Approaches ":():J"
• Hint: Assess the extent & distribution of .-i
o ± Osteonecrosis
osteosclerosis when considering diagnosis o
• Osteopetrosis • Diffuse vs. regional sclerosis
VI
VI
<ll
o Diffuse osteosclerosis with o
o Diffuse: Metastases, renal osteodystrophy, C
undertubulation & cortical thickening; sickle cell anemia, myelofibrosis, fluorosis,
VI
bone within bone appearance hypoparathyroidism, osteopetrosis,

• Pycnodysostosis pycnodysostosis, Erdheim-Chester,
o Diffuse osteosclerosis with short stature,
Engelmann-Camurati
short broad hands o Regional: Metastases, sickle cell anemia,
• Engelmann Disease Paget, radiation osteonecrosis, Gaucher,
(Engelmann-Camurati) (Mimic) hypertrophic osteoarthropathy,
o Bilateral symmetric cortical thickening &
mastocytosis, plasma cell myeloma
medullary cavity narrowing
• Axial versus appendicular sclerosis
o Spindle-shaped long bones with expanded
o Involves axial & appendicular skeleton
diaphyses, periosteal & endosteal sclerosis; • Metastases, renal osteodystrophy, sickle
epiphyses spared cell disease, Gaucher,
o Involves (with decreasing frequency) tibia,
hypoparathyroidism, osteopetrosis,
femur, humerus, ulna, radius, hands, feet, pycnodysostosis
clavicle, ribs, pelvis o Predominates in axial skeleton
• Erdheim-Chester • Paget disease, myelofibrosis, fluorosis,
o Diffuse or patchy density results from
mastocytosis, POEMS
trabecular coarsening, medullary sclerosis o Predominates in appendicular skeleton
o Metadiaphyseal cortical thickening with
• Hypertrophic osteoarthropathy,
epiphyses spared Engelmann-Camurati, Erdheim-Chester
o Appendicular common, axial rare
• POEMS
Metastases, Bone Marrow Renal Osteodystrophy, Healed
Lateral radiograph shows diffuse sclerosis of prostatic

metastases throughout the lumbar spine (anterior &
Anteroposterior radiograph shows diffuse increased
bone density with periosteal new bone. & indistinct
II
fXJsterior elements) as well as visualized ribs _ trabeculae related to new mineralization of previously
excessive unmineralized osteoid of osteomalacia.
61
(J)
:J GENERALIZED INCREASED BONE DENSITY, ADULT
o
Q)
(J)
(J)
o
~
-
(J
.s:::.
a.
ro
~ (Leh) Lateral radiograph
Sickle Cell Anemia: MSK Complications Paget Disease
Ol shows diffuse patchy

.Q sclerosis in the
"0
ro metadiaphyses •• of this
a:: patient with sickle cell
"0 anemia, representing
Ql
VI dystrophic calcification in
III healing bone infarctions.
III
Ql
Ol mixed lytic-sclerotic pattern
III
of thickened disorganized
E trabeculae & osteoporosis in
a patient with diffuse Paget
disease. Bone overgrowth &
remodeling results in
protrusio •• & bowing
deformity Ell of proximal
femurs.
Myelofibrosis Radiation Osteonecrosis (Mimic)

patchy osteosclerosis.
Normal fatty marrow has
been replaced by fibrous
tissue, typical of
myelofibrosis. The patient
also had splenomegaly (not
shown). (Right)
shows osteosclerosis of
sacrum & visualized pelvis
Ell as well as lower lumbar
spine. Note vascular clips.
from lymph node dissection.
Patient was treated 15 years
prior for endometrial
carcinoma.
Gaucher Disease Complications of Fluoride

patchy increased bone
density" Note the right
hip resurfacing
hemiarthroplasty" placed
because of avascular
necrosis in this patient with
longstanding Gaucher
disease. (Right) Lateral
trabecular thickening &
coarsening; involving
anterior" & posterior ••
spinal elements. Patient is
being treated with fluoride
for osteoporosis.
II
62
GENERALIZED INCREASED BONE DENSITY, ADULT 3
III
CO
CIl
OJ
III
III
CIl
Co
(Left) AP radiograph shows ;U

III
heavy periosteal new bone C-
•• in the tibia & fibula, o·
CO
mimicking diffuse increased ~
Q)
density. The hand and all -0
:::r
other imaged long bones
demonstrate similar
o
.-1
periosteal reaction. Patient
has 10 hypertrophic
o
III
III
osteoarthropathy (1)
(pachydermoperiostosis) . o
C
(Right) Lateral radiograph III
shows diffuse increased bone

density with marked bowing
deformity of femur" &
patchy sclerosis of femoral
neck HI related to chronic
hypoparathyroidism.
Mastocytosis
(Lem Anteroposterior
mixed lytic & sclerotic
density. Although
mastocytosis generally
produces either focal
sclerosis or diffuse
osteoporosis, this patient has
a mixture of both. (Right)
shows diffuse increased
density throughout the axial
and appendicular skeleton.
The appearance is of
"marble bone", or
osteopetrosis.
Erdheim-Chester POEMS
radiograph shows
generalized increased
density in the marrow of
both the femur and tibia ••
sparing the cortices and
epiphyses Ell. The findings
were bilateral and the axial
skeleton was normal.
Appearance is typical of
Erdheim-Chester disease.
the unusual sclerosing
pattern Ell of myeloma in
this patient with POEMS
syndrome. The sclerosis may
be focal, or more diffuse as
in this case.
II
63
<Jl
::J GENERALIZED INCREASED BONE DENSITY, CHILD
o
Q)
<Jl
<Jl
o DIFFERENTIAL DIAGNOSIS • Renal Osteodystrophy (Healing)
....: o Patchy sclerosis as unmineralized osteoid
-
u
.r:
0..
ro
~
Common
• Physiologic Periosteal Reaction of Newborn
(osteomalacia) calcifies and bone
resorption (hyperparathyroidism) heals
Ol (Mimic) o Coarsened trabeculae, periosteal new bone,
.Q
-0
ro • Renal Osteodystrophy (Healing) widened metaphyses
a: • Child Abuse (Mimic) • Child Abuse (Mimic)
"C
Ql Less Common o Average age: 1-4 years
VI
l'Cl
• Sickle Cell Anemia: MSK Complications o Fractures of varying ages, metaphyseal
al
Ql • Complications of Prostaglandins (Mimic) corner fractures, periosteal new bone
Cl
l'Cl • Congenital Cyanotic Heart Disease Helpful Clues for Less Common Diagnoses
E
• Complications of Vitamin A • Sickle Cell Anemia: MSK Complications
• Complications of Vitamin D o Bone pain begins after age 2-3
• Scurvy (Mimic) o Multiple bone infarctions may create
• Neuroblastoma (Mimic) "bone within bone" appearance
• Leukemia (Mimic) o Long bone periostitis and generalized
• Osteomyelitis patchy increased density
Rare but Important • Complications of Prostaglandins (Mimic)
• Caffey Disease (Infantile Cortical o IV prostaglandins used in
Hyperostosis) (Mimic) ductus-dependent congenital heart disease
• Idiopathic Hypercalcemia of Infancy o Soft tissue swelling, periosteal elevation
• Erythroblastosis Fetalis and extensive periosteal new bone
• Osteopetrosis • Congenital Cyanotic Heart Disease
• Pycnodysostosis o Represents 2° hypertrophic
• Polyostotic Fibrous Dysplasia osteoarthropathy
• Hypoparathyroidism o Thick, widespread periostitis in diaphysis,
• Complications of Fluoride metaphysis, and epiphysis
• Engelmann-Camurati Disease • Complications of Vitamin A
• Osteosclerotic Dysplasias o Excessive intake; occurs after age 1 year
• Hyperphosphatasia Ouvenile Paget) o Cortical thickening, soft tissue nodules

• Melorheostosis o Involves ulna, metatarsal, clavicle, tibia,
• Tuberous Sclerosis other tubular bones, ribs
• Van Buchem Disease • Complications of Vitamin D
• Ribbing Disease o Excessive intake; given for rickets
o Dense metaphyseal bands; variable cortical
thickening & thinning
ESSENTIAL INFORMATION • Scurvy (Mimic)
Key Differential Diagnosis Issues o Occurs later than 8 months
• Generalized density due to intrinsic o Typically osteopenic but coarsened

alteration of bone vs. dense circumferential trabeculae, subperiosteal hemorrhage and
overlay of periosteal new bone periosteal new bone may dominate
• Hint: Consider age at presentation • Neuroblastoma (Mimic)
• Hint: May involve diaphysis, metaphysis o Typically aggressive osteolytic process but
&/or epiphysis may have periostitis & periosteal new bone

• Leukemia (Mimic)
Helpful Clues for Common Diagnoses o Similar to neuroblastoma, particularly
• Physiologic Periosteal Reaction of meta diaphyseal
Newborn (Mimic) • Osteomyelitis
o Seen in 35% of infants age 1-4 months
o Congenital syphilis-transplacental
o Thin, uniform symmetric periosteal new
bone; in humerus, femur, tibia
II
64
GENERALIZED INCREASED BONE DENSITY, CHILO 3
III
(0
<1l
• Symmetric diaphyseal periosteal o Axial skeleton osteosclerosis with sclerotic OJ
III
reaction; widened, serrated metaphysis; metaphyseal bands III
<1l
epiphyses spared • Complications of Fluoride C.
o Rubella-1st trimester maternal infection o Excessive intake; axial skeletal changes ;0

III
a.
• Irregular, alternating sclerotic and lytic predominate o·
areas create "celery stick" pattern o Coarsened trabeculae; ± diffuse periosteal co
~
III
Helpful Clues for Rare Diagnoses new bone; extensive ligament calcification "U
=r
• Caffey Disease (Mimic) • Engelmann-Camurati Disease o
.-i
o Presents 4-12 years with waddling gait,
o Seen first 5 months o
o Involves mandible, clavicles, scapulae, ribs,
muscle weakness III
III
<1l
o Spindle-shaped with diaphyseal cortical o
tubular bones; ± asymmetric c::
o Spindle-shaped bones due to diaphyseal
thickening; metaepiphyses spared III
involvement; lamellated periosteal • Osteosclerotic Dysplasias

o Frontometaphyseal: Prominent cranial
reaction when healing
involvement, flared iliac wings
• Idiopathic Hypercalcemia of Infancy
o Craniometaphyseal: Prominent cranial
o Seen after first 5 months; looks similar to
hypervitaminosis D involvement, normal pelvis
o Pyle: Minimal cranial involvement,
• Erythroblastosis Fetalis
o Diffuse diaphyseal sclerosis and transverse
marked metaphyseal flaring
metaphyseal bands • Hyperphosphatasia Ouvenile Paget)
o Sclerosis with narrowed medullary space
• Osteopetrosis
o Short, large skull, bowed long bone
o Osteosclerosis with mottled metaphyses;
"bone within bone" appearance • Melorheostosis
o Cortical and/or endosteal hyperostosis;
• Pycnodysostosis
o Like osteopetrosis but with short stature,
usually limited to one extremity
short broad hands, acroosteolysis • Tuberous Sclerosis
o Sclerotic bone blends with normal bone·
• Polyostotic Fibrous Dysplasia
o Triad: Polyostotic fibrous dysplasia,
involves hands, feet, long bones & spin~s
cutaneous pigmentation, precocious • Van Buchem Disease
o a.k.a., Hyperostosis corti calis generalisata
puberty; female> male
o Normal stature, diffuse osteosclerosis
o Mildly expanded, ground-glass matrix;
generally not diffuse dense sclerosis enlarged mandible, ribs, clavicles '
• Hypoparathyroidism • Ribbing Disease
o Hyperostosis, predilection for femur/tibia
Physiologic Periosteal Reaction of

Newborn (Mimic)
AnterofXJ5terior radiograph shows sublle diffuse

increased density of the upper extremity long bones
Posteroanterior radiograph shows growth plate
widening E±I as a result of unmineralized osteoid of
II
which is bilaterallysymmetric and results from subtle osteomalacia. The trabeculae are coarsened, and there
diaphysealperiostitis III. isgeneralized increased density. 65
en GENERALIZED INCREASED BONE DENSITY, CHILD
:::l
o
Ql
en
en
o
t--"
-
()
.c
0-
ro
Child Abuse (Mimic)
Ol shows new bone formation

.Q HI resulting from
"
ro
0::
subperiosteal hemorrhage in
this child with nonaccidentaJ
"t:l trauma. Note the
Ql
en metaphyseal corner fracture
ltI •. typical of this trauma.
!Xl
Ql
Cl radiograph shows sclerosis in
ltI
the proximal tibial
E metaphysis due to infarction
and dystrophic calcification
•. Multiple long bone
infarctions in sickle cell
anemia can result in
apparent diffuse increased
bone density.
Complications of Prostaglandins (Mimic) Complications of Vitamin A

radiograph shows uniform,
thick, periosteal new bone
{ormationin the humerus.
in this patient who received
prostaglandins for several
days to maintain a patent
ductus arteriosus. (RighI)
shows cortical hyperostosis
of the ulna III which does
not involve the metaphysis
or epiphysis. If the
hypervitaminosis continues,
it may result in deformity of
the metaphyses and
epiphyses.
increased density of
diaphyses" due to
subperiosteal hemorrhage
and periosteal new bone.
Note dense metaphyseal
bands (white line of Frankel)
HI and metaphyseal
(fe/ken) fracture III (RighI)
diffuse soft tissue swelling
and moth-eaten appearing
humerus with extensive
cfoaking periostitis resulting
in increased density.
Findings represent metastatic
neuroblastoma.
II
66
GENERALIZED INCREASED BONE DENSITY, CHILD 3
III
to
<tl
CD
III
VI
Caffey Disease (Infantile Cortical <tl
a.
Osteomyelitis Hyperostosis) (Mimic)
OJ
radiograph shows widened a.
provisional calcification zone o'
of syphilitic osteochondritis . ..•
<0
OJ
There are lucent -0
::T
metaphyseal bands III with
subtle diaphyseal periostitis
o
_-I
EiII along the long bones,
typical of congenital syphilis.
o
en
en
(Right) Anteroposterior <1l
radiograph shows Caffey o
c
disease at age one month en
with the typical marked
thick, wavy periosteal new
bone" typical of cortical
hyperostosis. This patient's
mandible was also involved
(not shown).
Osteopetrosis Pycnodysostosis
radiograph shows uniform
increased density in
osteopetrosis. There is mild
undertubulation •. with
relative widening of the distal
femoral metadiaphyses.
radiograph in a child with
pycnodysostosis also shows
uniformly dense bone,
similar to osteopetrosis. This
short-limbed dwarf also has
micrognathia and shortened
fingers (not shown) typical
of pycnodysostosis.
Polyostotic Fibrous Dysplasia Engelmann-Camurati Disease

radiograph shows a long,
mildly expansile tibial
diaphyseal lesion III with
ground-glass matrix, typical
offibrous dysplasia.
Additional lesions are
present in distal tibia and
talus'" in this female with
precocious puberty. (Right)
shows bilateral diaphyseal
corticalthickening. with
normal metaphyses and
epiphyses. Process becomes
smoother and thicker,
involving entire diaphysis, as
patient matures.
II
67
VJ
::l SCLEROSING DYSPLASIAS
o
OJ
VJ
VJ
o DIFFERENTIAL DIAGNOSIS o Mimics of bone island or generalized
I- sclerosis are relatively common
u Common
:c o Distribution of osseous abnormality,
0-
ro • Enostosis (Bone Island) clinical history, or other radiographic clues
~
Ol
.Q
• Melorheostosis (Leri-Weill) are most useful for differentiation
"0
ro
• Sclerotic Metastasis (Mimic)
a: • Osteitis Condensans Ilii (Mimic) Helpful Clues for Common Diagnoses
"0 • Osteitis Pubis (Mimic) • Enostosis (Bone Island)
Q)
Vl o Focal dense sclerosis, generally rounded, in
• Osteitis Condensans of Clavicle (Mimic)
'"
lD
• Osteoma (Mimic) medullary space
o Edges "fade" into normal bone, making the
Q)
Cl
• Osteopoikilosis
'E" • Hyperossified Brown Tumors (Mimic) lesion appear somewhat spiculated
o MR low signal on all sequences,
• POEMS (Mimic)
non-enhancing
Less Common • Melorheostosis (Leri-Weill)
• Osteopetrosis (Albers-Schonberg) o Irregular cortical hyperostosis; may involve
• Osteopathia Striata (Voorhoeve) either periosteal or endosteal cortical
• Engelmann-Camurati Disease (Progressive thickening, or both
Diaphyseal Dysplasia) o Usually monostotic or monomelic (single
• Ribbing Disease (Hereditary Multiple limb)
Diaphyseal Sclerosis) o May follow sclerotome distribution
• Sarcoid (Mimic) (medial or lateral distribution in limb)
Rare but Important o "Flowing" elongated pattern likened to
• Pycnodysostosis (Maroteaux-Lamy) dripping candle wax
• Erdheim-Chester Disease (Mimic) • Sclerotic Metastasis (Mimic)
• Intramedullary Osteosclerosis o Solitary: May be radiographically
• Osteosclerosis (Worth Disease) indistinguishable from bone island;
• Pyle Dysplasia enhance with MR
• Hyperostosis Corticalis Generalisata (Van o Generalized: Rarely breast or prostate
Buchem) metastases will have a symmetric
• Kenny-Caffey Syndrome (Mimic) generalized distribution making them
• Mastocytosis (Mimic) difficult to distinguish from osteopetrosis
in the pelvis or spine
• Osteitis Condensans Ilii (Mimic)
ESSENTIAL INFORMATION o Location-specific, often bilaterally
Key Differential Diagnosis Issues symmetric
• Sclerosing dysplasias are a spectrum of o High signal on fluid-sensitive MR
disease, ranging from the innocuous bone sequences; enhancing
island through the severely disabling • Osteitis Pubis (Mimic)
osteopetrosis o Same as Osteitis Condensans Ilii
o Most are identified by their radiographic • Osteitis Condensans of Clavicle (Mimic)
distribution, which can be quite specific o Same as Osteitis Condensans Ilii
o Sclerosing dysplasias can be mixed • Osteoma (Mimic)
(particularly melorheostosis + bone o Hamartoma which may be
islands/ osteopoikilosis/ osteopathia striata) radiographically indistinguishable from
o Histology usually does not differentiate the bone island
sclerosing dysplasias from one another; o Location within paranasal sinus or
dense hamartomatous bone is nonspecific calvarium is usually diagnostic
• Aside from the two most common (bone o Familial polyposis: Cortical surface
island & melorheostosis), sclerosing osteomas in long bones
dysplasias are uncommon or rare diseases • Osteopoikilosis
o Metaphyseal or epiphyseal
II
68
SCLEROSING DYSPLASIAS 3
Cl>
(C
<ll
o Low signal on all sequences, o Affects diaphyses; over long term may III
Cl>
non-enhancing extend to metaphyses III
<ll
• Hyperossified Brown Tumors (Mimic) o Normal axial skeleton Co
o Autosomal dominant, male> female, ;;u

o Patients treated for Ql
a.
hyperparathyroidism/renal osteodystrophy begins in 1st decade 0'
may hyperossify their brown tumors • Ribbing Disease (Hereditary Multiple ,
<0
Ql
'0
during the healing process Diaphyseal Sclerosis) ~
o If small, gives appearance of o Asymmetric intramedullary diaphyseal o
--i
osteopoikilosis sclerosis
o Long bones; no axial or calvarial
o
o If large, gives appearance of bone islands III
III
(l)
or sclerotic metastases involvement o
c:
o Search for other radiographic hints of o Autosomal recessive; onset after puberty III
hyperparathyroidism (resorptive patterns, Helpful Clues for Rare Diagnoses

abnormal bone density) • Pycnodysostosis (Maroteaux-Lamy)
Helpful Clues for Less Common Diagnoses o Severe sclerosis involving entire skeleton
• Osteopetrosis (Albers-Schonberg) o Distinguished from osteopetrosis by 3
o Diffuse & dense sclerosis of all bones, axial findings
& appendicular • Acroosteolysis (resorption of phalangeal
o Range of severity; severe "marble bone" is tufts)
most easily diagnosed • Diminutive (obtuse) angle of mandible
o Impaired osteoclasts do not allow normal • Wormian bones
bone remodeling during skeletal growth • Erdheim Chester (Mimic)
• Undertubulation (dense, widened o Intramedullary sclerosis, without cortical
metadiaphyses) thickening; bilaterally symmetric
• "Bone-in-bone" appearance: Particularly o Restricted to metadiaphyses of long bones;
vertebrae & iliac wing no axial involvement
• Osteopathia Striata (Voorhoeve) o Lipidosis, not dysplasia
o Striated densities, metaphyseal • Intramedullary Osteosclerosis
• Engelmann-Camurati Disease (Progressive o Intramedullary sclerosis without cortical
Diaphyseal Dysplasia) thickening; may not be bilateral
o Fusiform thickening of cortical bone, o Mid-tibia is most common location
bilaterally symmetric in long bones; o Not hereditary; this is most reliable
hyperostosis of calvarium differentiating factor from Ribbing disease
Enostosis (Bone Island)
Anteroposterior radiograph shows a giant bone island,

incidentally noted during another examination. It is
Coronal T7WI MR is identical 10 any other sequence,
showing uniform low signal, fading into normal marrow;
II
asymptomatic. Note that the margins "fade" off into this mirrors exactly the radiographic picture of oone
normal bone; sometimes they can appear spiculated. island. There is no enhancement if concrasl is given.
69
CIl
::> SCLEROSING DYSPlASIAS
o
Q)
CIl
CIl
o
t--""
<.)
:ca. Melorheostosis (leri-Weill) Melorheostosis (leri-Weill)
~
OJ radiograph shows the
.Q elongated, rather flowing
"0
ro (termed "dripping candle
a:: wax") endosteal sclerosis ••
"0 in this patient with
Q)
CIl melorheostosis. In this
III
process, the dense bone may
en form either on the periosteal
Q)
OJ or endosteal cortex, or both.
III
E shows sclerosis in the
scleroderma I pattern ••
(medial side) in the same
patient as previous image.
The dysplasia is polyostotic
but monomelic, typical for
melorheostosis.
Melorheostosis (leri-Weill) Melorheostosis (leri-Weill)

(Left) Lateral radiograph in a
patient with meJorheostosis
shows many of the lesions
are round, typical of bone
island •. This dysplasia
often displays not only the
elongated "dripping wax"
but also rounded or striated
patterns. (Right) Sagittal PO
FSEFS MR shows a lobulated
dense bone lesion
exclusively involving the
cortex of the ulna III low
signal on a/l sequences. The
location & dense sclerosis is
typical.
Sclerotic Metastasis (Mimic) Osteitis Condensans lIii (Mimic)

within the lesser trochanter
III The cortical destruction
of the lesser trochanter
should differentiate this
prostate metastasis lesion
from bone island. (Right)
Axial bone CT shows
sclerosis along the iliac
margin of the 51joint Ell
typical of osteitis condensans
i/li. It often appears triangular
on a radiograph. It is usua/ly
symmetric, but may be
unilateral, and is easily
distinguished from a
sclerosing dysplasia.
II
70
SCLEROSING DYSPlASIAS 3
Cll
to
(l)
ll:J
Cll
1/1
(l)
a.
Osteitis Pubis (Mimic) Osteitis Condensans of Clavicle (Mimic)
(Left) Coronal T2WI FS MR ;;0
Q)
shows high signal within lhe Cl.
pubic rami. in a lypical <:5"
<0
MR appearance of osteitis ~
Q)
pubis. Though lhe "0
::T
radiographic appearance is
of sclerosis, lhe MR is
o
-l
dislinclly differenl from lhe
uniformly low signal of a
o
1/1
1/1
sclerosing dysplasia. (Right) (1)
Axial NECT shows sclerosis o

C
of lhe medial clavicle lIllI. 1/1
The lesion was intensely hot

on bone scan, & mosliy low
signal on T2 MR. It remained
stable over a I-year
follow-up period.
Osteoma (Mimic) Osteoma (Mimic)

dense sclerosis within the
fromal sinus EB The
appearance is of a bone
island, bul lhe localion
within a paranasal sinus is
lypical of osleoma. Hislology
does nol differemiale lhe
IwO. (Right) AP radiograph
shows lobulaled corlically
based sclerotic lesions •.
Allhough lhese may nol be
dislinguishable from
melorheoslosis (and is
hislologically idemica/), in a
patient with intestinal
polyposis, they are
considered osteomas.
(Leh) Coronal T I WI MR
shows mulliple round low
signa/lesions in a
melaphyseal dislribution lIllI.
They remained low signal on
fluid sequences, as well as
post-contrast, confirming the
diagnosis of osteopoikilosis.
(Right) Posleroanlerior
round sclerotic lesions III
suggesting osteopoikilosis.
This patient had a
parathyroid adenoma
removed; these are Brown
tumors, hyperossified in the
healing phase.
II
71
lfJ
::> SClEROSING DYSPLASIAS
o
Q)
lfJ
lfJ
o
r-:
u
:ca. Hyperossified Brown Tumors (Mimic) POEMS (Mimic)
ro (Left) Posteroanterior
•...
Ol radiograph shows dense
.2 sclerosis in the tuft •. Prior
"0
ro image showed a lytic lesion;
0:: the patient had a parathyroid
"0 adenoma resected and the
Ql
lfJ Brown tumor healed with
III dense ossification. (Right)
III
Q)
Ol shows diffuse sclerosis of the
III
pelvic osseous structures.
E This is a case of sclerosing
myeloma. Most cases show
more discrete round sclerotic
lesions, but occasionally they
are diffuse, mimicking
osteopetrosis.
sclerosis of the entire
skeleton. There is
undertubulation in the
proximal & distal femora ••
due to inadequate osteoclast
resorption during the
remodeling process of
growth. (Right)
shows the bone-in-bone
appearance _ seen
secondary to failure of
osteoclastic activity during
growth of the bone.
Engelmann-Camurati Disease Engelmann-Camurati Disease

(Progressive Diaphyseal Dysplasia) (Progressive Diaphyseal Dysplasia)
dense sclerosis of the cortical
bone, both endosteal &
periosteal. It is limited to the
diaphysis (note normal
metaphyses) & is symmetric,
typical of
Engelmann-Camurati
disease. (Right)
shows the early
manifestation of diaphyseal
cortical thickening and
sclerosis in a young patient
with Engelmann·Camurati
disease.
II
72
SCLEROSING DYSPlASIAS 3
III
lC
<l>
tIJ
III
<n
<l>
a.
Sarcoid (Mimic) Sarcoid (Mimic)
(Left) Coronal T1 WI MR ;;0
OJ
shows multiple, round, low a.
signal metaphyseal lesions o'
•• which might mimic ...•
<0
OJ
osteopoikilosis. However,
fluid sensitive sequences "o-::r
show high signal in this case .-1
of sarcoid granulomas.
o
<n
<n
(1)
sclerosis occupying the o

c:
femoral head (biopsy trocar <n
in place), which could
suggest either giant bone
is/and or solitary sclerotic
metastasis. Biopsy showed
sarcoid.
Pycnodysostosis (Maroteaux-lamy)
dense scferosis, with mild
undertubulation, suggesting
osteopetrosis. However, the
patient also had a decreased
angle of the mandible, more
typical of pycnodysostosis.
patient as previous image,
shows severe acroo5leolysis
•• along with dense
scferosis of all the bones.
This feature differentiates
pycnodysostosis from
osteopetrosis.
Erdheim-Chester Disease (Mimic) Intramedullary Osteosclerosis

scferosis of the medullary
canal of the diaphysis •.
sparing the epiphysis. The
process is limited to the
medullary space; the cortex
is of normal width & density.
shows diffuse sclerosis within
the medullary canal of the
mid tibial diaphysis 1I!lI. This
finding was bilateral in this
patient which is a common
but not required feature of
intramedullary osteosclerosis.
II
73
rJl
:J HYPERTROPHIC CALLUS FORMATION
o
Q)
rJl
rJl
o DIFFERENTIAL DIAGNOSIS o Over time decreased density, more
r-: ill-defined: Resorbs or incorporates
u Common
:c • Infection
0-
ro • Motion (Poor Immobilization) o Open fracture or open reduction (ORIF)
~
Ol
.Q
• Fracture, Nonunion o Hint: Worsening pain
"0 • Fracture, Delayed Union
CU
0:: • Bone Graft (Mimic) Helpful Clues for less Common Diagnoses
"C
• Infection • Complications of Steroids
CIl
rJl o Insufficiency or rib fxs: Prominent callus
ns less Common
!Xl o Atrophic callus more typical
CIl
Ol
• Complications of Steroids o Generalized osteoporosis
ns • Cushing Disease
E o Spine compression fxs, AVN
• Brain and Spinal Cord injury • Cushing Disease
• Fracture with Thermal Injury, Burns o Endogenous steroid production
Rare but Important o Finding same as with steroid use
• Osteogenesis Imperfecta • Brain and Spinal Cord injury
o Disuse osteoporosis with poorly controlled
motion of body - fx & hypertrophic callus
ESSENTIAL INFORMATION • Fracture with Thermal Injury, Burns
Key Differential Diagnosis Issues o Overlying soft tissues abnormal or grafted
• Hint: External callus with hardware fixation Helpful Clues for Rare Diagnoses
concerning for complication • Osteogenesis Imperfecta
o Infection or delayed union o Femur most common
Helpful Clues for Common Diagnoses o Generalized osteoporosis
• Motion (Poor Immobilization) o Limb, vertebral deformities
o Hardware failure or delayed treatment o Other fractures, varied ages
• Fracture, Nonunion Other Essential Information
o Rounded, sclerotic fracture edges • Degree of callus formation dependent on
• Fracture, Delayed Union age, site of fracture, type of immobilization
o Represent continuum of healing o Minimal external callus with hardware
o Time frame varies by location, type of • Diaphyseal callus> metaphyseal callus
fixation, patient age, condition of tissues • Callus thick cortex> thin cortex
• Bone Graft (Mimic) • Minimal external callus with carpal, tarsal
o Seen on post-operative images bones, bone protuberances (Le., malleoli)
Motion (Poor Immobilization) Motion (Poor Immobilization)
II Anteroposterior radiograph shows second metatarsal

(racture. The callus IIlI/acks organization and is larger
wteral radiograph shows a transverse supracondylar
humerus (racture Elil The extensive callus IIlI does
than expected, consistent with hypertrophic callus due bridge the fracture, but is disorganized and results from
to Jackof immobilization. motion due to Jackof immobilization.
74
HYPERTROPHIC CALLUS FORMATION 3
'"
to
<1>
III
'"
t/I
<1>
Q.
Fracture, Nonunion
(Left) Anteroposterior ;:0
OJ
radiograph shows a n.
nonunited fibular fracture o·
<0
1IllI. The callus is mature and ""'OJ
more extensive than "0
::r
expected; this is a result of ()
continued motion . •-1
Secondary stress fractures
are present HI in the tibia.
o
VI
VI
(Right) Lateral radiograph <ll
shows plate fixation. The o
c::
plate has lifted from the VI
bone (not shown). The

fracture line is still visible.
External hypertrophic callus
extends from the fracture
margins without evidence of
union •.
Bone Graft (Mimic)

diaphyseal fracture with
plate fixation. The plate is
fractured EilI allowing
motion. This leads to
development of a nonunion
with extensive callus
formation a without solid
osseous union 1ll!:I. (Right)
shows dense granular
material surrounding the
distal tibial diaphysis EilI.
This bone substitute/filler is
placed to fill the gap created
by distraction through the
fracture.
Infection
radiograph shows sequelae
from hardware for tibiotalar
fusion III. Extensive external
cal/us is present around the
distal tibia EilI and is the
result of infection during
healing. (Right)
shows thin, osteoporotic,
bowed tibia & fibula.
Extensive callus surrounds &
bridges between the bones.
This finding may be seen in
patients with osteogenesis
imperfecta tarda.
II
75
en
:::l BONE WITHIN BONE APPEARANCE
o
Q)
en
en
o DIFFERENTIAL DIAGNOSIS o Systemic, symmetric increase in bone
~
-
u
~
C>-
eo
~
Common
• Neonatal Spine, Normal
density
o Normal serum calcium, alkaline
phosphatase and phosphorus levels
OJ
.Q
• Osteopetrosis • Renal Osteodystrophy, Healing
-0
eo • Renal Osteodystrophy, Healing o Skeletal response to any chronic renal
0::: • Immobilization disease
"C
Ql • Paget Disease o Primary hyperparathyroidism causes
en
<ll
co Less Common sclerosis only in healing stage
Ql • Osteomyelitis, with Involucrum o Rugger jersey spine more common
01
<ll • Hypervitaminosis D appearance than "bone in bone"
E • Striped appearance of spine
• Leukemia
• Subperiosteal Hemorrhage • Dense endplates with lucent vertebral
• Bone Infarct body centers
• Acromegaly • Immobilization
• Reflex Sympathetic Dystrophy o Induces osteopenia
• Linea Aspera Hypertrophy (Mimic) o Produces growth arrest and recovery lines
• Cement & Bone Fillers (Mimic) • Paget Disease
• Sickle Cell Anemia: MSK Complications o Spine and iliac wings commonly affected
• Gaucher Disease o Cortical thickening producing bone
enlargement is the classic finding
Rare but Important
o Mixed sclerotic and lytic phase is more
• Tuberculosis common than purely sclerotic phase
• Heavy Metal Poisoning o Polyostotic form results in deformed,
• Erdheim Chester sclerotic skeleton in end stage
• Oxalosis
• Thorotrast Exposure Helpful Clues for Less Common Diagnoses
• Osteomyelitis, with Involucrum
o Infarction of bone with fibroosseous wall
ESSENTIAL INFORMATION o Focal disease
Key Differential Diagnosis Issues o Long bones
• Alternating bands of sclerosis producing • Hypervitaminosis D
similar outline of bone in marrow space o Disrupts enchondral bone formation
• During stress or severe illness, osteoblasts o Excessive calcification of cartilage cells
form a thin line under the zone of o Dense metaphyseal bands, generalized
proliferative cartilage sclerosis in children
o Line ossifies when chondroblastic and • Leukemia
osteoblastic activity resumes o Growth arrest and resumption
• "Bone within bone" appearance is not classic o Radiolucent metaphyseal bands
for any particular diagnosis without history • Bone involvement in 50% of cases
• Can be presenting radiologic appearance
• Subperiosteal Hemorrhage
• Neonatal Spine, Normal o Blood tracking along periosteum calcifies
o Approximately half of 1-2 month old
- outline of underlying bone
infants have this finding o Due to trauma, scurvy
o Spontaneously resolves
o Scurvy has radiolucent band beneath
o Ovoid vertebral shape with dense superior
widened zone of provisional calcification
and inferior endplates is normal • "TriimmerfeId zone"
• Osteopetrosis • Bone Infarct
o Primary bone dysplasia causing failure of
o Irregularly calcified lesions in medullary
osteoclast activity cavity
II
76
BONE WITHIN BONE APPEARANCE 3
Ql
(Q
<1l
o Serpiginous or streaky region of infarction • Periphery of the rod tract, without llJ
III
can follow outline of bone cortex cement, can calcify '"a.
<1l
o Most often in ends of long tubular bones o Allographic bone (fibula) is typically split
;;0
o Associated with other entities and placed superficial to native bone Q)
a.
• Sickle cell anemia, pancreatitis, collagen Helpful Clues for Rare Diagnoses o'
(Q
vascular disease, occlusive vascular ~
• Tuberculosis Q)
'0
disease, Gaucher disease, Caisson disease o Localized bone-in-bone changes ::T
o Enchondromas can rarely have a similar o Appearance can be related to fusion of
o
.-i
appearance bones or periostitis with bone expansion o
• Acromegaly o Slow clinical course compared with '"'"
<1l
o Additional differentiating radiographic o
bacterial osteomyelitis C
findings • Heavy Metal Poisoning '"
• Tubular bone widening in skeletally o Lead and bismuth most commonly
mature patient • Faulty resorption of calcified cartilage
• Enlarged sella on CT, MR, radiographs o Phosphorus blocks resorption of bone
• Phalangeal and heel pad thickening trabeculae
• Excessively pneumatized sinuses • Erdheim Chester
• Increased vertebral body and disk height o Symmetric patchy or diffuse osteosclerosis
• Spadelike phalangeal tufts o a.k.a. lipid granulomatosis
• Bony proliferation at entheses o Metadiaphyseal and diaphyseal cortical
• Reflex Sympathetic Dystrophy thickening
o Subcortical osteoporosis
• Epiphyses relatively spared
o Predilection for this appearance in wrist
• Oxalosis
and foot o Deposition of calcium oxalate crystals -
• Linea Aspera Hypertrophy (Mimic) excessive cartilage calcification
o Dense parallel lines along middle third of
o Sclerotic metaphyseal bands
femur visible on AP radiograph o Pagetic and "woolly" sclerosis
o Longitudinal ridges along posterior femur
• Thorotrast Exposure
• Hypertrophy of medial and lateral ridge o Reticuloendothelial cells phagocytize
from muscle attachments radioactive thorium dioxide producing
• Cement & Bone Fillers (Mimic) radiation osteitis
o Associated with post-operative changes,
o Dense opacification of liver, spleen and
usually removal of pin or rod from long lymph nodes
axis of bone, with residual cement
Osteopetrosis
Lateral radiograph of the spine demonstrates

oval-shaped vertebral bodies with peripheral lucency
Lateral radiograph shows diffuse scferosis
bone-in-bone appearance III due to oste<xlasl
and
II
and a central bone-in-bone appearance EB This is a remodeling failure, leaving cortical bone within the
normal varianllhal spontaneously resolves. enlarged mature bone.
77
Vl
::::l BONE WITHIN BONE APPEARANCE
o
Ql
Vl
Vl
o
r:
-
u
.<=
a.
ro
Osteopetrosis Renal Osteodystrophy, Healing
0> radiograph shows lhe typical

.2 bone~in-bone appearance
"ro
0::
which can be seen in
osteopetrosis =:I.
The bones
are mildly diffusely sclerolic.
"Q)
III
III
shows the bone-in-bone
OJ
Q) appearance =:I which can
en be seen in vertebral bodies
III
in children with renal
E osteodyslrophy. Note the
generalized oSLeopenia and
the peritoneal dialysis
catheterlllll.
Immobilization Paget Disease

(Left) Anteroposlerior
disuse osteoporosis in a
palienl with Pagel disease,
which has caused
overgrowlh of lhe femur.
With disuse, the femur has
acquired a bone-in-bone
appearance =:I.
(Right)
Anteroposlerior radiograph
shows classic Paget disease
with lhickened, enlarged
bone =:Iextending from lhe
subarticular region to end in
a blade of grass
configuration proximally. The
central cavity IlIlI has a
bone-in-bone appearance.
Paget Disease Osteomyelitis, with Involucrum

(Left) Laleral radiograph of
the tibia shows sclerotic EilI
and lyUc regions consistent
wilh the mixed phase of
Pagel disease. The distal
blade of grass or
flame-shaped pattern =:I
outlines the proximal
sclerosis producing an
outline of lhe overlying
bone. (Right)
Anleroposlerior radiograph
shows sequestrum III with
surroundinginvolucrum.
giving a bone-in-bone
appearance in a patient with
osteomyelitis in the
pre-antibiotics era.
II
78
BONE WITHIN BONE APPEARANCE 3
III
to
CIl
OJ
III
1Il
CIl
Q.
Bone Infarct
(Left) Axial TI WI MR shows ::0
OJ
a classic bone infarct •. C-
with serpiginous low signal. O
<0
The infarct pattern matches ~OJ
the outline of the bone, and "0
::T
gives a bone-in-bone
appearance. The low signal
o-1
lesions in the patella and
condyle are Brown tumors.
o
en
en
(Right) Anteroposterior CIl
radiograph of the middle o
c:
third of the femoral diaphysis en
shows two parallel sclerotic
lines" representing the
medial and lateral lips of the
linea aspera, located along
the posterior aspect of the
femur.
Cement & Bone Fillers (Mimic) Cement & Bone Fillers (Mimic)
shows Girdlestone anatomy
~ of the hip after removal
of a total hip prosthesis. A
longitudinal sclerotic density
• with a lucent center in
the femoral medullary space
is due to a cement fragment
left when the femoral
prosthesis stem was
removed. This mimics a
(Right) Coronal bone CT in
the same patient as previous
image, beller demonstrates
the Girdlestone configuration
of the hip HI and cement
fragment •.
Erdheim Chester
shows rectangular regions of
increased density in central
portion of each vertebral
body. from bone infarcts,
which have a faint
Central endplate depression
~ of L4 mimics sickle cell
disease. (Right)
shows medullary sclerosis,
with trabecular thickening
•• producing a faint
This was bilaterally
symmetric and did not
involve the cortices.
II
79
(f)
:J OSTEOPENIA
o
<1l
(f)
(f)
o DIFFERENTIAL DIAGNOSIS o Separate differential diagnosis for

r-: osteoporosis available: See "Osteoporosis"
-
u
£
e>-
m~
Common
• Osteoporosis
• Radiographic Technique (Mimic)
o Correlate with other radiographic
Ol
o • Radiographic Technique (Mimic) examinations, clinical history
"0
m Less Common Helpful Clues for Less Common Diagnoses
0:::
"0
• Osteomalacia/Rickets • Osteomalacia/Rickets
CIl
l/l
• Renal Osteodystrophy o Abnormal bone formation due to the
IV
al • Multiple Myeloma inability to mineralize osteoid
CIl
Cl
• Neoplasm o Coarse, ill-defined trabeculae
IV
E o Looser zones, pseudofractures
o Cortical tunneling
o Pediatric: Metaphyseal cupping & fraying
Key Differential Diagnosis Issues o Osteopenia also seen with related diseases
• Terms osteoporosis and osteopenia in such as hypophosphatasia
context of bone mineral density (DEXA • Renal Osteodystrophy
scans) are different from their use in context o Combination of osteomalacia and HPTH
of this chapter o Osteomalacia: See above
o In the context of this chapter o Hyperparathyroidism (HPTH)
• Osteopenia: Radiographic finding • Bone resorption: Subperiosteal,
indicative of decreased bone density subchondral, subligamentous,
• Osteoporosis: Decrease in amount of subtendinous, cortical tunneling
normally formed bone • Multiple Myeloma
o Relative to DEXA o Osteopenia 2° to diffuse tumor infiltration
• Osteopenia and osteoporosis are degrees and osteoporosis induced by tumor itself
of decreased bone miheral density o Generalized osteopenia may be only
relative to a control population abnormality
• Multitude of causes including all those in o Otherwise, may see lytic lesions typical of
this differential multiple myeloma or plasmacytoma
Helpful Clues for Common Diagnoses • Neoplasm
• Osteoporosis o Osteopenia 2° to tumor infiltration
o Multiple causes of decreased bone volume (leukemia most frequent)
including steroids, chronic medical disease o May have associated lytic or blastic lesions
Osteoporosis Osteoporosis
II Anteroposterior radiograph shows gracile

normal length with severe oSleopenia and subacute
limbs of 12teral radiograph shows osteopenia and fusion of
several lower cervical vertebral bodies HI as a result of
fracture". This patient suffers from a severe case of ankylosing spondylitis (AS). Osteoporosis is typically
osteogenesis imperfecla liJrda. seen in late AS due to fusion and immobility.
80
OSTEOPENIA 3
Ql
to
(l)
llJ
Ql
III
(l)
C.
Osteomalacia/Rickets Renal Osteodystrophy
(Left) Anteroposterior ;U
Q)
radiograph shows severe c.
generalized bone 1055 as well o'
ce
as metaphyseal cupping and ~
Q)
fraying" in this child with "0
:r
rickets. (Right)
o
.-1
shows osteopenia and
dysmorphic femoral necks
o
en
en
EiII and trochanters which CD
are the result of renal o
c
osteodystrophy. The en
osteopenia in end stage renal
osteodystrophy is secondary
to a combination of
hyperparathyroidism and
osteomalacia (rickets].
Multiple Myeloma Multiple Myeloma

radiograph of the pelvis
which is atypical for the
patient '5 age and consistent
with his multiple myeloma.
the spine shows diffuse
osteopenia. Note the mild
superior endplate
compression fractures HI.
This appearance proved to
be the result of multiple
myeloma. Myeloma may
present with diffuse
infiltration and osteopenia,
without focal lesions.
Neoplasm Neoplasm
radiograph of the pelvis
and metaphyseal lucent lines
EiII in a child. (Right) Lateral
radiograph of the spine from
image, shows diffuse and
severe o5teopenia. A mild
compression deformity of the
L I vertebra" is also seen
which was out of proportion
to a mild injury. The findings
represent a diffuse infiltrative
process which proved to be
leukemia.
II
81
(/)
::> OSTEOPOROSIS, GENERALIZED
o
Q)
(/)
(/)
o DIFFERENTIAL DIAGNOSIS • AVN & infarcts are common associations

t--=" with steroids, alcohol, sickle cell anemia,
u Common
:c Gaucher disease as etiologies
CL
co • Senile Osteoporosis
OJ
o • Postmenopausal
"0 • Steroids • Senile Osteoporosis
co o No distinguishing radiographic features
0:: • Alcohol
'1:l o Same for postmenopausal, alcohol,
Gl • Smoking
III
• Non-Weightbearing smoking, non-weightbearing, chronic liver
ltl
10
• Diabetes Mellitus disease
Gl
OJ
• Chronic Liver Disease • Steroids
ltl
E • Renal Osteodystrophy o AVN, infarcts, hypertrophic callus
• Malnutrition & Anorexia • Renal Osteodystrophy
• Multiple Myeloma o Combination HPTH & osteomalacia
• Rheumatoid Arthritis o Osteomalacia: Coarse ill-defined
trabeculae, Looser's zones, pseudofractures,
Less Common cortical tunneling, metaphyseal cupping &
• Sickle Cell Anemia flaring (rickets)
• Juvenile Idiopathic Arthritis • Malnutrition & Anorexia
• Ankylosing Spondylitis o Generalized soft tissue wasting
• Hyperparathyroidism • Multiple Myeloma
• Hyperthyroidism o Focal lesions most common in skull, spine
• Cushing Disease o Multiple punched out lytic lesions
• Pregnancy o Expansile lytic lesions uncommon
• Thalassemia o May present as osteoporosis without focal
• Calcium Deficiency lesions
• Amyloid Deposition • Rheumatoid Arthritis
• Estrogen Deficiency (Non-Menopausal) o Bilateral symmetric arthritis, hands & feet;
• Gaucher Disease also hips, knees, SI joints, elbow
• Hemochromatosis (Primary) o Uniform joint space narrowing, marginal
• Ochronosis (Alkaptonuria) erosions, peri-articular osteoporosis
• Heparin • Sickle Cell Anemia
• Hypogonadism o Osteoporosis most severe in the spine
• Homocystinuria o Multiple bone infarcts & AVN common
• Osteogenesis Imperfecta o H-shaped vertebra, coarse trabecula
• Mastocytosis o Widening diploic space sparing skull base
• Scurvy o Osteomyelitis, septic arthritis, dactylitis
• Acromegaly • Juvenile Idiopathic Arthritis
• Idiopathic Juvenile Osteoporosis oRange monoarticular to bilateral
• Fabry Disease (Vertebral Bodies) symmetric polyarticular arthritis
o Small joints of hands, feet; also wrist,
ESSENTIAL INFORMATION shoulder, knee, ankle, cervical spine
o Uniform joint space narrowing, marginal
Key Differential Diagnosis Issues erosions, peri-articular osteoporosis
• Osteoporosis • Ankylosing Spondylitis
o Decreased amount of normal bone o Hip, shoulder arthritis
o Insufficiency fractures common to all o Fusion spine & SI joints
• Osteopenia: Radiographic finding indicative o Enthesopathy
of decreased bone density; nonspecific • Hyperparathyroidism
o Osteoporosis is one cause of osteopenia
II
82
OSTEOPOROSIS, GENERALIZED 3
Ql
to
<ll
o Bone resorption: Subperiosteal, • Ochronosis (Alkaptonuria) OJ
Ql
subchondral, subligamentous, o Disc changes: Extensive mineralization, VI
<ll
subtendinous, cortical tunneling narrowing, vacuum, endplate sclerosis Q.
;;0
o Chondrocalcinosis, soft tissue calcium
Helpful Clues for Rare Diagnoses III
Q.
deposition, Brown tumors o·
• Heparin to
• Hyperthyroidism ~
o No specific radiographic changes III
o Cortical tunneling
o Accelerated skeletal maturation
• Hypogonadism "::ro
o No specific changes -l
• Cushing Disease • Homocystinuria o
o Hypertrophic callus VI
o Scoliosis, abnormal vertebral shape VI
<ll
o Limited appendicular involvement o
• Osteogenesis Imperfecta C
• Thalassemia o Wormian bones, kyphoscoliosis, fractures
VI
o Marrow hyperplasia: Widened diploic

o Bowing & deformities due to "soft bones"
space, hair on end appearance, rodent o Bones thin & gracile or short & tubular
facies, diaphyseal widening, deformity
• Mastocytosis
mimicking Erlenmeyer flask o May see ill-defined focal lytic lesions
o H-shaped vertebra, coarse trabecula
o Characteristic cutaneous manifestations
o Extramedullary hematopoiesis
o Extensive marrow infiltration on MR
• Calcium Deficiency
• Scurvy
o Mimics osteomalacia
o Metaphyseal lucent & dense lines, beaking
• Amyloid Deposition o Wimberger sign, periostitis
o Soft tissue masses; bilateral symmetric
• Acromegaly
arthritis with subchondral cysts, erosions, o Enlarged bones: Mandible, skull, face
joint spaces normal to widened o Thickened cortices, increased medullary
• Estrogen Deficiency (Non-Menopausal) canal, spade-like (phalangeal) tufts
o No specific radiographic changes
o Enthesopathy, cortical tunneling
• Gaucher Disease o Widened joints, thickened heel pad
o Erlenmeyer flask deformity & AVN
o Enlarged disc space & costochondral
characteristic, H-shaped vertebra junctions
• Hemochromatosis (Primary)
• Idiopathic Juvenile Osteoporosis
o Arthropathy of MCP joints, wrists, elbows,
o Diagnosis of exclusion
shoulder with chondrocalcinosis; uniform
• Fabry Disease (Vertebral Bodies)
joint space narrowing, osteophytes, large o Characteristic skin lesion
subchondral cysts
Senile Osteoporosis
Lateral radiograph shows multiple compression fractures

IIlI in this elderly woman with senile osteoporosis.
Sagittal NEeT shows marked postmenopausal
osteoporosis involving all vertebral bodies and posterior
II
Patient has already been treated with vertebroplasty EllI. elements. At this time, vertebral body shape and height
continue to be maintained.
83
'"
::J
o
OSTEOPOROSIS, GENERALIZED
CIl
o'"'"
~
()
:c
0-
Steroids Non-Weightbearing
m (Left) Anteroposterior
~
C> radiograph From a renal
.Q transplant patient on steroids
"0
m shows difFuse osteopenia
0::
"'"
Q)
=
and AVN within the lunate
and proximal pole of the
scaphoid Ell. (Right) AP
III radiograph shows a patient
III
Q)
with Paget disease who has
C> been bedridden For a year.
III
The bones are severely
E osteoporotic from
non-weightbearing,
superimposed on the
sclerotic Pagetic changes.
Osteoporosis results in
de(ormities, including
protrusio •.
Diabetes Mellitus
shows vascular calcification
Ell in this young diabetic
patient. There is diFFuse
osteopenia, typically seen in
this disease, which has
resulted in calcaneal
insufficiency avulsion
Fracture _ (Right)
coarsening of trabeculae,
resorption of the distal
clavicle" and a large
Brown tumor _ Findings
are typical of renal
osteodystrophy.
Malnutrition & Anorexia

shows insufficiency fracture
.:I through an osteoporotic
calcaneus in this young
woman with anorexia.
the lumbar spine shows
diFFuseosteoporosis and
multiple compression
fractures _ which are not
normal For a patient of this
age and sex (50 year old
man). There were no Focal
lytic lesions. Myeloma may
present with diffuse marrow
infiltration.
II
84
l»
(Q
CD
!Xl
l»
II>
CD
C.

III
radiograph shows advanced C.
rheumatoid arthritis with o·
severe osteopenia, erosion of .,
(Q
III
the distal clavicle and "0
::r
acromion. insufficiency ()
fracture of the proximal -i
humerus" and changes of
long-standing rotator cuff
o
(f)
(f)
tear. (Right) Lateral (\)
radiograph shows diffuse o

c:
(f)
sickle cell anemia. There are
H-shaped vertebra" seen
throughout the thoracic
spine, typical of the AVN
and collapse pattern seen in
these patients.
Juvenile Idiopathic Arthritis Ankylosing Spondylitis

reveals extensive
osteoporosis which is a
common finding in /lA.
Extensive fusion of the facet
joints" and disc spaces EilI
is present and has extended
cephalad to involve the
occipita-cervical junction
••. (Right) Lateral
osteopenia of the lumbar
spine atypical for a 29 year
old man. Squaring of the
vertebral body corners is
present. consistent with
early changes of ankylosing
spondylitis.
Ankylosing Spondylitis Hyperparathyroidism

complete ankylosis of the
cervical spine and diffuse
osteopenia in this patient
with ankylosing spondylitis.
Fracture through the C7
vertebra. and posterior
elements. (termed
pseudarthrosis) is seen
fol/owing minor motor
vehicle crash. (Right) AP
osteopenia of the humerus,
typical of aI/ the osseous
structures in this patient with
hyperparathyroidism. There
is a Brown tumor located
within the cortex HI.
II
85
VI
:> OSTEOPOROSIS, GENERALIZED
o
<Il
VI
VI
o
t-
u
:c
0-
Cushing Disease
ro (Leh) Anteroposterior
'-
Cl radiograph shows diffuse
.Q osteopenia and an expansile
"0
ro lytic lesion of the right ilium
a::: • in this patient with
hyperparathyroidism and a
"
Ql
VI
nl
brown tumor of the iliac
wing. (Right) Anteroposterior
III
Ql
Cl osteopenia in this patient
nl
with Cushing disease.
E Sclerosis in the femoral head
from AVN •• is present, an
uncommon finding with
endogenous steroid excess.
Thalassemia
findings of thalassemia with
"squaring" of the bones,
especially the metacarpals
•• due to marrow packing
with accompanying thinning
of the endosteal cortex.
(tMSK Req). (Right)
as well as a distended hip
joint •. Erosions are seen at
the femoral head, with
collapse" This is a patient
with myeloma and focal
amyloid deposition within
the hip joint.
Ochronosis (Alkaptonuria)
osteopenia and an
Erlenmeyer flask deformity of
the distal femur. These
findings are characteristic of
Gaucher disease, related to
marrow packing. (Right)
=
calciFication within the disks
as well as diffuse
ochronosis.
II
86
III
(C
CD
CD
III
C/l
CD
Co
Homocystinuria Osteogenesis Imperfecta
(Left) Lateral radiograph ::0
OJ
shows severe osteoporosis C-
and early compression o'
(C
fractures in a teenager with ~OJ
homocysUnuria. Other -0
::T
images, not shown, include ()
hands showing .-l
arachnodactyly. (Right)
o
en
en
shows severe osteopenia, CD
gracile bones with "growth" o
c
lines" in the metaphyses in en
this skeletally immature
individual with osteogenesis
imperfecta tarda.
Osteogenesis Imperfecta Mastocytosis

short broad, multiply
fractured femora" and
tibiae Ell. The bones are
severely osteopenic, which
helps distinguish this case of
osteogenesis imperfecta
congenita from a dwarf
syndrome. (Right) AP
osteopenia and a midshaft
femoral fracture. While these
findings are suggestive of
osteogenesis imperfecla, the
history of CI complaints was
consistent with the biopsy
diagnosis of mastocytosis.
(tMSK Req).

classic signs of scurvy. The
bones are diffusely
osteopenic. Associated
findings include Wimberger
sign (sclerotic ring around
epiphysis) Ell and the white
line of Frankel (dense
metaphyseal line) ••
a basicervical femoral neck
fracture" in this skeletally
immature patient with no
history of trauma. The
patient was eventually
diagnosed with idiopathic
juvenile osteoporosis, a
diagnosis of exclusion.
II
87
en REGIONAL OSTEOPOROSIS
:0
o
Q)
en
en
o DIFFERENTIAL DIAGNOSIS o Large joints lower extremity: Consider
t--"' transient osteoporosis/regional migratory
u Common
:c osteoporosis
0.
CIl • Disuse/Immobilization
OJ • Loss or Absence of Overlying Soft Tissues
.Q
-0 (Mimic) • Disuse/Immobilization
CIl
0:: o Clinically evident cause
• Complex Regional Pain Syndrome (CRPS)
-c o Segmental (foot, hand)
Q)
• Inflammatory Arthritis
o Larger joint (elbow, knee) involvement not
I/)
III o Rheumatoid Arthritis
to o Juvenile Idiopathic Arthritis
common, only with distal joint
Q)
OJ o Ankylosing Spondylitis
involvement
III
E o Occurs after 6-8 weeks immobilization
o Inflammatory Bowel Disease Arthritis
o Increased fracture risk
• Septic Joint
o Rapid bone turnover
less Common • Loss or Absence of Overlying Soft Tissues
• Regional Migratory Osteoporosis (Mimic)
• Transient Osteoporosis of the Hip o Segmental distribution
• Hemophilia o Uniform appearance
Rare but Important o Mastectomy most common cause
• Hypothyroidism o Surgical resection overlying soft tissues
• Forequarter amputation or hip
disarticulation
ESSENTIAL INFORMATION o Atrophy
Key Differential Diagnosis Issues • Stroke
• Need to correlate with clinical information • Neuromuscular disorders
• Important to determine if monoarticular or • Associated osteoporosis from disuse
polyarticular o Rotation may mimic, especially on CXR,
• Beware: Must exclude septic arthritis if pelvis

monoarticular; consider a clinical emergency o Grid cutoff may mimic
• Varied radiographic appearance of • Complex Regional Pain Syndrome (CRPS)

osteoporosis o a.k.a. reflex sympathetic dystrophy, RSD,
o Uniform Sudeck atrophy
o Mottled or spotty o Segmental distribution most common
o Band-like lucency either subchondral or o Involvement of multiple digits less
metaphyseal common
o Cortical tunneling & scalloping o Lower extremity more common
o Subperiosteal and endosteal resorption o Early clinical phase: Severe burning pain,
(unusual, mainly CRPS) soft tissue swelling, hypersensitivity,
• Hint: Mottled or band-like appearance sweating, vasomotor alterations
implies rapid onset; consider disuse, CRPS o Late clinical phase: Muscle atrophy, joint
• Hint: Cortical tunneling suggests contracture, skin changes

inflammatory arthritis, CRPS o Joint space preservation
• Peri-articular osteoporosis may be subjective o Radiographic changes 3-6 months after
if other changes not apparent clinical symptoms
• Hint: Distribution may suggest etiology o Bone scan or MR changes earlier
o Segmental (Le., spine, foot, hand): • Inflammatory Arthritis
Consider disuse or CRPS o General comments
o Peri-articular: Consider inflammatory • Peri-articular

o Focal (limited portion of a bone usually • Secondary to hyperemia
part of epiphysis) or digit: Consider partial • Uniform appearance
regional migratory osteoporosis, CRPS • Pain, limited range of motion
o Single joint: Consider infection o Rheumatoid Arthritis
II
88
REGIONAL OSTEOPOROSIS 3
Ql
(D
(I)
• Bilateral symmetric Helpful Clues for less Common Diagnoses CJ

Ql
• Small joint of hands, feet; also wrist, • Regional Migratory Osteoporosis

III
(I)
Co
elbow, knee, shoulder, ankle o Peri-articular osteoporosis
• Periarticular osteopenia may be earliest ;0
o Joint space preservation Ql
a.
manifestation of arthritis o Partial transient osteoporosis involves only o·
(D
• Uniform joint space narrowing ~
portion of joint or 1-2 contiguous digits Ql
"0
• Marginal erosions o Lower extremity joints predominate :T
o Juvenile Idiopathic Arthritis ()
o Diagnosis requires multiple joint -i
• JIA: Childhood onset
• Ranges from monoarticular to symmetric
involvement, staggered clinical onset o
III
o Pain, swelling, no history of trauma III
(I)
polyarticular disease o Clinical onset precedes radiographic o
c:
• Small joints of hands, feet; also wrist, changes by 6-8 weeks
III
elbow, knee, shoulder, ankle o MR bone marrow edema pattern earlier

• Marginal erosions • Transient Osteoporosis of the Hip
• Periosteal new bone o Osteoporosis femoral head> acetabulum
• Uniform joint space narrowing o Joint space preservation
o Ankylosing Spondylitis
o Pain, swelling, decreased range of motion
• AS: Peri-articular osteoporosis less o Clinical onset precedes radiographic
frequent than other arthridites
changes by 6-8 weeks
• Hip, shoulder more common than o Early MR bone marrow edema pattern
smaller joints
• Hemophilia
• Evaluate SI joints & spine to aid o Peri-articular osteoporosis
diagnosis o Knee, elbow, ankle, hip, shoulder common
• Segmental osteoporosis in the spine with o Ballooned epiphyses, dense effusion
long-standing disease
o Inflammatory Bowel Disease Arthritis Helpful Clues for Rare Diagnoses
• Skeletal manifestations identical to AS • Hypothyroidism
• Clinical history of bowel disease o Osteoporosis uncommon; clinical
• Septic Joint manifestations varied
o Monoarticular Other Essential Information
o Uniform joint space narrowing • Causes of immobilization include paralysis,
o Marginal erosions; cortical indistinctness stroke, polio, fracture fixation,
o Low grade fever, elevated WBC weightlessness (astronauts)
o Aspirate to confirm diagnosis
Disuse/Immobilization Disuse/Immobilization
AP radiograph shows severe osteoporosis HI distal to a

nonunion or the tibia-fibula _ The moth-eaten pattern
Axial bone CT shows a pattern or spotty osteoporosis
scattered within the distal femur and patella including
II
or osteoporosis develops due to disuselimmobilizaUon, small lucencies in the subchondral bone _ cortical
and can appear highly aggressive. thinning. and medullary lucencies EiIIl due to disuse.
89
f/l
:> REGIONAL OSTEOPOROSIS
o
Ql
f/l
f/l
o
t- Loss or Absence of Overlying Soft
-
O
..c
C-
ro
Tissues (Mimic)
Ol radiograph shows decreased

.Q density of the right
"0
ro hemipelvis and proximal
a: femur. This decreased
"0 density is due 10 atrophy of
Ql
f/l the overlying soft tissues and
1'0 diminished bone density due
a3
Ql
to disuse in this patient with
en polio. (Right) Posteroanterior
1'0
radiograph shows that the
E left hemithorax is less dense
than the right due 10 surgical
resection of the soft tissues
and osseous structures of the
shoulder girdle for sarcoma.
Complex Regional Pain Syndrome Complex Regional Pain Syndrome

(CRPS) (CRPS)
shows linear subchondral
lucency within base of the
middle and lateral
cuneiforms _ Subchondral
lucency at the metatarsal
bases has a spotted
appearance. in this
patient with CRPS. (Right)
shows severe osteopenia in a
speckled or spotty
distribution centered around
the carpus •. This patient
developed CRPS following
an episode of /uxatio erecta
of the shoulder.
Rheumatoid Arthritis
radiograph shows
perj·articular osteoporosis
involving the carpus and
MCP joints _ Many other
RA features are noted,
including soft tissue nodules,
joint space loss, and
marginal erosions. (Right)
shows decreased bone
density for a 41 year old
male. There is diffuse joint
space loss, cortical
indistinctness and several
focal marginal erosions Ell
all typical of rheumawid
arthritis.
II
90
REGIONAL OSTEOPOROSIS 3
III
to
It)
[II
III
VI
It)
Q.
Juvenile Idiopathic Arthritis Ankylosing Spondylitis
(Left) Lateral radiograph ;;0
III
shows decreased bone c-
density in this patient with o·
<0
j/A. Thinning of the cortices, ~
III
especially the radial head "0
::T
and capitellum is apparent
_ The patient also had
o-I
advanced maturation of
these epiphyses relative to
o
VI
VI
the opposite elbow. (t MSK CD
Req). (Right) Lateral a
c:
radiograph shows osteopenia Cf)
of the lower cervical spine

•• with fusion of several
lower cervical vertebral
bodies. Findings suggest the
diagnosis of ankylosing
spondylitis.
Ankylosing Spondylitis Septic Joint

radiograph shows aggressive
osteoporosis with a pattern
of lucent metaphyseal bands
_ This pattern is mDre
commonly seen in disuse
osteoporosis, but is present
with early inflammation in
this patient with AS. (Right)
shows peri-articular
DsteDpenia Df the IP jDint of
the great toe. AssDciated
bDne destructiDn E!lI and
periDstitis lead tD the
diagnosis of septic arthritis
with osteomyelitis.
Transient Osteoporosis of the Hip

(Left) Lateral radiDgraph
with thinning of the anterior
cortex of the distal femur,
proximal tibia _ and
generalized decreased
patellar density in a young
man. His hip developed the
same process 6 months later.
(Right) AP radiograph shDws
diffuse DsteDpenia Df the left
hip. NDte IDss Df the nDrmal
cortical line Df the femoral
head. and the central
pDrtiDn Df the acetabulum
Ell. Septic hip must be
considered, but this proved
to be transient osteoporosis.
II
91
(/)
::J CORTICAL TUNNELING
o
<1>
(/)
(/)
o DIFFERENTIAL DIAGNOSIS Helpful Clues for Common Diagnoses

1--
-
U
.c
Cl.
co
~
Common
• Disuse Osteoporosis
• Disuse Osteoporosis and Immobilization
o Lower extremity common
o Regional pattern of osteoporosis
Ol
.Q
• Immobilization
• Rheumatoid Arthritis • Rheumatoid Arthritis
"co
0:: • Hyperparathyroidism (HVfH) o Hands, feet predominate early in disease
o Peri-articular osteopenia, marginal erosions
"t:l
Cl) • Renal Osteodystrophy
(/) o Uniform joint space narrowing
III • Osteomalacia/Rickets
al o Includes juvenile onset disease
Cl)
Cl
Less Common • Hyperparathyroidism (HPTH)
III
• Complex Regional Pain Syndrome (CRPS) o Hands commonly show findings well
E
• Thyrotoxicosis o Generalized osteoporosis
• Acromegaly o Subperiosteal, subchondral,
Rare but Important subligamentous, subtendon resorption
• Hypophosphatasia • Renal Osteodystrophy
o Combination osteomalacia & HVfH
• Osteomalacia/Rickets
ESSENTIAL INFORMATION o Diffuse skeletal involvement
Key Differential Diagnosis Issues o Ill-defined, coarse trabeculae
• Hint: Usually not an isolated finding; this is o Looser zones, pseudofractures
an aggressive pattern of bone resorption & o Rickets: Metaphyseal cupping, fraying
other associated processes are likely present Helpful Clues for Less Common Diagnoses
• Appearance of cortical tunneling is due to • Complex Regional Pain Syndrome (CRPS)
widening of haversian canals o Lower extremity common
• Indicative of high bone turnover, but with o Regional pattern of osteoporosis
several different etiologies o May have trophic soft tissue changes
o t Osteoclastic activity: ' • Thyrotoxicosis
Hyperparathyroidism o Phalanges of hands, feet
o Hyperemia: CRPS o Generalized osteoporosis
o ~ Stress on bone: Disuse/immobilization • Acromegaly
osteoporosis o Generalized osteoporosis
o Un mineralized osteoid: o Spade-like phalangeal tufts
Osteomalacia/rickets o Cortical thickening, enthesopathy
Disuse Osteoporosis Rheumatoid Arthritis
II Axial NEeT nicely demonstrates the findings of disuse

osteofX>rosis including worm-like lucencies within the
Anteroposterior radiograph shows lypical changes of
juvenile idiopathic arthritis, many of which are due to
92
cortex consistent with resorption of bone from the
margins of the Haversian canals Ell
hyperemia. The hyperemia leads to rapid bone
=-
turnover, in turn causing intracorucal tunneling
CORTICAL TUNNELING 3
l»
(0
III
III
l»
III
CD
C.
(Left) Posteroanterior ;;0

Q)
radiograph shows cortical c.
o·
tunneling appearing as
longitudinallucencies
with adjacent subperiosteal
= <0
~
Q)
"0
:::r
resorption.
findings of
characteristic
o
.-1
hyperparathyroidism. (Right)
o
III
(fJ
shows metastatic calcium CD
deposition and cortical o
c
phalanges =
striations within the
in this patient
with renal osteodystrophy.
(fJ
Osteomalacia/Rickets Osteomalacia/Rickets
radiograph shows
intracorticallucencies = in
this child with rickets. These
findings are due to
nonmineralized osteoid
lining Haversian canals.
(RighI) Posteroanterior
radiograph shows lack of
distinction between
medullary and cortical bone
=
of the distal radius and ulna
as a result of cortical
tunneling in this patent with
rickels.
Complex Regional Pain Syndrome

(CRPS)
shows cortical tunneling lEa
along with a moth-eaten
pattern in a patient with
complex regional pain
syndrome, related to
nonunion of a tibial fracture.
radiograph
cortical tunneling along
with extreme osteoporosis
=-
shows severe
and metaphyseal widening in

this patient with
hypophosphatasia.
II
93
(/)
:::l PSEUDOARTHROSIS
o
Q)
(/)
(/)
o DIFFERENTIAL DIAGNOSIS o Interspinous, supraspinous ligament
- ossification
t--"
u Common
.r: o Sacroiliac joint fusion
Q.
ro • Fracture, Nonunion o Enthesopathy, hip & shoulder arthritis
~
OJ
o • Failed Graft • DISH, Post-Trauma
1:l
ro Less Common o Following disruption of fused spine
0:: o Ligament ossification
"tl
• Ankylosing Spondylitis, Post-Trauma
ell
(/)
• DISH, Post-Trauma • ALL, iliolumbar, sacrotuberous,
ro
III • Fibrous Dysplasia sacrospinous, stylohyoid, OPLL
ell o Enthesopathy
Cl Rare but Important
ro o Sacroiliac joint changes
E • Neurofibromatosis • Fusion upper 1/3, bridging osteophytes
• Congenital Pseudoarthrosis • Fibrous Dysplasia
• Ochronosis (Alkaptonuria) o Mildly expansile, ground-glass matrix
• Osteogenesis Imperfecta o Well-defined ± sclerotic margins
o Monostotic or polyostotic
ESSENTIAL INFORMATION Helpful Clues for Rare Diagnoses
Key Differential Diagnosis Issues • Neurofibromatosis
• Hint: Similar spinal risk of pseudoarthrosis o Tibia, clavicle, radius, ulna
with ankylosing spondylitis, DISH, o Fracture by age 2
ochronosis o May be only manifestation of
neurofibromatosis
o Congenital pseudoarthrosis similar
• Post-Operative (Nonunion & Failed Graft) • Ochronosis (Alkaptonuria)
o Hint: Motion, especially in spine
o Following disruption of fused spine
o Hint: Look for hardware failure
o Vertebral osteoporosis, extensive discal
o Tibia common due to poor blood supply
mineralization
o Nonbridging callus, may be hypertrophic
o OA-like changes SI joints, hips, knees
o Smooth sclerotic margins
o Absence of osteophytes
Helpful Clues for Less Common Diagnoses • Osteogenesis Imperfecta
• Ankylosing Spondylitis, Post-Trauma o Generalized osteoporosis
o Following disruption of fused spine o Bowing & other deformities of "soft" bones
o Syndesmophytes, facet joint ankylosis o Multiple fractures of varying ages
Fracture, Nonunion Fracture, Nonunion
II Lateral T2WI FSEMR shows a fluid-filled cleft. within

a midthoracic vertebra in this patient with osteoporosis
AP radiograph shows
a patient who has
screw ~ & plate ElII fraclUres in
developed pseudarthrosis. The
and a compression fracture following minor trauma. original construct was too rigid to permit the
micromotion required to promote osteoblastic activity.
94
PSEUDOARTHROSIS
Failed Graft
(Left) Sagittal NECT reveals a
C5 carpectomy and a strut
graft from C4 to C6 •. The
margins of the graft-C6
interface are smooth and
sclerotic. consistent
pseudoarthrosis. (RighI)
Sagittal STIR MR shows a
pronounced oblique fracture
involving the lower thoracic
spine with a fluid-filled
pseudoarthrosis Ell in this
patient with ankylosing
spondylitis.
DISH, Post-Trauma
(Left) Sagittal bone CT
demonstrates OPLL and
DISH" Fracture is present
resulting in deformity of the
inferiorvertebra" The
Fracture margins are smooth
and sclerotic consistent with
pseudoarthrosis. (Right)
shows two sites of osseous
dysplasia. in this child
with the cystic type of
pseudoarthrosis associated
with neurofibromatosis.
Osteogenesis Imperfecta
fracture through the tibia and
fibula with smoothly tapered
fracture margins •. The
appearance is classic for
congenital pseudoarthrosis.
radiograph shows
intramedullary rodding of
both femora. The right
femoral rod is fractured with
pseudoarthrosis of the mid
femoral diaphysis. in this
patient with osteogenesis
imperfecta.
II
95
en ENTHESOPATHY
::>
o
Q)
en
en
o DIFFERENTIAL DIAGNOSIS o Olecranon most common site
f- o Nonspecific
-
U
.r:
a.
ro
~
Common
• Degenerative Helpful Clues for Common Diagnoses
OJ
• DISH • Degenerative
.Q o No specific distribution
"0
ro
• Baastrup Disease
0::: o Well-defined
• Subacromial Spur
o No erosions or soft tissue swelling
"0
Ql
• Plantar Fasciitis
II)
C'Cl • Haglund Syndrome • DISH
CO o Especially pelvis, calcaneus, patella,
Ql
• Tendon/Ligament Microtrauma with
OJ Calcification (Mimic) olecranon
C'Cl
E • Ankylosing Spondylitis • Well-defined
• Avulsion Fractures, Pelvic (Mimic) • May be "bulky"
o Ligament ossification
• Psoriatic Arthritis • Anterior longitudinal (ALL), iliolumbar,
sacrotuberous, sacrospinous, stylohyoid
less Common o Sacroiliac joint
• Chronic Reactive Arthritis • Fusion upper 1/3, osteophytes
• Rheumatoid Arthritis • Baastrup Disease
Rare but Important o Supraspinous ligament
• Fluorosis o Spinous processes abnormal
• Hypoparathyroidism • Hypertrophied
• Hypophosphatasia • Marginal sclerosis and cysts
• Hypophosphatemia (Vitamin D Resistant • Bursa between hypertrophied processes
Rickets) • Subacromial Spur
o Result of impingement
o Associated bone proliferation on greater
ESSENTIAL INFORMATION tuberosity
Key Differential Diagnosis Issues • Plantar Fasciitis
• Enthesis: Insertion of tendon or ligament o Well-defined plantar enthesophyte
onto bone o Enthesophyte not causative
• Enthesopathy: Bone proliferation within o Thickened plantar fascia
enthesis o Fascial, perifascial edema
• Enthesitis: Inflammation at enthesis o Bone marrow edema at insertion
o May lead to erosion, bone formation • Haglund Syndrome
• Hint: Calcaneus common site RA, o Achilles enthesophyte
seronegative spondyloarthropathies o Achilles tendinosis
o Retrocalcaneal bursitis/erosions in all o Retrocalcaneal bursitis (no erosion)
o Achilles enthesophyte in all o Prominent bump on superior surface
• Least common: Chronic reactive arthritis posterior process of calcaneus
o Plantar surface reflects overall • Tendon/Ligament Microtrauma with
characteristics of arthritis Calcification (Mimic)
• RA: Well-defined erosion, sharp o Atypical sites
enthesophytes o Consider when absence of other findings
• Seronegative: III-defined erosion, • Ankylosing Spondylitis & IBD
whiskering new bone formation, sclerosis o Pelvis, proximal femur, calcaneus, patella
o Subligamentous bone resorption plantar • Associated erosion, sclerosis at enthesis
fascia in hyperparathyroidism may mimic o Spinal fusion
• Hint: Lower extremity common • Syndesmophytes
o Especially pelvis, proximal femur • Interspinous, supraspinous ligament
o Nonspecific ossification
• Upper extremity o Sacroiliac joint fusion (synovial portion)
II
96
ENTHESOPATHY 3
III
(Q
CD
o Hips, shoulder arthritis • Rheumatoid Arthritis OJ
III
• Avulsion Fractures, Pelvic (Mimic) o Calcaneus only site of enthesopathy VI
CD
o Result of healing process • Plantar enthesophyte well-defined Co
o Especially ASIS,ischial tuberosity • Achilles enthesophyte :;0

III
0-
• Psoriatic Arthritis • Retrocalcaneal bursitis, erosion Cr
o Pelvis, proximal femur, calcaneus, patella o Erosive arthritis ,
<0
III
"0
o Calcaneal involvement • Hands, feet predominate in early disease ::T
• Ill-defined plantar enthesophyte, erosion • Bilateral symmetric disease o
_-i
• Achilles enthesophyte • Peri-articular osteopenia
o
• Retrocalcaneal bursitis, erosion • Marginal erosions VI
VI
<1l
o Erosive and proliferative arthritis • Uniform joint space narrowing o
C
• Hands, feet most common Helpful Clues for Rare Diagnoses
VI
• Bilateral, asymmetric distribution • Fluorosis

• Uniform joint space narrowing o Enthesopathy most common in pelvis, ribs
• Spectrum: Marginal erosions to arthritis o ALL, iliolumbar, sacrotuberous ligament
mutilans ossification, OPLL
• New bone formation at erosion margins o Spine, pelvis changes dominate
• Joint fusion • Diffuse sclerosis
• Paravertebral ossification • Osteophytes
• Periostitis o Appendicular periostitis
• Phalangeal tuft bone resorption • Hypoparathyroidism
Helpful Clues for less Common Diagnoses o Nonspecific enthesopathy distribution
• Chronic Reactive Arthritis o ALLossification
o Calcaneus involvement characteristic o Diffuse sclerosis
• Plantar enthesophyte common: o Spinal osteophytes
Ill-defined appearance, ± erosion o Calvarial thickening, subcutaneous
• Achilles enthesophyte uncommon calcifications, hypoplastic teeth
• Retrocalcaneal bursitis, erosion • Hypophosphatasia & Vitamin D Resistant
o Enthesopathy at other sites less common Rickets
than other spondyloarthropathies o Nonspecific enthesopathy distribution
o Erosive and proliferative arthritis o Ill-defined, coarse trabeculae
• Lower extremity, spine dominate o Looser's zones, pseudofractures
• Otherwise similar to psoriasis
Lateral radiograph shows degeneraUve enthesophytes at

the attachment of the plantar fascia E!lI and the insertion
Anteroposterior radiograph shows new bone formation
along the superior aspect of the greater trochanter in this
II
of the Achilles tendon !lEI. elderly individual with degenerative enthesopathy 1IllI.
97
I/)
:J ENTHESOPATHY
o
Ql
I/)
I/)
o
r:
-
()
.c
a.
III
DISH Subacromial Spur
OJ radiograph shows a classic

.Q case of DISH with pelvic
"0
III enthesopathy including
0:: enthesopathy along the
-c ischial tuberosity ElII. (RighI)
Ql
I/) Anteroposterior radiograph
III shows a large subacromial
III
Ql
spur. which arisesfrom
en the acromial attachment of
III
the coracoacromialligament
E as a result of impingement.
Plantar Fasci itis

shows plantar fasciitis with a
thickened ligament. An
associated
marrow-containing
enthesophyte = is present.
(RighI) Sagittal T1WI MR
shows typical changes of
prominent" bump"
marked thickening of the
=
Haglund syndrome including
and
Achilles tendon Elll A small

focus of ossification is
present near the Achilles
tendon insertion ilia.
Tendon/ligament Microtrauma with

Calcification (Mimic) Ankylosing Spondylitis
(Left) Axial NEeT shows
linear calcification within the
gluteus maxim us tendon near
its insertion. as well as
irregularity at the tendon
insertion onto the posterior
femoral cortex" likely
from prior trauma. (Right)
shows classic signs of
ankylosing spondylitis with
enthesopathy at the ischial
tuberosities •.
II
98
ENTH ESOPATHY 3
III
co
(l)
en
III
l/I
(l)
C.
Avulsion Fractures, Pelvic (Mimic) Psoriatic Arthritis
(Left) Anteroposterior :;0
Dl
radiograph shows typical C-
case of an avulsion of the O
CO
anterior superior iliac spine. ~Dl
At four weeks follow-up new -0
::T
bone formation
site •. (Right)
is seen at the
o
-l
shows extensive ill-defined
o
l/I
l/I
enthesopathy at the malleoli CD
.:II. The productive changes o
c
seen here are typical of en
either psoriatic arthritis or
Psoriatic Arthritis Chronic Reactive Arthritis

radiograph shows prominent
enthesopathy seen at the
anterior superior iliac spine
IS! in this patient with
psoriatic arthritis. (Right)
dense reactive change with
ill-defined enthesopathy at
the attachment of the plantar
fascia. in thispatient with
Hypophosphatemia (Vitamin D Resistant

Rickets)
radiograph shows loss of
normal cortical definition on
the ischial tuberosity, an
early indicator of
enthesopathy = This
finding is commonly seen in
any of the
spondyloarthropa thies.
radiograph of a patient with
vitamin 0 resistant rickets
who must take massive
doses of vitamin D, resulting
in prominent enthesopathy
at the ischial tuberosity.
and anterior superior iliac
spinelSl.
II
99
(/)
::l TENDON & LIGAMENTOUS OSSIFICATION
o
Q)
(/)
(/)
o DIFFERENTIAL DIAGNOSIS • Ossification Posterior Longitudinal

r-: Ligament (OPLL)
o Common
::ca. o All levels, especially cervical
C1l
~ • DISH o 20% have DISH
Ol
.Q
• Post-Traumatic • Ankylosing Spondylitis
"0
C1l
• Ossification Posterior Longitudinal Ligament o Interspinous, supraspinous ligaments
0::: (OPLL) • Dagger sign
• Ankylosing Spondylitis
"Q)
(/)
• Idiopathic Achilles Tendon Ossification
o Syndesmophytes
<Il o Enthesopathy
III
Q) less Common o Sacroiliac joint fusion (synovial portion)
Ol
C1l
• Fluorosis o Hip, shoulder arthritis
E • Idiopathic Achilles Tendon Ossification
• Stylohyoid Ligament Ossification &
Eagle-Barrett Syndrome o Isolated finding
Rare but Important Helpful Clues for less Common Diagnoses

• Hypophosphatasia • Fluorosis
• Hypoparathyroidism o ALL, iliolumbar, sacrotuberous Iig., OPLL
o Spine, pelvis changes dominate
• Diffuse sclerosis, osteophytes
ESSENTIAL INFORMATION o Appendicular periostitis, enthesopathy
Key Differential Diagnosis Issues • Stylohyoid Ligament Ossification &
• Hint: Similar spinal manifestations in DISH, Eagle-Barrett Syndrome
OPLL, fluorosis, hypoparathyroidism o Syndrome: Throat, swallowing pain
Helpful Clues for Common Diagnoses Helpful Clues for Rare Diagnoses
• DISH • Hypophosphatasia
o Anterior longitudinal ligament (ALL) o Diffuse skeletal involvement
o Iliolumbar, sacrotuberous, sacrospinous, o Ill-defined coarse trabeculae
stylohyoid ligaments o Looser's zones, pseudofractures
o Enthesopathy • Hypoparathyroidism
o Sacroiliac joint changes o ALL
• Fusion upper 1/3, osteophytes o Diffuse sclerosis, spinal osteophytes
o 50% have OPLL o Calvarial thickening, subcutaneous
• Post-Traumatic calcifications, hypoplastic teeth
o Random sites
II Anteroposterior radiograph shows extensive ossification

within the iliolumbar ligament bilaterally •.
Anteroposterior
superimposed
radiograph shows linear calcification
on the obturator foramen III.
Ossification of this ligament may be seen with many representing sacrotuberous ligament ossification,
conditions, most commonly DISH. commonly seen in DISH.
100
TENDON & LIGAMENTOUS OSSIFICATION 3
III
(0
11l
lD
III
(I)
Ossification Posterior longitudinal 11l
Co
Post-Traumatic ligament (OPll)
(Left) Coronal bone CT ;;0
OJ
shows irregular linearly Co
oriented ossification. o'
co
which follows the course of ~
OJ
the ligamentum teres. An
unusual finding, this "(';-::r
mineralization is either the -;
result of intrinsic
degeneration or prior injury
o
(I)
(I)
to the ligament. (RighI) Ctl
Lateral radiograph shows o
C
(I)
thick ossification of the
ligament extending along the
anterior spinal canal". The
finding is typical of GPLL.
radiograph shows extensive
enthesopathy, or ossification
of the tendon insertions at
the ischial tuberosities 11II.
Note the fused SI joints in
this patient with ankylosing
spondylitis. (RighI) Lateral
radiograph shows
ossification of the distal
Achilles tendon, slightly
proximal to the tendinous
insertion". It is slightly
rounded and smoothly
marginated, contrasting with
the more angular plantar
fascial enthesophyte ElII.
Stylohyoid ligament Ossification &

Fluorosis Eagle-Barrett Syndrome
radiograph shows
calcification of the
sacrospinousligaments.
which is a common finding
in patients with fluorosis.
(RighI) Sagittal oblique
NECT shows extensive
ossification of the stylohyoid
ligament _ The finding is
bilateral and symmetric in
this patient with Eagle-Barrett
syndrome.
II
101
rn
:J BONE AGE, ADVANCED
o
<1l
rn
rn
o DIFFERENTIAL DIAGNOSIS • Marked advancement in bone age is more
t-=' likely to indicate elevated sex hormones
u Common
:c Helpful Clues for Common Diagnoses
0-
ro • Familial Tall Stature
~ • Excessive Sex Hormone
Ol
o • Idiopathic Precocious Puberty
o Induces early growth plate maturation
"0
ro • Excessive Sex Hormone
0::: • Juvenile Idiopathic Arthritis OIA) • Juvenile Idiopathic Arthritis alA)
"0 o Chronic hyperemia causes growth centers
Cl> • Hemophilia
Vl
• Physeal Fractures to ossify early, enlarge, & fuse prematurely
'"
ell
• Radiation-Induced Growth Deformities • Hemophilia
Cl>
Cl • Similar JIA, + dense effusion
Less Common
E'" • Radiation-Induced Growth Deformities
• Hyperthyroidism o Vascular obliteration - premature fusion
• Hypothalamic Mass o Associated with bone hypoplasia, slipped
• Pituitary Gigantism capital femoral epiphysis, scoliosis
• Adrenocortical Tumor o Watch for "port-like" distribution
• Adrenal Hyperplasia o Associated radiation-induced sarcoma
• Exogenous Obesity
• Ectopic Gonadotropin Tumor Helpful Clues for Less Common Diagnoses
• Polyostotic Fibrous Dysplasia, • Hypothalamic Mass
o Early onset of normal maturation process
McCune-Albright
o Hypothalamic hamartoma or mass effect
Rare but Important from suprasellar tumors
• Chronic Septic Arthritis, Non-Bacterial • Adrenocortical Tumor or Hyperplasia
• Encephalitis o Hypersecretion of androgens and cortisol
• Primary Hyperaldosteronism • Ectopic Gonadotropin Tumor
• Beckwith-Wiedemann Syndrome o Hepatoblastoma/teratoma/chorioepithelioma
• Polyostotic Fibrous Dysplasia
ESSENTIAL INFORMATION o Ground-glass bone lesions + cafe au lait
spots + precocious puberty
Other Essential Information
• Skeletal maturation more than two standard
deviations above the mean • MR brain to exclude hypothalamic lesion
• Determining etiology highly dependent on • Pelvic ultrasound (females) for evidence of
lab findings and clinical presentation gonadotropin/estrogen stimulation
Juvenile Idiopathic Arthritis (JIA) Juvenile Idiopathic Arthritis (J IA)
II ute,al ,adiog,aph of the affected left elbow shows

advanced skeletal maturaUon in the capitellum III
uteral radiograph of the unaffected right elbow, in the
same patient as previous image, for comparison. The
radial head E!il & olecranon III This early skeletal capitellum" and radial head ElllI are normal. ItMSK
maturation is due to chronic hyperemia. ItMSK Req). Req).
102
BONE AGE, ADVANCED
(Left) Lateral radiograph of a ;0

Q)
teenager's knee shows a Q.
huge effusion Ia and o

co
~
overgrowth of the epiphyses Q)
IlIi'I with the femoral -0

::T
condyles particularly
enlarged in a male paaenl
o
-i
with hemophilia. (Right)
o
CJ>
CJ>
of the same knee as previous <1>
image, shows epiphyseal o
c
overgrowth Ia and CJ>
intercondylar notch
widening [;8 which can be
seen with hemophilia or
juvenile idiopathic arthritis.
Bone age was advanced.
(Left) Coronal bone CT

shows a remote fracture of
the distal tibia IlIi'I and
development of bridging of
bone across the physeal
plate Ia. This will result in a
short limb from premature
growth plate closure. (Right)
3D bone CT shows focal
convex left scoliosis =
in a
patient treated with radiation
therapy for neuroblastoma.
The affected thoracolumbar
vertebrae are short on the
right from early physeal
fusion, yielding a flattened
curvature without congenital
segmentation anomalies.
Polyostotic Fibrous Dysplasia,

McCune-Albright
radiograph shows a short
humerus (relative to thorax)
in a patient radiated at a
young age for Ewing
sarcoma. Note the aggressive
osteoid-producing tumor
an associated
=
radiation-induced
osteosarcoma. (Right)
shows numerous lesions =
of mixed density and with a
narrow zone of transition.
The right femoral lesion
extends to the epiphyseal
plate resulting in a
shepherd's crook deformity.
II
103
'"o
:::J BONE AGE, DELAYED
Q)
'"'"
o
I-
-
U
.r:
a.
~
Common
• Constitutional Delay of Puberty (Normal
• Skeletal maturation more than two standard
Ol Variant) deviations below the mean
.2
"0
co • Chronic Disease o Formally evaluated with serial PA
0::: o Chronic Liver Disease radiographs of left hand
"0
QI
o Renal Osteodystrophy o Standards of Greulich and Pyle classically
'"ctl
al
o Congenital Heart Disease used for comparison
o Rickets
QI Helpful Clues for Common Diagnoses
Ol
ctl o Juvenile Idiopathic Arthritis
E
• Majority of common diagnoses cause
o Thalassemia
delayed bone age due to delay of puberty
o Cerebral Palsy
o Are identifiable by clinical history
• Excessive Exercise
• Malnutrition Helpful Clues for Less Common Diagnoses
o Anorexia • Lead Poisoning
o Malabsorption Conditions o Widened metaphyses, dense metaphyseal
• Complications of Steroids lines
• Fetal Alcohol Syndrome • Down Syndrome (Trisomy 21)
o Additional findings = flared iliac wing, flat
Less Common
acetabular roof, c1inodactyly,
• Lead Poisoning
microcephaly, atlantoaxial instability
• Cushing Disease Helpful Clues for Rare Diagnoses
• Hypopituitarism • Hypogonadism
• Pseudohypoparathyroidism o Results in long limbs with
• Craniopharyngioma disproportionally short trunk
Rare but Important Alternative Differential Approaches
• HIV-AIDS: MSK Complications • Stippled epiphyses: Hypothyroidism,
• Growth Hormone Deficiency Warfarin embryopathy, chondrodysplasia
• Hypogonadism punctata, multiple epiphyseal dysplasia,
• Hypothyroidism trisomy 21, trisomy 18, prenatal infection,
• Warfarin Embryopathy Morquio syndrome
Chronic Disease Renal Osteodystrophy
II AP ,adiogfaph shows delayed skeletal maw,alion in this AP ,adiograph shows sulxhondral resorption at the 511
cenlefS =.
5 yea' old. Note the liny femo,al head ossification
The widened metaphyses 11\:I indicate
rickets in this patient with long-term renal disease.
Ell & slipped capital femoral epiphyses from ricke15•
in this 10 year old with renal osteodystrophy
skeletal maturalion is severely delayed.
The
104
BONE AGE, DElAYED 3
III
co
(l)
CJ
III
tII
(l)
Co
Rickets Juvenile Idiopathic Arthritis
(Left) Posteroanterior ;;0
OJ
radiograph shows the a.
widened zone of provisional o'
CO
calcification with frayed, ~OJ
cupped metaphysis at the "0
::T
distal radius and ulna __
typical of rickets. Note that
o
-l
despite the chronologie age
of 1 year, the skeletal
o
C/l
C/l
maturation is severely Cll
delayed. (Right) o
C
Posteroanterior radiograph C/l
shows an open physis • in

a 22 year old patient with
/IA, indicating delayed bone
age. Note also the fused
carpals and significant
metacarpal erosive disease.
shows open physis __ as
well as immature bone
marrow distribution with a
crescent of red marrow in
the epiphysis" and solid
red marrow in the
meta diaphysis Ell. She is a
19 year old competitive
gymnast who practices 5
hours daily. (Right) PA
radiograph of the wrist in the
image, shows open physes at
the distal radius & ulna ••.
This patient is at least 2
standard deviations younger
than her chronologie age.
Lead Poisoning
squared bones, indicating
severe marrow packing in a
patient with thalassemia.
This five year old patient also
shows delayed bone age,
related to the chronicity of
the disease. (Right)
shows the dense
metaphyseal lines ••.
resulting from deposition of
lead during growth. Chronic
lead poisoning can lead to a
delay in skeletal maturation.
II
105
<ll
::J SOFT TISSUE OSSIFICATION
VJ
VJ
i=
~ DIFFERENTIAL DIAGNOSIS o Timing & zoning identical to heterotopic
(f)
ossification
I- Common
-
U
£
0-
ro
~
• Heterotopic Ossification
o Myositis Ossificans (Late)
• Loose Bodies
o Ossified round to oval masses located in &
around joints
OJ
o • Loose Bodies • May migrate away from joint within
'6
ro less Common tendon sheath
0:::
'0 • Fracture Fragment (Mimic) o Location & typical appearance can be
Ql
III • DISH confirmed with CT, MR
III
OJ • Leiomyoma, Deep Helpful Clues for less Common Diagnoses
Ql
Cl • Cement & Bone Fillers (Mimic) • Fracture Fragment (Mimic)
III
E • Hematoma o Borders of bone fragment angular when
• Synovial Osteochondromatosis acute, rounded when chronic
• OPLL o Donor site usually has identifiable
• Osteosarcoma, Parosteal deformity
• Extraskeletal Osteosarcoma o Cartilage fragments mayor may not ossify
• Osteosarcoma, Metastasis • DISH
Rare but Important o Enthesopathic changes in spine and pelvis
• Liposarcoma, Soft Tissue predominate
• Lipoma, Soft Tissue • Flowing ossification anterior to vertebral
• Post-Operative Scar bodies
• Rhabdomyosarcoma, Embryonal o Ligamentous ossification, with iliolumbar
• Fibrodysplasia Ossificans Progressiva most common
• Giant Cell Tumor, Soft Tissue Implants • Leiomyoma, Deep
o Smooth muscle benign neoplasm with
dense popcorn ossification
ESSENTIAL INFORMATION o Very commonly seen on pelvic imaging
Key Differential Diagnosis Issues due to uterine fibroids
• Calcification is not the same as ossification • Cement & Bone Fillers (Mimic)
o Ossification has mature features, such as o Bone graft may extrude into soft tissues
trabeculae and cortex o Cement extravasation may mimic bone
• Hematoma
Helpful Clues for Common Diagnoses o Peripheral ossification if chronic
• Heterotopic Ossification • Most commonly involving intracranial
o Numerous causes of soft tissue ossification
epidural hematomas
• Blunt trauma, tendon tear, burns, o Subperiosteal hemorrhage ossifies with
paralysis, tumor, neurologic infection more mature bone in the periphery
(poliomyelitis, tetanus, Guillain-Barre)
o Calcifies at approximately one month post
o Intraarticular ossified masses may appear
insult, then ossifies later to be in soft tissue, depending on imaging
o Ossification is most mature peripherally,
plane
with center less mature o Extraarticular extension into surrounding
o Common sites of injury may suggest this
soft tissues may occur
diagnosis when changes are early o Bursal synovial osteochondromatosis
• Thigh after trauma and hip after joint projects outside joint on radiographs
replacement or paralysis
• OPLL
• Myositis Ossificans (Late) o Multilevel ossification of posterior
o Implies muscle ossification
longitudinal ligament in spine
• Term is sometimes used interchangeably • Mid cervical spine level most commonly
with heterotopic ossification involved
o Look for changes of myelopathy on MR
II
106
SOFT TISSUE OSSIFICATION 3
III
to
C1l
• Osteosarcoma, Parosteal o Malignant liposarcoma contains nodular CD

III
o Dense ossified mass most commonly soft tissue elements or thick septations III
C1l
posterior to distal femur o Ossification is uncommon but can occur 0-
• Contiguous with underlying femoral in both benign and malignant tumors ;0

III
a.
cortex • Post-Operative Scar o'
o Ossification follows course of operative to
~
o Seen in older patients compared with
III
conventional osteosarcoma incision 1:1
::r
o Low grade lesion o Most common in anterior abdominal wall, o
.-1
• Extraskeletal Osteosarcoma above umbilicus (f)
o Older patients than conventional o Male predominance o
;:t'
osteosarcoma • Rhabdomyosarcoma, Embryonal -I
Cii'
o Slow growing mass may be large at o Embryonal subtype more common in III
c
presentation children <1l
o Difficult to differentiate from other soft o Soft tissue mass with metaplastic foci of
tissue sarcomas ossification
• 50% demonstrate mineralization • Mass may invade adjacent bone
• Separate from adjacent bone • Fibrodysplasia Ossificans Progressiva
o Lower extremities & pelvis most o Abnormal ossification of the soft tissues
commonly involved • Accelerated by minor trauma
o Metastases common at diagnosis o Ossification fatally limits respiratory
• Osteosarcoma, Metastasis movement
o Metastases ossify in a similar fashion to the o Associated finding of short great toe with
primary tumor valgus orientation
o Lung and nodal soft tissue masses most • Giant Cell Tumor, Soft Tissue Implants
common o Foci of benign giant cell tumor implanted
o Other "bone forming metastases" into soft tissue
(including breast, colon and urinary tract • Iatrogenic from surgery or biopsy
carcinomas), tend to calcify, rather than • Post-traumatic from pathologic fracture
ossify through primary lesion
o Characteristic peripheral ossification in
• Liposarcoma & Lipoma, Soft Tissue 1-2% of soft tissue implants
o Fat-containing soft tissue mass
• Ossification histologically identifiable in
high proportion of soft tissue implants
Heterotopic Ossification Heterotopic Ossification
=
AnterofXJsterior radiograph shows mature ossification
involving the medial thighs in this horseback rider.
Note the peripheral cortex and central trabeculae,
Anteroposterior
mature
radiograph shows a solid sheet of
ossificaUoll
space is narrowed •
III around the hip. The hip joint
and there is a suprapubic
II
suggesting it is likely at least several months old catheter E!iI in place. suggesting paralysis.
107
Q)
:::J SOFT TISSUE OSSIFICATION
Ul
Ul
i=
;t:
o
en
~
-
t)
.<::
a.
ro
~
radiograph shows a grade III
Heterotopic Ossification Myositis Ossificans (late)
OJ acromioclavicular
.Q dislocation, with elevation of
"0
ro the clavicle. relative to the
0:: acromion. Ossification 111
"0 between the clavicle and
Q)
Ul coracoid indicates disruption
CIl of the coracoclavicular
lD
ligaments. (Right) Axial bone
CI>
Ol
CIl
CT shows osseous matrix =
at the surface of the scapula.
E Ossification zoning, with
mature peripheral
ossification, is typical of
myosWs. Osteosarcoma
typically has more mature
matrix centrally.
Fracture Fragment (Mimic) DISH

(Left) Axial NEeT shows an
osseous body III in the 50ft
tissues, which separated
from the posterior acetabular
rim Hl indicating a recent
episode of posterior
subluxation or dislocation of
the hip. (Right)
iliolumbar ligament
bilaterally III. This may be
seen with DISH, sacroiliac
joint osteoarthritis, trauma,
fluorosis and X-linked
hypophosphatemia.
Cement & Bone Fillers (Mimic) Synovial Osteochondromatosis

materia' HI in the 50ft tissues
surrounding a tibia fracture.
This material is
hydroxyapatite, a bone
substitute that is
osleoconduclive, acting as a
scaffold for the ingrowth of
new bone. (Right) Lateral
radiograph shows an
elevated anterior fat pad E!Il
with the joint containing
several large, similarly sized
ossified rounded bodies _
II
108
SOFT TISSUE OSSIFICATION 3
III
(Q
tD
OJ
III
VI
tD
Co
Osteosarcoma, Parosteal Extraskeletal Osteosarcoma
(Left) Anteroposterior ;0
OJ
radiograph shows a.
=
well-differentiated
ossification wrapping
around and appearing
0·
(Q
iil
1:l
:::r
"pasledrr on the metaphyseal
region of the tibia. The tumor
o
.-1
bone is quite mature. (Right)
=
(J)
Axial NECT shows a large o
;::l>
mass between the right
:j
gluteus maximus and medius VI
muscles. The mass contains VI
C
areas of dense calcification (1)
or ossification =.
Extraskeletal osteosarcoma is
seen in older patients than
conventional osteosarcoma.
Osteosarcoma, Metastasis Osteosarcoma, Metastasis

ossification of a retrocardiac
mass = in this patient with
known metastatic
osteosarcoma. Innumerable
bilateral pulmonary nodules
• are a/50 present, some of
which are clearly ossified
similar to the primary tumor.
(Right) Axial CECT shows
lymph node =
ossification of an enlarged
from
metastatic osteosarcoma.
This showed increased
radiotracer uptake on bone
scan.
Liposarcoma, Soft Tissue Fibrodysplasia Ossificans Progressiva

shows a fatty mass
containing prominent
appearing ossified =. MR
showed fat, calcification and
soft tissue regions of the
mass making it suspicious for
malignancy, proven
liposarcoma. (Right) AP
bone bridging between ribs,
as well as between the
humerus and rib cage III.
The end result is complete
loss of motion of the rib
cage, increasing risk of
pneumonia and early death.
II
109
Q)
:J NODULAR CALCIFICATION
(/)
(/)
i=
.t=o DIFFERENTIAL DIAGNOSIS • Maintain a high suspicion for malignancy
(fJ when calcification is present with a mass
1-- Common
<.) Helpful Clues for Common Diagnoses
::c0- • Phlebolith
m • Pyrophosphate Arthropathy • Phlebolith
~
Q) o Small round calcification in vessel
.2 • Tendinitis, Calcific
"0
• Bursitis, Calcific o Characteristic central lucency
m
0::: o Common in lower extremities & pelvis
• Injection Granuloma
't:l
Ql • Myositis Ossificans (Early) • Pyrophosphate Arthropathy
(/)
o Calcium pyrophosphate dihydrate (CPPD)
01 • Progressive Systemic Sclerosis
Cll
Ql • Loose Body (Mimic) crystal deposition
Cl o Chondrocalcinosis in knee menisci, wrist
01
E Less Common TFCC & hip labrum can be nodular
• Gout • Tendinitis, Calcific
• Avulsion Fractures (Early) o Hydroxyapatite Deposition Disease
• Dermatomyositis (HADD) in tendons
• Hyperparathyroidism/Renal Osteodystrophy o Additional deposition in capsule,
• Mixed Connective Tissue Disease ligaments & bursae
• Hypervitaminosis D • Bursitis, Calcific
• Hematoma o HADD involving the bursa
• Synovial Osteochondromatosis o Shoulder & hip most common
• Rheumatoid Nodule • Injection Granuloma
• Soft Tissue Tumors Containing Nodular o Classic gluteal location; central lucency
Calcification • Myositis Ossificans (Early)
o Hemangioma, Soft Tissue o Amorphous calcification one month post
• Maffucci Syndrome trauma, before ossification
o Uterine Fibroid o Radiolucent zone between bone and
o Synovial Sarcoma myositis, unlike malignancy
o Hemangiopericytoma o Correlate with history of regional trauma,
Rare but Important although patients may not recall trauma
• Metastatic Calcification • Progressive Systemic Sclerosis
• Systemic Lupus Erythematosus o Lobulated calcifications + tuft resorption
• Calcific Myonecrosis • Loose Body (Mimic)
• Tumoral (Idiopathic) Calcinosis o lntraarticular; features of ossification
• Trevor Fairbank (Dysplasia Epiphysealis Helpful Clues for Less Common Diagnoses
Hemimelica) • Gout
• Thermal Injury, Burns o Calcified tophi - pressure erosions &
• Sarcoidosis intraosseous collections
• Chondrodysplasia Punctata (Mimic) o First MTP joint, Achilles tendon insertion
• Pseudohypoparathyroidism & olecranon bursa common
• Parasites • Avulsion Fractures (Early)
• Melorheostosis o Cartilaginous fragments may calcify
o Small osseous fragments can mimic
ESSENTIAL INFORMATION calcification
• Dermatomyositis
Key Differential Diagnosis Issues o Inter- & intramuscular calcification
• Overlap in radiographic appearance of • Hyperparathyroidism/Renal
calcified collections Osteodystrophy
o Calcification = structureless density o Subperiosteal resorption, vascular
o Ossification = organized density with calcification & evidence of renal failure
cortex and/or trabeculae o Wrist, knee, hip, shoulder & elbow
• Mixed Connective Tissue Disease
II
110
NODULAR CALCIFICATION 3
III
(Q
CD
o Dermatomyositis & scleroderma findings o Disturbance of calcium or phosphorus lJl
III
• Hypervitaminosis D metabolism (can resolve with treatment)
o Large, calcified, periarticular masses • Systemic Lupus Erythematosus
'"
CD
Co
o Associated ligamentous & intervertebral o Rare calcifications, most common in lower ;0

III
a.
disc calcification extremity o'
lO
• Hematoma o Joint subluxation without erosion ~
III
"0
o Even with history of trauma, need • Calcific Myonecrosis :T
follow-up to exclude malignancy unless o Amorphus or plaque-like calcification in o
-~
there is complete lack of enhancement on muscle compartment, usually lower (IJ
MR extremity o
;:1'
• Synovial Osteochondromatosis • Tumoral (Idiopathic) Calcinosis ::!
o Multiple intraarticular densities o Diagnosis of exclusion, with same '"'"c:
CD
• Rheumatoid Nodule appearance as metastatic calcification
o Soft tissue masses with periarticular • Trevor Fairbank (Dysplasia Epiphysealis
erosions, osteopenia, joint space narrowing Hemimelica)
• Soft Tissue Tumors Containing Nodular o Lobulated intraarticular osteochondroma
Calcification mimics calcification
o Hemangioma, Soft Tissue o May simulate loose bodies
• Mass with fat, vessels & phleboliths • Thermal Injury, Burns
• Maffucci syndrome = enchondromatosis o Stippled calcification in area of burn or
+ hemangiomas along contracture bands
o Uterine Fibroid • Sarcoidosis
• Popcorn calcifications in midline pelvis o Large calcified periarticular masses are rare
o Synovial sarcoma • Chondrodysplasia Punctata (Mimic)
• Up to 50% contain dystrophic o Dwarfism with congenital stippled
calcification, usually peripheral epiphyses
• Vast majority are extraarticular • Pseudo hypoparathyroidism
o Hemangiopericytoma o Calcifications + short metatarsals &
• Cannot differentiate from a benign metacarpals
hemangioma by imaging alone • Parasites
o Variable by type
• Metastatic Calcification • Melorheostosis
o Classic undulating cortical hyperostosis +
o Large deposits around large joints
rare soft tissue calcification
Phlebolith
Anteroposterior radiograph shows several nodular

calcifications III of varying sizes in the low pelvis. These
AnterofXJsterior radiograph shows nodular calcification
• in the medial meniscus due to chondroca/cinosis.
II
are typical for phleboliths. A lucent center III is classic More typical linear hyaline • & triangular meniscal
but not always present. chondrocalcinosis iii involves the lateral compartment.
111
Q)
=> NODULAR CALCIFICATION
(J)
(J)
i=
;;=
o
(f)
r-:
-
(,)
.c
a.
ro
~
(Left) Anceroposterior
radiograph shows nodular
Tendinitis, Calcific
Ol calcification. in the
.Q expected region of the distal
"0
ro supraspinatus tendon,
a:: consistent with calcific
"tl tendonitis. (Right)
CIl
VI Anceroposterior radiograph
shows a nodular calcific
'"
CO
deposit. located superior
CIl
Cl to the greater tuberosity.
'"
E While the deposit looks solid
in this radiograph, the
distribution became linear on
internal rotation, confirming
location in the bursa, rather
than tendon, as is illustrated
in the prior case.
Injection Granuloma
peripherally calcified lesions
11II in the right gluteal region
from prior injections. The
central lucency is commonly
seen but can also be presenc
in phleboliths. (Right) Lateral
radiograph shows early
myositis in the antecubital
fossa & forearm. Note that
the early bone formation is
amorphous __ appearing
nodular & calcified at this
lime. This appearance
suggests an injury 4-8 weeks
earlier, possibly an elbow
dislocation.
Progressive Systemic Sclerosis

shows an extraarLicu/ar
globular calcification.
along the volar aspect of the
index finger with a typical
appearance for scleroderma.
nodular bodies. in the
axillary recess and along the
biceps tendon sheath. These
loose bodies are technically
ossified but can appear
calcified, depending on their
maturity.
II
112
Ql
to
III
OJ
Ql
/JI
III
Co
Gout Avulsion Fractures (Early)
(Left) Oblique radiograph ;:0
Q)
shows an impressive soft c.
tissue tophus _ containing o
<0
density typical of sodium ~
Q)
urate deposition. There is a "0
:::r
large erosion at the PIP ()
which has resulted in a -l
classic overhanging edge Ell. (f)
(Right) Lateral radiograph o
;::l>
shows an avulsion fracture
• from the base of the =i
/JI
middle phalanx. This is a /JI
C
volar plate fracture, most CD
commonly seen following
dorsal dislocation. The size
of the fracture fragment
varies from a sliver of bone
to a sizable fragment.
Hyperparathyroidism/Renal
Dermatomyositis Osteodystrophy
extensive myofascial
calcification with focal areas
of more confluent nodular
calcification •. (Right)
shows severe osteopenia,
prominent vascular
calcification and globular
50ft tissue calcification"
suggesting
hyperparathyroidism. The
patient proved to have a
parathyroid adenoma.
Rheumatoid Nodule
numerous, rounded,
calcified bodies within the
knee joint" as well as
extension of the collection
into the posterior soft tissues
•• of the knee. (Right)
shows a focal nodular
density. which causes
bone Ell. While this could
represent a giant ce/J tumor
of the tendon sheath,
narrowing of the second
MCP joint and a marginal
erosion" suggests
II
113
NODULAR CALCIFICATION
Hemangioma, Soft Tissue Hemangioma, Soft Tissue

shows multiple round
calcifications. associated
with a soft tissue mass in the
thigh. These are phleboliths
within a hemangioma.
(Right) Axial NECT in the
same patient as the prior
case illustrates the round,
calcified phleboliths •
within the fatty stroma ElIII
that is typical for
hemangiomas.
Maffucci Syndrome Uterine Fibroid

enchondromas. withinthe
phalanges and metacarpals
and a soft tissue
hemangioma containing
multiple round phleboliths
•. Enchondromatosis + soft
tissue hemangiomas =
mass in the pelvis containing
nodular calcification _ This
type of calcification is typical
for uterine fibroids, although
this is an unusually large
example.
Synovial Sarcoma Hemangiopericytoma

shows a mass HI
posteromedial to the knee in
a young adult containing
peripheral, dystrophic,
nodular calcification _.
One should always consider
this dx if there is a mass in
the lower extremity of a
young adult. (tMSK Req).
(Right) Axial NECT shows an
anterior compartment mass
containing phleboliths _
which enhance intensely.
Vascular tumors range from
benign to malignant and it is
not easy to differentiate them
by imaging features.
II
114
III
to
ll>
III
III
C/l
ll>
C.
Metastatic Calcification Systemic lupus Erythematosus
OJ
radiograph shows extensive C.
amorphous calci(ication __ o
(Q
consistent with metastatic ~
OJ
calcium deposition, around -0
::T
the shoulder in a dialysis
patient. Amorphous calcium
o
.--1
deposition is commonly (f)
bilateral and asymptomatic. o
(Right) Frog lateral
~
::j
en
globular sort tissue en
c:
calcifications. around the C1l
hip. SLEpatients occasionally

develop dystrophic soft
tissue calcification,
predominantly in the lower
extremities. (t MSK Req).
Calcific Myonecrosis Tumoral (Idiopathic) Calcinosis

radiograph shows nodular to
sheet-like calcification 11:I
involving the anterior
compartment of the lower
leg. This is a common
location for the sequelae of
compartment syndrome.
radiograph shows a dense,
cfoud-like collection of
nodular calcifications.
surrounding an otherwise
normal shoulder Renal
failure and collagen vascular
diseases may cause a similar
appearance.

Hemimelical Pseudo hypoparathyroidism
shows lobulated ossification
• which is intraarticular
and apparently arises (rom
the medial femoral condyle.
Il is a calcification mimic and
represents Trevor Fairbank,
essentially an intraarticular
osteochondroma. (Right)
shows subtfe soft tissue
calcification. as well as
short first metatarsal HI This
is the combination of
findings that makes the
diagnosis of
pseudo-hypoparathyroidism.
II
115
Q)
:::J LINEAR AND CURVILINEAR CALCIFICATION
l/l
l/l
i=
~ DIFFERENTIAL DIAGNOSIS • Most commonly seen type of
o
en arteriosclerosis on extremity radiographs
f-" Common • Pipe stem appearance with contiguous,
o
:!: • Arteriosclerosis granular calcification
0-
ro
~ • Chondrocalcinosis • Medium-sized vessels involved
Ol
.2 • Aneurysm • Common in diabetics
"0
ro • Hemangioma, Soft Tissue • No narrowing of vessel lumen
0:: • Hyperparathyroidism/Renal Osteodystrophy o Arteriolar sclerosis involves small arteries
"C
Ql
l/l
• DISH and arterioles
C1l
al Less Common • Causes wall thickening and luminal
Ql
• Dermatomyositis narrowing
Cl
C1l
• Progressive Systemic Sclerosis • Predominantly affects kidneys
E
• Synovial Sarcoma • Chondrocalcinosis
o Nonspecific cartilage calcification
• Hypercalcemia
• Calcified Chronic DVT • Involves hyaline or fibrocartilage
• Thermal Injury, Burns • Linear to globular configuration
depending on location
Rare but Important o Common in knee menisci, wrist triangular
• OPLL fibrocartilage complex, symphysis pubis
• Systemic Lupus Erythematosus o Can involve joint capsule, synovium,
• Pseudohypoparathyroidism ligaments, and tendons
• Cysticercosis o Associated with numerous entities
• Echinococcal Cyst • Calcium pyrophosphate deposition
• Filariasis disease (CPPD), gout, hemochromatosis,
• Leprosy hyperparathyroidism, ochronosis,
• Dracunculiasis oxalosis, acromegaly, Wilson disease,
• Complications of Fluoride degenerative/idiopathic causes
• Armillifer Armillatus Infection • Aneurysm
o Arteriosclerosis outlines a larger than
ESSENTIAL INFORMATION expected caliber for vessel on radiographs
o Attention to aorta on chest, thoracic, and
Key Differential Diagnosis Issues lumbar studies
• Extremely common finding o Attention to popliteal artery on lateral
• Key factors: Location & pattern of knee radiographs
calcification • Hemangioma, Soft Tissue
Helpful Clues for Common Diagnoses o Soft tissue mass consisting of abnormal
• Arteriosclerosis blood vessels
o Follows expected course of blood vessels • 7% of all benign soft tissue masses
o Three types: Atherosclerosis, Monckeberg o Usually intramuscular
arteriosclerosis, arteriolar sclerosis o Curvilinear calcification of blood vessels
o Atherosclerosis consists of intimal plaques o Linear dystrophic calcification in
that narrow the vessel lumen thrombus
• Coarse, irregular, patchy calcifications o Partially/completely calcified phleboliths
• Morbidity and mortality with • Hyperparathyroidism/Renal
involvement of aorta, coronary and Osteodystrophy
cerebral arteries o Cartilage calcification in wrist, knee, hip,
• Plaques can cause ulceration, thrombosis or shoulder in 20-40%
and embolic complications o Also, Rugger jersey spine, distal clavicular
o Monckeberg (medial) arteriosclerosis refers osteolysis, subperiosteal bone resorption,
to calcification of the middle vessel wall Brown tumors, or salt-and-pepper skull
(media)
II
116
LINEAR AND CURVILINEAR CALCIFICATION 3
III
lQ
<D
o Calcifications can outline venous valves OJ
• Thermal Injury, Burns VI
• Dermatomyositis <D
o Fine, stippled linear calcification Co
o Irregular calcification with wide variety of
o Localized to area of injury or can extend
appearances
along contracture bands
o Involves striated muscle, fascia, and skin
o Can be extensive, involving the trunk and Helpful Clues for Rare Diagnoses
extremities • Cysticercosis
o Associations: Muscle atrophy and/or o "Rice grain" linear to oval calcifications
osteoporosis • Noncalcified central area
o Other findings include interstitial lung o Oriented parallel to muscle fibers
disease, esophageal dysmotility o Intracranial calcifications seen on CT
o Sometimes seen with occult neoplasm in • EchinococcaI Cyst
patients> SO years old o Hydatid cysts in organs, muscle, or
• Progressive Systemic Sclerosis subcutaneous tissue peripherally calcify
o Synonym: Scleroderma • Filariasis
o Elongated globular calcifications most o Dead coiled or linear worms calcify
common o Very fine calcifications best seen in web
• Curvilinear appearance early spaces of hands and feet
o Associated findings • Leprosy
• DIP and PIP erosions o Linear calcification of affected nerves
• Soft tissue atrophy • Dracunculiasis
• Acroosteolysis o Small crescentic calcifications
• Hypercalcemia • Complications of Fluoride
o Extensive clinical differential diagnosis o Iliolumbar, sacrotuberous, and paraspinal
• 90% due to hyperparathyroidism or ligamentous calcification most common
malignancy • Armillifer Armillatus Infection
• Differentiate with associated lab o Snake parasite larvae calcifies in soft tissues
abnormalities • Liver, mesentery, intestinal wall, lung,
o Cartilage calcification caused by pleura, scrotum
hyperparathyroidism is most common o West Africa infection rate 23% (visible on
• Calcified Chronic DVT radiographs in up to 7%)
o Irregular calcifications along venous 04-8 mm coiled, horseshoe, crescentic, or
distribution linear calcifications
Anteroposterior radiograph shows M6nckeberg

(media/) arteriosclerosis, one of the three types of
Axial CfCT demonstrates coarse, irregular calcifications
61 of the abdominal aorta that narrow the vessel
II
arteriosclerosis, which has fine, granular calcification lumen, typical for atherosclerosis, the most common
with a pipestem appearance •. form of arteriosclerosis.
117
Q)
:::J LINEAR AND CURVILINEAR CALCIFICATION
'"
'"
F
~
o
(/)
~
-
()
.r:
a.
ro
~
radiograph of the knee
Chondrocalcinosis Chondrocalcinosis
01 shows a typical case of

o chondroca/cinosis with
'6 calcification of the
ro
0:: fibrocartilage (meniscus) ElIII
"0 and articular hyaline
Ql
cartilage I&J. (Right)
'"
Ol
lD
of first MTP joint shows
Ql
Ol chondrocalcinosis not only
Ol
in the articular cartilage ~
E but also in the joint
capsule/ligaments ~ and
bursa ElIII.
Hemangioma, Soft Tissue

(Left) Axial NEeT
demonstrates a partially
calcified aortic aneurysm.
measuring up to 6.3 cm. The
rupture rate of aneurysms
increases with maximal
diameter. (Right) Lateral
radiograph shows a
hemangioma containing
several calcified phleboliths
III with varying shape
depending on projection and
associated pathologic
fracture. from pressure
erosion. rtMsK Req).
Hyperparathyroidism/Renal Hyperparathyroidism/Renal
Osteodystrophy Osteodystrophy
radiograph shows diffuse,
intermediate density soft
tissue calcification •. This is
a prominent feature in
hyperparathyroidism. (Right)
Axial NEeT of the symphysis
pubis shows
chondroca/cinosisllII due to
renal osteodystrophy from
this patient's end stage renal
disease.
II
118
III
(Q
CIl
CD
III
VI
CIl
Co
(Left) Anteroposterior ;u
III
radiograph shows C>-
sacrotuberous ligament o
(Q
calcification. which is ~
III
seen in DISH; sacrospinous "0
::T
ligament
seen as
calcification
well. (Right)
may be
o
--i
(fJ
shows iliolumbar o
;:l>
ligamentouscalcification. --i
frequently seen in DISH. (ij.
Note the fusion of the VI
C
non-articular portions of the Cl>
sacroiliac joints as well HI
Dermatomyositis
ligament" Though this is
seen more frequently on
OPLL, it may be seen in
DISI-/ as well. Note the
flowing anterior osteophytes
which have effectively fused
the spine Ell. (t MSK Req).
the right thigh shows
extensive, sheet-like
and fascial planes

patient with
=
calcification of the muscles
in this
dermatomyositis.
Dermatomyositis Progressive Systemic Sclerosis

(Left) Axial NEeT of both
thighs shows extensive,
sheet-like calcification of the
muscles and fascial planes
• and also demonstrates
scattered fluid-fluid levels
•. (Right) Lateral
radiograph shows linear
sheet-like calcification in the
subcutaneous tissues.
Although this pattern of
calcjfication most often
evokes the diagnosis of
dermatomyositis, it can be
seen in scleroderma (PSS) as
well.
II
119
Q)
:> LINEAR AND CURVILINEAR CALCIFICATION
en
en
t=
.t=o
Cf)
....-
-
t)
.r:
a.
ro
~
shows curvilinear
Ol calcification in an
.Q extraarticular location
"0
ro posterior 10 the knee •.
a: Though any 50ft tissue tumor
"C may COnlain dySlrophic
Ql
II) calcification~it occurs most
l'll frequenlly in synovial
III
sarcoma. (tMSK Req).
Ql
Cl (Right) AP radiograph shows
l'll
E pubic symphysis & labrum of
the hip III as well as
juxtaarticular calcifications
III in a patient with
paraneoplastic syndrome &
hypercalcemia.
Calcified Chronic DVT Thermal Injury, Burns

(Left) Lateraf radiograph of
the feg demonstrates a
serpiginous; calcified mass in
the calf. corresponding 10
a previousfy documented
area of venous thrombus.
Varicose veins HI and
phleboliths •. are also
present (Right)
demonstrates a pin tract ~
through the distal femoral
diaphysis, refated to
suspension of the burned
extremity, and resultant
myositis ossificans EiI.
OPLL
shows linear ossification of
the posterior longitudinal
ligament" typical of the
disease termed OPLL.
Although it is quite obvious
in this case, the ossification
may be thinner and much
more subtle. (t MSK Req).
(Right) Axial bone CT
confirms the ossification seen
in the previous image to be
of the posterior longitudinal
ligament" and
demonstrates the degree of
stenosis suffered by this
patient.
II
120
III
(0
<D
tlJ
III
VI
<D
Q.
Systemic lupus Erythematosus Pseudo hypoparathyroidism
Ql
radiograph shows both Q.
globular and linear o·

to
~
calcification in the soft Ql
tissues in a patient with SLE. "0
::T
It is unusual, but not
unheard of, for such
o-i
calcifications to be seen in
(fJ
this disease. (Right) o
;::ll
shows soft tissue calcification ::!
VI
• as well as a short first VI
c
metatarsal Ea. This <1l
combination is considered
the radiographic hallmark of
pseudo- or
Cysticercosis
radiograph shows
=
rice-shaped calcified bodies
within the soft tissues.
The size and shape of these
bodies is typical of the
parasite Cysticercosis.
(Right) Axial NECT
demonstrates a dominant
cyst IlIII with an adjacent
daughter cyst III in the
spleen, due to infection with
the Echinococcus tapeworm
resulting in hydatid disease
(echinococcosis).
leprosy Complications of Fluoride

radiograph of the hand
shows tremendous
acroosteofysis, which has
destroyed most of the
phalanges. Additionally,
there is linear calcification in
the location of a digital nerve
•. (tMSK Req). (Right)
shows calcification of the
sacrospinous ligaments" in
a patient with fluorosis. Note
the character and location of
the calcifications are both
slightly different than that of
pelvic arterial calcification.
II
121
QJ
:J SOFT TISSUE NEOPLASM CONTAINING CALCIFICATION
'"'"
i=
<l=
o DIFFERENTIAL DIAGNOSIS • 4-10 weeks: Earliest formation of osteoid;
(f) appears subtle, not dense, amorphous
I- Common • 10 weeks-6 months: Progressive
o • Myositis Ossificans (Mimic)
:2C- maturation; with maturation, develops
eo
~ • Synovial Sarcoma the zoning typical of myositis (immature
Ol
.Q • Periosteal Chondroma (Mimic) at center, mature bone peripherally)
-0
eo • Hemangioma, Soft Tissue • 6+ months: May begin to resolve and
0:: • Soft Tissue Chondroma decrease in size
"co
QJ • Intraarticular Chondroma o Time of greatest risk for confusion: 4-10
'"
CO Less Common weeks post trauma, when the osteoid
QJ
Cl • Malignant Fibrous Histiocytoma (MFH) formation is amorphous and appears
co similar to aggressive tumor bone formation
E • Liposarcoma, Soft Tissue
• Nerve Sheath Tumors o MR shows the halo of more mature bone,
• Osteosarcoma, Periosteal or Surface (Mimic) even at 4-10 weeks post trauma; helps to
• Mesenchymal Chondrosarcoma differentiate from tumor
• Dystrophic Calcification within any Soft • Be aware that there may be periosteal
Tissue Tumor reaction adjacent to myositis, with
• Parosteal Lipoma marrow and soft tissue edema; this may
mimic a greater level of aggressiveness
Rare but Important
• Synovial Sarcoma
• Extraskeletal Osteosarcoma o Relatively common soft tissue sarcoma
• Extraskeletal Myxoid Chondrosarcoma (though less frequently seen than
malignant fibrous histiocytoma or
ESSENTIAL INFORMATION liposarcoma)
o Most frequent soft tissue sarcoma to
Key Differential Diagnosis Issues contain dystrophic calcification
• Hint: Whenever possible, determine the • 50% of synovial sarcomas contain
nature of the calcification dystrophic calcification
o If calcification can be identified as either
• Pattern of calcification is linear or
osteoid, chondroid, or dystrophic, go to globular, central or peripheral; therefore,
the alternative differential approach not predictable .
(below), segmented by type o Preferential location: Extraarticular, lower
o Calcified osteoid: Amorphous, less dense
extremity
than bone o Prime age group is young to middle aged
o Calcified chondroid: Denser than bone, adult; generally younger than patients
rings and arcs or punctate with MFH or liposarcoma
o Dystrophic calcification: Often globular,
o Hint: Soft tissue mass in the lower
very dense extremity containing dystrophic
• Hint: Be very careful to avoid confusing calcification in a young to middle aged
early myositis ossificans with tumor! adult is most likely synovial sarcoma
o To differentiate, use zoning pattern and
• Periosteal Chondroma (Mimic)
timing of bone formation o Considered a mimic since it is an osseous
o Biopsy of myositis in its early amorphous
surface lesion rather than soft tissue mass
phase mimics osteosarcoma histologically o Chondroid matrix adjacent to osseous
Helpful Clues for Common Diagnoses cortex; often causes underlying scalloping
• Myositis Ossificans (Mimic) (but not invasion) of bone
o Related to trauma which may not be • Hemangioma, Soft Tissue
recalled by patient (or may be denied) o Phleboliths (central lucency within round
o Appearance varies significantly with time calcifications) in tangle of vessels;
• 0-4 weeks: Doughy mass, but no lipomatous stroma
calcification • Soft Tissue Chondroma
II
122
SOFT TISSUE NEOPLASM CONTAINING CALCIFICATION 3
III
(Q
CD
o Generally dense rings and arcs pattern of o May have associated bone formation, often III
III
chondroid in a painless soft tissue mass arising from the underlying cortex III
CD
• Intraarticular Chondroma o Bone may extend horizontally from the Cl.
o Usually site-specific; arises in Hoffa fat pad osseous cortex, giving the appearance of a :;0
Ql
bizarre periosteal reaction a.

o Rounded calcific densities O·
(Q
Helpful Clues for Rare Diagnoses ~
Helpful Clues for Less Common Diagnoses Ql
"0
• Soft Tissue Neoplasms • Extraskeletal Osteosarcoma ~
o Any soft tissue tumor may develop o Older adult age group
o-;
dystrophic calcification o Lower extremity predominates (j)
o
o Character of the dystrophic calcification is ;:l!
Alternative Differential Approaches -;
not specific or helpful in differentiation • Differentiate into groups according to type iii"
III
o Most common is synovial sarcoma (50%) C
of calcification <D
o Others in which it is (uncommonly) seen
o Osteoid
• Malignant Fibrous Histiocytoma: No • Myositis ossificans (mimic of soft tissue
other specific features, except relative neoplasm)
frequency of MFH in older patients • Osteosarcoma, periosteal or surface
• Liposarcoma: Appearance of lipomatous (mimic of soft tissue neoplasm)
tissue varies significantly with grade of • Extraskeletal osteosarcoma
lesion; low grade shows fatty tissue, o Chondroid
often with thickened septa or nodularity; • Periosteal chondroma
high grade may have so much cellularity • Soft tissue chondroma
that no lipomatous tissue remains • Intraarticular chondroma
• Nerve Sheath Tumors: Lesion in • Mesenchymal chondrosarcoma
distribution of nerve, often shows nerve • Extraskeletal myxoid chondrosarcoma
entering or exiting lesion; shape may be o Dystrophic calcification
oval, elongated, or teardrop; target sign • Synovial sarcoma
(central low signal on T2 imaging) often
• Hemangioma
seen, either with benign or malignant • Malignant fibrous histiocytoma
peripheral nerve sheath tumors • Liposarcoma, soft tissue
• Parosteal Lipoma • Nerve sheath tumors
o Lipoma closely associated with cortex of
• Dystrophic calcification within any soft
long bone tissue tumor
o Lipoma is simple in appearance
• Parosteallipoma
Myositis Ossificans (Mimic) Synovial Sarcoma
AnlerofXJsterior
(ormation
radiograph
in the soft tissues
shows
HI
amorphous
wM,
osteoid
dense periosteal
Oblique radiograph shows dense dystrophic
calcification surrounding and within a round soft tissue
II
reaction elicited in the adjacent femoral shaft •. This is mass •. Synovial sarcoma is the most frequent soft
myositis, but mimics a surface osteosarcoma. tissue sarcoma to contain calcium. rtMsK Req).
123
Q)
::> SOFT TISSUE NEOPLASM CONTAINING CALCIFICATION
(/)
(/)
t=
0:=
o
CJJ
r:
() Periosteal Chondroma (Mimic) Hemangioma, Soft Tissue
:c
0-
ro radiograph shows an
~ apparent soft tissue lesion
0>
.Q containingtumor matrix.
"0
ro causing extrinsic scalloping
0:: of the underlying humerus
"tl HI. While it mimics a 50ft
Q)
(/) tissue neoplasm, it is actually
ltl a surface lesion of bone.
al
Q)
Cl radiograph shows a 50ft
ro tissue mass containing round
E calcific densities which have
a distincllucenl center _.
These are typical phleboliths,
seen in hemangioma.
Soft Tissue Chondroma Intraarticular Chondroma

shows dense chondroid
matrix. with well-formed
rings and arcs •. The mass
was painless. but resected
because it bothered the
patient. It is typical of a 50ft
tissue chondroma. (Right)
punctate chondroid matrix
located entirely within the
Hoffa fat pad". The mass
has caused a small focal
erosion in the anterior tibia
Ill. The appearance is
typical for intraarticu/ar
chondroma.
Malignant Fibrous Histiocytoma (MFH) Liposarcoma, Soft Tissue

(Leh) Axial NEeT shows a
large subcutaneous lesion.
which contains dense
dystrophic calcification. This
is an unusual lesion, since
MFH more frequently is a
deep lesion, and only rarely
contains dystrophic
calcification. (Right) AP
radiograph shows dense 50ft
tissue calcification within a
large 50ft tissue mass. Fat
density is faintly seen
proximally and distally within
the mass Ell This is unusual
occupying the majority of a
low grade liposarcoma.
II
124
SOFT TISSUE NEOPLASM CONTAINING CALCIFICATION 3
III
to
<l>
lJl
III
VI
Osteosarcoma, Periosteal or Surface <l>
Co
Nerve Sheath Tumors (Mimic)
(Left) Axial NECT shows AI
OJ
eccentrically located C-
dystrophic calcification O
within a mass lEt· the sciatic

,
<0
OJ
nerve is not identified as a "0
::T
separate structure. A
peripheral nerve sheath
o
-l
tumor must be strongly (JJ
suspected. (Right) o
;:l>
-l
shows a tumor osteoid (ii'
located adjacent to the VI
c
humeral diaphysis" This <ll
proved to be a high grade
surface osteosarcoma,
slightly different from a
periosteal osteosarcoma.
Dystrophic Calcification within any Soft

Mesenchymal Chondrosarcoma Tissue Tumor
large soft tissue mass.
containing a chondroid
matrix and extensive
necrosis. The mass is
retroperitoneal, and does not
arise (rom the iliac wing. This
is a rare form of
dystrophic calcification ••
within a large 50ft tissue
mass which also contains fat
EliII. Biopsy showed
pleomorphic spindle cell
sarcoma. Any soft tissue
mass may contain dystrophic
calcification.
Parosteallipoma Extraskeletal Osteosarcoma

dystrophic calcification IIlI
within a large lipoma EliII.
This is a rare type of lipoma,
termed parosteallipoma,
which may elicit prominent
reactive bone formation.
osteoid matrix .:I within a
large 50ft tissue mass. in
the buttocks of an elderly
patient. There is tumor
necrosis. Extraskeletal
osteosarcoma is rare, and
tends to be seen in an older
patient age group than
conventional osteosarcoma.
II
125
'"o
::J BONE MARROW EDEMA SYNDROMES (pROXIMAL FEMUR)
Q)
'"'"
o o Failure of the tensile trabeculae
0::: o Tends to occur in older and/or physically
~ Common inactive patients
"C
Ql • Arthritis o Radiograph key to evaluate bone density
VI
l'll • Insufficiency Fracture • Osteonecrosis, Hip
CD
Ql
• Osteonecrosis, Hip o Stages of osteonecrosis
Cl
l'll
• Stress Reaction • Ill-defined subchondral and femoral
E • Stress Fracture head edema, may be mistaken for
• Metastases, Bone Marrow transient bone marrow edema
Less Common • Progresses to well-defined, slightly
• Transient Bone Marrow Edema heterogeneous lesions
• Septic Joint • May develop subchondral fracture and
• Osteomyelitis subsequently collapse
• Rapidly Destructive Osteoarthritis of Hip • Develops secondary osteoarthritis
o Tends to exclude joint space and
Rare but Important acetabulum until late stages
• Peritumoral Reactive Marrow Edema o Hint: Look at both hips; often bilateral
• Leukemia even when symptoms initially present
• Lymphoma unilaterally
• Stress Reaction
ESSENTIAL INFORMATION o Ill-defined endosteal edema parallels the
medial femoral cortex/calcar region
Key Differential Diagnosis Issues o No definable fracture
• Bone marrow edema is a nonspecific MR o Represents microtrabecular fracture along
appearance compressive trabeculae
• Presents as low signal on Tl; high signal on o Result of abnormal stress on normal bone;
T2 & fluid sensitive sequences seen in distance runners, military recruits
• Hint: Survey surrounding structures • Stress Fracture
including acetabulum, soft tissues, etc. when o Marrow edema along medial femoral neck
considering differential diagnosis and/or proximal femur may mask cortical
• Hint: Correlate appearance with patient age break
& relevant history o Cortical break often best seen on Tl MR
• Hint: Radiograph appearance will assist with o Typically located along the medial femoral
diagnosis neck and proximal femur (compressive
Helpful Clues for Common Diagnoses trabeculae)
• Arthritis o Occurs as a result of abnormal stress on
o Marrow edema often results from reactive normal bone; seen in distance runners,
marrow related to adjacent cartilage military recruits
damage • Metastases, Bone Marrow
o Most common: Osteoarthritis o Consider age, history of primary neoplasm
o Other arthropathies: Inflammatory o Lesion may be infiltrative without or with
arthritis, crystalline arthritis (gout & cortical breakthrough and soft tissue mass
CPPD), spondyloarthropathies o Hint: Lesions in lesser trochanter should
o Both femoral head and acetabulum show be considered metastatic disease until
abnormalities including joint space proven otherwise
narrowing, subchondral edema & o Hint: Look for additional osseous lesions
eburnation, subchondral cyst formation & Helpful Clues for Less Common Diagnoses
osteophytic ridging • Transient Bone Marrow Edema
• Insufficiency Fracture o Acute onset hip pain, most common in
o Typically originates in the lateral femoral
middle-age men
neck & propagates medially o Joint space normal; no arthritis present
II
126
L BONE MARROW EDEMA SYNDROMES (PROXIMAL FEMUR) 3
III
(Q
o Small joint effusion often present o Resembles a neuropathic or infected joint 'I"II
III
• Mimics septic arthritis or acute gout or • Hip aspiration needed to exclude these VI
pseudogout diagnoses '"

Q.
• Hip aspiration needed to exclude Helpful Clues for Rare Diagnoses

s::
;u
infection or crystals
o Radiograph demonstrates focal osteopenia
• Peritumoral Reactive Marrow Edema o
VI
o Reactive (non-neoplastic) marrow edema VI
of femoral head in the area surrounding a primary or
(l)
o
c
• Septic Joint secondary tumor
VI
o Joint effusion always present

o Generally associated with malignant
• Hip aspiration needed to evaluate for tumors (e.g., osteosarcoma,
infection or crystals
chondrosarcoma, giant cell tumor)
o Radiographs initially normal
o May also be seen with benign tumors such
• Develops regional osteopenia over time as osteoid osteoma
o Cortex may lose crispness or distinctness
o Edema tends to overestimate actual tumor
o Underlying arthritis may co-exist
extent; gadolinium may help distinguish
• Look for joint space narrowing, regional tumor from edema
osteopenia, erosions or osteophytes
• Leukemia
• Osteomyelitis o Most common childhood malignancy; also
o May occur as extension of septic joint,
seen in adults
hematogenous or direct implantation (e.g.,
o Nonspecific increased marrow signal on
trauma, hardware, etc.)
fluid-sensitive sequences; replaces normal
o Progressive regional osteopenia of
marrow fat on Tl
proximal femur and acetabulum;
o Radiographs are key and reveal regional or
progressive joint space loss
diffuse osteopenia; band-like metaphyseal
o Hint: Look for soft tissues changes such as
lucent zone
cellulitis, abscess or sinus tract
• Diffuse osteopenia, metaphyseal
• Rapidly Destructive Osteoarthritis of Hip
radiolucent bands; osteolysis; periostitis
o Rapid dissolution of hip joint over weeks
• Lymphoma
to months
o May be so infiltrative as to appear only as
• Femoral head flattening and lateral
osteopenia on radiograph
subluxation
o Nonspecific marrow signal on MR, as in
• Joint space loss, subchondral cysts,
leukemia
sclerosis of both sides of joint
• Osteophytes uncommon
Arthritis Insufficiency Fracture
Coronal T2WI FS MR shows cartilage thinning III &

subchondral edema 11:I of acetabulum & femoral head,
Coronal STIR MR shows intense edema of femoral
head/neck IlII with fool f1allening of the articular
II
so called "kissing" lesions. Ring osteophytes HI encircle surface & low signal of subchondral fracture _.
the femoral neck in this patient with osteoarthritis. Surrounding soft tissue edema is also noted Ell.
127
en BONE MARROW EDEMA SYNDROMES (PROXIMAL FEMUR)
::>
o
Q)
en
en
o
0::
~
Osteonecrosis. Hip Stress Reaction
"t:l
Q) (Left) Coronal STIR MR
en shows crescentic
01
1Il subchondral high signal ••
Q) in the right hip with no
Ol
01 associated arthritis. Subtle
E signal abnormality suggesting
AVN is also present in the
anterior left femoral head
HI. (RighI) Coronal T2WI FS
MR shows high signal along
rhe medial femoral neck ••
without a discrete fracture
line. The locarion &
orientation of this signal
indicates stress reaction,
rather than stress fracture.
Stress Fracture Metastases, Bone Marrow

shows foea/linear low signal
~ in the medial femoral
neck with extensive
surrounding edema _
typical of an acure
basicervical stress fracture.
(Right) Axial STIR MR shows
marrow infiltration Ell in the
left femoral neck wirh diffuse
signal but no obvious
cortical destruction. A
second lesion" in rhe right
symphysis shows cortical
break in this patient with
prostate metastases.
Transient Bone Marrow Edema Transient Bone Marrow Edema

shows intense edema in right
femoral head & neck HI
with acute onset hip pain 6
weeks prior. There is no
cartilage loss or arthritis. The
acetabulum is normal. Small
joint effusion" is typical of
rransient edema. (RighI)
in the same patient as
previous image, reveals focal
osteopenia HI of the femoral
head & neck with a normal
adjacent acetabulum. Hip
aspirate was normal.
II
128
BONE MARROW EDEMA SYNDROMES (PROXIMAL FEMUR) 3
Dl
(Q
<D
lD
Dl
CII
<D
0-
Septic Joint Osteomyelitis
(Left) Coronal STIR MR s:
shows moderate right hip ;;0
joint effusion. with o
en
arthritis. There is mild en
femoral head reactive CD
o
marrow edema _ Hip c
en
aspirate yielded
Staphylococcus aureus.
(Right) Coronal T2WI MR
shows Girdles tone
arthroplasty following
infection of THA. Prosthesis
is removed & replaced by
multiple antibiotic-
impregnated beads EllI.
Intense edema of proximal
femoral shaft" confirms
ongoing osteomyelitis.
Rapidly Destructive Osteoarthritis of Hip Rapidly Destructive Osteoarthritis of Hip

shows edema in the
collapsed & distorted right
femoral head" as well as
the adjacent acetabulum a.
Note the right iliacus fluid
Ell which is an extension of
a large debris-filled iliopsoas
bursal effusion. (Right)
obtained 1 month earlier,
during an arthrogram _
shows moderate
osteoarthritis with joint space
narrowing, subchondral
eburnation & cyst {ormation
•. Note the spherical
femoral head.
Peritumoral Reactive Marrow Edema Peritumoral Reactive Marrow Edema

shows a moderate joint
effusion Ell in this 17 yo.
Diffuse marrow edema IIll
involves neck &
subtrochanteric femur.
Calcar buttressing is present
_ This is confusing, until
CT is seen (next image).
(Right) Axial NECT in the
same patient, reveals an
osteoid osteoma. This lytic
lesion with central
radiodens€nidus. incites
an intense reactive marrow
edema on MR which may
obscure underlying tumor.
(tMSK Req).
II
129
C/)
::l SUBCHONDRAL EDEMATOUS-LIKESIGNAL
o
Q)
C/)
C/)
o DIFFERENTIAL DIAGNOSIS o Osteochondral fragment may stay in place,
0::: become flattened, or become completely
:2 Common loose & displaced
"0
Ql • Trauma • Reactive Marrow Edema
l/l
co o Bone Bruise o Bone & adjacent cartilage normal but
II)
Ql
o Osteochondral Fracture adjacent tissues are not (e.g., meniscal tear)
Cl
co o Reactive Marrow Edema • Arthritis
E • Arthritis o Osteoarthritis: Cartilage loss; osteophytes
o Osteoarthritis o Inflammatory: Marrow edema ± cartilage
o Inflammatory Arthritis defects; effusions; erosions
o Crystalline Arthropathy o Crystalline: Crystals penetrating
• Insufficiency Fracture cartilage/subchondral bone with resultant
• Osteonecrosis edema; ± erosions or osteophytes
less Common • Insufficiency Fracture
• Transient Bone Marrow Edema Syndrome o Intense edema out of proportion to
• Septic Joint arthritis; may obscure fracture line
• Osteomyelitis • Osteonecrosis
o Subchondral edema may progress to
• Peritumoral Edema
hemorrhage & fluid in fracture/collapse
stage; late subchondral edema from
ESSENTIAL INFORMATION cartilage loss & secondary OA
Key Differential Diagnosis Issues Helpful Clues for less Common Diagnoses
• Signal intensity: Hypointense Tl WI; • Transient Bone Marrow Edema Syndrome
hyperintense T2WI, STIR just deep to o Diagnosis of exclusion; acute onset pain,
osteochondral interface typically in middle aged men
Helpful Clues for Common Diagnoses • Septic Joint vs. Osteomyelitis
o Septic joint: Effusion, synovial thickening
• Bone Bruise
o Compression or impaction injury o Osteomyelitis: Edema on one side of joint,
o Hint: Look for associated soft tissue injury marginal erosions, periostitis
• Osteochondral Fracture • Peritumoral Edema
o Injury crossing chondral plate into o Osteoid osteoma, giant cell tumor,
adjacent subchondral bone malignant tumors such as osteosarcoma &

chondrosarcoma
Bone Bruise
II Axial STIR MR shows subchondral edema in the laleral

femoral condyle iii & poslerolalerallibial plaleau •.
Coronal STIR MR shows a small hyperinlense area in
the lalar subchondral bone III with adjacent hyaline
There is a large join! effusion • & ACL lear (nol carljfage injury iii. An ATFL lear (nol shown) is
shown). This bruise pal/ern is common with ACL injury. accompanied by a small join! effusion. in this injury.
130
SUBCHONDRAL EDEMATOUS-LIKE SIGNAL 3
III
to
ell
OJ
III
VI
ell
C.
Reactive Marrow Edema Arthritis
(Left) Coronal PO FSf FS MR s:
shows subtle reactive
;0
marrow edema II in patient o
VI
with medical meniscal tear VI
Cll
(not shown). Note the intact o
cartilage. There was no c:
C/l
cartilage damage at surgery.
(Right) Axial T7 C+ FS MR
shows edema in the lateral
patella & extensive
prepatellar 50ft tissue
swelling Ell. There is a joint
effusion with synovial
enhancement III A small
non-displaced fracture has
occurred through a gouty
erosion ffi
Insufficiency Fracture
(Left) Sagittal PO FSf MR
shows hypointense posterior
lateral femoral condylar
signal. paralleling the
articular surface with slight
flattening of the articular
surface due to an
insufficiency fracture. (Right)
Coronal PO FSf F5 MR
shows high signal within
multiple carpal bones. &
multiple joint effusions with
synovial thickening Ell. This
proved to be Staphylococcus
septic arthritis.
Osteomyelitis Peritumoral Edema

shows high signal at multiple
subchondral sites within the
pelvis (sacral ala III & iliac
wing III) in a child with
normal radiograph. Biopsy
proved chronic multifocal
osteomyelitis. (Right) Sagittal
TlWI FS MR shows a mildly
expansile hyperintense
patellar lesion. with a thin
rim and no cortical
breakthrough. The bone
adjacent to this giant cell
tumor demonstrates
non-neoplastic peritumoral
edema Ell
II
131
en ABNORMAL EPIPHYSEAL MARROW SIGNAL
:::l
o
Q)
en
en
o DIFFERENTIAL DIAGNOSIS o History of acute or subacute trauma
a::: o Hint: Look for adjacent soft tissue injury
~ Common • Fracture
"t:l
Q)
• Reactive Marrow Edema o Intense diffuse edema may obscure
en
ra • Bone Bruise fracture line
a:l • Fracture
Q) o Traumatic - Hint: Look for adjacent soft
Cl • Osteonecrosis
ra tissue injury
E • Transient Bone Marrow Edema o Insufficiency - Hint: Look for articular
• Legg-Calve-Perthes surface flattening
• Osteomyelitis • Osteonecrosis
• Septic Joint o Serpentine margin between normal &
• Arthritis avascular bone
o Osteoarthritis o "Double line" sign: Outer margin low
o Inflammatory Arthritis . signal while inner margin high signal
o Juvenile Idiopathic Arthritis OIA) • Transient Bone Marrow Edema
Less Common o Diagnosis of exclusion; may require hip
• Anemia aspiration to exclude septic arthritis
• Neoplasm o History is key: No trauma, minimal
o Metastases, Bone Marrow arthritis, acute onset
o Primary Bone Neoplasm • Legg-Calve-Perthes
• Stem Cell Stimulation o Edema which may progress to femoral
head low signal & flattening
Rare but Important o Small femoral ossification center;
• Myelofibrosis thickened articular cartilage
• Gaucher Disease o Boys> girls; age 4-8 at risk as foveal
arteries regress
ESSENTIAL INFORMATION • Osteomyelitis
o May be difficult to distinguish from septic
Key Differential Diagnosis Issues joint in early stages
• Epiphyses convert to fatty (yellow) marrow o Marrow edema on one side of joint,
before 1 year of age marginal erosions, periostitis; ± bone or
• Abnormal epiphyseal marrow defined as soft tissue abscess
change in normal fatty signal o Brodie abscess: Abscesses may be
o Normal: Tl WI - hyperintense; T2WI - epiphyseal or in carpals/tarsals in infants;
intermediate; fat-suppression - meta-epiphyseal in children
hypointense • Septic Joint
• Differential diagnoses include epiphysis, o Effusion, synovial thickening, ± adjacent
apophyses or epiphyseal equivalent (carpals, marrow edema
tarsals) • Arthritis
• Other differentials may be tailored to o Osteoarthritis: Cartilage loss, osteophytes,
location, such as proximal femur subchondral edema &/or cysts
Helpful Clues for Common Diagnoses o Inflammatory: Marrow edema, effusion, ±
• Reactive Marrow Edema erosions, ± cartilage loss
o Marrow edema typically related to o Juvenile idiopathic: Soft tissue swelling,
adjacent abnormality (e.g., tendon or periostitis, erosions are late finding
meniscal tear) Helpful Clues for Less Common Diagnoses
o No history of direct trauma; no cartilage
• Anemia
damage, infection or neoplasm o Marrow undergoes reconversion from fatty
• Bone Bruise to hematopoietic marrow in an orderly
o Marrow contusion related to fashion
microtrabecular fracture
II
132
ABNORMAL EPIPHYSEAL MARROW SIGNAL 3
III
(C
C1l
o Epiphyses are last to reconvert; thus o Fibrosis most common in areas of normal OJ
III
epiphyseal involvement is indicative of adult hematopoiesis (spine, pelvis, ribs) <II
C1l
chronic long standing anemia o Associated anemia results in reconversion Q.
o Sickle cell anemia & thalassemia at risk for of fatty marrow including epiphyses s:
;u
osteonecrosis o Epiphyses subsequently become fibrotic
with trabecular thickening & sclerosis
o
• Neoplasm <II
<II
<1>
o May be primaq or secondary (metastatic) • Gaucher Disease o
C
o Epiphyseal involvement is less common o Marrow packing disorder results in anemia, <II
than meta diaphyseal undertubulation, osteonecrosis, osteopenia

o Marrow replacement may be patchy or o Associated anemia results in reconversion
diffuse of fatty marrow including epiphyses
o ± Cortical breakthrough with associated o Undertubulation: Erlenmeyer flask
soft tissue mass deformity, cortical thinning
o Hint: Age is a useful determinate o Osteonecrosis of epiphyses, metaphyses &
• Child: Leukemia, metastases, diaphyses as well as axial skeleton
chondroblastoma o Osteopenic: At risk for fractures
• Young adult: Giant cell tumor, leukemia, o Most common in Ashkenazi Jews
lymphoma Alternative Differential Approaches
• Older adult: Metastases, lymphoma, • Adult Versus Child
leukemia, clear cell chondrosarcoma o Adult
• Stem Cell Stimulation • Trauma, osteonecrosis, transient bone
o Medication related: Erythropoietin,
marrow edema syndrome, osteomyelitis,
Neupogen arthritis, metastases, multiple myeloma,
o Facilitates stem cell repopulation; often
lymphoma, giant cell tumor, stem cell
used in conjunction with chemotherapy stimulation, myelofibrosis, Gaucher
o Marrow reconversion is patchy & can
disease
mimic metastatic disease
o Child
o In- & out-of-phase imaging may help
• Trauma, Legg-Calve-Perthes,
distinguish normal hematopoiesis from
osteomyelitis, juvenile idiopathic
metastatic infiltration
arthritis, leukemia, lymphoma,
Helpful Clues for Rare Diagnoses chondroblastoma, stem cell stimulation,
• Myelofibrosis Gaucher disease
Reactive Marrow Edema Fracture
at the posterior meniscal root =

Coronal STIR MR shows a radial medial meniscus tear
with adjacent
epiphyseal reactive marrow edema EEl. The ligaments &
Axial PO FSE FS MR shows an impaction fracture of the
medial patellar facet EEl with a bone bruise of the distal
lateral femoral condyle lEI in this patient with transient
II
cartilage were normal at arthroscopy. lateral patellar dislocation.
133
lI)
::> ABNORMAL EPIPHYSEAL MARROW SIGNAL
o
Q)
lI)
lI)
o
0::
~
"
Gl
lI)
III
shows a serpentine udouble
lD line" sign of avascular
Gl necrosis with outer low HI &
en inner high II signal intensity
III
E marking the avascular
region. Note adjacent
reactive marrow edema _.
=
shows diffuse marrow
in the lateral femoral
condyle. Prior his lOry of
edema
similar process in the medial

femoral condyle which
resolved about 3 months
prior to this presentation
represents the migratory
(orm of this process.
Osteomyelitis
shows capital femoral
epiphysis flattening with a
well-demarcated
hypointense III ischemic
area in Legg-Calve-Perches.
Mild coxa magna deformity
is present (Right) Coronal
STIR MR shows diffuse
metaphysis =
edema of epiphysis &
with a
discrete rim·enhancing lesion
III spanning the physis,
representing a subacute
osteomyelitis/Brodie abscess.
There is mild periosteal
edema Ell.
Osteoarthritis Juvenile Idiopathic Arthritis (JIA)

shows typical endstage
osteoarthritis (R> L) with
joint space loss, femoral
head flattening, acetabular
remodeling, & subchondral
=(epiphyseal) marrow edema

Involvement of both
sides of the joint'" &
osteophytic ridging Ell assist
in diagnosis. (Right) Coronal
T2WI MR shows dramatic
diffuse marrow edema
throughout the carpals
(epiphyseal equivalent) with
extensive synovitis Ell &
multiple erosions" (a late
finding in f/A).
II
134
ABNORMAL EPIPHYSEAL MARROW SIGNAL 3
III
u:l
<l>
OJ
III
IJl
<l>
Co
Anemia Metastases, Bone Marrow
(Left) Coronal T2WI MR ~
shows absence of normal
;0
fatly marrow signal. This o
IJl
sickle cell patient's marrow is IJl
(\)
fully hematopoietic including o
the normal fatty epiphyses C
IJl
ElII. Note left femoral head
avascular necrosis with
=-
edema, flattening & collapse
(Right) Axial Tf C+ FS
MR shows a renal cell
metastatic lesion in the
trochlear epiphyseal region
with marrow replacement
ElII & cortical breakthrough
• with a soft tissue mass III
in the joint. Moderate
enhancement is present.
Primary Bone Neoplasm

(Left) Coronal Tf C+ FS MR
shows a well-circumscribed
enhancing tibial epiphyseal
lesion HI with intense
peritumoral edema III. The
cartilage lobules IIIas well
as the location are typical in
this chondrobJastoma.
(Right) Coronal PO FSf MR
shows a large low signal
meta-epiphyseal lesion
bone. The low signal is due
to inlralesional calcification
in this giant cell tumor Note
the pathological fracture in
the lateral tibial plateau 1IlI.
(Left) Coronal Tf WI MR
shows bland intermediate
marrow replacement
including the epiphyses,
which are normally high
signal on Tf WI. This is
fibrotic marrow typical of
myelofibrosis. Note the small
islands or retained normal fat
•. (Right) Coronal Tf WI
MR shows slightly speckled,
intermediate
Gaucher infiltration
is complicated by
=-
signal of diffuse
This
osteonecrosis HI of the
femoral head, neck &
acetabulum.
II
135
rJ)
:J INCREASED MARROW FAT
o
Q)
rJ)
rJ)
o DIFFERENTIAL DIAGNOSIS o Primary trabecular struts thicken as
cr secondary trabeculae are resorbed
:2; Common o May be diffuse or focal
"0
Q) • Osteoporosis • Normal Aging
rJ)
• Normal Aging o Diffuse increased yellow marrow in aging
'"
aJ
• Focal Fatty Deposition
Q) population
Cl
• Discogenic Endplate Changes o Retains hematopoietic elements in
E'" proximal femurs, flat bones of pelvis &
Less Common
• Intraosseous Hemangioma spine longer than in the extremities
• Intraosseous Lipoma o Minimal osteopenia by radiograph
• Steroid-Induced Increased Fat • Focal Fatty Deposition
• Radiation-Induced Increased Fat o Typically visible in those of advancing age
• Osteonecrosis o Tend to be rounded and discrete lesions in
the vertebral bodies but can involve entire
Rare but Important
vertebral body
• Bone Marrow Failure o Trabeculae are normal within and around
• Anorexia the lesion
• Liposclerosing Myxofibrous Tumor o T2 signal may be low, intermediate, or
• Hypopituitarism high SI
• Weightlessness • Discogenic Endplate Changes
o Degenerative changes in vertebral end plate
ESSENTIAL INFORMATION resulting from red marrow being replaced
by fatty yellow marrow
Key Differential Diagnosis Issues o Also known as Modic type 2 changes
• Increased marrow fat may be focal or diffuse o Modic degenerative end plate types
o Represents either a true increase in fat or a
• Type 1: Low SI T1 and high SI T2
marked decrease in hematopoietic marrow • Type 2: High SI Tl and isointense SI T2
elements
• Type 3: Low SI T1 and T2
• Normal adult marrow
o Hematopoietic (red) marrow content: 40% Helpful Clues for Less Common Diagnoses
fat, 40% water, 20% protein • Intraosseous Hemangioma
• Intermediate signal intensity (SI) on T1, o Most common in vertebra and skull
T2 & fluid-sensitive sequences o High SI T1 due to fat in interstices of
o Fatty (yellow) marrow content: 80% fat, tumor
15% water, 5% protein o High SI T2 due to vascular components
• High SI on T1 and interstitial edema
• Lower SI on T2 & fluid-sensitive o Mayor may not enhance
sequences o Radiographs show intralesional vertical
• Normal red vs. yellow marrow distribution striations due to thickened trabeculae
o Predominantly red marrow at birth • Intraosseous Lipoma
o Epiphyses/apophyses convert to yellow o Most common in proximal femur and
marrow in 1st year of life calcaneus
o Red to yellow marrow proceeds distal to o Appears predominantly high SI while
proximal; appendicular to axial skeleton adipocytes viable but becomes cystic with
• Hint: Radiographs may be useful in dystrophic calcification as it evolves due to
differential diagnosis ischemia and necrosis
o Radiographs show well-circumscribed,
Helpful Clues for Common Diagnoses mildly expansile lucent lesion with
• Osteoporosis variable dystrophic calcification
o Pronounced osteopenia may be confirmed
• Steroid-Induced Increased Fat
by radiograph o Corticosteroids shown to actually enlarge
the adipocytes
II
136
INCREASED MARROW FAT 3
III
(0
<1>
o At increased risk for AVN, insufficiency • Anorexia III
III
fractures o Radiographs show marked osteopenia VI
<1>
o Hint: Look for fat deposition in o Hint: Look for marked soft tissue and Co
surrounding soft tissues muscle wasting s:

;0
• Radiation-Induced Increased Fat • Liposclerosing Myxofibrous Tumor
o Benign fibroosseous tumor with mixed
o
o Complete loss of hematopoietic elements VI
VI
<1>
accounts for apparent increase in marrow content which may include lipoma, o
c
fat myxoma, fibrous dysplasia, fat necrosis VI
o Hint: Distinct transition between and ossification in varying amounts

irradiated and nonirradiated marrow • Hypopituitarism
o Hint: Look for radiation changes in o Findings similar to bone marrow failure
surrounding soft tissues • Weightlessness
• Osteonecrosis o Long periods of weightlessness result in
o High SI T1 seen in early infarction as diffuse (disuse) osteoporosis
adipocytes are the last to die following Alternative Differential Approaches
acute ischemic event • Diffuse increased marrow fat
o High SI T1 in chronic stages may
o Osteoporosis
represents mummified fat cells or fatty o Normal aging
replacement of fibrosis o Steroid-induced increased fat
o Hint: Look for serpentine margin
o Bone marrow failure
bordering necrotic area o Anorexia
o Hint: Double line sign represents interface
o Hypopituitarism
between necrotic and reparative marrow o Weightlessness
Helpful Clues for Rare Diagnoses • Focal increased marrow fat
• Bone Marrow Failure o Focal fatty marrow
o Includes acquired (aplastic anemia and o Discogenic fatty deposition
myelodysplastic syndromes) and inherited o Intraosseous hemangioma
(Fanconi anemia, etc.) o Radiation-induced increased fat
o Profound depletion of hematopoietic o Intraosseous lipoma
elements o Osteonecrosis
o Appearance similar to radiation changes
but without discrete transition between
normal and depleted marrow
Sagittal PO FSE MR shows 1055 of secondary trabeculae.

reinforced primary trabeculae (bone struts) •• and
Coronal T1WI MR shows fatty marrow distribution in a
normal 70 year old man with patchy intermediate signal
II
increased marrow fat, typical of OSleo(XJfOSis in this 86 red marrow" in intertrochantericand subtrochanteric
year old woman. bone; yellow marrow &I in all other osseous regions.
137
1Il
:::l INCREASED MARROW FAT
o
Q)
1Il
1Il
o
0:::
~
Focal Fatty Deposition
~Q) (Left) Sagillal T7WI MR
1Il
Ol shows focal rounded high
III signal area. in left
Q) paracentral L3 vertebra with
Cl
Ol a normal trabecular pattern
E within and around the area~
typical of focal fally deposit.
This was also bright on T2WI
(not shown). (Right) Sagittal
T7 WI MR shows the
significant disc height loss
and endplate irregularity of
degenerative disc disease
ElII. The high signal of fatty
marrow in the adjacent
endplates.:l is seen in
endstage discogenic
changes.
(Left) Sagillal T7WI MR

shows mixed high signal.
of fally infiltration admixed
with low signal, representing
the trabecular thickening
often seen in osseous
hemangioma. This lesion was
high signal in T2WI (not
shown). (Right) Axial T2WI
MR shows the extent of this
focal high signal lesion ElII in
this thoracic inlraosseous
hemangioma in the same
patient. Note the punctate
appearance of the low signal
thickened trabecular struts
ilia seen in cross-section.
Intraosseous Lipoma Steroid-Induced Increased Fat

shows a well-defined fat
signal intensity lesion ElII
with central low signal.
intensity due 10
mineralization. This is typical
of intraosseous lipoma. The
calcaneus and proximal
femur are common locations
for this lesion. (Right)
Coronal T7WI MR shows
diffuse increased marrow fat
in left hip of a patient treated
with corticosteroids for renal
transplantation •. Note the
crescent·shaped signal in
femoral head" suggesting
early AVN.
II
138
INCREASED MARROW FAT 3
Ql
to
lD
[ll
Ql
tII
lD
Co
(Left) Sagittal T/ WI MR s:
shows diffuse increased
;:0
signal in the lumbar spine o
and sacrum with sharp
demarcation between
''""
C1l
o
irradiated and non-irradiated c
bone at the T/2-L7 level E!lI. '"
Note two associated
insufficiency fractures =.
(Right) Coronal T/WI MR
shows increased (atty
marrow HI in the Femoral
shaft, surrounded by a thin,
serpentine rim of calcium
(low signal, IDI. This is
chronic bone infarction in
Gaucher disease.
(Left) Sagittal T/ WI MR
shows a paucity of cellular
elements in this 68 year old
with aplastic anemia. This
results in an apparent
increase in marrow fat. Note
the prominent basivertebral
plexus =. (Right) Sagittal
T/ WI MR reveals diffuse
increased fatty marrow in a
patient status post L4-5
anterior Fusion•. There is a
paucity of subcutaneous fat
iii in this anorexic female
who is 4'/0" & weighs 78
pounds.

(Left) Axial T/ WI MR shows
well-circumscribed,
non-aggressive, lesion 11:I in
posterior subcapital femur
with thin sclerotic margin
and slight heterogeneity but
no cortical breakthrough,
confirmed to be an LSMFT
by biopsy. (Right)
AP radiograph, in a different
patient, shows the more
typical location
(intertrochanteric) and
appearance (geographic
with sclerotic margin and
subtle internal mineralization
=J ofa LSMFT.
II
139
en MARROW HYPERPLASIA
:::J
o
(!)
en
en
o DIFFERENTIAL DIAGNOSIS o Osteopenia often a key radiographic
e::: feature
:2: Common o Selected types of anemia are discussed
"'C
Ql • Anemia below
en
• Complications of Smoking • Complications of Smoking
'"
II)
• Sports Anemia
Ql o Seen in smokers; mild to moderate obesity;
Cl
• Sickle Cell Anemia: MSK Complications female> male
'E" • Thalassemia o Etiology unknown; mild leukocytosis
less Common noted
• Hematopoietic Stimulation o Patchy reconversion marrow in distal
• Polycythemia Vera femoral metaphysis
• Leukemia • Sports Anemia
• Myelofibrosis o Seen in marathon runners & other
high-performance athletes
Rare but Important
o Group known to have chronic low grade
• Anti-Viral Drug Effect anemia of uncertain etiology
• Spherocytosis o Patchy metaphyseal hematopoiesis in
distal femur/proximal tibia with
ESSENTIAL INFORMATION epiphyseal sparing
• Sickle Cell Anemia: MSK Complications
Key Differential Diagnosis Issues o Inherited anemia
• Marrow hyperplasia results from an increase o Radiographs: Osteopenia, widening of
in one or more marrow cell lines including medullary spaces, trabecular & cortical
RBC, WBC, platelets or their precursors thinning
• Hematopoietic (red or cellular) versus fatty o MR: Widespread marrow reconversion or
(yellow) marrow failure of initial red to yellow marrow
• Marrow appearance should be age conversion
appropriate o Bone infarction more common than in
o Predominantly red marrow at birth thalassemia
o Epiphyses/apophyses convert to yellow
• Thalassemia
marrow in 1st year o Inherited anemia
o Red to yellow marrow conversion proceeds
o MR: Marked increased hematopoietic
from distal to proximal; appendicular to marrow may include epiphyses
axial skeleton o Radiographs: Osteopenia, widened
• Hint: In diffuse hyperplasia, look for medullary space, cortical thinning,
"flip-flop" sign-vertebral body marrow darker coarsened trabeculae, Erlenmeyer flask
than adjacent discs on T1 WI deformity
Helpful Clues for Common Diagnoses o Bone scan: Generalized decreased uptake
• Anemia Helpful Clues for less Common Diagnoses
o Three main classes: Acute loss, excessive
• Hematopoietic Stimulation
destruction, decreased production o Marrow stem cell stimulation (e.g.,
o Marrow capable of response will do so in
erythrocyte or granulocyte
predictable pattern colony-stimulating factor)
• Fatty marrow "re-converted" to red o Used in chemotherapy, anemia of chronic
marrow in reverse order disease, renal disease
• Reconversion proceeds from axial to o Typically stimulates somewhat patchy
appendicular skeleton; proximal to distal reconversion of marrow which may
long bones simulate metastatic disease
• Epiphyses/apophyses recruit late in • Hint: In- & out-of-phase imaging may
process help distinguish normal versus
neoplastic marrow
II
140
MARROW HYPERPLASIA 3
III
to
ID
o Reconversion proceeds axial to • Chronic: Osteopenia, may progress to OJ
III
appendicular, proximal to distal, ± myelofibrosis, diffuse marrow infiltration <II
ID
Co
epiphyseal involvement • Myelofibrosis
• Polycythemia Vera o Chronic myeloproliferative disease s:
;0
o Erythrocytosis, leukocytosis, o Cellularity varies ranging from
hypercellularity to marked hypocellularity
o
thrombocytosis affects older adults <II
<II
ID
o Marrow reconversion in proximal long as fibrosis worsens o
C
bones typically spares o Marrow infiltration typically follows <II
epiphyses/apophyses until late stage reconversion pattern: Axial to

o Femoral osteonecrosis due to vascular appendicular, proximal to distal, epiphyses
thrombosis spared until late
o May evolve to myelofibrosis over time o Progresses to osteosclerosis
o Hyperuricemia may present as gouty o Massive splenomegaly is key finding
arthritis Helpful Clues for Rare Diagnoses
• Leukemia • Anti-Viral Drug Effect
o Neoplastic proliferation of one or more
o Anti retroviral medications in HIV
marrow cell lines population
o Children
o Significant drug-related osteopenia
• Acute lymphocytic leukemia (ALL)most o HIV-associated avascular necrosis
common o Anemia results in marrow reconversion
• Osteopenia with metaphyseal sclerotic o Look for myositis in combination with
bands, osteolytic lesions, periostitis significant marrow reconversion
• Marrow hyperplasia from disease & • Spherocytosis
associated anemia; may be focal or o Inherited hemolytic anemia with onset in
diffuse early adolescence
o Adults
o Marrow fails to convert from red to yellow
• Acute myelocytic leukemia (AML) most marrow
common o Osteopenia, cortical thinning,
• Acute: Bone pain, rheumatoid-like extramedullary hematopoiesis
arthritis may be present, diffuse marrow
infiltration
• Chronic lymphocytic leukemia (CLL)
most common
Coronal T 1WI MR shows extensive hematopoiesis HI

the knee metadiaphyses with partial replacement of the
in Coronal STIR MR shows islands of reconverted red
marrow HI in the distal femoral metaphysis. Note the
II
normal epiphyseal fatty marrow ~ as well. Patient has body habitus =:I in this 36 year old female smoker.
known hemolytic anemia.
141
'"
::>
o
MARROW HYPERPLASIA
Q)
o'"'"
a:::
~
Sports Anemia Sports Anemia
"0
Q) (Left) Sagittal PO FSE FS MR
'" shows patchy, somewhat
=
I'll
CO striated intermediate signal
Q) in the distal femoral
Cl
I'll metaphysis representing
E reconversion marrow in this
27 year old marathon
runner. (Right) Sagittal STIR
=
MR shows a stress fracture
of the plantar calcaneus.
The marrow shows diffuse
intermediate marrow signal
BI. This is related to
significant marrow
hyperplasia in this 2S year
old anorexic female who
runs to "control her weight".
Sickle Cell Anemia: MSK Complications Sickle Cell Anemia: MSK Complications
shows fatty marrow
replacement in the pelvis &
signal =
proximal femur BI. High
results from an
apophyseal bone infarction
in this sickle cell patient.
Epiphyseal fatty marrow !lIEI
is still present. (Right)
Sagittal TI WI MR shows
homogeneous vertebral body
signal lower than adjacent
discs, related to patient's
sickle cell anemia &
hemosiderin from multiple
transfusions. Vertebral body
signal should be higher than
discs on T 7 sequence.
the radiographic pattern of
marrow hyperplasia in this
11 year old thalassemic.
Cortical thinning, "squaring"
of small hand bones &
profound osteopenia BI are
due to a marrow space
packed with cells. (tMSK
Req). (Right) Lateral
radiograph shows medullary
(diploic) space widening &
trabecular thickening
resulting in "hair on end"
appearance.
II
142
MARROW HYPERPLASIA 3
Ql
to
<1l
[Jl
Ql
IJl
<1l
0.
(Left) Coronal TI WI MR :;::

shows reconversion of
;:0
yellow to red marrow o
C/l
throughout the proximal C/l
femurs. & pelvis/spine Ell C1>
o
in response to erythropoietin c:
C/l
therapy for
chemotherapy-related
anemia. (Right) Coronal
TI WI MR shows diffuse,
intermediate-signal marrow
replacement. of the
femoral metadiaphyses with
epiphyseal sparing Ell. This
signal is a combination of
marrow hyperplasia &
developing fibrosis in this 66
year old.
leukemia leukemia
(Left) Coronal TtWI MR
shows profound marrow
hyperplasia with bland
intermediate signal marrow
Ell in all visualized bones.
Note the marked
lymphadenopathy E±J in this
case of chronic lymphocytic
leukemia in this 75 year old.
(Right) Coronal TlWI MR
shows diffuse leukemic
infiltration with hypointense
meta diaphyses •• & patchy
epiphyseal involvement Ell.
Note the similarity to the first
image in this series,
hemolytic anemia. Clinical
history is key in diagnosis.
(Left) 5agiLtai TI WI MR
shows typical diffuse dark T I
marrow of myelofibrosis.
This results from a mix of
hypercellularity & developing
fibrosis. Note vertebral
bodies are darker Ell than
discs. the so-called
"flip-flop" sign. (Right)
5agittal TlWI MR shows
profound diffuse marrow
hyperplasia with only a few
remnants of normal marrow
fat at the endplates • &
basivertebral plexus Ell. This
is multifactorial due to AtD5
& long term anti-viral therapy
in this 52 year old.
II
143
(/l
:J BONE LESIONS WITH FLUID/FLUID LEVELS
o
Q)
(/l
(/l
o DIFFERENTIAL DIAGNOSIS o Less permeative appearance than
a::: conventional osteosarcoma
2 Common o Can be entirely lytic and mimic ABC
"tl
Ql
• Aneurysmal Bone Cyst (ABC) o Watch for any hint of aggressiveness
(/l
C1l • Osteosarcoma, Telangiectatic
00 Helpful Clues for Less Common Diagnoses
Ql
0)
Less Common • Giant Cell Tumor (GCT)
C1l • Giant Cell Tumor (GCT) o Expansile subchondral lesion in skeletally
E
• Unicameral Bone Cyst mature patient lacking a sclerotic border
• Chondroblastoma o May coexist with aneurysmal bone cyst
Rare but Important • Unicameral Bone Cyst
• Hyperparathyroidism, Brown Tumor o Centrally located, well-defined, lytic lesion
• Teratoma, Sacrococcygeal o Fluid-filled cavity; "fallen fragment" sign
• Osteoblastoma o Mild or no bone expansion

• Chondroblastoma
o Lytic epiphyseal lesion with sclerotic
ESSENTIAL INFORMATION margin in skeletally immature patient
• Fluid-fluid levels can be present in benign • Hyperparathyroidism, Brown Tumor
and malignant entities o Lytic, expansile lesion without matrix
• Hint: A high proportion of fluid-fluid levels o Classic term "osteitis fibrosis cystica" better
have been suggested to favor a benign describes cystic appearance of tHis reactive
process, but this finding should never be giant cell lesion from hyperparathyroidism
relied upon for diagnosis • Teratoma, Sacrococcygeal
Helpful Clues for Common Diagnoses o Mixed solid and cystic lesion with
• Aneurysmal Bone Cyst (ABC) enhancement of solid areas

o Expansile, lytic lesion with septations & o Large sacral mass with components of all 3
and fluid-fluid levels, usually in long bone germ cell layers

o Majority of patients < 20 years old • Fluid, soft tissue, fat, bone, teeth, hair
• Osteosarcoma, Telangiectatic • Osteoblastoma
o Aggressive features such as periosteal o Circumscribed, lytic lesion with reactive
reaction, cortical breakthrough and soft sclerosis and variable calcification/matrix

tissue mass may not always be present o Fluid-fluid levels are rare unless due to
secondary aneurysmal bone cyst
Aneurysmal Bone Cyst (ABCl Osteosarcoma, Telangiectatic
II Axial T2WI MR shows an expansile mass involving

posterior elements of CJ ElIl which has mixed signal,
with low signal areas as well as many cysUc-appearinf}
=
Axial T2WI MR shows a mixed intensity lesion EllI in the
distal femur. Fluid-fluid levels without a soft tissue
mass suggested aneurysmal bone cyst but pathology
high signal regions w/fluid-fluid levels" (t MSK Req). revealed telangiectatic osteosarcoma.
144
BONE LESIONS WITH flUID/flUID LEVElS 3
III
CO
C1l
[II
III
III
C1l
C.
Osteosarcoma, Telangiectatic
(Left) Axial T2WI MR shows ~
a distal femo,allesion with ::0
aggressive features including o
en
cortical breakthrough & soft en
tissue mass EilI. It has high CO
o
signal areas which appear c
en
lobulated and a few fluid
levels=. Regions without
fluid levels & the cortical
breakthrough alert one that
this is not ABC. (t MSK Req).
shows a multiloculated,
expansile mass iii in distal
tibia extending into posterior
fluid-fluid levels=
sofllissues. Scattered
present in this GCT.

are
Unicameral Bone Cyst Chondroblastoma

shows a cystic lesion in the
calcaneus EilI. A fluid-fluid
level ~ is frequently seen in
bone cysts. A post-contrast
image demonstrated an
enhancing rim around the
low signal central fluid
collection. (Right) Sagittal
T2WI FS MR shows a
skeletally immature patient
with an epiphyseal lesion EilI
having a rather lobulated
cartilaginous appearance as
well as fluid-fluid levels =.
The latter are uncommon in
chondroblastoma. (t MSK
Req).
Hyperparathyroidism, Brown Tumor Teratoma, Sacrococcygeal

multiple fluid·fluid levels in
this Brown tumor Ilia. Note
the subperiosteal resorption
at the tibial cortex =. This
aggressive resorption was
secondary to a parathyroid
adenoma. (Right) Sagittal
TTWI MR shows a mixed
intensitysacralmass.
involving the bone and
extending into the anterior
and posterior soft tissues. A
fluid·fluid level is evident
along the dependent portion
of this sacral teratoma III.
II
145
OJ
:J LESION WITH BRIGHT 11 SIGNAL
Cf)
Cf)
i=
.;=o DIFFERENTIAL DIAGNOSIS • Atypical Lipomatous Tumor
(fJ o Appearance of fatty mass can be similar to
0::: Common lipoma or liposarcoma
::;;:
• Lipoma, Soft Tissue • May have thickened septae or nodularity
"'C
Ql • Atypical Lipomatous Tumor o Needs biopsy or excision to exclude
VI
ra • Hematoma, Subacute malignancy
In
Ql • Hemangioma, Soft Tissue • More cellular than typical lipoma upon
Cl
ra less Common pathologic examination
E
• Liposarcoma, Soft Tissue • Hematoma, Subacute
• Liposarcoma, Myxoid o Subacute musculoskeletal hemorrhage has
• Fat Necrosis high T1 signal
• Hemangiopericytoma • Acute & chronic blood has low T1 signal
• Intervertebral Disc Calcification o Must prove lack of underlying malignancy
• Chondrocalcinosis before dismissing as simple hematoma
• Lipomatosis • Resolution or significant decrease in size
on follow-up
Rare but Important • Lack of enhancement with subtraction
• Lipoma Arborescens, Knee post-processing helpful
• Lipomatosis, Nerve • Hemangioma, Soft Tissue
• Hibernoma o Vascular mass, classically containing fat
and phleboliths
I ESSENTIAL INFORMATION • Small lesions are less likely to contain fat
than larger lesions
Key Differential Diagnosis Issues o May be associated with erosion or cortical
• Bright T1 signal = higher signal intensity thickening of underlying bone
than skeletal muscle on T1WI o Maffucci syndrome when present with
• Relatively short list of entities that have multiple enchondromas
high T1 signal on MR
o Fat Helpful Clues for less Common Diagnoses
o Blood • Liposarcoma, Soft Tissue
o Protein o Complex fatty mass
o Crystal • Septae > 2 mm in thickness

• Bright T1 signal does not differentiate • Internal enhancement
benign from malignant soft tissue lesions • Nodular soft tissue elements
o Size greater than 5 cm increases suspicion
Helpful Clues for Common Diagnoses of malignancy
• Lipoma, Soft Tissue o Deep location as an indicator of
o High Tl signal mass similar to
malignancy has been challenged
subcutaneous fat • Liposarcoma, Myxoid
o With or without identifiable capsule
o Myxoid soft tissue mass with
• Capsule may enhance predominantly low Tl signal
o May contain fine septations
o Look for at least a small region of lacy or
• < 2 mm in thickness amorphous fat, producing high T1 signal
o May have mildly increased signal on T2WI
• Some lesions will have no identifiable fat
o Homogeneous fat suppression
onMR
o No nodules or soft tissue elements
• Fat Necrosis
o Located in any area of the body that
o Classic location over a pressure point or
contains fat bony protuberance
• Intramuscular lipomas may have o Range of appearances similar to lipoma,
traversing or indenting muscle fibers atypical lipomatous tumor & liposarcoma
• Follow course of fibers to differentiate • Fatty mass, thickened capsule
from thick septations of liposarcoma • May have nodular elements
II
146
LESION WITH BRIGHT 11 SIGNAL 3
III
(C
<0
o Unencapsulated fat necrosis has a less • Lipomatosis ll:J
III
mass-like appearance o Exuberant, unencapsulated fat collection
in anterior mediastinum and pelvis
'"
<0
C.
• Hemangiopericytoma
o Cannot differentiate benign hemangioma o No soft tissue elements or thickened septae ~
;u
from malignant hemangiopericytoma on o Displaces normal structures without (J)
imaging alone invasion o
;::
o Similar appearance to hemangioma Helpful Clues for Rare Diagnoses
-i
iii'
• Mass with vessels, fat, phleboliths • Lipoma Arborescens, Knee '"<1l
C
• Intervertebral Disc Calcification o Represents a benign intraarticular lipoma
o High Tl signal in disc from calcification is
o Frond-like appearance of fatty nodules
relatively uncommon floating in synovial fluid
• Typical appearance is low T1 signal due
• Lipomatosis, Nerve
to calcification o Fatty and fibrous nerve infiltration
• Tl proton shortening may be related to o Commonly affects median nerve and
surface area of calcium crystals digital branches
o High T1 signal may also occur with disc
• Ulnar nerve involvement second most
ossification common
• Most commonly seen with ankylosing o Formerly known as fibrolipomatous
spondylosis and multiple myeloma hamartoma
o Correlate with radiographs or CT for
o Associated with macrodactyly in one third
presence of calcification
of patients
• Chondrocalcinosis • Less commonly associated with
o Calcium crystal deposition in menisci may
neurofibromatosis
produce high T1 signal
• Hibernoma
o If chondrocalcinosis reaches surface of
o Benign, fat containing tumor
meniscus, it may simulate meniscal tear o Similar appearance to lipoma on CT
• Decreased sensitivity, specificity and • May contain vessels, nodules suggesting
accuracy for meniscal tear when liposarcoma
chondrocalcinosis present o Does not follow pure fat signal intensity
o Correlate with radiographs or CT for
onMR
presence of calcification
• Tl signal is higher than skeletal muscle,
o Articular cartilage chondrocalcinosis may
but lower than subcutaneous fat
appear as low T1 centrally with high T1
o Biopsy or excise for definitive diagnosis
halo
lipoma. Soft Tissue
Coronal T1WI MR through the posterior calf shows a

lobulated mass" with high TI signal, which is the
Axial TI WI MR shows a large fatty mass" within the
thigh. The largesize and nodular thickening of septa.
II
same as subcutaneous fat. A few fine muscle fibers or make this lesion worrisome for low grade liposarcoma,
septations. flow through the mass, but it was an atypicallifXJmatous tumor upon excision.
147
LESION WITH BRIGHT 11 SIGNAL
Hematoma. Subacute Hematoma. Subacute

(Leh) Axial TI WI MR shows
"0
Ql high TI WI signal. within
VI the extensor carpi radialis
"'
ell
Ql
longus and brevis tendon
sheaths. This was subacute
Cl blood from a distal radius
.E"' fracture. The tendons were
normal. (Right) Axial TI WI
MR shows a mass ~ in the
subcutaneous tissues
posterior to the olecranon
~ Signal within the mass is
relatively high on all
sequences, consistent with
subacute hemorrhage. This is
hemorrhagic p05Hraumatic
olecranon bursitis.
Hemangioma, Soft Tissue Liposarcoma, Soft Tissue

shows a mass in the thigh
which contains fatty signal
Ell and low signal
phleboliths • located
anterior to the femur. Fatty
stroma is usually found in
soft tissue hemangiomas,
along with a tangle of
vessels. (Right) Axial TI WI
MR shows a large mass.
located deep to the gluteus
maximus muscle. The mass is
predominantly high T I
signal, similar to
subcutaneous fat. Thick
septations 11:I suggest a
malignant fatty tumor.
Fat Necrosis
(Left) Axial TI WI MR shows
a posterior thigh mass.
with inhomogeneous signal
intensity. Areas of high TI
signal intensity Ell represent
the lipomatous portion of the
tumor, which is unusually
large in this example. (Right)
Axial TlWI MR shows a
well-defined mass.
composed of high T I signal,
similar to subcutaneous fat,
overlying the trochanteric
region 0( the hip. This was
excised due to pain, history
0( malignancy and thickened
capsule. The location is
classic for fat necrosis.
II
148
lESION WITH BRIGHT 11 SIGNAL 3
III
to
(l)
OJ
III
VI
(l)
a.
Fat Necrosis Intervertebral Disc Calcification
(Leh) Coronal T1WI MR s:
shows numerous bilateral ;U
masses in the gluteal (f)
o
subcutaneous fat. Some of ~
these masses have purely rat :j
signal intensity. and en
en
represent fat necrosis from c
C1l
medication injection. (Right)
Sagittal T1WI MR shows
hyperintense signal within
every lumbar intervertebral
disc •. There is typical
squaring or the lumbar
vertebral bodies in this
patient with ankylosing
spondylitis.
Chondrocalcinosis Lipoma Arborescens, Knee

(Leh) Coronal T1WI MR
shows a region of meniscal
high signal intensity" in
the same region as
chondrocalcinosis was
identified radiographically.
This may mimic a meniscal
tear when the high signal
extends to the meniscal
surface. (Right) Coronal
TI WI MR through the
anterior knee shows a very
large lobulated mass.
within the knee joint, having
signal intensity identical to
that or subcutaneus rat.
Lipomatosis, Nerve Hibernoma

(Left) Axial T 1 WI MR shows
marked enlargement or the
median nerve ~ with fat
signal filling the space
between individual nerve
fascicles ~ This creates the
classic "telephone cable"
appearance of this condition.
It caused a clinical carpal
tunnel syndrome. (Righi)
Coronal T1WI MR or the
elbow shows a mass. with
T 1 signal higher than muscle,
although not as high as
subcutaneous fat. This is
typical ror the brown rat in a
hibernoma.
II
149
Q)
::l SOFT TISSUE LESIONS WITH PREDOMINATElY LOW 11 & 12 SIGNAL
rJ)
rJ)
F
;l:'
o DIFFERENTIAL DIAGNOSIS • Foreign Body
(f) a Endless variety of material embedded in
0::: Common body, patient may not recall event
:2 • Post-Operative Changes a Often has intense surrounding
"'C
Q)
rJ)
• Foreign Body inflammatory reaction
III • Hematoma, Chronic • Hematoma, Chronic
In
Q) • Flow Voids a Acute high signal serum has resorbed
Cl
III • Densely Calcified/Ossified Lesions leaving debris & fibrous tissue
E • Plantar Fibromatosis a Peripheral or central calcification often
• Gout present
• Air • Flow Voids
• Aneurysm a Rapidly flowing blood produces flow voids
• Pigmented Villonodular Synovitis (PVNS) a Blood excited by 90 degree pulse has left
• Giant Cell Tumor Tendon Sheath the slice before the refocusing pulse, thus
• Arteriovenous Fistula no echo (no signal)
Less Common • Densely Calcified/Ossified Lesions
a Heterotopic ossification, synovial sarcoma,
• Desmoid-Type Fibromatosis
• Elastofibroma injection granulomas, extraskeletal
• Fibroma of Tendon Sheath osteosarcoma, osteosarcoma metastases,
• Metastases, Hemorrhagic progressive systemic sclerosis,
• Amyloid Deposition fibrodysplasia ossificans progressiva,
• Melanoma melorheostosis
• Gout
Rare but Important a Low signal seen on all sequences is typical
• Infection, Calcified or Fungal of sodium urate deposition in tophi
• Arteriovenous Malformation a Tophi have variable moderate
• Cavernous Hemangioma inhomogeneous enhancement
• Extramedullary Hematopoiesis
• Air
• Concentrated Gadolinium a Lack of protons for excitation
a Causes include: Trauma,
ESSENTIAL INFORMATION iatrogenic/post-operative, extension into

soft tissues from joint, infection
Key Differential Diagnosis Issues • Aneurysm
• Radiographs and CT can help differentiate a Turbulent blood flow in aneurysm
some low Tl & T2 signal entities a Low signal in thrombus
a Ossification
a Loss of phase coherence on MR
a Calcification • Pigmented Villonodular Synovitis (PVNS)
a Metal
a Single or multiple masses in and around
a Air
joints
• Paramagnetic substances alter MR signal • Intraarticular masses can have similar
a Blood products, iron, copper, melanin
appearance to gout & amyloid deposition
a Metal, gadolinium, air a Blooming signal on gradient echo imaging
a Blooming signal on gradient echo images
from hemorrhage
Helpful Clues for Common Diagnoses • Giant Cell Tumor Tendon Sheath
• Post-Operative Changes a Localized form of PVNS occurring in
a Micrometallic artifact occurs from scalpel tendon sheath, see characteristics above
use, drilling, sawing, scraping a Similar imaging appearance to fibroma of
• Metal particles are so small they are not tendon sheath

evident on radiographs or CT • Arteriovenous Fistula
a Cement & bone graft material are apparent a Large, tubular flow voids due to direct
on radiographs & CT communication between artery & vein
II
150
SOFT TISSUE LESIONS WITH PREDOMINATELY LOW 11 & 12 SIGNAL 3
III
10
C1l
o Low signal from paramagnetic properties ~
of melanin VI
• Desmoid-Type Fibromatosis C1l
o Metastases can be hemorrhagic, producing Co
o Low MR signal due to immobile protons in
low signal intensity s::
fibrous tissue ;U
o Enhancement helps differentiate this from Helpful Clues for Rare Diagnoses C/J
o
;:::0
other low signal lesions • Infection, Calcified or Fungal
-i
• Elastofibroma o Aspergillosis & other fungal elements may (ji'
VI
o a.k.a., Elastofibroma dorsi cause low signal on T2WI C
C1l
o Located between scapula & rib cage • Edema in surrounding soft tissues
o May mildly enhance • Enhancement of involved tissues
• Fibroma of Tendon Sheath o Chronic calcification also will cause low
o lsointense or hypointense to skeletal signal but is visible on radiographs & CT
muscle on T1 & T2 images • Arteriovenous Malformation
o May have very low signal bands of o Congenital connection of arteries & veins
collagen within mass o High flow lesions producing flow voids
o Variable enhancement o Lacks a discrete soft tissue mass
• 50% moderate to marked enhancement • Cavernous Hemangioma
• 50% little to no enhancement o Lobulated mass with fatty septae
o Not locally aggressive o ± Phleboliths and fluid-fluid levels
o Can be intraarticular o Prominent enhancement of vessels
• Metastases, Hemorrhagic • Extramedullary Hematopoiesis
o Breast carcinoma, bronchogenic o Paravertebral masses are common
carcinoma, renal cell carcinoma, o Associated abnormal bone marrow signal
melanoma, thyroid carcinoma, teratoma, • Obliterated macroscopic marrow fat,
choriocarcinoma signal intensity lower than muscle on
o Low signal on T2WI from blood Tl WI, lack of signal dropout on opposed
breakdown products and/or calcification phase imaging
• Amyloid Deposition • Concentrated Gadolinium
o Intra articular low signal masses are most o Soft tissue extravasation of IV gadolinium
common but can be extraarticular or inadvertent injection of non-dilute
o Often a complication of multiple myeloma gadolinium into joint for MR arthrography
• Melanoma
Foreign Body
Coronal TI WI MR shows scattered low signal foci ••

throughout the region of the distal supraspinatus
Coronal oblique MR arthrogram TlWI FS shows a low
signal foreign body •• in the posterior shoulder joint.
II
tendon. These foci or low signal are micrometallic This is a screw which has pulled out The hol/ow core is
artifacts (rom a rotator cuff repair. filled with fluid.
151
Q)
:> SOFT TISSUE LESIONS WITH PREDOMINATElY lOW T1 & T2 SIGNAL
1Il
1Il
i=
~
o
CJ)
a:::
~
(Left) Axial TI C+ MR shows
'0
G> regions allow signal.
1Il surrounded by areas of mild
ltI
In enhancement. within the
G> deltoid muscle. This is a
Cl
ltI foreign body reaction,
E related to the multiple
injections received. (Right)
Coronal TlWI MR shows
bilateral injection
granulomas" in the gluteal
subcutaneous fat. These low
signal foci are common and
are due to a variety of
medications.
Plantar Fibromatosis
(Left) Sagittal PO FSEMR
shows a focal/ow intensity
mass. in the lateral band
of the plantar fascia at the
level of the calcaneus. Low
signal was also present on
T 1 WI. The lesion showed
mild enhancement
post-contrast. (Right)
homogeneous low signal
malleolus =-
mass distal to the medial
The mass is
bone, with the adjacent
tendons displaced medially.
Air Pigmented Villonodular Synovitis (PVNS)

(Left) Coronal TI WI MR of
the pelvis shows multiple
low signal air bubbles" in
one of several renal cell
carcinoma metastases Ell
This air was presumed due
to extension from the
sacroiliac joint since there
was no history of biopsy and
there was no clinical
evidence of infection. (Right)
Sagittal TlWI F5 MR shows
an unusual case of PVNS in
the pes anserinus region. The
mass. containsnodular
areas of persistently low
signal, which were present
both pre- and post-contrast.
II
152
SOFT TISSUE LESIONS WITH PREDOMINATELY LOW T1 & T2 SIGNAL 3
III
(0
<1l
OJ
III
t/l
<1l
Co
Giant Cell Tumor Tendon Sheath Arteriovenous Fistula
(Left) Axial T2WI MR shows s:
a lobular mass 11:I with ;U
relatively low T2 signal that (f)
was isointense to muscfe on

o
;::r
T1WI. The mass arises deep :j
to the flexor tendons Ell and t/l
t/l
extends radially and volarly. C
CIl
A superficial location ;s more
common. (Right) SagiLLal
T1 WI MR shows an atrophic
distal thoracic spinal cord 11:I
caused by massively
enlarged, tortuous vessels
seen as prominent flow voids
_ representing enlarged
arterial feeders (posterior
spinal arteries) and
arterialized draining veins.
Desmoid-Type Fibromatosis Elastofibroma

shows a low signal mass III
within the far lateral aspect
of the soleus muscle. The
mass has a small amount of
surroundingedema. and
diffusely enhanced with
gadolinium administration.
shows a chest wall mass 11:I
that is nearly isointens€ to
muscle, located between the
lower tip of the scapula Ell
and the rib cage. The mass
remained similar to muscle
intensity on T2WI.
Fibroma of Tendon Sheath Arteriovenous Malformation

shows an oval, lobulated
mass 11:I in the lateral fooL.
The mass abuts the flexor
digitorum longus tendon and
has heterogeneous,
predominantly low T2 signal.
Undulating areas of very low
signal in the mass 11:I are due
10 dense collagen. (Right)
region of tubular low signal
structures Ell in the forearm.
Prominent flow voids are
indicative of an
arteriovenous malformation.
II
153
<ll
::J SOFT TISSUE LESIONS WITH FLUID/flUID LEVElS
en
en
i=
¢::
o DIFFERENTIAL DIAGNOSIS o Fat admixed with joint fluid and blood due
(f)
to fracture
cr Common • Superior layer is fat, central layer is fluid,
:2
• Hematoma dependent layer is blood cells
"0
Ql • Hemarthrosis/Lipohemarthrosis • Vascular & Lymphatic Malformations
II)
Ol
en • Vascular & Lymphatic Malformations o Cavernous fluid-filled spaces
Ql • Medication Injection o May also contain regions of fat
Cl
Ol
Less Common o Lymphangioma does not have central
E
• Tumoral (Idiopathic) Calcinosis enhancement like hemangioma
• Polymyositis/Dermatomyositis o Difficult to differentiate benign
• Malignant Neoplasm hemangioma from malignant
• Non-Neoplastic Structure hemangioendothelioma with imaging
• Neoplasm, Mixed Fluid Contents alone
• Synovial Sarcoma, Cystic • Medication Injection
• Ganglion or Synovial Cyst o Typical distribution in subcutaneous fat of
• Bursitis gluteal region and anterior abdomen

• Tenosynovitis o Small volume of multiple injection sites
o May peripherally calcify
Rare but Important o Steroids and illicit drugs are most likely to
• Soft Tissue Abscess cause tissue irritation and complications
• Myositis Ossificans such as abscess
• Peripheral Nerve Sheath Tumor, Benign &
Malignant Helpful Clues for Less Common Diagnoses
• Hemangioma, Synovial • Tumoral (Idiopathic) Calcinosis
o Multiloculated calcific collections around
large joints
ESSENTIAL INFORMATION o Patients with renal disease
Key Differential Diagnosis Issues o Fluid-fluid levels have milk of calcium
• Fluid-fluid levels can be present in benign appearance on CT
and malignant entities • Polymyositis/Dermatomyositis
• Any fluid collection in the body may o Sheet-like calcification of muscles and
contain material of different densities fascia
o Confluence of mucinous or cystic regions o May have coexisting findings of
with debris scleroderma
o Blood separation into serum and cells o Fluid-fluid levels have calcific dependent
o Sedimentation of necrotic tumor cells layer and are relatively uncommon
o Liquified fat cells in fluid • Malignant Neoplasm
o Necrosis from growth beyond blood
Helpful Clues for Common Diagnoses supply, radiotherapy, or chemotherapy
• Hematoma o Variety of tumor types may have
o Blood products separate and layer
spontaneous hemorrhage producing
producing fluid-fluid level fluid-fluid levels
o History of surgery, trauma or
• Synovial sarcoma, 18-25% of all subtypes
pharmaceutical anticoagulation have fluid-fluid levels
o Be extremely vigilant for underlying
• Liposarcoma
hemorrhagic malignancy • Fibrosarcoma
• Enhanced MR, with pre- and • Leiomyosarcoma
post-contrast subtraction when high Tl • Malignant fibrous histiocytoma
signal present or follow-up • Primitive neuroectodermal tumor
• Hemarthrosis/Lipohemarthrosis • Angiomatoid fibrous histiocytoma
o Blood in joint fluid from fracture, ligament
• Non-Neoplastic Structure, Mixed Fluid
injury, hemophilia Contents
II
154
SOFT TISSUE LESIONS WITH FLUID/FLUID LEVELS 3
III
to
(0
o Fluid-fluid level, often due to fat or blood, • Tenosynovitis lD

III
in normal or abnormal body structure o Fat in tendon sheath from adjacent VI
(0
fracture, especially around ankle C.

• Hemosalpinx, hematocolpos, bladder
diverticulum, bronchogenic cyst, o Debris or hemorrhage in tendon sheath is s:
;u
pancreatic pseudocyst, subarachnoid relatively uncommon CJJ
hemorrhage, venous varix o
Helpful Clues for Rare Diagnoses ~
o Excreted contrast produces fluid-fluid level -;
• Soft Tissue Abscess iij.
in urinary bladder, gallbladder o Complex fluid with thick, enhancing rim
VI
c::
Cl>
o Iatrogenic cerebrospinal fluid leak, seroma
o Contents are typically too viscous to have
• Neoplasm, Mixed Fluid Contents fluid-fluid levels
o More common in body, rather than
o May have concurrent layering hemorrhage
musculoskeletal, diagnoses • Myositis Ossificans
• Endometrioma, hamartoma, ovarian o Fluid-fluid levels relatively uncommon but
teratoma, craniopharyngioma, phyllodes occur in central aspect of lesion
tumor, galactocele o Range of appearances from early
• Synovial Sarcoma, Cystic calcification to late peripheral ossification
o Uncommon subtype of synovial sarcoma
• Periphery is more mature than center
o Approximately 70% have fluid-fluid levels
• Peripheral Nerve Sheath Tumor, Benign &
• Ganglion or Synovial Cyst Malignant
o Ganglion and synovial cyst terminology
o Very high T2 signal of mass may simulate
often used interchangeably cyst or be cystic
• Can use term synovial cyst for lesions • Target appearance on MR
extending from a synovial-lined space: o Cystic regions have fluid-fluid levels from
Joint, bursa, tendon sheath hemorrhage, necrosis or confluent cystic
o Very common fluid-filled lesion with
or mucinous regions
uncommon fluid-fluid level • More common in large lesions
• Hemorrhage or debris in lesion • Hemangioma, Synovial
• Bursitis o Fluid-filled spaces similar but smaller than
o Usually a simple fluid collection with a
cavernous hemangioma
smooth border o Very rare lesion
o May contain layering debris producing
fluid-fluid level
• Uncommon, but most common in
iliopsoas bursa
Hematoma Hematoma
Axial T2WI FS MR shows a complex mass BI in the

right iliopsoas muscle containing a Fluid-fluid level •.
Axial CECT shows marked enlargement of the right
abdominal wall musculature B1. Fluid-fluid levels are
II
This anticoagulated patient was careFully Followed to present within the hematoma resulting from the
exclude underlying malignancy. hematocrit effect as the blood separates B.
155
Q)
:::l SOFT TISSUE lESIONS WITH flUID/flUID LEVElS
(/)
(/)
t=
0:::
o
(j)
0:: Hemarthrosis/Lipohemarthrosis Vascular & Lymphatic Malformations

~
"C
Q) shows a knee
(/)
lipohemarthrosis due to a
'"
lD tibial plateau fracture. Two
Ql ffuid-ffuid levels correspond
Cl
10 fat-ffuid ••• superficially
'E" and ffuid-cells •• dependent
in the joint. (Right) Axial
STIR MR shows a
multiloculated mass EiII in
the right neck and
submandibular space with
multiple ffuid-ffuid levels III
consistent with layering
blood products. The lesion
lacked contrast
enhancement, typical for
lymphatic malformation.
Medication Injection Tumoral (Idiopathic) Calcinosis

(Leh) Axial T2WI FS MR
shows multiple small lesions
with ffuid-ffuid levels III in
the subcutaneous fat of the
right gluteal region. Signal
intensity varies with
medication content and
associated bleeding. (Right)
Axial NECT shows a
multiloculated mass EiII
along the posterolateral chest
wall. Fluid-ffuid levels III
were subtle on MR since the
dependent calcified material
had low signal intensity.
Prone positioning is for
CT-guided biopsy.
bilateral sheet-like
calcification Ell of the
muscles and fascial planes of
the thighs, with scattered
ffuid-ffuid levels ~ due 10
dermatomyositis. (Right)
Axial T2WI FS MR shows a
very large, heterogeneous
mass Ell in the posterior
thigh. The mass contains
areas of signal intensity
higher and lower than
subcutaneous fat. Fluid-ffuid
levels" suggest
hemorrhage within a portion
of the mass.
II
156
SOFT TISSUE lESIONS WITH flUID/flUID LEVElS 3
III
to
11l
llJ
III
III
11l
C.
Non-Neoplastic Structure Synovial Sarcoma, Cystic
(Left) Sagittal T2WI MR ~
shows a low signal fluid-fluid ?J
level" in caudal thecal sac (fJ
from subarachnoid
o
;:1'
hemorrhage. The dependent ::j
blood was relatively lJl
lJl
isointense on T1WI. (Right) C
CD
Axial NEeT shows a soft
tissue mass arising in or
anterior abdominal muscles
Ell. Note that there is a
prominent fluid level" in
this synovial sarcoma.
Synovial Sarcoma, Cystic Bursitis

a medial thigh
heterogeneous mass HI. in
which a large portion of the
lesion ;5 distinctly cystic,
with a fluid level". The
solid regions intensely
enhanced. (Right) Sagillal
FISP 3D WE MR shows
increased signal in the distal
patellar tendon'" and
edema within the tibial
tubercle bone marrow HI
from Osgood-Schlatter.
Bleeding into the deep
in(rapalellar bursa is evident
by a fluid-fluid level ••
Peripheral Nerve Sheath Tumor, Benign

& Malignant
shows increased signal in the
right hemimandible ••• and
soft tissues Ell due to
osteomyelitis and abscess. A
subtle fluid-fluid level E±J is
apparent within a focal
collection in the buccal
space. (Right) Axial T2WI FS
MR shows a large mass Ell in
the posterior cervical space
of the left neck. This benign
schwannoma is hyperintense
to muscle, markedly
heterogeneous and has a
fluid-fluid level. suggesting
hemorrhage.
II
157
QJ
:J TARGET LESION OF SOFT TISSUES
en
en
i=
<l::
o DIFFERENTIAL DIAGNOSIS Helpful Clues for Less Common Diagnoses
UJ
0::: Common • Schwannoma, Conventional
~ • Neurofibroma, Cellular o Target sign less common than in
"0
QJ
neurofibroma
en Less Common o Ovoid mass draped over nerve
t'll
In • Schwan noma, Conventional o Deep location & larger nerve involvement
QJ
Cl • Centrally Calcified Mass favors schwannoma over neurofibroma
t'll
E • Malignant Peripheral Nerve Sheath Tumor • Centrally Calcified Mass
• Metastasis o Meningioma, synovial sarcoma
• Aneurysm o Any soft tissue mass may calcify
Rare but Important • Malignant Peripheral Nerve Sheath Tumor
• Amyloid Deposition o Can be indistinguishable from benign
• Melanoma nerve sheath tumor on imaging
• Epithelioid Sarcoma o Ill-defined borders suggest malignancy
• Metastasis
o Variable calcification or ossification can
ESSENTIAL INFORMATION produce low signal center
Key Differential Diagnosis Issues • Aneurysm
• Target lesion = mass with low signal o Lamellated appearance due to mural
intensity centrally surrounded by high thrombus + rapid or turbulent blood flow
signal intensity (or reverse pattern) Helpful Clues for Rare Diagnoses
o Discussion limited to musculoskeletal MR • Amyloid Deposition
o Radiologic target sign on radiographs, o Paramagnetic effect may cause blooming
ultrasound & CT due to different entities on gradient echo sequences
Helpful Clues for Common Diagnoses o Central calcification is rare
• Neurofibroma, Cellular • Melanoma
o Fusiform mass in subcutaneous tissues o Rim-enhancement with variable
o Target sign on T2WI is classic finding paramagnetic effect from melanin
o Diffusely involves affected nerve • Epithelioid Sarcoma
o Marked tenderness to palpation can o Rare tumor, most common in distal upper
suggest neurogenic tumor over other soft extremity
tissue masses o Mimics appearance of peripheral nerve
sheath tumor
Neurofibroma, Cellular Schwannoma, Conventional
II Axial T2WI MR shows a mass III between brachialis

muscle & biceps tendon, in the expected location of the
Axial TI C+ MR shows a 50ft tissue mass IIlI of the
lower leg, eroding the libial cortex !II. The lesion had
median nerve. The mass was isointense to muscle on low signal on TI WI, high signal on T2WI, and a target
T1WI with a target sign~ on T2WI. (tMSK Req). sign ~ on T2WI and enhanced images.
158
TARGET LESION OF SOFT TISSUES 3
Ql
to
(1)
ell
Ql
l/I
(1)
Schwannoma, Conventional Centrally Calcified Mass a.

(Left) Coronal Tl c+ FS MR s:
shows a mass III in the right ;:0
sciatic notch, which had low (f)
o
signal on Tl WI and high ~
signal on T2WI, with intense ::i
enhancement. Low signal l/I
l/I
seen centrally was more C
(1)
extensive than the known
areas of calcification. (Right)
=
Axial T2WI MR shows a mass
in the medial thigh with
high peripheral signal and
inhomogeneous low central
signal on T2WI. This was a
tumor with central
calcification.
Malignant Peripheral Nerve Sheath

Centrally Calcified Mass Tumor
shows a calcified
meningioma. This
well-defined intradural,
extramedullary mass
displaces the distal cord ElII
and has a target appearance
due to enhancement. and
central low signal. due to
calcification. (Right) Axial
T2WI MR shows a
neurogenic sarcoma in an
unusual location. The mass
•• had low signal intensity
on Tl WI and a target sign on
T2W/IB A longitudinally
elongated contour suggested
a neurogenic origin.

shows a lamellated mass ••
in popliteal fossa of the knee.
This mass is in the expected
location of the popliteal
artery. Signal characteristics
are due to mural thrombus
and blood flow of varying
speed and turbulence.
shows a round mass III in
the anteromedial shoulder of
a patient with multiple
myeloma. The mass had Jow
to intermediate signal on
TlWI and T2WI with a
persistently low signal center
• due to calcification.
II
159
<ll
:J CYSTIC MASSES
en
en
i=
.t=o DIFFERENTIAL DIAGNOSIS • Lies between medial head gastrocnemius
(f)
& semimembranosus in popliteal fossa
0:: Common • Smooth border with teardrop to rounded
~ • Ganglion Cyst
't:l
shape
Q) • Synovial Cyst • Irregular border when cyst ruptures into
III
<Il o Popliteal Cyst proximal calf or distal thigh
al
Q) o Meniscal Cyst o Meniscal Cyst
Cl
<Il o Labral Cyst • lntraarticular knee synovial cyst,
E • Sebaceous Cyst adjacent to meniscus
• Soft Tissue Abscess • Suggests underlying meniscal tear
• Bursitis o LabraI Cyst
• Hematoma • Synovial cyst in shoulder or hip
• Malignant Tumor, Necrotic • Suggests underlying labral tear
• Hemangioma, Soft Tissue • Sebaceous Cyst
Less Common o Well-defined round mass in subcutaneous
• Lymphangioma fat
• Myxoma (Mimic) o Common lesion but uncommonly purely
• Sarcoma, Soft Tissue (Mimic) cystic
o No central enhancement
Rare but Important
• Soft Tissue Abscess
• Hydatid Cyst o Ill-defined, ragged borders
• Eccrine Hidradenoma o Irregular, thick peripheral enhancement
• Bursitis
ESSENTIAL INFORMATION o Well-defined, smooth-bordered fluid
collection in region of bursa
Key Differential Diagnosis Issues • Anatomic bursae around joints
• Cystic soft tissue masses have high T2WI & • Pseudobursa due to pressure, for example
low T1WI signal over osteochondroma
o Border of lesion may enhance o Presence of rice bodies suggests
o May have complex, but nonenhancing,
rheumatoid arthritis
central contents o May also have thickening of associated
• Enhancement pattern is extremely tendons
important o Greater trochanteric bursitis at hip
o Some soft tissue masses appear cystic on
• Mild amount of fluid adjacent to each
T1WI & T2WI images but are solid greater trochanter may be asymptomatic
o Central enhancement confirms solid mass o Subacromial-subdeltoid bursitis at shoulder
& malignancy must be excluded • Fluid from joint may extend through full
Helpful Clues for Common Diagnoses thickness rotator cuff tear
• Ganglion Cyst o Pes anserine bursitis at anteromedial knee
o Well-defined border, often multiloculated o Patellar bursitis at anterior knee
o Lacks synovial lining & contains viscous or • Superficial to patellar tendon
mucinous fluid o Iliopsoas bursitis most likely to mimic
o Similar appearance to synovial cyst on cystic neoplasm
imaging • Lateral to femoral vessels & iliopsoas
• Synovial Cyst muscle and tendon
o Well-defined, smooth border • Medial to the anterior inferior iliac spine
o Connects to joint or tendon sheath • Extends proximally into deep pelvis &
o Has synovial lining & contains synovial can simulate adnexal mass on ultrasound
fluid • May have complex internal contents
o Popliteal Cyst (synovium, debris)
• Synovial cyst in popliteal fossa
II
160
CYSTIC MASSES 3
III
(Q
CD
• Higher incidence with prior hip surgery o Well-defined to infiltrative, multiloculated III
III
& hip joint disease producing large masses VI
CD
effusion o May erode or cause resorption of adjacent a.
• Hematoma bone s:
;0
o Well-defined to irregular mass o Calcifications are rare
en
o No internal enhancement • Myxoma (Mimic) o
;::
o Complex internal contents common o Well-defined, round to oval mass in --i
(ii'
• Acute blood causes increased muscle VI
C
Tl-weighted signal o Contains central areas of enhancement CD
• Can appear lamellated or septated when o Mazabraud syndrome = multiple myxomas

subacute to chronic + fibrous dysplasia
o Peripheral and internal calcification • Sarcoma, Soft Tissue (Mimic)
chronically o Signal intensity mimicking simple to
o Associated evidence of trauma complex cysts on Tl WI & T2WI
• Malignant Tumor, Necrotic • May have cystic appearance even
o Well-defined to irregular mass without necrosis
o Thick, irregular peripheral & internal o Presence of central or nodular
enhancement enhancement makes mass suspicious for
o Centrally located necrosis lacks neoplasm
enhancement Helpful Clues for Rare Diagnoses
o Sarcomas, high grade and treated
• Hydatid Cyst
• Hemangioma, Soft Tissue o Multiple, round, peripherally calcified
o Elongated tangle of vessels
lesions
o Enhancement varies by type of vessels
o Daughter cysts common
producing mass
o Organ involvement seen before soft tissue
• MR angiography can best delineate type involvement
of feeder vessels
• Eccrine Hidradenoma
o Fat & phleboliths are classic findings
o Benign sweat gland tumor
o Occasional hypertrophy or periosteal
o Enhancing mural nodule (gland which
thickening of adjacent bone
produces fluid portion of mass)
Helpful Clues for Less Common Diagnoses o Located in subcutaneous fat adjacent to
• Lymphangioma skin
Sagittal STIR MR demonstrates a multiloculated mass

11III and adjacent thickened synovium • with minimal
Sagillal T2WI FS MR shows a cyst" on the dorsum of
the wrist, with homogeneously high signal intensity and
II
adjacent joint space narrowing of the libiolalar joint a connecting tailllII which tracks pmximally and deep,
This cyst pmduced antem/ateral ankle impingement into the radio-carpal joint, fmm which it pmbably arose.
161
<ll
:J CYSTIC MASSES
III
III
i=
0:=
eno
0:::
:2 (Left) Coronal T2WI FS MR
-0
Q)
demonstrates a well-defined
III (Iuid collection lEI lateral to
CO
III the abductor pollicis longus
<ll and extensor pollicis brevis
Cl
co tendons 1ElII. A marker.
E indicates that this was a site
of pain. (Right) Axial PO FSf
FS MR shows a high signal
collection ID extending
between the
semimembranosus. and
medial head of the
gastrocnemius HI tendons in
the classic location for a
popliteal or Baker cyst.
Meniscal Cyst
(Left) Axial PO FSf FS MR
shows high signal fluid lEI
dissecting through the
posterior soft tissues of the
knee. This collection merged
into the popliteal cyst
(shown on previous image).
A ruptured popliteal cyst can
look somewhat infiltrative at
the point of rupture. (Right)
a meniseal cyst =-
meniseal tear IlIl as well as
Medial
meniscal cysts often migrate
further from the meniscal
tear than is seen with lateral
meniscal cysts.
labral Cyst labral Cyst

a typical posterior shoulder
paralabral cyst" The
posterior and inferior labral
lear which connects to the
cyst is seen •. In this case,
there ;5 no associated muscle
atrophy. (Right) Axial T1WI
FS MR shows the torn
anterior hip labrum &l
extending into a paralabral
cyst lEI. Note in addition the
thickened pulvinar
occupying space within the
joint, typical of DOH •.
II
162
CYSTIC MASSES 3
Ol
CO
CD
llJ
Ol
VI
CD
C.
Soft Tissue Abscess
(Leh) Axial Tl C+ FS MR ~
shows a thick enhancing rind ;0
surrounding fluid within the (j)
glenohumeral joint.:ll. There

o
;::>
is also an abscess within the =i
anterior deltoid muscle Elll VI
VI
as well as an abscess c
en
surrounding the ruptured
pectoralis major tendon _.
(Right) Sagittal Tl C+ MR
shows a large 50ft tissue
mass E!lI with central fluid
contents _ extending from
a subtle defect in the
posterior (emur. This was an
abscess with adjacent
osteomyelitis from Yersinia
pestis.
Bursitis Bursitis
(Leh) Coronal T2WI FS MR
demonstrates a fluid
collection • lateral to the
left greater femoral
trochanter, consistent with
greater trochanteric bursitis.
The iliotibial band E!lI is
located just lateral to the
inflamed bursa. (Right) Axial
T2WI MR shows a cyst E!lI
adjacent to the pes
anserinus, wrapping around
the tibia. There were several
components of the cyst,
involving all three tendons of
the pes anserinus.
Bursitis Bursitis
shows a large bursa E!lI
complicating an
osteochondroma _. The
bursa is high in signal
intensity and contains
inhomogeneous areas. The
periphery of the bursa
enhanced. (Right) Coronal
PO FSf FS MR shows the
typical tear-drop-shaped
fluid collection within the
iliopsoas bursa _ extending
proximally, traveling medial
to the anterior inferior iliac
spine ~ and lateral to the
iliopsoas muscle and tendon
~
II
163
Q)
::J CYSTIC MASSES
V>
V>
i=
4::
eno
ci Hematoma Hematoma
~
"0
CI>
V>
CO
en
=
shows a heterogeneous mass
lying between the medial
head of the gastrocnemius
CI> and the soleus due to
Cl plantaris tendon rupture.
CO
E Increased signal within the
medial head of the
gastrocnemiusmuscle. is
consistent with partial
thickness tearing. (Right)
hyperintense collection _
extending from a defect at
the site of the medial
gastrocnemius rupture. The
plantaris tendon has
ruptured and retracted.
Malignant Tumor. Necrotic Malignant Tumor, Necrotic

shows an inhomogeneous
mass = with predominantly
peripheral enhancement in
the adductor brevis muscle.
This is a typical case of a soft
tissue fibrosarcoma with
central necrosis 11II. (Right)
Axial T1 C+ FS MR shows
fibrosarcoma involvement of
all of the muscles in the
anterior compartment =
and irregular regions within
the mass that lack
enhancement 111 consistent
with necrosis.

shows a high signal,
lobulated soft tissue mass.
in the thigh. A phlebolith 11II
was low signal on all
sequences. Fatly stroma is
usually found in soft tissue
hemangiomas, along with
the tangle of vessels. (Right)
Axial STIR MR shows a
perineural cyst = located
normal tibial nerve HI Lack
of enhancement as well as
normal tibial nerve make a
nerve sheath tumor unlikely.
The cystic structure is an
elongated lymphangioma.
II
164
CYSTIC MASSES 3
III
CO
C1l
OJ
III
III
C1l
C.
Myxoma (Mimic) Myxoma (Mimic)
(Leh) Axial T2WI MR shows ;;::
a solitary, high signal AI
intramuscular mass" with (J)
o
septae. (Right) Axial T1 C+ ~
F5 MR in the same patient as -;
C:;;.
previous image, shows areas C/l
of irregular enhancement 11m C
Cll
within the lesion 1IlI.
Histologically these lesions
consist of myxoid matrix and
spindle-shaped stromal cells.
Multiple intramuscular
myxomas suggests
Mazabraud syndrome.
Sarcoma, Soft Tissue (Mimic) Sarcoma, Soft Tissue (Mimic)

(Leh) Coronal STIR MR
shows a myxoid liposarcoma
•• with the majority of the
lesion of high signal, but
internal foci of fat _ have
low signal. The mass solidly
enhanced, except for the
fatty tissue. (Right) Coronal
T1 C+ FS MR shows the
same myxoid liposarcoma
•• as the prior image,
composed of high signal
central enhancement with
central low signal fat _.
Sarcoma, Soft Tissue (Mimic) Eccrine Hidradenoma

(Leh) Sagittal TI C+ MR
shows a round sofllissue
mass. with calcification
HI and thick peripheral
enhancement, with the
exception of a central cystic
region •. It is important to
consider the diagnosis of
synovial sarcoma when
calcification is present in a
50ft tissue mass. (Right)
nodule with inhomogeneous
low signal Ell intimately
associated with the skin and
surrounding fluid"
secreted by this eccrine
hydradenoma.
II
165
OJ
::J SUBCUTANEOUS MASS
C/l
C/l
f=
4=
o
(/J
a::: Common Key Differential Diagnosis Issues
::2: • Sebaceous Cyst • Extensive differential diagnosis for
"0
C1> • Varicose Veins subcutaneous masses
VI
III • Hematoma • Many entities are not possible to
CO
C1> • Lipoma, Soft Tissue differentiate from each other on the basis of
Cl
III • Adenopathy imaging alone
E • Abscess • Benign and malignant masses can have an
• Fat Necrosis identical appearance on MR
• Foreign Body o Imaging should not dissuade from biopsy
• Gout or excision unless the mass is clearly a
• Epidermoid Inclusion Cyst blood vessel or simple lipoma
• Glomus Tumor • Subcutaneous location allows safe & easy
• Neurofibromatosis excisional procedures
• Melanoma Helpful Clues for Common Diagnoses
• Malignant Fibrous Histiocytoma • Sebaceous Cyst
• Desmoid-Type Fibromatosis o a.k.a., Epidermoid cyst, keratinous type
• Vascular Malformation o Slightly hyperintense to muscle on T1WI
Less Common o High signal on T2WI + may contain
• Lymphoma angular low signal foci
• Atypical Lipomatous Tumor o Lacks central enhancement
• Liposarcoma, Soft Tissue • Varicose Veins
• Metastases, Subcutaneous o Tubular configuration is easily identifiable
• Tumor Recurrence as a blood vessel
• Dermatofibrosarcoma Protuberans o Enhancement characteristics altered if
• Venom Induced Complications vessels are thrombosed
• Synovial Sarcoma • Hematoma
• Spindle Cell Lipoma o Correlate with history of trauma
• Leiomyoma o Must be vigilant to exclude underlying
• Lipodystrophy hemorrhagic malignancy
• Kaposi Sarcoma • Lack of enhancement and/or interval
Rare but Important follow-up
• Lipoma, Soft Tissue
• Multiple Myeloma
o Follows fat signal intensity on all
• Squamous Cell Carcinoma
sequences ± low signal capsule
• Merkel Cell Carcinoma
o May have thin septations measuring less
• Pilomatrixoma/Pilomatrix Carcinoma
than 2 mm in diameter
• Mycosis Fungoides (T-Cell Lymphoma)
• Spindle Cell Sarcoma • Adenopathy
o Typical location of lymph nodes
• Angiosarcoma of Soft Tissue
o Enlargement & obliterated fatty hilum
• Granuloma Annulare
suggests neoplastic involvement
• Myxofibrosarcoma
• Fibrous Hamartoma of Infancy • Fat Necrosis
o a.k.a., Post-traumatic pseudolipoma
• Angiomatoid Fibrous Histiocytoma
o Follows fat signal intensity on all
sequences similar to lipoma
• Soft Tissue Chondroma
o May contain fibrosis & septations
• Heterotopic Ossification
suggesting an atypical lipoma or
• Eccrine Hidradenoma
liposarcoma
o Predominantly located over pressure
points or bony protuberances in the body
II
166
SUBCUTANEOUS MASS
• Foreign Body oNon-fatty elements including thickened,

o Low signal intensity foreign material enhancing septae (> 2 mm) or nodules
surrounded by intense inflammatory help differentiate from simple lipoma
reaction & enhancement • Metastases & Tumor Recurrence
• Gout o Correlate with clinical history of
o Soft tissue tophi malignancy & site of primary lesion
• Low to intermediate signal on T1WI resection
• Variable low to high signal on T2WI • Lipodystrophy
o Associated with juxtaarticular erosions o Term refers to abnormal collections of fat
having overhanging edges or atrophy of fat
• Epidermoid Inclusion Cyst o Lumps or atrophy from repeated injection
o History of trauma causing implantation of of medication in same site
dermal elements into subcutaneous tissues o HIV-related accumulation of fat in
or bone abdominal, axillary, dorsocervical regions
• Glomus Tumor & loss of fat in face, buttocks, extremities
o Mass associated with the nail bed • Kaposi Sarcoma
o May erode underlying bone o Local extension from skin may erode
• Neurofibromatosis underlying bone & cause periosteal
o Mass follows course of nerve reaction
o May demonstrate classic target sign on
T2WI & enhanced images • Multiple Myeloma
• Melanoma o Extramedullary involvement is rare
o Metastases tend to vary in size ±
o Subcutaneous mass can be a solitary
surrounding edema plasmacytoma
o Heterogeneous T1 signal on MR depends
• Pilomatrixoma/Pilomatrix Carcinoma
on melanin content o Solid skin appendage tumor involves
• Malignant Fibrous Histiocytoma dermis & may contain calcification
o Large masses with heterogeneous
• Fibrous Hamartoma of Infancy
enhancement and a necrotic center are o Suspect diagnosis when patient is less than
more suggestive of malignancy 2 years old
Helpful Clues for Less Common Diagnoses • Eccrine Hidradenoma
• Atypical Lipoma & Liposarcoma o Mass with solid peripheral nodule &
surrounding nonenhancing fluid
Sebaceous Cyst Sebaceous Cyst
Sagittal PO FSE FS MR shows a well-defined

subcutaneous mass" adjacent to the knee joint. Note
Axial T1 WI MR shows a subcutaneous mass IIlI in the
distal thigh, which is mildly hyperintense to muscle and
II
the low signal debris IIIl within the predominately T2 lacked central enhancement. This lesion also had
hyperintense lesion. A meniscal tear Ell is also visible. internal/ow signal foci on T2WI, as seen on prior case.
167
Q)
::l SUBCUTANEOUS MASS
III
III
t=
<t::
o
(f)
c:: Varicose Veins Hematoma

~
(Left) Coronal CECT shows
'0
ell numerous subcutaneous,
III tubularmasses. involving
'"
al the right flank. These
ell collateral vessels developed
Cl
due to occlusion of the IVC
'"
E and thrombosis of the
subsequently placed
IVC-femoral graft HI (Right)
Axial TlWI MR shows a
subcutaneousmass.
lateral to the hip. The mass
had low T 1 signal, high T2
signal and lacked central
enhancement. This
hematoma occurred after
significant blunt trauma.
Lipoma, Soft Tissue Abscess

(Left) Axial Tl WI MR shows
an encapsulated
subcutaneous mass 11::I in the
medial elbow. The mass
followed the signal intensity
of subcutaneous fat on all
sequences, consistent with a
simple lipoma. There were
no aggressive features.
(Right) Axial Tl C+ FS MR
shows multiple peripherally
enhancing abscesses III in
the gluteal subcutaneous fat
and musculature, associated
with sacral osteomyelitis HI.
A few low signal foci of air
are present in the most
superficial abscess •.
Fat Necrosis
(Left) Coronal Tl WI MR
=
shows a subcutaneous mass
having a very similar
appearance to a lipoma. The
diagnosis of fat necrosis was
made after excision and is
suggested on imaging by the
thick surrounding capsule
and location over the greater
trochanter. (Right) Coronal
Tl C+ FS MR shows two
foreign bodies with
surrounding intense
enhancement. located
beneath the metatarsal
heads. This was due to
embedded glass shards.
II
168
SUBCUTANEOUS MASS 3
Ql
<0
<Il
CD
Ql
'"
<Il
Co
Glomus Tumor Neurofibromatosis
(Leh) Axial TI C+ FS MR s:
;;0
shows a small, round,
homogeneously enhancing (J)
o
mass" along the radial side ;::I>
of the index finger. The mass -l
(jj'
had high signal on T2Wf and
enhanced slightly more '"
c
CD
prominently than the
adjacent nail bed Ill. (Right)
Axial T2WI FS MR shows an
oval subcutaneousmass.
along the dorsum of the
hand. The mass has fairly
homogeneous high signal on
T2Wf but lacks the classic
target sign of benign
tumors.
Melanoma Malignant Fibrous Histiocytoma

multiple subcutaneous
masses = in the
posterolateral chest wall.
These masses vary in size
and have surrounding
inffammatory changes in the
fat Ill. The appearance is
nonspecific but suggests a
neoplastic process. (Right)
Axial TI C+ FS MR shows a
largesubcutaneousmass.
in the upper arm. There is
irregular, thick peripheral
enhancement and central
necrosis III Signal intensity
was high on T2Wf and low
on TlWI.
Vascular Malformation Lymphoma

(Leh) Axial T2Wf FS MR
shows a mass III in the
lower leg that had been
present since childhood The
mass involvesthe skin.
causing marked thickening.
An MR angiogram showed
very slow filling of this
vascular malformation.
(Right) Axial TI C+ FS MR
shows an enhancing nodular
mass III in the anteromedial
thigh with surrounding
edema all. Lymphoma was
suspected based on the
patient history, but otherwise
the appearance of the lesion
is nonspecific.
II
169
Q)
:J
(/)
SUBCUTANEOUS MASS
(/)
i=
.:t=
o
CIl
a:: Metastases, Subcutaneous
~ Tumor Recurrence
"Cl
Q) a subcutaneous mass. in
(/)
the left paraspinous region
III
CO with heterogeneous
Q) increased signal on T2WI.
Cl
III This mass had low signal on
E T1 WI and enhanced
diffusely. Pathology revealed
metastatic high grade
gastrointestinal carcinoma.
(Right) Axial NEeT shows an
irregular subcutaneous mass
• in the anterior chest wall.
This was recurrent breast
carcinoma in the
mastectomy surgical site.
Dermatofibrosarcoma Protuberans Spindle Cell lipoma

(Left) Axial T1 WI MR shows
superficial mass III with a
low signal capsule
surrounding a central region
of increased signal. On
T2WI, the peripheral portion
remained low signal and the
central portion had higher
signal. The entire lesion
diffusely enhanced. (Right)
heterogeneous, high signal
intensity subcutaneous mass
IIlI in the posterolateral
knee. The lesion had mild
heterogeneous
enhancement
leiomyoma Squamous Cell Carcinoma

shows an oval subcutaneous
mass IIlI in the lateral ankle
that had minimally enlarged
over 6 years. The target sign
__ a low signal center on
T2WI and enhanced images,
gives this mass a similar
appearance to a nerve
sheath tumor. (Right)
a heterogeneous mass =
along the medial aspect of
the elbow. This was excised
and found to be squamous
cell carcinoma, metastatic to
the medial epitrochlear
lymph node.
II
170
SUBCUTANEOUS MASS 3
III
to
ID
OJ
III
VI
ID
0-
Pilomatrixoma/Pilomatrix Carcinoma
(Left) Axial T1 C+ FS MR s:
;0
shows a heterogeneously
enhancing subcutaneous (f)
mass. in the back. The

o
;:l>
mass had nonspecific low :j
signal on T I WI and high VI
VI
signal on TlWI. This was C
ID
excised and found to be a
pilomatrix carcinoma. (Right)
Axial CECT shows irregular
s.ubcutaneous nodules and
skin thickening. along the
anterior abdominal wall. This
diagnosis was clinically
apparent as purple plaques
and ulcerated masses.
Spindle Cell Sarcoma Myxofibrosarcoma

shows a subcutaneous mass
• along the dorsum of the
toe. Signal intensity was low
on T1 WI, high on TlWI and
showed diffuse
enhancement. Other
etiologies such as giant cell
tumor of tendon sheath or
fibroma of tendon sheath
could have this appearance.
(Right) Coronal T I C+ FS
MR shows an ill-defined,
diffusely enhancing mass.
in the subcutaneous fat of
the medial elbow. There is a
marked surrounding edema,
which is nonspecific 1lIll.
Angiomatoid Fibrous Histiocytoma Eccrine Hidradenoma

shows a multi/obulated
enhancing mass 1m in the
posteromedial thigh. The
mass had nonspecific low
signal on T1 WI and high
signal on T2WI. The more
superficial component 11III
had lower signal intensity on
all sequences. (Right) Axial
T2WI MR shows a mass mil
in the subcutaneous tissues
of the midfoot with a
peripheral, solid nodule HI
and a large amount of
surrounding fluid PJ:Il which
is produced by this sweat
gland tumor.
II
171
ENLARGED MUSCLE
DIFFERENTIAL DIAGNOSIS o Normal architecture & MR appearance

• Hematoma
Common o Pain, history of trauma, anti-coagulation
• Exercise Induced Muscle Hypertrophy o Random muscle involvement
• Hematoma • Rectus abdominus, rectus femoris,
• Compensatory Muscle Hypertrophy hamstring muscles common
Less Common o Partial or focal enlargement
• Diabetes: MSK Complications (Myonecrosis) o Architectural distortion
• Pyomyositis o Fluid-fluid levels (US, CT or MR)
• Rhabdomyolysis o MR appearance
• Compartment SY!ldrome • Bright T1WI signal is specific finding
• Denervation Hypertrophy • Low T2WI signal rim (hemosiderin)
• Intramuscular Neoplasm • Compensatory Muscle Hypertrophy
o Lymphoma o Trauma, surgery, denervation of associated
o Malignant Fibrous Histiocytoma muscles
o Liposarcoma o Single muscle or muscle group
o Hemangioma, Soft Tissue o Otherwise identical to exercise induced
o Lymphangioma hypertrophy
o Rhabdomyoma Helpful Clues for Less Common Diagnoses
o Rhabdomyosarcoma, Soft Tissue • Diabetes: MSK Complications
Rare but Important (Myonecrosis)
• Fibromatosis Colli o Pain, history of poorly controlled diabetes
• Muscular Dystrophy o Random muscle/muscles involved

• Pseudotumor, Orbit • Anterior compartment thigh classically
• Graves Disease, Orbit involved
o Partial or generalized enlargement
o Early
ESSENTIAL INFORMATION • Normal architecture
Key Differential Diagnosis Issues • Bright T2WI signal, enhancement
• Important features o Late
o Clinical presentation • Architecture distortion
• Presence or absence of pain • Necrotic muscle mimics fluid
o Muscles involved • Limited generalized enhancement
• Single muscle • Periphery of necrotic muscle may
• All muscles in compartment enhance
• Contiguous muscles • Pyomyositis
o Morphology of muscle enlargement o Pain, history of soft tissue injury/injection
• Generalized: Involves entire muscle o Single muscle
• Partial: Involves segments of muscle, no • May extend to contiguous muscles

discrete mass o Focal enlargement
• Focal: Mass o Architecture distortion around abscess
o Architectural distortion: Preservation or o MR: Fluid signal mass with rim
disruption internal fat distribution enhancement

o Imaging characteristics • Rhabdomyolysis
• MR preferred imaging modality o Pain, weakness, fever
o Elevated CK, myoglobin, potassium;
Helpful Clues for Common Diagnoses acidosis; renal failure
• Exercise Induced Muscle Hypertrophy o Random muscle involvement
o Asymptomatic o Partial or generalized enlargement
o Typically all muscles of an extremity
o Imaging changes identical to myonecrosis
o Generalized enlargement
• See above for imaging characteristics
II
172
ENLARGED MUSCLE 3
III
lC
~
• Compartment Syndrome • Muscular Dystrophy OJ
III
o Pain, paresthesia, diminished/absent o Under 20 years of age tIl
~
o Painless, profound progressive weakness a.
pulses
o All muscles in compartment o Calf musculature only s:
;;0
o Generalized enlargement • Posterior compartment: Especially soleus Ul
o Leads to myonecrosis (see above for o Generalized enlargement o
;:l>
imaging characteristics) o Architecture: Increased internal fat -l
(ii'
• Denervation Hypertrophy (pseudohypertrophy) l/l
c:
o Lumbar spine disease most common cause o MR appearance reflects increased fat ~
o Painless • Pseudotumor, Orbit
o Generalized enlargement o Clinical
o Single muscle • Pain, diplopia, proptosis
• Tensor fascia lata, semimembranosus • Conjunctivitis, lid swelling
muscle common o Extra-ocular muscles
o True hypertrophy: Normal architecture • Superior complex, medial rectus
o Pseudohypertrophy: Increased internal fat commonly involved
o MR appearance • Bilateral in 1/3
• Normal T1WI signal o Generalized enlargement
• Increased T2WI signal • Involves tendon insertion
• Intramuscular Neoplasm • Bulging inner margin of muscle
o ± Pain o Normal architecture
o Single muscle o MR appearance
• May extend to contiguous muscles • Intramuscular hyperintense T2 signal
o Focal enlargement • Inflammatory changes adjacent fat
o Architectural distortion • Graves Disease, Orbit
o Abnormal nonspecific MR appearance o Painless
o Exophthalmos, lid retraction, limited
• Fibromatosis Colli motion of globe
o Bilateral asymmetric involvement
o Neonatal torticollis
o Partial enlargement lower 1/3
extra-ocular muscles
o Generalized enlargement, spares tendon
sternocleidomastoid muscle
o Hyperintense T2WI signal
insertion
o Normal architecture
• May have linear low signal 2° collagen
o MR: Hyperintense T2WI signal
Hematoma
Axial CECT shows enlargement of the right rectus

abdominis muscle with internal fluid-fluid levels lEI
Axial CECT shows true hypertrophy of the levator
scapulae muscle • following radical neck disseclion.
II
consistent with hematoma. The bleeding was secondary The muscle is enlarged but otherwise identical to the
to anti-coagulation. surrounding musculature.
173
ENLARGED MUSClE
Diabetes: MSK Complications

(Myonecrosis)
"0
Q) enlargement with
III myonecrosis and fatty
"'
al
Q)
replacement of the medial
gastrocnemius and both
OJ heads of the soleus in this
l'Cl
E patient with diabetic
myonecrosis. (Right) Axial
CECT shows a low density
lesion with a thin enhancing
rim causing enlargement of
the deltoid muscfe 11II
consistent with pyomyositis
fof/owing recent
intramuscular injection.
Rhabdomyolysis Compartment Syndrome

enlarged left paraspinal
musculawre • with
hyperintense signal
secondary to rhabdomyolysis
due to prolonged surgical
positioning. (Right) Axial
T2WI FS MR shows marked
enlargement of the anterior
tibialis muscfe .:I with
edema in the adjacent
extensor haf/ucis longus
muscfe IIlI and bowing of
the interosseous membrane
HI resulting in compartment
syndrome.
Denervation Hypertrophy
(Left) Coronal T1 C+ MR
shows enlargement o( the
gastrocnemiusmuscle.
with mild diffuse
enhancement and mild
increase in intramuscular fat
resulting from denervation
hypertrophy. (Right) Coronal
T1 WI MR shows primary 50ft
tissue lymphoma enlarging
the right gluteus minimus
and gluteus medius muscles
with distortion of the internal
muscle architecture.
II
174
ENLARGED MUSClE 3
III
CO
CIl
CD
III
VI
CIl
Co
Malignant Fibrous Histiocytoma
(Left) Axial T1WI MR shows s:
a malignant fibrous
;U
histiocytoma creating focal (f)
enlargement of the anterior

o
;::l>
forearm musculature as a
=J
VI
large infiltrating mass which VI
is nearly isointense with C
CIl
muscle on T1 imaging"
shows a nice example of a
poorfy differentiated
liposarcoma" which
contains no fat. The mass
causes marked enlargement
of the gluteus medius
muscle. Remember that high
grade liposarcoma often
contains little or no fat.
Hemangioma, Soft Tissue Rhabdomyosarcoma, Soft Tissue

shows a nice example of
intramuscular hemangioma.
Tubular structures = are
present within a background
of fatty stroma III. (Right)
Axial T1WI MR shows
marked enlargement of the
right gluteus maximus
muscle" with
heterogeneous internal signal
secondary to
rhabdomyosarcoma.
Fibromatosis Colli Pseudotumor, Orbit

typical CT appearance of
fibromatosis colli with
generalized enlargement of
the left sternocleidomastoid
muscle .; density remains
typical of normal muscle.
shows typical MR example of
pseudotumor with
enhancing tissue involving
the left orbital apex and
lateral rectus muscle =
with
contiguous involvement of
the ipsilateral anterior
cavernous sinus _
II
175
Q)
:J MUSCLE ATROPHY
C/l
C/l
i=
<l=
o DIFFERENTIAL DIAGNOSIS o Atrophy, such as in the rotator cuff, may
(f)
have preceded surgery
0:: Common • Immobilization
~ • Post-Operative
"0
o Muscle atrophy begins after 10 days of
Q)
C/l
• Immobilization immobilization
Ol
CO
• Tendon, Injury • Correlate findings with time of injury
Q) • Spinal Cord Injury o Atrophy from prolonged immobilization
01
Ol • Peripheral Nerve Injury (> 4 months) may be irreversible,
E • Neuropathy especially in elderly patients
• Complications of Steroids • Tendon, Injury
• Diabetes: MSK Complications o Common involving the rotator cuff and
less Common gluteus minimus tendons
• Muscle Injury • Full thickness tendon tear results in
• Neurofibromatosis atrophy of the associated muscle
• Cushing Disease • Spinal Cord Injury
• Muscular Dystrophy o Rapid muscle atrophy below level of injury
• Thermal Injury, Burns • 18-46% decrease in muscle cross
• Charcot-Marie-Tooth Disease sectional area 6 weeks post injury
• Amyotrophic Lateral Sclerosis o Associated findings: Cord atrophy, cord
• Guiliain-Barre Syndrome disruption, tethered cord, myelomalacia,
• Meningomyelocele syrinx
• Peripheral Nerve Injury
Rare but Important
o Often possible to identify the abnormal
• Polio nerve based on muscle denervation pattern
• Neuropathy
(Pseudoachondroplasia) o Associated neuropathic changes in joints
• Tethered Cord Syndrome include distention, debris, disorganization,
• Arthrogryposis deformity, dislocation
• Werdnig-Hoffmann Disease • Complications of Steroids
• Farber Disease o Myopathy with high-dose steroid therapy
• Progeria o Weakening of bone leads to increased
fractures with resultant immobilization
ESSENTIAL INFORMATION • Diabetes: MSK Complications
o Multiple potential causes for atrophy
• Neuropathy, muscle infarction, increased
• Replacement of muscle fibers by fat incidence of fracture leading to
produces high signal on Tl WI and low immobilization, infection
signal on fat-suppressed sequences
o Muscle atrophy may also present as a Helpful Clues for less Common Diagnoses
decrease in muscle volume without • Muscle Injury
interdigitating fat o Myonecrosis
• High signal on T2WI FS MR in the • Compartment syndrome
remaining atrophic muscle may represent • Diabetic myonecrosis
ongoing de nervation or inflammation • Trauma
• Distribution, history and associated findings • Neurofibromatosis
are most helpful for differentiating etiologies o Peripheral neuropathies associated with
involvement of large nerve root and
Helpful Clues for Common Diagnoses subcutaneous neurofibromas
• Post-Operative • Cushing Disease
o Associated with micrometallic artifact or
o Proximal muscles more severely affected
other evidence of surgical intervention than distal
II
176
MUSCLE ATROPHY 3
III
~
(l)
o Associated clinical findings: Cushingoid o Associated findings: Posterior spinal defect tIl
III
facial appearance, truncal obesity, skin (or post-operative repair), low lying spinal C/l
(l)
atrophy cord Co
o MR to assess for pituitary, adrenal or ;s:

Helpful Clues for Rare Diagnoses ;u
ectopic corticotropin-producing tumor
• Polio Ul
o
• Muscular Dystrophy o Virtual eradication of new cases in the ;:l>
o MR imaging of thighs and calves can be -i
Western hemisphere 00·
used to assess the extent and pattern of o Symmetric or asymmetric atrophy in
C/l
C
(\)
muscle atrophy affected limb(s)
o Least affected muscles in thigh include
• SpondyloepiphyseaI Dysplasia
gracilis, semimembranosus, (PseudoachondropIasia)
semitendinosus and sartorius o Delayed, irregular ossification centers
• Thermal Injury, Burns o Platyspondyly
o Necrosis of muscle, peripheral neuropathy,
o Odontoid hypoplasia or os odontoideum
skin contractu res o Horizontal acetabular roofs
• Charcot-Marie-Tooth Disease o Short, broad, tubular bones
o Also known as hereditary motor sensory
• Arthrogryposis
neuropathy o Contracted distal joints, limb shortening,
o Different types, all with lower extremity
decreased muscle mass, abnormal tendon
muscle wasting attachments, absent patella, missing or
o Associated findings: Stork leg or inverted
extra carpal and tarsal bones
champagne bottle appearance of leg, pes • Werdnig-Hoffmann Disease
cavus, scoliosis o Also known as spinal muscular atrophy,
• Amyotrophic Lateral Sclerosis type 1
o Adult onset motor neuron disease may o Extensive muscle degeneration, flexed
initially involve the upper or lower limbs abducted hips, flexed knees
o Brain imaging reveals T2WI hyperintense
o Unable to move extremities except fingers
corticospinal tracts, from corona radiata to and toes
brainstem
• Progeria
• Guillain-Barre Syndrome o Accelerated aging with associated findings
o Spine imaging reveals thick nerve roots
of atherosclerotic disease, osteoporosis,
and enhancing cauda equina arthritis, acroosteolysis & muscle atrophy
o History of ascending, symmetric paralysis
in young patient with normal bone age
• Meningomyelocele
Post-Operative Immobilization
Axial TI WI MR shows fatty atrophy •• of a

gastrocnemius muscle nap lID. This was placed after
Sagittal TlWI MR shows chronic fatty atrophy" of the
calf flexor muscles. Atrophy is secondary to surgical
II
arthrodesis of the ankle ~ and subtalar [;8 joints. The
sarcoma resection. The normal muscle undergoes
atrophy due to altered biomechanics (disuse). (oot musculature -= is normal.
177
Q)
:J MUSCLE ATROPHY
VJ
VJ
i=
.:t::
o
(f)
0:: Tendon, Injury Peripheral Nerve Injury

~
"t:l
CIl shows bilateral gluteus
VJ minimusmuscleatrophy.
'"
lD due to bilateral gluteus
CIl minimus tendon tears. This is
Cl
a relatively common injury in
E'" older patients that can cause
chronic pain. (Right) Axial
T7WI MR shows chronic
atrophy 11II of the left flexor
hal/ucis longus muscle
demonstrated by high signal
fat interdigitating with the
muscle fibers. The tendon
was normal suggesting a
nerve branch injury as the
etiology.

the sequelae of quadrilateral
space syndrome with
atrophy =
disproportionate fatty
of the teres
minor muscle without
tendon tea; The adjacent
infraspinatus muscle. is
normal. (Right) Coronal
T1WI MR shows enlarged
medial ~ and lateral 11II
plantar branches of the
posterior tibial nerve. Muscle
atrophy ~ is present. Nerve
entrapment in this case is
probably due to scarring and
thickening of the retinaculum
HI
Diabetes: MSK Complications

(Left)Axial T1WI MR shows
mild fat atrophy" in the
supinator muscle, a sign of
denervation of the radial
nerve. This is consistent with
a high radial neuropathy
likely related to remote
trauma. The other muscles
demonstrate normal bulk
and signal. (Right) Sagittal
T7WI MR shows prominent
fatty atrophy involving the
calf muscles 11II and, less
prominently, the foot
muscles III A combination
of neuropathy and disuse are
likely etiologies in this
diabetic patient.
II
178
MUSClE ATROPHY 3
III
<C
<D
OJ
III
VI
<D
Co
Neurofibromatosis
(Left) Coronal TI WI MR ~
shows fally infiltration HI of ?J
the right calf musculature (fl
due to subacule
o
;:1'
gastrocnemius soleus strain. -;
Compare the paltern of (ii.
VI
"marbling" seen in the C
C1l
norma"efl leg. with the
abnormal righlleg. (Right)
Axial T1WI MR shows
marked fally atrophy. of
posterior calf muscles in a
patient wilh
neurofibromatosis and
mulliple prior thigh surgeries.
Peripheral neuropathy and
posl-operative changes likely
contribute to alrophy.

marked atrophy of all
visualized muscles, including
the paraspinal muscles ~
and abdominal wall" with
extensive fatty infiltration.
This is caused by muscular
dystrophy. (Right) Sagillal
PO FSEMR shows severe
fally replacement of the
majority of the muscles
aboutlhe knee, typical of
muscular dystrophy. The
atrophy is not uniform; the
vastusmedialis. and
semimembranosus &I
muscles show some residual
muscle fibers.
Meningomyelocele Polio
shows profound chronic fally
alrophy • of the paraspinal
muscles in a patient with a
repaired meningomyelocele.
The atrophy is due to severe
chronic denervation. (Right)
Axial T2WI MR of both
thighs shows near complete
replacemenl of the righl
thigh musculature with
hyperinlense fat _ The
appearance of the leftlhigh
• is normal. Chronic
denervalion and atrophy of
lhe right thigh is due to a
remote history of polio.
II
179
Q)
:J INTERMUSCULAR EDEMA
C/)
C/)
F
¢:'
o DIFFERENTIAL DIAGNOSIS • Venous Insufficiency
en o Best diagnosed with ultrasound
0:: Common examination
::?: • Trauma
"'C
• Venous flow reversal, enlarged deep to
Q)
C/)
• Intramuscular Injection superficial perforating vessels
<ll
al
• Venous Insufficiency o Range of soft tissue changes from mild
Ql • Popliteal Cyst, Rupture subcutaneous edema to soft tissue
Cl
<ll • Tendon Tear ulceration
E • Bursitis • Popliteal Cyst, Rupture
• Deep Venous Thrombosis o Classic location of popliteal cyst between
less Common medial head of gastrocnemius and
• Soft Tissue Abscess semimembranosus in popliteal fossa
• Syndesmosis Sprain o Ruptured fluid may track proximally and
• Infectious Myositis distally in leg
• Polymyositis/Dermatomyositis o Symptomatic and often associated with
• Soft Tissue or Bone Neoplasm underlying knee pathology
• Radiation-Induced Non-Neoplastic Soft o Hint: If the fluid is not contiguous with a
Tissue Abnormalities popliteal cyst, evaluate for venous
• Complications of Iodinated Contrast thrombosis
• Diabetes: MSK Complications • Tendon Tear
• Compartment Syndrome o Inflammatory fluid from tendon tear
tracks along the fascial planes of the
Rare but Important associated and surrounding muscles
• Necrotizing Fasciitis
• Bursitis
• Nephrogenic Systemic Fibrosis o Fluid in unexpected areas may still
represent an obscure or pseudo-bursa
ESSENTIAL INFORMATION o Fluid extends along fascial planes from
location of bursa when ruptured
• Deep Venous Thrombosis
• Look for an underlying cause and evaluate o Marked edema within and between
for pertinent history to differentiate similar muscles and soft tissues
appearing etiologies o Can produce pain and be clinically
• Intermuscular and intramuscular edema unsuspected
often coexist o May involve dominant deep venous
Helpful Clues for Common Diagnoses structure or intramuscular plexus
• Trauma • Examine vessels for lack of t T2 signal
o Edema and hemorrhage tracks along facial • Peripheral enhancement of thrombus
planes from injury site Helpful Clues for less Common Diagnoses
o Intermuscular edema can be located • Soft Tissue Abscess
proximal, distal and at the injury site o Thick, enhancing rind of tissue around
o Edema associated with fracture is obvious
abscess
o Injury with hematoma may simulate
• Surrounding inflammatory fluid may
neoplasm especially if injury is not track beyond extent of infection
remembered by patient • Central, nonenhancing necrotic center
• Necessitates follow-up to exclude • Syndesmosis Sprain
hemorrhagic malignancy o Tear or partial tear of ankle syndesmotic
• Intramuscular Injection ligaments
o Commonly has linear edema extending • Anterior and posterior tibiofibular
from skin surface due to needle tract ligaments, transverse tibiofibular
o Medication will diffuse within muscle and
ligament, interosseous membrane
along fascial planes o Widened tibiofibular space (diastasis)
II
180
INTERMUSCULAR EDEMA 3
III
fO
CIl
• Infectious Myositis a Low Tl and high T2 signal edema is tll

III
a Intramuscular and intermuscular edema present within and between muscles
with a nonspecific appearance a Enhancement is present with muscle
'"
CIl
Q.
a Wide range of etiologies produces a wide ischemia and absent with infarction ~
;u
range of severity a Commonly bilateral & involving thighs
(fl
• Viral, bacterial, fungal, parasitic a Difficult to differentiate from traumatic, o
;:r
• Polymyositis/Dermatomyositis infectious or inflammatory muscle ::!
a Abnormal muscle & subcutaneous fat from conditions on imaging alone '"c'"
(1)
inflammation, edema & calcification • Compartment Syndrome
a Typical sheet-like involvement of muscles a High T2 signal and enlargement of all
and subcutaneous tissues with calcification muscles in compartment
evident on radiographs/CT a Lower extremity (calf, foot) most
• Soft Tissue or Bone Neoplasm commonly involved
a Any bone or soft tissue malignancy may a Muscle herniation may be present
induce an inflammatory response, with a Findings necessitate clinical measurement
adjacent edema in soft tissues of compartment pressures
• Radiation-Induced Non-Neoplastic Soft Helpful Clues for Rare Diagnoses
Tissue Abnormalities • Necrotizing Fasciitis
a High T2 signal involving soft tissues in
a Gas tracking along fascial planes is classic
region of radiation therapy o Thickened deep and superficial fascia
a Lack of enhancement and non mass-like
o Fascial enhancement is patchy or uniform
appearance differentiates from residual or a Is a clinical diagnosis, although imaging
recurrent tumor can be suggestive
• Complications of Iodinated Contrast • Nephrogenic Systemic Fibrosis
a Extravasation of IV contrast material into
a Low T1 and high T2 signal in skeletal
soft tissues is almost always apparent at muscle, intermuscular fascia and skin
time of imaging a Correlate with history of relatively recent
a Instruct patient to report signs of
gadodiamide administration (within 3
persistent or increasing pain, skin months) and renal insufficiency
blistering, numbness, tingling, or increased a Similar appearance to polymyositis
swelling - surgical consult a Severe muscle swelling can mimic
• Diabetes: MSK Complications necrotizing fasciitis
a Muscle ischemia and infarction due to
diabetes is uncommon
Trauma
Axial STIR MR shows edema along the deep fascial

plane IllI and within the fibers of the medial head of the
Axial PO FSE FS MR shows high signal edema IllI
dissecUng through the popliteal fossa soft Ussues.Note
II
gastrocnemius HI muscle. The soleus muscle I!!II is that there is not a mass-like configuration. This fluid
normal. This is a grade I gastrocnemius muscle stIain. merged distally with a classic popliteal cyst.
181
Q)
:::l INTERMUSCULAR EDEMA
(J)
(J)
i=
~
o
(f)
cr: Tendon Tear Bursitis

::2;
"tl
Q) shows intermuscular edema
(J)
III
lEI and a hematoma HI in
In the posterior calf due to
Cl) plantaris tendon rupture.
Cl
III Increased signal within the
E medial head of the
gastrocnemius muscle is due
to partial thickness tearing
1m. (Right! Axial T2WI FS
MR shows a distended
bicipital radial bursa IIEI
arising between the radius
HI and biceps tendon _.
The biceps have changes of
tendinosis with mild
surrounding soft tissue
edema ffi
Deep Venous Thrombosis Soft Tissue Abscess

shows edema lEI in the
musculature surrounding the
left hip. Deep venous
thrombosis HI is seen as low
T2 signal intensity in the
vessel and has caused
edema throughout the
adjacent musculature. The
thrombosis extended from
the common iliac artery to
the common femoral artery.
(Right! Axial T2WI FS MR
shows intermuscular edema
= due to a soft tissue
abscess 1m and osteomyelitis
HI. The infecting agent was
mycobacterium tuberculosis.
shows disruption of the ankle
syndesmosis, including not
only the anterior tibiofibular
ligament but also the
interosseous membrane •.
There was extensive
surrounding edema lEI in the
subcutaneous fat and
between the muscles,
without evidence of a
fracture. (Right! Axial T2WI
FS MR shows high T2 signal
from edema" both in and
around the thigh muscfes in
a dermatomyositis patient.
CT showed these areas to be
partially calcified.
II
182
INTERMUSCULAR EDEMA 3
III
to
(l)
o:l
III
<II
Radiation-Induced Non-Neoplastic Soft (l)
Co
Soft Tissue or Bone Neoplasm Tissue Abnormalities
(Lefl) Axial T2WI FS MR :s:
shows a low signal mass E!II
;U
expanding the proximal CIl
fibula, with edema III
o
;::I>
tracking between the -i
adjacent muscles. This was a iii'
(f)
desmoplastic fibroma but c:
(l)
any neoplasm may incite
inflammatory fluid. (RighI)
intermuscular edema III in
the posterior thigh. The
patient had a prior medial
thigh sarcoma resEction that
was treated with radiation.
Lack of enhancement made
recurrence or metastasis
unlikely.
Complications of Iodinated Contrast Diabetes: MSK Complications

(Leh) Axial T2WI FS MR
shows increased signal HI in
the soft tissues adjacent to
the extensor pollicis brevis
tendon III This could be
mistaken for de Quervain
tenosynovitis; but
corresponding high Tf signal
confirmed contrast
infiltration into the sort
tissues. (RighI) Axial T2WI FS
MR shows bilateral intra- III
and inter- • muscular
edema in this diabetic
patient. Lack of
enhancement in the affected
muscles suggests muscle
ischemia or myonecrosis.
Compartment Syndrome Necrotizing Fasciitis

(Leh) Axial TlWI FS MR
shows edema and swelling of
the anterior compartment.
with adjacent intermuscular
edema" The bowed
interosseous membrane HI
compromises neurovascular
structures. (RighI) Sagittal
STIR MR shows edema ••
extending along the
gastrocnemius muscle. The
longitudinal distribution of
the collection suggests
fasciitis and a more rounded
posterior fluid collection =:I
had a thin enhancing rim
suggesting abscess.
II
183
Q)
:J TENOSYNOVITIS/TENOSYNOVIAL FLUID
II)
II)
i=
<:::
a DIFFERENTIAL DIAGNOSIS o Sheath fluid without synovial thickening
(f)
• Arthritis
a::: Common o Most common: Inflammatory (RA),
~ • Normal Variant
"'C
crystalline (gout) or seronegative
Q)
I/)
• Tendon, Injury o Look for associated arthropathy features
C1l
al
• Arthritis (e.g., erosions, osteophytes, osteopenia)
Q)
Cl Less Common Helpful Clues for Less Common Diagnoses
C1l
E • Repetitive Trauma • Repetitive Trauma
• Infection o Variable sheath fluid; ± normal tendon
• Iatrogenic o Correlate with mechanism of injury (e.g.,
Rare but Important FHL in ballet dancers)
• Giant Cell Tumor, Tendon Sheath • Infection
• Synovial Osteochondromatosis o Pyogenic, fungal or tuberculous
• Fibroma of Tendon Sheath o Look for co-existing medical problems,
immunocompromise, etc.
o Extensive fluid, often in multiple sheaths
ESSENTIAL INFORMATION & joints; thick enhancing synovium
Key Differential Diagnosis Issues • Iatrogenic
• All tendons covered by sheath except o History of recent injection, or prior surgery
Achilles tendon which may result in tenosynovitis
• Evaluate by X-ray, ultrasound, CT or MR Helpful Clues for Rare Diagnoses
• Stenosing tenosynovitis: Adhesions restrict • Giant Cell Tumor, Tendon Sheath
tendon & fluid motion in sheath o Multiple heterogeneous nodules; variable
Helpful Clues for Common Diagnoses enhancement; normal tendon; fluid rare
• Normal Variant o Hemosiderin may cause GRE "blooming"
o A small amount of fluid is normal • Synovial Osteochondromatosis
o Tendons communicating with joint may o Extensive sheath fluid with multiple small
have sheath fluid reflecting joint effusion ovoid bodies
(e.g., long head biceps & shoulder joint or • Fibroma of Tendon Sheath
flexor hallucis longus and tibiotalar joint) o Ovoid hypodense enhancing intrasheath
• Tendon, Injury mass < 2.5 em; fluid rare
o Look for tendon thickening, thinning or o Mild adjacent osseous erosion
complete disruption
Normal Variant
II Sagitlal PO FSEFS MR shows a small amount of fluid in

the flexor hallucis longus tendon sheath III This is
Axial T2WI FS MR shows a complete tear of the
posterior tibial tendon with associated tenosynovitis •.
normal. Note the intimate relationship with the tibiotalar The adjacent FOL III & FHL III. tendons & sheaths are
joint_ normal.
184
TENOSYNOVITIS/TENOSYNOVIAL FLUID 3
III
to
C1)
OJ
III
Ul
C1)
Q,
Arthritis Repetitive Triluma
(Left) Axial PO FSf FS MR s:
shows thickened extensor ::0
tendon sheaths with (f)
o
extensive synovial pannus ;::l>
ElII & a small tendon sheath =1
effusion (hyperintense rim) U>
U>
• in 30 year old female C
CD
with rheumatoid arthritis.
MR shows tenosynovitis in a
70 year old ballerina learning
to dance on toe. The FHL is
normal but surrounded by
fluid which is restricted
behind the talus resulting in
stenosing tenosynovitis.
Infection
fluid ElII in flexor tendon
sheaths, fCU & distal
radioulnar joint with synovial
pannus & debris. in this
steroid dependent woman
infected with
Mycobacterium marinum.
(Right) Coronal STIR MR
shows ulnar" mass which is
/I
the fCU. tendon sheath

filled with fluid and debris
ElII related to wrist
arthroplasty failure _ &
foreign body reaction.
Giant Cell Tumor, Tendon Sheath Synovial Osteochondromatosis

(Left) Oblique TlWI MR
shows hypodense,
multinodular mass.
eroding the 1st MCP •. It
encases the flexor tendon &
enhances moderately (not
shown), representing giant
eelltumor of tendon sheath.
shows popliteus tendon
sheath. involvement in
this multinodular process.
Minimal enhancement in &
around multiple small bodies
ElII (seen as punctate bodies
on radiograph), represents
synovial
II
185
Ql
:J ENLARGED PERIPHERAL NERVES
en
en
i=
~ DIFFERENTIAL DIAGNOSIS • Clinical symptoms should alert you to
o
(f)
possibility of nerve mass or disturbance
a::: Common o "Shocking" sensation is elicited when a
~ • Neurofibromatosis
"t:l
neurogenic tumor is tapped
Ql
en
• Tunnel Syndromes (Carpal, Ulnar, Tarsal) o Similar sensation is found with entrapped
nl • Trauma
al nerves (signs elicited for tunnel
Ql • Morton Neuroma syndromes)
Cl
nl • Traumatic Neuroma o Percutaneous biopsy of a neurogenic
E • Benign Peripheral Nerve Sheath Tumor tumor is exquisitely painful
(Benign PNST) • Hints for MR imaging of nerves
• Malignant Peripheral Nerve Sheath Tumor "neurograms"
(MPNST) o TI without fat-saturation is extremely
Less Common helpful in locating the course of the nerve
• Lipomatosis, Nerve (Fibrolipomatous • Perform at least one TI sequence without
Hamartoma) fat-saturation; axial often most useful
• Macrodystrophia Lipomatosa o Fluid sensitive sequences are useful in
• Charcot Marie Tooth identifying enlargement and/or
hyperintensity of nerve
Rare but Important
o Post-contrast imaging is useful in
• Cystic Lymphangioma (Mimic) identifying an irritated nerve; normal
• Neurogenic Sarcoma nerves do not enhance
• Perineurioma, Intraneural o Imaging planes deserve attention; choose
• Acromegaly plane that will best follow the course of
nerve of interest
ESSENTIAL INFORMATION • Sciatic nerve with reference to piriformis:
Sagittal plane especially useful
Key Differential Diagnosis Issues • Sciatic nerve roots: Angled coronal of
• Anatomy & morphology should alert you to sacrum shows all nerve roots
neural origin of these lesions • Nerves following a curved course around
o Any lesion in or adjacent to a
a joint (e.g., peroneal around fibular
neurovascular bundle should make a neck or ulnar through ulnar tunnel of
neural lesion a consideration elbow): Axial plane may be most useful
o Hint: Neural lesions tend to be elongated,
or oval/teardrop-shaped Helpful Clues for Common Diagnoses
o Hint: The associated nerve is often seen • Neurofibromatosis
entering or exiting lesion o Generalized longitudinal enlargement of
o Hint: "Target" sign should raise suspicion nerve fascicles may be seen
for tumor of neurogenic origin o Any nerve may be involved
• Target seen as low signal centrally o May have additional "beaded" appearance
surrounded by high SI on T2 imaging due to focal neurofibromas
• Target highly suggestive of neural tumor, • Tunnel Syndromes (Carpal, Ulnar, Tarsal)
but not exclusive to this type of lesion o Tunnels with transiting nerves, restricted
• Target sign originally described in by retinacula, are at risk
neurofibroma o Nerves may be compressed by lipoma,
• Target sign may be seen in neurofibroma, ganglion cyst, displaced fractures most
schwannoma, or MPNST; not specific frequently
o Hint: Watch for associated muscle • Nerves usually are compressed but less
abnormalities (know innervation patterns) frequently may be enlarged,
• Denervation hypertrophy hyperintense, and enhance with contrast
• Muscle atrophy • Trauma
• Hyperintense muscle o Direct trauma may transect nerve
II
186
ENLARGED PERIPHERAL NERVES 3
Ql
(Q
lD
o If not transected, nerve may swell & o Some degree of macrodactyly is present in lJl
Ql
become hyperintense 2/3 of patients In
lD
C.
• Morton Neuroma o MR is characteristic & pathognomonic
o Perineural fibrosis causes enlargement of • Cable-like longitudinal configuration of s:
::0
interdigital nerve enlarged nerve fascicles within (j)
o 2nd & 3rd intertarsal spaces most surrounding fatty stroma o

~
common; short axis (coronal) imaging • Each fascicle is enlarged to -i
(ii'
shows best; prone positioning may help approximately 2-3 mm due to perineural In
c:
CIl
o Teardrop-shaped, location specific; low fibrosis
signal on Tl with surrounding fat • Fascicles are low signal on all sequences;
o Slightly hyperintense on T2, enhances surrounding stroma follows fat signal on
intensely all sequences
• Traumatic Neuroma • Macrodystrophia Lipomatosa
o Focal enlargement of nerve at site of o Localized giantism, particularly involving a
trauma portion of the hand or foot
o Hypointense rim on T2 images is o Adjacent digits involved, generally
frequently seen following the distribution of a nerve
• Benign Peripheral Nerve Sheath Tumor o All mesenchymal elements are involved
(Benign PNST) • Bones & soft tissue proportionately t
o Intimately involved with nerve; tends to • Lipomatous hypertrophy predominates
be elongated with nerve seen entering or • Involved nerve may show focal t in size
exiting mass • Charcot Marie Tooth
o Often shows target sign on T2 sequence o Denervation edema, hyperintense &
o Size helps differentiate malignant from enlarged nerve
benign; other features not helpful Helpful Clues for Rare Diagnoses
Helpful Clues for Less Common Diagnoses • Cystic Lymphangioma (Mimic)
• Lipomatosis, Nerve (Fibrolipomatous o Single or multiple cystic masses, may
Hamartoma) mimic adjacent nerve enlargement
o Median nerve most frequently involved; o Cystic nature is demonstrated by lack of
radial & ulnar nerve involvement have contrast-enhancement
been reported o Normal nerve (in size and signal
o With median nerve involvement, presents characteristics) seen adjacent; may be
with carpal tunnel symptoms & volar mass compressed and develop symptoms
Tunnel Syndromes (Carpal, Ulnar,

Neurofibromatosis Tarsal)
Coronal PO FSf FS MR shows massive enlargement of

the fascicles of the median nerve Ell and ulnar nerve
Coronal PO FS MR shows hyperintensity of an enlarged
posterior tibial nerve HI. There is atrophy of quadratus
II
•. seen in a patient with neurofibromatosis. plantae & abductor digiti minimi Ell. This patient had
an unsuccessful tarsal tunnel release 1 year prior. 187
Q)
:J ENLARGED PERIPHERAL NERVES
In
In
i=
.t::
o
C/)
0::
::2: Trauma Morton Neuroma
"C
CI> shows thickening of the
VI
•••
III
CI>
=-
posterior cord of the brachial
plexus This resulted from
direcllrauma; the patient
Cl
had a /uxatio erecta (inferior)
•••
E shoulder dislocation 4 weeks
earlier (Right) Coronal T7 WI
FS MR reveals a
teardrop-shaped, intensely
enhancing, plantar mass 11III
arising between the 2nd and
3rd MT heads. Altered
weight-bearing, related to a
silicone implant in the 1st
MT Bllikely contributed to
the development of the
neuroma.
(Left) Axial T7 WI MR shows

a significantly enlarged sural
nerve 11III located in the
posterior subcutaneous
tissues of the leg. A marker
EiII was placed at the site
where pressure elicits an
exquisitely painful shocking
sensation. (Right) Axial T7 WI
MR shows a more proximal
cut in the same patient as
previous image. At this level,
the suralnerve. is only
slightly enlarged. Note its
relationship to the lesser
saphenous vein II!:I. This
patient sustained a blow to
the region 6 months earlier.
Benign Peripheral Nerve Sheath Tumor Malignant Peripheral Nerve Sheath

(Benign PNST) Tumor (MPNST)
shows a mass in the location
of peroneal nerve. with
nerve extending distally from
it EiII. Mass deviates the
gastrocnemius 11II. By
location & appearance, this
is a benign PNST. (Right)
a large, inhomogeneous
=-
mass in the posterior thigh
which proved to be a
MPNST of the sciatic nerve.
Note the enlargement and
nodularity of the proximal &
distal nerves, representing
multiple neurofibromas 11II.
ItMSK Req).
II
188
ENLARGED PERIPHERAL NERVES 3
III
(Q
C1l
[II
III
l/I
Malignant Peripheral Nerve Sheath lipomatosis, Nerve (Fibrolipomatous C1l
Co
Tumor (MPNST) Hamartoma)
(Left) Coronal oblique T7 C + ~
FS MR shows enhancement
;:0
& enlargement of multiple en
sacral nerve roots" in a
o
;:l>
patient who had a sciatic
=!
l/I
MPNST resected 6 months en
earlier. This represents c
CO
recurrence extending
proximally up all the
contributing nerve roots.
shows mild enlargement of
the individual fascicles of the
median nerve HI with
surrounding lipomatous
stroma. The mass displaces
the flexor tendons IJIID. The
appearance is typical.
Charcot Marie Tooth

shows tremendous
lipomatous overgrowth both
intra- and extra-articularly
Ell. There is hyperintensity
==
and enlargement of fascicles
in the tibial and peroneal
nerves all typical of
macrodystrophia lipomatosa.
(Right) Axial PO FSEFS MR
shows enlargement of the
tibial nerve Eill as well as
denervation edema of the
muscles of the posterior
compartment of the leg. The
patient had a cavus foot
deformity, typical of Charcot
Marie Tooth.
Neurogenic Sarcoma
multiple perineural cysts
located adjacent to the tibial
=
..'~'
nerve Hl which itself is
normal in size. The cysts did
. e2:'- ..
not enhance, proving their
' . '
cystic nature, and their
mimicking of tibia! nerve
.~~ ,_.r~
;"
•..,.•••.
'~
enlargement. (Right) Axial
T7WI MR shows a tubular
.. . '
..... - subcutaneous mass III.
deviating the flexor tendons,
r . which proved to be quite

elongated. It became
invasive at one point. This is
an example of a rare lesion,
neurogenic sarcoma.
II
189
INTRAARTICULAR LOW SIGNAL MATERIAL, ALL SEQUENCES
DIFFERENTIAL DIAGNOSIS • Cortical bone with attached cartilage

"0 shows a stripe of low signal (cortex)
Cl>
II)
Common associated with a stripe of slightly higher
l'Cl
co • Metallic Foreign Bodies signal (cartilage)
Cl>
Cl
• Loose Bodies • Mature loose body with trabeculae
l'Cl
E
• Synovitis follows normal bone signal, high on Tl
• Gout and low with fat suppression
• Silastic Implant • Synovitis
• Synovial Osteochondromatosis o Inflammatory arthritic cases usually
• Pigmented Villonodular Synovitis (PVNS) polyarticular
• Intraarticular Gas o Small innumerable nodular masses lining
Less Common the entire synovium of joint
• Hemophilic Arthropathy o Low signal nodularity is outlined well by
• Nodular Synovitis high signal effusion on T2 sequences
• Amyloid Deposition o Synovium often thick, showing uniform
enhancement
• Gout
ESSENTIAL INFORMATION o Monoarticular or pauciarticular
Key Differential Diagnosis Issues o May be juxtaarticular as well as
• Clinical information may be useful intraarticular
o Monoarticular vs. pauciarticular vs. o Frequent associated erosions; may have
polyarticular process soft tissue tophi which mimic the
• Of those entities listed, synovitis is the intraarticular deposition signal
most likely to be polyarticular characteristics
(inflammatory arthropathies) o T2 sequences often have admixed low and
• Of those entities listed, gout, hemophilic high signal, varying according to amount
arthropathy, and amyloid deposition are of density of sodium urate deposition
most likely to be pauciarticular o Enhances with contrast, also with varying
• Of those entities listed, loose bodies, regions of low signal, depending on
synovial osteochondromatosis, PVNS, & amount of density of sodium urate
nodular synovitis are most likely to be deposition
monoarticular o At-risk population: Elderly males,
• Consider adding a gradient echo sequence if Polynesians, patients with underlying
suspect an entity which would show disease with rapid metabolic turnover (end
blooming (PVNS, hemophilic arthropathy) stage renal disease, multiple myeloma)
• Silastic Implant
o Implant is low signal on all sequences,
• Metallic Foreign Bodies often surrounded by synovitis
o Depending on composition, may show
susceptibility artifact o Bodies show varying MR signal, depending
o Some metal, particularly titanium, is
on size, maturity, & composition
visualized without distorting artifact • Cartilaginous bodies have different
• Loose Bodies characteristics than osseous bodies
o If an osteochondral body is secondary to
• Small immature osseous bodies have
delamination, it may be oblong & different characteristics than larger
curvilinear in shape, matching the defect mature bodies, which follow the signal
(often a convex surface) of normal bone on all sequences
o Long-standing loose bodies tend to be
o May present as conglomerate mass, rarely
more round or oval in shape extending into adjacent soft tissues
o MR signal reflects composition of body
• Soft tissue extension, though rare, may
• Cortical bone is low signal on all be highly invasive
sequences
II
190
INTRAARTICULAR LOW SIGNAL MATERIAL,ALLSEQUENCES 3
III
(Q
Cl)
• Pigmented Villonodular Synovitis (PVNS) o May have some high signal components CD
III
o Nodular deposits may be scattered on T2 and post-contrast VI
Cl)
throughout joint, or focally conglomerate o Primary or secondary (particularly in end Co
o Deposits may escape through capsular stage renal disease or myeloma)

perforations to extraarticular locations Alternative Differential Approaches t-
o
o May cause large erosions & cysts
o Low signal on T1, varying low to high
• Intraarticular low signal masses, all a:
sequences (without exception)
signal on T2 o Metallic Foreign Bodies or silastic implants
o Generally enhances significantly
o lntraarticular Gas
o Iron deposition in synovium results in
• lntraarticular masses which are usually low
"blooming" on gradient echo imaging signal, but whicq have exceptions or might
• Intraarticular Gas show regions of high signal on fluid
o Non-dependent portions of joint sensitive sequences or with contrast
o Low signal on all sequences, blooms on
o Loose Bodies: Signal depends on
gradient echo composition
o Generally small round bubbles; larger
o Synovitis: Enhances with contrast
amount may conform to shape of o Gout: May have high signal areas mixed
confining articular tissues with low signal on T2; enhances
Helpful Clues for Less Common Diagnoses o Synovial Osteochondromatosis: Signal of
• Hemophilic Arthropathy bodies depends on composition (mature
o Iron deposition from repeated bleeds bone versus cartilage)
results in low signal synovium which o Pigmented Villonodular Synovitis: Mixed
blooms on gradient echo low and high T2 signal, usually enhances
o May have mixed low & high signal on T2 o Hemophilic Arthropathy: Usually deposits
and post-contrast due to synovitis are low signal on all sequences; may
• Nodular Synovitis enhance if synovitis is active
o Same signal characteristics as generalized o Nodular Synovitis: Mixed T2 SI, enhances
synovitis or PVNS o Amyloid Deposition: Synovitis enhances
o Nodular pattern, most frequently located • Processes which "bloom" on gradient echo
in Hoffa fat pad o Metallic Foreign Bodies
• Amyloid Deposition o Pigmented Villonodular Synovitis (PVNS)
o Low signal deposition in bone, tendon, or o lntraarticular Gas
synovium o Hemophilic Arthropathy
Metallic Foreign Bodies
Coronal oblique MR arthrogram TlWI FS shows a

screw (with hollow core) located posteriorly in the
Coronal oblique T2WI FS MR shows a loose screw
located far anteriorly within the joint •• followlfJg
II
shoulder joint IIlI. This screw is metallic, and is low capsular repair The screw is low signal, with fluid
signal on all sequences. entering its hollow center.
191
c
·0
INTRAARTICULAR LOW SIGNAL MATERIAL, ALL SEQUENCES
--,
ci
~
"tl
Ql
III loose Bodies Synovitis
CIl
III (Left) Coronal oblique T2WI
Ql FS MR shows a large loose
Cl
CIl
body floating in the knee
E effusion". The body has a
strip of very low signal and
another of moderately low
signal; representing the
cortex and cartilage~
respectively. (Right) Sagittal
T2WI FS MR shows diffuse
nodularity of the synovium
=- which remains
signal on all sequences,
low
though it may enhance. This

patient has rheumatoid
arthritis.
Gout Silastic Implant

shows a low signal
intraarticular mass
surrounding & distal to the
medial malleolus". The
appearance is nonspecific on
T7 imaging but was also low
signal on T2 & proved to be
gout. (Right) Sagittal T7 C +
FS MR shows a silastic
implant placed in the
subtalar joint. surrounded
by synovitis. This was placed
several years earNer for
coalition. The implant is low
signal on all sequences.
Synovial Osteochondromatosis Synovial Osteochondromatosis

shows a large fluid collection
within the subdeltoid bursa
•• which appears to contain
many tiny low signal bodies.
Radiograph was normal.
(same case as previous
image) confirms the multiple
low signal bodies, & the
diagnosis of synovial
chondromatosis. In this case,
the bodies remained low
signal on all sequences. In
other cases, they may
acquire other signal,
depending on how much
cartilage/bone they contain.
II
192
INTRAARTICULAR LOW SIGNAL MATERIAL, ALL SEQUENCES 3
OJ
to
~
OJ
OJ
II>
~
Co
Pigmented Villonodular Synovitis (PVNS) Pigmented Villonodular Synovitis (PVNS)
(Leh) Sagittal PO FSE MR
shows a large effusion
containing multiple nodular
bodies". The radiograph
was normal. These bodies
remained low signal on T1
and nWI. (Right) Sagittal
n° CRE MR (same knee as
previous image) shows
"blooming" of the areas of
low signal, now seen to be
lining the suprapatellar bursa
•• Hoffa fat pad" &
posterior capsule Ell. This
wide articular distribution, as
well as the blooming effect
on CRE confirms the
diagnosis of PVNS.
(Left) Axial MR arthrogram

T1WI FSshows air which has
assumed a triangular shape
•• trapped between the
glenohumeral ligament &
humeral head; it was
inadvertently injected during
the arthrogram. Air is low
signal on all sequences.
(Right) Axial PO FSEMR
shows low signal collections
within the subdeltoid bursa
Ell & glenohumeral joint 11II
in a patient with a history of
hemophilic bleeds. With
chronicity, iron is deposited
in the synovium, resulting in
low signal masses.
Nodular Synovitis
(Leh) Sagittal T2WI FS MR
shows predominantly low
signal within a discrete mass
adjacent to Hoffa fat pad ••.
This signal characteristic,
along with the location,
make the diagnosis of
nodular synovitis highly
probable. (Right) Sagittal
T2WI MR shows low signal
material within an
erosion/subchondral cyst
Ell. as well as densely &
diffusely thickened rotator
cuff tendons" This patient
has end stage renal disease;
the imaging is typical of
amyloid.
II
193
-0
C ANECHOIC MASS
~
o
IJ)
CO
E DIFFERENTIAL DIAGNOSIS o Synovium thickness variable depending on
=> chronicity, underlying cause
"tl
Q)
Common • Bursitis
VI
C'll • Ganglion Cyst o Acute: Thin wall, anechoic (chronic
III
Q)
• Synovial Cyst becomes more echogenic)
en • Joint Effusion (Mimic)
C'll • Tenosynovitis (Mimic)
E • Bursitis o Fluid surrounding tendon; ± synovial
• Tenosynovitis (Mimic) thickening; ± tendon injury
• Hematoma • Hematoma
• Soft Tissue Abscess o Acute: Hyperechoic
• Muscle Injury (Mimic) o Subacute (3+ days): Anechoic
Less Common o Subacute (organizing): Echogenic
• Aneurysm (Mimic) o Chronic (liquifying): Anechoic
• Pseudoaneurysm • Soft Tissue Abscess
• Seroma o Thickened, irregular wall
• Lymphocele • Muscle Injury (Mimic)
o Partial: Irregular cavity, accentuated with
Rare but Important
muscle contraction
• Myxoma o Complete: Muscle retracted, hematoma
• Hemophilic Pseudotumor creates "mass"
ESSENTIAL INFORMATION • Aneurysm (Mimic)
Key Differential Diagnosis Issues o Saccular or fusiform, ± luminal thrombus
• Anechoic: Minimal echoes, + o Pseudoaneurysm: History of
thru-transmission & posterior enhancement catheterization
• Seroma/Lymphocele
Helpful Clues for Common Diagnoses o History of prior surgery
• Ganglion Cyst
o Ovoid or lobulate; thin-walled; ± Helpful Clues for Rare Diagnoses
septations • Myxoma
o Synovial cysts communicate with joint & o Discrete hypoechoic mass, ± cystic areas
ganglia do not • Hemophilic Pseudotumor
• Joint Effusion (Mimic) o Masses may be anechoic or more complex
o Follows pattern of hematoma
Ganglion Cyst Synovial Cyst
II Transverse ultrasound shows a discrete anechoic mass Dual ultrasound shows a thin-walled, multiseptate,
194
•• with posterior enhancement
ganglion cyst.
III superficial to the
index finger flexor digilorum tendon Ell This is a the gastrocnemius =
anechoic mass interposed between the medial head of
representing a Baker cyst.

& the semimembranosus Ell
ANECHOIC MASS 3
III
to
lD
CD
III
'a."
lD
(Leh) Dual uluasound shows C

;:+
joint effusion" near the Ol
medial humeral condyle ElII
in rheumatoid arthritis with
'"
o
C
::l
associated synovial a.
proliferation III (Right)
Transverse ultrasound of the
biceps tendon. with
associated tenosynovitis.
Note the anechoic halo ElII
surrounding the long head
biceps. Longitudinal
ultrasound (not shown)
delineated linear tendon
fibers.
Hematoma Soft Tissue Abscess

(Left) Transverse ultrasound
shows a well-defined
anechoic mass ElII displacing
the muscle belly _ This is a
chronic hematoma with a
remote history of trauma.
(Right) Longitudinal
ultrasound shows an
irregular abscess cavity ElII
with marked thickening of
the margin III Note the
adjacent tendon III
Muscle Injury (Mimic) Myxoma

(Leh) Transverse ultrasound
shows an irregular anechoic
mass _ just superficial to
the femur ElII, defining this as
a quadriceps partial tear.
(Right) Transverse
ultrasound at the mid femur
shows a discrete anechoic
cyst. which is, in fact,
within a more solid mass HI
in this myxoma
Imisinterpreted as a ganglion
by MR (not shown)l. Note
the adjacent femoral cortex
~
II
195
PHOTOPENIC LESIONS & FALSENEGATIVE SCANS
DIFFERENTIAL DIAGNOSIS • Arthroplasty/Hardware

~
<1l o Characteristic shapes
OJ
U Common • Radiographs not usually required
:J
Z • Overlying Metallic Object • Cement & Bone Fillers and Bone Graft
"t:l • Arthroplasty/Hardware o Bone fillers & graft initially create defect
Gl
l/I
III
• Artifact: Post Processing to Remove Bladder • As incorporate, defect may disappear
[JJ Activity • Osteomyelitis, Early
Gl
Cl
III
• Cement & Bone Fillers o Prior to bone destruction
E • Bone Graft o Radiographs negative, MR marrow edema
• Osteomyelitis, Early • Post-Radiation
• Post-Radiation o Geographic photopenic defect, may
• Surgical Resection involve several bones
• Multiple Myeloma o Due to poor vascular supply
• Breast Metastases • Surgical Resection
• Osteonecrosis (Especially Femoral Head) o Amputation, resection, curettage
• Vascular Compromise • Multiple Myeloma
Less Common o Usually false negative
• Anaplastic & Aggressive Tumors • Breast Metastases
o See Aggressive & Anaplastic Metastases
below
ESSENTIAL INFORMATION • Osteonecrosis (Especially Femoral Head)
Key Differential Diagnosis Issues o Disruption of blood supply ...•round
• Mechanisms osteopenic focus in angiographic phase
o Disruption of blood supply leading to poor • Vascular Compromise
delivery of radioisotope o Prohibits delivery of radiopharmaceutical
o Limited bone response to destructive Helpful Clues for Less Common Diagnoses
process • Anaplastic & Aggressive Tumors
• Correlation with radiographs should be o Limited response to destructive process
confirmatory o Uptake often patchy, diminished, or nl
Helpful Clues for Common Diagnoses o Ill-defined lytic or permeative lesions
• Overlying Metallic Object o Tumors: Renal, thyroid, oat cell,
o Pacemaker, electrical stimulation devices neuroblastoma, sarcoma (both primary &
o Bladder shield metastatic)
Artifact: Post Processing to Remove

Arthroplasty/Hardware Bladder Activity
II Anterior oone scan centered over the knees

right knee replacement which creates a photopenic
Sh()IN5 a Anterior bone scan shey,¥s the photopenic defect III
created when acUvity from the bladder is electronically
defect in the expected locaUon of the femoroUbial subtracted.
196 arUculaUon III
PHOTOPENIC LESIONS & FALSE NEGATIVE SCANS 3
III
(C
(I)
lJl
III
l/I
(I)
Co
Post-Radiation
(Left) Anterior and posterior Z
c
bone scans demonstrate Q.
geographic defect involving CD
=
OJ
severa/thoracic vertebral ~
bodies and adjacent ribs s:
CO
corresponding to previous Co
radiation port. Note the Q.

::>
sharp zone of transition. CO
(Right! Posterior bone scan
shows a photopenic defect
in the right sacral ala
which is much smaller than
=
the corresponding defect on
CT scan in this patient with
multiple myeloma. Note the
tiny defect in the left sacral
ala.
Osteonecrosis (Especially Femoral Head)

(Left) Axial bone CT (same
patient as previous) shows a
large lytic lesion with
nonsclerotic geographic
margins in the right sacral ala
ElII. On the bone scan the
majority of the lesion is
photopenic. A second
smaller lesion is present in
the left ala =. (Right!
Anterior pin-hole images of
each hip from a bone scan
shows absent activity within
the right femoral head =
on the left =
compared to normal activity
in this patient
with Legg-Calve-perthes
disease.
Anaplastic & Aggressive Tumors

(Left! Oblique and lateral
bone scan images fail to
demonstrate the expansile
lytic thyroid metastasis seen
on a CT examination. (Right!
Axial NECT (same patient as
previous) shows classic
appearance of thyroid
metastasis with expansile
lytic lesion of the left side of
the C3 vertebral body and
neural arch =:II. No
corresponding lesion is seen
on the bone scan.
II
197
SOFT TISSUE UPTAKE ON BONE SCAN
DIFFERENTIAL DIAGNOSIS o Calcification is not always radiographically

~
<1l
Q)
apparent
C3 Common • Mechanisms of soft tissue abnormalities
:J
Z • Injection Site (Mimic) leading to radiopharmaceutical uptake
'"0 • Urine Contamination (Mimic) o Dystrophic calcification
Q)
III
III
• Camera Contamination (Mimic) o Metastatic calcification
al • Dilated Pelvicaliceal System (Mimic) o Calcinosis
Q)
01 • Gastric Secretion of Free Pertechnetate o Ossification, neoplastic & nonneoplastic
III
E (Mimic)
• Myocardial Infarction Helpful Clues for Common Diagnoses
• Amyloid Deposition, Especially Cardiac • Amyloid Deposition, Especially Cardiac
o Heart most common site
• Sickle Cell Anemia, Spleen
• Calcification within Neoplasm radiopharmaceutical uptake
o Associated findings
• Breast with Breast Cancer
• Generalized Soft Tissue from Poor • Bilateral symmetric arthritis with
Radiopharmaceutical Preparation subchondral cysts, erosions, joint spaces
• Renal Failure normal to widened
• Soft tissue masses
Less Common • Sickle Cell Anemia, Spleen
• Brain Infarct o Calcified spleen may be apparent
• Malignant Pleural Effusion o Associated findings
• Malignant Ascites • Osteoporosis, coarse trabecula
• Dystrophic Calcification, Any Cause • Multiple infarcts & AVN, H-shaped
• Synovial Osteochondromatosis vertebra
• Malignant Pericardial Effusion • Osteomyelitis, septic arthritis, dactylitis
• Heterotopic Ossification • Widened diploic space sparing skull base
• Infarcted Tissue, Other • Breast with Breast Cancer
• Soft Tissue Ossification, Any Cause o Not all uptake in breast is malignant
• Neuroblastoma o Correlate with mammogram
• Metastatic Calcification, Especially Stomach, • Renal Failure
Liver, Kidney, Peri-articular Soft Tissues o May lead to diffuse renal uptake
• Pericarditis o May have Superscan
• Myonecrosis o Leads to metastatic calcification
Rare but Important o Associated renal osteodystrophy
• Osteosarcoma (combination osteomalacia & HPTH)
• HPTH: Bone resorption subperiosteal,
subchondral, subligamentous,
ESSENTIAL INFORMATION subtendinous, cortical tunneling;
Key Differential Diagnosis Issues osteoporosis, brown tumors
• Hint: Nonpathologic mimics are most • Osteomalacia: Coarse ill-defined
common trabecula, Looser's zones,
o Always exclude urine contamination; pseudofractures, metaphyseal cupping &
hands can touch anywhere & spread urine fraying (child)
droplets • Neostosis, Rugger jersey spine
• Not always perineal or lower extremity Helpful Clues for Less Common Diagnoses
• Clean site then re-image • Synovial Osteochondromatosis
• One reason to check all scans before o Primary or secondary to arthritis
patient leaves department o Multiple intraarticular osteocartilaginous
• SPECT scanning may aid in localization bodies
• Injection site should always be identified • Neuroblastoma
• Hint: Correlation with radiographs & CT o Uptake typically within primary in adrenal
may be useful gland
II
198
SOFT TISSUE UPTAKE ON BONE SCAN 3
Dl
to
(1)
o Patient under 2 years old • Calcinosis OJ

Dl
• Myonecrosis o Collagen vascular disease, idiopathic IJI
(1)
o Associated with prior trauma, tumoral calcinosis Q.
o Commonly peri-articular Z
compartment syndrome, diabetic c
(")
rhabdomyolysis, snake venom, infection • Metastatic calcification co
OJ
especially anaerobic o Any condition leading to hypercalcemia ~
• Common etiologies: Renal $:
C1>
Helpful Clues for Rare Diagnoses Q.
osteodystrophy, HPTH, Q.
• Osteosarcoma :::J
hypoparathyroidism, cases of extensive C1>
o Both extraskeletal primary & metastases
bone destruction
o Lungs common site of metastases
o Common sites include Gl tract especially
Alternative Differential Approaches stomach, kidney, lungs, peri-articular soft
• Discussion of the various causes is best tissues
focused around the mechanism of • Neoplasm with calcification
radiopharmaceutical uptake o Primarily adenocarcinomas, especially
• List presented below includes many specific mucinous
sites & etiologies typically seen although o Mechanisms not always clear
there are many potential causes • May be dystrophic
• Dystrophic calcification • Psammomatous
o Occurs at sites of previous tissue damage • Enchondral (chondroid tumors)
with random sites of involvement o Colon, breast, ovary (mucinous), Gl,
o Hematoma, abscess, trauma, necrosis, neuroblastoma, endometrial
infarction, tuberculosis, vascular o Soft tissue chondroid tumors
abnormalities o Primary tumor and metastases can calcify
• Ossification • Calcified metastases most commonly
o Neoplastic ossification occurs in seen in liver
osteosarcoma, may be primary o Wide differential diagnosis for soft tissue
extraskeletal or metastatic disease neoplasm containing calcification
o Nonneoplastic ossification
• Wide differential diagnosis for
heterotopic ossification
• Wide differential diagnosis for soft tissue
ossification
• Idiopathic pulmonary ossification
Injection Site (Mimic) Urine Contamination (Mimic)
Anterior bone scan shows linear accumulation of

activity within the antecubital fossa ~ at the injection
Posterior bone scan ShONS {ocal area or radioisotope
uptake adjacent to the right scapula ffi No mass was
II
site. This activity is the result of poor flushing after present. The uptake is from urine contamination which
radioisotope injection. can occur anywhere on the skin surface.
199
~
ro
Q)
13 Urine Contamination (Mimic) Dilated Pelvicaliceal System (Mimic)
:::l
Z (Leh) Anterior bone scan
shows an amorphous
"Ql
III
accumulation of activity
the perineal region and
in
'"
CD upper thigh consistent with
Ql
Cl urine contamination ffi
(Right) Anterior and
'"
E posterior bone scan shows
accumulation of radioisotope
within a dilated left
pelvocaliceal system ~ and
normal activity within the
right renal parenchyma Ii8
Gastric Secretion of Free Pertechnetate

(Mimic) Myocardial Infarction
(Left) Anterior bone scan
shows activity within the
stomach traveling through
the proximal jejunum ffi
With a poor radioisotope tag
free pertechnetate is secreted
by the stomach. (Right)
Anterior bone scan shows
doughnut-shaped uptake in
the left hemithorax .::II
consistent with myocardial
uptake resulting from an MI.
The uptake is quite extensive
and consistent with a severe
myocardial insult.
Amyloid Deposition, Especially Cardiac Sickle Cell Anemia, Spleen

shows accumulation of
activity within the
myocardium of all four
chambers of the heart III
secondary to amyloid
deposition. (Courtesy K.
Morton, MO). (Right)
Posterior bone scan shows
intense uptake in the left
upper quadrant ffi The
shape of the uptake indicates
that it is within the spleen in
this child with sickle cell
anemia.
II
200
III
CO
CIl
III
III
VI
CIl
Co
Calcification within Neoplasm Calcification within Neoplasm
(Left) Lateralbone scan Z
c
centered over the knee £t
demonstrates uptake in the ctl
III
distal thigh _ The ~
orthogonal view helped to s:
ctl
confirm that the activity was c.
located in the solt tissue & Q.
:J
not osseous. (Courtesy K. ctl
Morton, MOJ. (Right) Axial
CECT in the prone position
01 the same patient shows
soft tissue sarcoma with
multiple loci 01calcification
_ this results in local
accumulation of activity on
bone scan.
Calcification within Neoplasm Breast with Breast Cancer

shows multiple ring-like
areas of activity in the RUQ
in the region 01 the liver _
This patient has metastatic
c%n cancer, one of the
most frequent neoplasms to
lorm calcific deposits in
metastases. This activity
should not be conlused with
normal renal activity •.
(Right) Anterior bone scan
shows dilluse uptake in right
breast" as well as a
relatively large intense focus
within same breast Ell This
patient has breast cancer.
(Courtesy K. Morton, MOJ.
Brain Infarct Brain Infarct

reveals local uptake in the
right hemisphere in this
patient with a stroke _
(Courtesy K. Morton, MOJ.
(Right) Lateral bone scan
shows focal activity within
the Irontal region 01 the
brain, consistent with an
acute inlarct •. (Courtesy
K. Morton, MOJ.
II
201
~
co
Ql
<3
:::J
Z (Left) Posterior bone scan
't:l reveals asymmetric activity
Ql within the hemithoraces with
III
III greater activity on the right
al 6B The uptake is not focal
Ql
Cl and is consistent with a
III malignant pleural effusion.
E (Right) Anterior bone scan
shows a protuberant
abdomen. containing
amorphous activity. This
patient has malignant asc;tes.
Note lhe negative defecl of
the bowel within the ascites
ElII. (Courtesy K. Morron,
MO).
Dystrophic Calcification, Any Cau e

centered over the right
forearm shows lobulated
uptake involving the forearm
~ and fingers ~ This
patient has Maffucci
syndrome with extensive soft
tissue hemangiomas and
multiple phleboliths. (Right)
Posteroanterior radiograph of
the right hand in the same
patient reveals a spectacular
example of Maffucci
syndrome with multiple
hemangiomas with
widespread phleboliths.
(Courtesy K. Morron, MO).
Mali nant Pericardial Effusion Heterotopic 0 sification

(Leh) Anterior bone scan
shows activity in the central
chest in the configuration of
the cardiac silhouette.
which is due to a malignant
pericardia I effusion.
(Courtesy K. Morron, MO).
(Right) Anterior bone scan
shows extensive uptake in
both thighs and in the region
of lhe left hemipelvis • in
this patient with extensive
heterotopic ossification.
(Courtesy K. Morton, MO).
II
202
III
to
l1>
OJ
III
VI
l1>
Q,
Soft Tissue Ossification, Any Cause Soft Tissue Ossification, Any Cause
(Left) Posterior bone scan Z
c
shows amorphous foci of C'l
uptake within both r0-
O>
hemithoraces, especially at ~
the lung bases _ This s:
Cll
patient has idiopathic c.
pulmonary ossification. Q.
:J
(Right) Posteroanterior Cll
shows density at both lung
bases. secondary lO
idiopathic pulmonary
ossification.
Neuroblastoma Osteosarcoma
(Left) Posterior bone scan
shows uptake in a right
adrenal mass. most likely
related to microcalcificalions
;n this patient with
neuroblaslOma. (Right)
Anterior and posterior bone
scan shows a case of
metastatic osteosarcoma
with radioisotope uptake
within a left lower lobe mass
•. A calcified mass was
evident on chest x-ray. In this
case the uptake mimics
cardiac uptake.
Osteosarcoma Osteosarcoma
shows intense activity
throughout the right
hemithorax. mimicking
the shape of the lung due lO
a large osteosarcomatous
mass within the pleural
space. (Courtesy K. MarlOn,
MO). (Right) Axial CECT
shows a large osteosarcoma
which has arisen in the
pleural space _ (Courtesy
K. MarlOn, MO).
II
203
SUPERSCAN
DIFFERENTIAL DIAGNOSIS o Osteomalacia/rickets

~
ctl
Ql
• Coarse ill-defined trabecula, Looser
U Common zones, pseudofractures, cortical
:J
Z • Metastases, Diffuse tunneling, metaphyseal cupping &
"0
Ql less Common fraying
V)
• Renal Osteodystrophy • Myelofibrosis
'"
Cll
• Myelofibrosis o Osteoporosis early then diffuse sclerosis
Ql
Cl
• Hyperparathyroidism (HPTH) o MR: Fibrotic marrow
E'" • Hyperthyroidism • Hyperparathyroidism (HJYfH)
• Mastocytosis o Bone resorption: Subperiosteal,
subchondral, subtendinous,
Rare but Important
subligamentous, cortical tunneling
• Aplastic Anemia o Osteoporosis, soft tissue calcium
• Leukemia deposition, Brown tumors
• Lymphoma • Hyperthyroidism
• Osteopetrosis o Osteoporosis
o Rapid bone turnover with cortical
ESSENTIAL INFORMATION tunneling
• Mastocytosis
Key Differential Diagnosis Issues o Osteoporosis
• Superscan: Diffuse, intense skeletal uptake o Characteristic cutaneous involvement
o Little/no activity in kidneys & soft tissues
• Clinical history usually diagnostic Helpful Clues for Rare Diagnoses
• MR will have nonspecific abnormal marrow • Aplastic Anemia
except in cases of metabolic disease o MR: Increased marrow fat
• Leukemia
Helpful Clues for Common Diagnoses o Osteoporosis, lucent metaphyseal bands,
• Metastates, Diffuse periostitis, permeative lytic lesions
o Prostate, breast, lung
• Lymphoma
o Widespread blastic or lytic lesions
o Variable radiographic appearance
Helpful Clues for less Common Diagnoses • Osteopetrosis
• Renal Osteodystrophy o Diffuse osteosclerosis
o Combination of HPTH & osteomalacia
o HPTH (see below)
Metastases, Diffuse Metastases, Diffuse
II Posterior bone scan shows diffuse uptake throughout

the skeleton. Minimal renal uptake is present This is a
Sagittal T1WI MR shows extensive blastic prostate
carcinoma with diffuse marrow involvement. Such
superscan in a patient with diffuse blastic prostatic disease correlates with a superscan appearance on
metastases. bone scan.
204
SUPERSCAN 3
III
(Q
(l)
OJ
III
tII
(l)
Co
(Left) Anterior bone scan Z

c
shows intense uptake in the ()
skull which is characteristic en

OJ
of secondary HPTH. The ~
intensity of skeletal uptake
appears relatively normal
which can be misleading but
note how the uptake is seen
even within the fingers. This
is not normal. (RighI) Lateral
radiograph shows a pattern
of trabecular resorption of
mixed lytic and dense areas
which has been termed "salt
and pepper". This correlates
with the intense uptake in
the skull on bone scan.
Mastocytosis leukemia
(Left) Bone scan shows the
nonspecific appearance of a
superscan in this patient with
mastocytosis. (Right)
Anterior bone scan shows
extremely intense uptake
throughout the skeleton. The
limited renal activity helps to
put the skeletal uptake into
perspective in this patient
with CML blast crisis.
Osteopetrosis Osteopetrosis
(Left) Anterior and posterior
bone scan shows diffuse
intense uptake throughout
the axial and appendicular
skeleton in this patient with
osteopetrosis. (RighI) Axial
bone CT shows a typical
case of osteopetrosis with
diffuse sclerosis throughout
the entire skeleton including
the pelvis as shown here. It is
easy to appreciate the diffuse
skeletal uptake on bone scan
seen in these patients.
II
205
PART III
Clinically Based
Elbow and Forearm
Wrist and Hand
Pelvis, Hip, and Thigh
Knee and Leg
Ankle and Foot
Spine
Systemic Disease
PAINFUL OR ENLARGED STERNOCLAVICULAR JOINT
DIFFERENTIAL DIAGNOSIS • Metastatic Calcification: Peri-articular

calcium deposition, unilateral or bilateral,
Common underlying hypercalcemia
• Osteoarthritis • Ankylosing Spondylitis
• Post-Traumatic o Bilateral symmetric, ranges from
~ • Dislocation enthesopathy to ankylosis
Q)
:Q
::> Less Common • Psoriatic Arthritis: Bilateral asymmetric,
o joint space narrowing, erosions, periostitis,
.s::
(f)
• Septic Joint
• Metastatic Calcification enthesopathy
"tl
Q)
• Ankylosing Spondylitis • Rheumatoid Arthritis
III
• Psoriatic Arthritis o Bilateral symmetric erosive arthritis
'"
tlI
>. • Rheumatoid Arthritis
• Osteitis Condensans of Clavicle o Unilateral, seen in middle aged women
'"
u
o Hint: Sclerosis in inferior aspect clavicular
r:: • Sternoclavicular Hyperostosis/SAPHO
U head, inferomedial osteophyte
Rare but Important
• Sternoclavicular Hyperostosis/SAPHO
• Mucopolysaccharidoses o Synovitis, Acne, Pustulosis, Hyperostosis,
• Tumoral (Idiopathic) Calcinosis Osteitis
• Ischemic Necrosis of the Clavicle o Older teenagers & adults, primarily men
o Unilateral or bilateral sclerosis clavicle,
ESSENTIAL INFORMATION sternum or both, enthesitis
o ± Manubriosternal, & 1st, 2nd
Helpful Clues for Common Diagnoses costochondral articulations
• Osteoarthritis: Joint space narrowing, o Chronic recurrent multifocal osteoarthritis
subchondral sclerosis & cysts, osteophytes (CRMO) is variant seen in children,
• Post-Traumatic: Clavicular head fx may adolescents; bone destruction, extensive
lead to malunion, unilateral osteoarthritis sclerosis leads to enlarged clavicle
• Dislocation: Majority anterior; if posterior
concern for trachea, neurovascular injury Helpful Clues for Rare Diagnoses
• Mucopolysaccharidoses: Wide clavicles
Helpful Clues for Less Common Diagnoses • Tumoral (Idiopathic) Calcinosis
• Septic Joint o Peri-articular calcium deposition
o Unilateral, peri-articular osteoporosis, joint
• Ischemic Necrosis of Clavicle: Clavicular
space narrowing, bone destruction head sclerosis in children 2° trauma, emboli
Post-Traumatic Dislocation
Anteroposterior radiograph shows fracture of the medial Frontal bone CT with 3D reconstruction shows a
head of the clavicle III with inferior displacement posterior dislocation of the right clavicle III relative to
which presented as a painful lump. the manubrium. The vascular structures are at risk in this
dislocation.
2
PAINFUL OR ENLARGED STERNOClAVICULAR JOINT n
~
o
III
-<
OJ
III
Septic Joint
'"
~
Co
abnormal signal within the CJl
distal clavicle. along with ::T
o
an effusion EiII in this drug c::
abuser with septic arthritis of a:
CD
the right sternoclavicular ~
joint. (Right) Axial bone CT
shows erosive change at the
sternoclavicularjoints.
and complete fusion at the
costovertebral. and
costochondral EiII joints in
this patient with ankylosing
spondylitis.
Osteitis Condensans of Clavicle Osteitis Condensans of Clavicle

characteristic appearance of
osteitis condensans of the
clavicle with sclerosis
involving the inferior medial
aspect of the left clavicle
head •. (Right) Axial bone
CT shows diffuse sclerosis
within the medial aspect of
the left clavicle •. No
periostitis or 50ft tissue mass
is seen in this patient with
osteitis condensans of the
clavicle.
Sternoclavicular Hyperostosis/SAPHO Sternoclavicular Hyperostosis/SAPHO

sclerosis (hyperostosis) of
the left first rib. and the
left side of the manubrium
•. The clavicles and
sternoclavicular joint are
both normal EiII in this
patient who fits the criteria
for SAPHo. (Right) Coronal
NECT shows dense sclerosis
(hyperostosis) involving the
left side of the sternum.
and marked increased
density within the left first
costochondral articulation
(osteitis) EiII in this patient
with sternoclavicular
hyperostosis.
III
3
ROTATOR CUFF SYMPTOMS
DIFFERENTIAL DIAGNOSIS • Similar insidious pain, weakness, loss of

range of motion as complete tear
Common o Partial rotator cuff tear
• Rotator Cuff Tendinosis/Tear • Pain with impingement test; may be
• Cervical Radiculopathy more painful than full thickness tear
• Suprascapular Neuropathy • May be on articular surface, bursal
• Subacromial Bursitis surface, or intrasubstance (interstitial)
• Shoulder Subluxation/Dislocation o Full thickness rotator cuff tear
• Osteonecrosis • Full thickness insertional tear within
• Fracture rotator crescent
• AC Joint Separation • ± Complete tear (complete anterior to
• Arthritis posterior extent of tendon)
o Osteoarthritis (OA) • ± Retraction & degeneration tendon
o Rheumatoid Arthritis (RA) • ± Fatty atrophy of muscles
o Hydroxyapatite Deposition Disease • Cervical Radiculopathy
(HADD) (a.k.a., Milwaukee Shoulder) o Combination of facet & uncovertebral
o Ankylosing Spondylitis (AS) joint arthropathy, disk disease, & listhesis
o Polymyalgia Rheumatica o Hint: Before ascribing shoulder pain to
Less Common cervical radiculopathy, be certain there are
• Septic Joint no abnormalities at the cervicothoracic
• Adhesive Capsulitis, Shoulder junction which could be causative
• Intraosseous Neoplasm • Cervical ribs or Pancoast tumor
• Suprascapular Neuropathy
Rare but Important
o Suprascapular nerve generally impinged at
• Myopathies spinoglenoid notch
• Myocardial Infarction o Most common etiology: Paraglenoid cyst,
usually associated with labral tear
ESSENTIAL INFORMATION o Supraspinatus and/or infraspinatus
• Muscle may appear normal
• Muscle may show high T2 signal and/or
enhancement
• Muscle eventually shows fatty atrophy
o Clinically, presents with pain & weakness,
similar to rotator cuff tear
• Subacromial Bursitis
o Presents clinically as subacromial
impingement
• Pain to palpation of rotator cuff within
the range of extension
• Pain and weakness like rotator cuff
injury, but ROM often preserved
o Compression of supraspinatus tendon by
productive changes or morphological
abnormality at AC joint
• Bursal fluid forms in subacromial region;
may extend to subdeltoid bursa
• Watch for partial bursal rotator cuff tear
• Shoulder Subluxation/Dislocation
o Generally have symptoms of instability
• May present with pain and weakness,
similar to rotator cuff injury
III
4
ROTATOR CUFF SYMPTOMS (')
:l
(i'
III
o Following dislocation, may have (reverse) • Ring osteophyte around glenoid; ring
Hill Sachs and/or (reverse) Bankart injuries osteophyte at anatomic humeral neck
-<
llJ
III
• May result in subtle subluxation; watch margin, largest inferiorly IJl
tD
for this on axial MR imaging • Rheumatoid Arthritis (RA) Co
• Watch for capsular redundancy o Pain, swelling, morning stiffness (Jl

::T
• Osteonecrosis o Osteopenia, subchondral cysts, erosions o
c
o Presents with generalized shoulder pain o Synovitis, sometimes with rice bodies a:
..,
CD
prior to collapse of subchondral bone o Chronic rotator cuff tear G)
o Radiograph: Subchondral fracture, • Elevation of humeral head - mechanical ..,
Co
increased density weight-bearing portion erosion medial humeral neck - at risk for CD
Ql
(superomedial head) surgical neck fracture :l
a.
o MR: Subchondral, ± serpiginous double • Hydroxyapatite Deposition Disease C
'0
line sign of osteonecrosis (HADD) (a.k.a., Milwaukee Shoulder) '0
..,
CD
• Fracture o Aggressive joint destruction otherwise
o Direct impact or related to dislocation mimicking osteoarthritis
o Greater tuberosity fracture (nondisplaced) o Consider with shoulder appearance of OA
may be occult radiographically but without history of trauma
o Presents with limited range of motion & • Ankylosing Spondylitis (AS)
pain; often present for MR as presumed o When peripheral joints are involved, it
rotator cuff injury tends to be hip or shoulder
• AC Joint Separation o Osteoporotic, erosive ± productive
o Pain and limited range of motion (ROM), • Polymyalgia Rheumatica
but generally should be differentiated from o Pain, weakness, & stiffness, especially hip
rotator cuff symptoms and shoulder; no structural abnormalities
o Grade 11:AC joint widened; grade Ill: AC
and coracoclavicular joints widened
• Septic Joint
• Osteoarthritis (OA) o Swelling, abscess, effusion, ± bone &
o Slowly progressive pain and limited ROM
cartilage destruction
o Often antecedent trauma
• Adhesive Capsulitis, Shoulder
• If no such history, consider deposition o Painful limited ROM; mimics RCT disease
etiologies (HADD or pyrophosphate) o Thickened & edematous inferior capsule
o Typical findings of OA: Cartilage thinning,
o Restricted capsule with arthrography, no
subchondral cysts filling of axillary or subscapularis bursae
Rotator Cuff Tendinosis/Tear Rotator Cuff Tendinosis/Tear
Coronal oblique T2WI FS MR shows calcific deposits

within the supraspinatus tendon • with surrounding
Coronal T7 FS MR arthrogram shows a full thickness
tear in the supraspinatus portion of the rotator cuffEill.
III
edema PIlI. The tendon is intact, but weakened. In this Though the tear is full thickness, it was not complete, as
case, the calcifications were visible on radiograph. residual fibers were seen in other images.
5
ROTATOR CUFF SYMPTOMS
Rotator Cuff Tendinosis/Tear Suprascapular Neuropathy

(Left) Sagittal PO FSf MR
shows higher signal than
expected within the
•... supraspinatus and
OJ
:!2 infraspinatus tendons &I as
:::J well as thickening of the
o
.r: tendon. Findings are of
en tendinosis. (Right) Axial TI
'0 C+ FS MR shows a large
GI
III spinoglenoid notch cyst III
III
III with rim-enhancement
crossing the pathway of the
~
III
suprascapular nerve. Note
o the mild enhancement of
c: infraspinatus Ill. Depending
U on the location of the cyst,
supraspinatus, infraspinatus,
or both may be involved.
Subacromial Bursitis Shoulder Subluxation/Dislocation

shows fluid in the
subacromial bursa III. A
slightly more posterior
coronal image showed an
abnormal morphology of the
acromion & associated
tendinopathy. (Right) Axial
PO FSf MR shows Hill Sachs
lesion ~ indicating prior
anterior dislocation. Note the
anterior subluxation of the
humeral head, which is
chronic, and the redundancy
of the posterior capsule IIll
This is an unstable shoulder.
Osteonecrosis Fracture
radiograph shows a
subchondral fracture III in
the weight-bearing portion of
the humeral head. This is a
osteonecrosis; the patient
used steroids for asthma.
shows, bone marrow edema
III & linear fracture line E±I
in the greater tuberosity. This
nondispJaced fracture was
radiographically occult; MR
was requested to evaluate
for rotator cuff tear. The cuff
and remainder of the
shoulder were normal.
III
6
ROTATOR CUFF SYMPTOMS ()
:l
o
III
-<
OJ
III
Osteoarthritis (OA) VI
<II
radiograph shows grade 3 (f)
AC separation __ ::T
o
Heterotopic bone is formed c
between the clavicle and a:
C1l
coracoid. indicating ~
coracoclavicular ligament
injury. (Right) Coronal T1 WI
MR shows complete
cartilage loss 11II and huge
osteophytes ringing the
margin of the joint Ell; this
ring osteophyte is
particularly large
inferomedially. The rotator >
cuff remains intact. 3
Rheumatoid Arthritis (RA)

(Leh) Coronal bone CT
shows uniform carlilage loss
without osteophytes iii.
Subchondral cysts & erosions
11II are typical of RA. The
elevated humeral head
shows a chronic rotator cuff
tear & there is a mechanical
erosion of the medial
humeral neck __ (Right)
glenohumeral joint fluid with
thick rind or
enhancing tissue
11II& subdeltoid bursa
abscesses Ell Note that with
this massive septic joint &
bursa, the pectoraUs muscle
is ruptured & retracted __
Adhesive Capsulitis, Shoulder Intraosseous Neoplasm

(Left) AP radiograph
obtained during arthrogram
injection shows effacement
of the subscapularis &
axilla,y bursae. Only 5 cc of
fluid could be injected into
this very tight shoulder
capsule EB This is typical of
adhesive capsulitis. (Right)
Axial bone CT shows an
eccentric slightly expanded
humeral head lesion Ell
containing a small amount of
chondroid matrix __
Chondroblastoma was
diagnosed, but not before
two arthroscopies for the
patient's pain & popping.
III
7
SHOULDER INSTABILITY

Common • Rotator Cuff Tear (RCT)
o Subscapularis tear frequently results from
• Rotator Cuff Tear (RCT)
dislocation, either anterior or posterior
• Labral Tear
o Subscapularis is important to integrity of
~ • Capsular Laxity
Q)
"0 • Humeral Head Fracture anterior shoulder joint
:J o Tear may be either of subscapularis plus
o • Glenohumeral Ligament Tear
£
(f)
fibers crossing bicipital groove, or isolated
Less Common to subscapularis
"0
Q)
l/l
• Glenoid Fracture • Labral Tear
01
In • Biceps Tendon Tear o Labrum functions to significantly increase
>. • Inflammatory Arthropathy the surface area of glenohumeral
01
C.l • Crystalline Arthropathy articulation
r:: • Glenoid Malformation o When secondary to dislocation, tear is
U usually anteroinferior or posterior;
Rare but Important
• Charcot, Neuropathic humeral head subluxates accordingly
• Axillary Nerve Injury o Labral tear may be isolated, but when
• Humeral Head Retroversion secondary to dislocation may be associated
• Neuromuscular Causes: Cerebral Palsy with other injuries
• Ehlers Danlos o May have associated IGHL disruption
• Marfan Syndrome (Bankart), periosteal sleeve stripping

• Intraarticular Neoplasm (Perthes) or disruption with rotation
(ALPSA)
o Often has adjacent articular cartilage
ESSENTIAL INFORMATION defect (GLAD)
Key Differential Diagnosis Issues • Capsular Laxity
• Shoulder is inherently unstable o Patulous capsule, distended by fluid
o Ball & socket joint, with very small area of o May have associated stripping of
osseous contact periosteum from scapula

o Integrity of joint largely maintained by o Related to prior dislocations; increased risk
soft tissues: Labrum, tendon, capsule & for recurrent dislocations
related glenohumeral ligaments o Rarely is isolated
• Instability may be related to osseous • Usually glenohumeral ligament

morphological abnormalities disruption, other injuries
o Hint: Always be aware of size, shape, & • Humeral Head Fracture
alignment of glenoid & humeral head o Hill Sachs (posterolateral) impaction
• Instability is rarely related to inflammation fracture with anterior dislocation

o Hint: Watch for patulous capsule with o Reverse Hill Sachs (anteromedial)
synovitis & ligamentous damage impaction with posterior dislocation

• Most frequently instability is related to o Both put patient at significant increased
traumatically-induced soft tissue injury risk for recurrent dislocations
o Hint: Soft tissue injury leading to o Remember these fractures occur above the
instability is often multifactorial; examine equator of the humeral head
all supporting soft tissues carefully • Glenohumeral Ligament Tear
• Hint: Subtle soft tissue injury may be seen o Often results from anterior shoulder
on routine MR, but often best seen with MR dislocation (occurs in up to 50%)
arthrogram o Rare as an isolated lesion
o Distension with arthrogram is useful, • Associated capsular stretching or tear
especially when there is a rotator cuff tear • Often associated Hill Sachs and Bankart
which decompresses the natural effusion or labral tear
III
8
o Anterior inferior glenohumeral band of o Makes an already small osseous

ligament (IGHL) is most important portion articulation even more insufficient
assisting in stability Helpful Clues for Rare Diagnoses
Helpful Clues for Less Common Diagnoses • Charcot, Neuropathic
• Glenoid Fracture o Destructive articular process
o Usually Bankart (anteroinferior) or reverse • Dislocation, highly unstable
Bankart (posteroinferior), related to • Destruction humeral head (often with
anterior or posterior dislocation straight cut-off at humeral neck)
o Makes the surface area of osseous contact • Debris: Subscapularis & axillary bursa
even more deficient; leads to instability • Often RCT, so debris extends into
o Subluxation seen on axillary lateral subdeltoid bursa
radiograph or axial MR • Clinical presentation is with shoulder
• Biceps Tendon Tear mass due to huge distension
o Role of biceps in stability is debated o Etiology usually is syringomyelia »
o Biceps dislocation/tear most frequently is • Axillary Nerve Injury 3
associated with subscapularis tendon tear, o Very rare etiology of drooping shoulder
which in turn is strongly associated with • Humeral Head Retroversion
instability o Glenohumeral joint is normally
• Inflammatory Arthropathy anteverted; a retroverted head predisposes
o Rheumatoid arthritis (less frequently to posterior instability
psoriatic or ankylosing spondylitis) • Neuromuscular Causes: Cerebral Palsy
o Synovitis distends joint; frequent RCT; o Fixed spasticity during skeletal growth -+
ligamentous laxity -+ instability glenohumeral malformation

• Crystalline Arthropathy • Ehlers Danlos
o Hydroxyapatite deposition disease o Ligamentous laxity -+ instability
(HADD): Calcific deposits & often • Marfan Syndrome
impressive destruction o Connective tissue disorder; phenotypic
o Pyrophosphate arthropathy: Deposition, heterogeneity
usually with more degenerative change o Ligamentous laxity may lead to instability
than destruction of joint • Intraarticular Neoplasm
• Glenoid Malformation o Distortion of humeral head/glenoid or
o Glenoid may be hypoplastic, usually truly intraarticular mass could lead to
posteriorly & inferiorly subluxation
Axial TI WI FS MR arthrogram shows a subscapularis

tendon tear IElll with fluid imbibed by the muscle fibers.
Axial TlWI FS MR arthrogram shows an anterior labral
tear III extending as a periosteal sleeve avulsion HI
III
There is also a tear of MGHL • and a glenolabral termed a Perthes lesion. This is one of the forms of labral
articular defect I!III; all contribute to anterior instability. injury which may contribute to instability.
9
labral Tear labral Tear

(Left) ABfR T1WI FS MR
arthrogram
labral tear =
shows an inferior
as well as
glenoid articular
cartilaginous defect (CLAD)
HI in a patient who
presented with instability.
(Right) Axial CT arthrogram
shows an anterior-inferior
labral tear, distracted with
external rotation =. A Hill
Sachs impaction was seen
more proximally at the
posterolateral humeral head.
The combination typically
results from anterior shoulder
dislocation, and predisposes
to recurrent dislocation.
Capsular laxity Humeral Head Fracture

arthrogram shows labral tear
with periosteal stripping
anteriorly. This has resulted
in a significantly patulous
anterior capsule a· this
redundancy leads to
instability. Note additionally
the partial subscapularis tear
with biceps dislocation ••.
(Right) Axial PO FSf MR
shows Hill Sachs impaction
fracture of the posterolateral
humeral head EB Note the
patulous posterior capsule
III and anterior labral tear
•. The head is subluxated
anteriorly.
Glenohumeral ligament Tear Glenohumeral ligament Tear

arthrogram shows an intact
MCHL" but imbibition of
contrast into a partial
subscapularis tear 11II. The
posterior capsule is
extremely redundant HI and
contains wavy fibers which
are part of the torn ICHL EB
The patient had
multidirectional instability.
arthrogram shows a
redundant rotator interval.
& wavy disrupted ICHL •
with a patulous joint capsule.
It is not surprising that
instability is multidirectional.
III
10
("')
j
n
Dl
-<
III
Dl
Glenoid Fracture Biceps Tendon Tear VI
l1>
(Left) Axial TI WI FS MR Q.
shows reverse bony Bankart (f)
Fracture"'. Note the ::T
o
cartilage disruption as well c::
Ell. The humeral head is c:
ro
posteriorly subluxated, ~
indicating at least a posterior G)
instability. (Right) Axial TI WI
~
0-
FS MR arthrogram shows a ro
Dl
partial biceps tear'" with :::J
dislocation into partial 0-
undersurface lear of the C
subscapularis tendon III
Note the empty bicipital
"
"ro~
groove Ell. The biceps
dislocation and subscapularis
injury contribute to anterior
instability.
Crystalline Arthropathy
in a paUent with rheumatoid
arthritis shows a rotator cuff
tear'" patulous joint ElIl &
extensive synovitis with rice
bodies. The combination
may lead to instability.
radiograph shows
with a chronic RCT and
degenerative change. HAOO
(Milwaukee shoulder) oFten
shows more destruction as
well as calciFicdeposits than
is seen here and is more
likely to be unstable.
Glenoid Malformation Charcot, Neuropathic

shows posterior hypoplasia
of the glenoid'" The
glenoid was hypoplastic
inFeriorlyas well. This
decreases the already small
area of osseous contact,
leading to Furtherinstability.
radiograph shows unstable,
dislocated humeral head
with "cut-off" sign at the
humeral neck Ill. There is
osseous debris within axillary
& subscapularis bursae ••
showing these structures to
be distended. This is typical
of Charcot shoulder.
III
11
ANTEROINFERIOR lABRAl/CAPSUlE INJURY

Common • Bankart Lesion
o Anteroinferior labroligamentous avulsion
• Bankart Lesion
from glenoid & periosteal sleeve tear; ±
• GLAD Lesion
adjacent glenoid fracture
~ less Common
Q) o Acute: Discrete or fragmented tear across
:Q
:J • ALPSA Lesion labral base
o
.r: • Perthes Lesion o Chronic: Fibrotic medial "mass"
(f)
"0
• HAGL Lesion • GLAD Lesion
Ql
Vl Rare but Important o Glenoid Labrum Articular Disruption
'"
[JJ • Congenital Hypermobility Syndrome o Labrum partial tear & adjacent cartilage
~ damage
'"c": ESSENTIAL INFORMATION Helpful Clues for less Common Diagnoses
U • ALPSA Lesion
Key Differential Diagnosis Issues o Anterior Labroligamentous Periosteal
• Hint: Watch for radiographic abnormality Sleeve Avulsion
o Hill-Sachs impaction deformity o Bankart but periosteal sleeve intact
o Glenoid fracture fragments o Acute: Torn labroligamentous complex
• CT: Malalignment, glenoid hypoplasia rolls medial & inferior
• MR: Marrow and soft tissue edema, labral o Chronic: Fibrotic medial "mass"
tears; sensitivity/specificity (S/S): 80/45-80% • Perthes Lesion
• MR/CT with intra-articular contrast: t o Bankart & intact but redundant periosteal
conspicuity; S/S: 95/86% sleeve
• ABduction External Rotation (ABER) view • HAGL Lesion
o Inferior glenohumerallabroligamentous o Humeral Avulsion of Glenohumeral
(IGHL) structures taut for improved Ligament
visibility, eliminates magic angle o Capsule avulsion of IGHL from humeral
o Position gently to avoid re-dislocation attachment without subscapularis tear; no
• Young adult dislocation: Bankart, variants age predilection
• Older adult dislocation = 1/3 supraspinatus
tear; 1/3 greater tuberosity fracture; 1/3
subscapularis/capsular avulsion • Congenital Hypermobility Syndrome
o Diagnosis of exclusion
Bankart Lesion Bankart Lesion
III Axial TI C+ FS MR shows complete disrupUon of the

anteroinferior labrum. & periosteal sleeve III with t
Axial NEeT in the same patient as previous image
shows a concomitant fracture HI (osseous Bankart)
51 crossing the labral base in a paUent with recent along the anleroinferior osseousglenoid.
dislocation.
12
ANTEROINFERIOR lABRAl/CAPSUlE INJURY
Bankart Lesion Bankart Lesion

(Left) Axial CECT
double-contrast arthrogram
in external rotation shows a
50ft tissue Bankart lesion
with air passing through the
anteroinferior labral tear III.
Note the completely Q
disrupted fragment E!lI
~
a.
displaced medially. Similar r0-
information can be obtained O>
:J
with a single contrast CT a.
arthrogram. (Right) ABER T7 C
"0
C+ FS MR shows a complete "0
CD
labral tear III (Bankart ~
lesion) with the abduction »
external rotation (ABER) 3
position placing tension
across the inferior capsule.
GLAD Lesion ALPSA Lesion

shows a partial tear III of the
anteroinferior labrum with
E!lI of a CLAD lesion. Note
biceps medial subluxation
11I1 into a subscapularis tear.
shows an anterior labral tear
with anterior & medial
displacement of the fragment
~ with intact scapular
periosteum III forming an
ALPSA lesion. This is an
acute injury with an
accompanying Hill-Sachs
lesion (not shown).
Perthes Lesion HAGLLesion

shows an anteroinferior
labral tear. & intact
periosteal sleeve E!lI (Perthes
lesion). The labral fragment
is not medially displaced &
the periosteal sleeve is
slightly redundant,
distinguishing this from an
ALPSA lesion. (Right) ABER
T7 C+ FS MR shows avulsion
of the anterior band inferior
glenohumeral ligament's
humeral attachment III
(HACL lesion) with extensive
intrasubstance. (partial
tear) of the anterior band
itself
III
13
NERVE ENTRAPMENT, SHOULDER
DIFFERENTIAL DIAGNOSIS o Compression sites: Anterior scalene,

costoclavicular, or pectoralis minor
Common of> M; compression may be neurogenic or
• Thoracic Outlet Synd. (Brachial Plexus) vascular
• Suprascapular Nerve Entrapment o X-ray: Cervical ribs, clavicle deformity
~
OJ Less Common • CT or MR angiography: Vascular injury
:2
::;J • Parsonage-Turner Syndrome • Image with arms in neutral &
£
o • Quadrilateral Space Synd. (Axillary N.) hyperextended position to highlight
(f)
compression
-0 Rare but Important • Suprascapular Nerve Entrapment
Q)
III
l'Il
• Long Thoracic Nerve Syndrome o Compression sites/muscles affected
In • Saturday Night Palsy (Radial Nerve)
2:- • At suprascapular notch: Supraspinatus,
l'Il infraspinatus muscles
U
c: ESSENTIAL INFORMATION • At spinoglenoid notch: Infraspinatus m.
<.> Helpful Clues for Less Common Diagnoses
• Entrapment neuropathy: Nerve function • Parsonage-Turner Syndrome
altered by compression, often at predictable o Acute brachial neuritis; M > F
site of anatomic narrowing o Patchy muscle involvement with
• Symptoms: Muscle weakness, paresthesias, supraspinatus, infraspinatus, deltoid most
muscle atrophy common
• MR: Look for nerve course & contour; • Quadrilateral Space Synd. (Axillary N.)
muscle signal intensity (SI) & distribution o Compression site: Space bounded by
• Look for: Ganglia, tumors, inflammation, triceps (medial), teres minor (superior),
post-trauma, scarring, edema, anomalies teres major (inferior), humerus (lateral)
• Muscle SI in entrapment o Muscles affected: Teres minor, deltoid
o Acute « 1 mo): T1 normal; STIR t SI; Helpful Clues for Rare Diagnoses
enhancement: + • Long Thoracic Nerve Syndrome
o Subacute (1-6 mos): T1 ± normal; STIR t SI; o Compression site: Serratus anterior
enhancement: ± between clavicle & 1st rib
o Chronic (> 6 mos): T1 t SI; STIR ~ SI; o Winged scapula; seen with crutches, sports
enhancement - none • Saturday Night Palsy (Radial Nerve)
Helpful Clues for Common Diagnoses o Compression site: Proximal radial groove
• Thoracic Outlet Synd. (Brachial Plexus) o Muscles affected: Triceps, anconeus
III Sagillal TI WI MR with arms in neutral position shows

the neurovascular bundle ~ passing between Ule
Sagittal T 1WI MR with arms hyperabducted in the same
patient shows flallening of the neurovascular bundle ~
clavicle 11:I & the 1st rib III with no compression in 50 with compression of the brachial plexus between the
year old female. clavicle III & 1s!rib Ill.
14
NERVE ENTRAPMENT, SHOULDER (")
::;,
n
III
-<
OJ
III
Suprascapular Nerve Entrapment VI
C1l
(Left) Coronal T2Wl FS MR Q.
shows a paralabral cyst Ell (j)
extending into the ::T
suprascapular notch" &
o
C
compressing the 0..
(1)
suprascapular nerve, ~
resulting in edema of the
supraspinatus & infraspinatus
muscles (not shown). (Right!
Sagittal PO FSEFS MR shows
a multiseptate cyst ••
compressing the
infraspinatus branch the or
suprascapular nerve as it
passes through the »
spinoglenoid notch Ell with 3
resultant infraspinatus
weakness.
Parsonage-Turner Syndrome Quadrilateral Space Synd. (Axillary N.)

shows edema in the
supraspinatus ••
infraspinatus Hl & deltoid
III muscles in a male with
acute onset shoulder pain in
early stage Parsonage-Turner
syndrome. (Right! Coronal
oblique TlWI MR shows
fatty atrophy of the teres
minor" & deltoid !Ill
muscles due to axillary nerve
neuropathy in quadrilateral
space syndrome
(quadrilateral space Ell). No
compressive lesion is seen;
fibrous bands may account
for the neuropathy.
(Left) Sagittal TI WI MR
shows the normal
relationship of the axillary
nerve" to the adjacent
joint structures including the
humerus [;8 subscapularis
Hl & teres minor !Ill
muscles. (Right! Sagittal TI
C+ FS MR shows the axillary
nerve. being compressed
superiorly toward the normal
shoulder structures including
the humeral head !Ill by a
large heterogeneous
liposarcoma presenting with
fatty Ell & solid ~
components.
III
15
§ ElBOW DEFORMITIES IN CHILDREN AND YOUNG ADULTS
'~"
QJ
o
LL
"0
DIFFERENTIAL DIAGNOSIS Helpful Clues for Less Common Diagnoses
C
Common • Juvenile Idiopathic Arthritis OIA)
'~" o Epiphyseal overgrowth, especially radius;
o • Complication of Fracture Healing
.0
peri-articular osteoporosis, uniform joint
W • Physeal Bar
space narrowing, marginal erosions,
"
<Il
III
III
Less Common periosteal new bone formation
CO • Juvenile Idiopathic Arthritis OIA) • Hemophilia
~ • Hemophilia o Epiphyseal overgrowth (may result in
III
.!:!
• Nontraumatic Radial Head Dislocation deformity), especially radius; peri-articular
c osteoporosis, uniform cartilage loss,
Rare but Important
u subchondral cysts, dense effusion
• Radiation Osteonecrosis • Nontraumatic Radial Head Dislocation
• Congenital Cubitus Valgus o Congenital: Hypoplastic capitellum, radial
• Radius & Ulna, Aplasia/Hypoplasia neck elongated, radial head domed-shaped

& dislocated posteriorly; painless,
decreased extension & supination
ESSENTIAL INFORMATION • Always associated anomalies such as
Helpful Clues for Common Diagnoses Fong disease; never unilateral & isolated
• Complication of Fracture Healing o Developmental: Neuromuscular conditions
o Malunion & nonunion such as cerebral palsy, Ehlers Danlos
o Cubitus valgus: Lateral condyle fracture o Hereditary multiple exostoses, Ollier
• Pain, instability, limited ROM, delayed disease
onset ulnar nerve palsy Helpful Clues for Rare Diagnoses
o Cubitus varus: Malrotated supracondylar • Radiation-Induced Growth Deformities
fracture, leads to ulnar nerve subluxation, o Regional osteoporosis & osseous
cosmetic rather than functional deformity underdevelopment, ± physeal bar
o Fishtail deformity: Gap between • Radiation Osteonecrosis
capitellum & trochlea o Regional osteoporosis, articular surface
• Physeal Bar collapse & fragmentation
o Following trauma, infection, radiation • Congenital Cubitus Valgus
o CT or MR may be required to detect o Turner & Noonan syndromes
• Appears as osseous bridge across physis • Radius & Ulna, Aplasia/Hypoplasia
• Location more important than size o VACTERLsyndrome, TARsyndrome
Complication of Fracture Healing Physeal Bar
III =
Anteroposterior radiograph shows a fracture of the
lateral condyle with proximal displacement, resulting =-
AP radiograph shows old Salter IV fracture of the lateral
condyle with proximal displacement of the
in a cubitus valgus deformity. Reformatted CT (not fragment. The displaced fragment allowed formation of
shown) demonstrated nonunion. a physeal bar, resulting in a cubitus valgus deformity.
16
ElBOW DEFORMITIES IN CHILDREN AND YOUNG ADULTS (")
j
o
III
'<
OJ
III
Juvenile Idiopathic Arthritis (]IA) Hemophilia VI
ltl
shows osteoporosis & m
overgrowth of capitellum •. r::T
When compared to the o
::i
opposite side there is OJ
advanced maturation of :>
a.
radius Ell & olecranon III in "Tl
this patient with }fA. (t MSK o
~
Req). (Right) Oblique CD
OJ
radiograph shows
overgrowth of the radial 3
head epiphysis ••
peri·articular osteoporosis, &
subchondral cysts. in this
individual with hemophilia.
Asymmetric overgrowth may
result in alignment
abnormalities.
Nontraumatic Radial Head Dislocation Nontraumatic Radial Head Dislocation

radiograph shows exostosis
of the proximal ulna •. The
capitellum is hypoplastic Illa
& the radial head is
dome-shaped & dislocated
Ell in this child with radial
head dislocation associated
with multiple hereditary
exostoses. (Right) Lateral
radiograph shows
characteristic congenital
radial head dislocation. The
head has a convex contour &
is dislocated posteriorly"
Additionally, the radial head
is overgrown & is long
relative to the ulna.

shows a hypoplastic radial
head. which resulted in
an increased carrying angle
nail-patella syndrome or
Fong disease. (Right)
shows phocomelia, with
predominance of radial·sided
abnormalities. The ulna ;s
short and bowed" and
the radius is nearly
completely aplastic •.
Other associated anomalies
helped to make the diagnosis
of VACTERLsyndrome.
III
17
E
~ LATERALELBOW PAIN
<tl
Q)
~
o
u..
DIFFERENTIAL DIAGNOSIS o Anterolateral head vulnerable to fracture
"0
C
<tl
due to less supporting bone
;:
Common o CT to assess for occult fracture or
o • Lateral Epicondylitis
.0 associated fractures
W • Radial Head/Neck Fracture • Fall on outstretched hand may also be
"C
Q)
• Radial Head Dislocation associated with scaphoid fracture
VI
III • Capitellar Osteochondritis o Radial head fracture is common in adults
CD
>.
• Capitellar Osteonecrosis • Fracture of the radial neck is more
III • Lateral Condylar Fracture common in children & teenagers
.!:! • Common Extensor Mechanism Injury o Essex-Lopresti fracture
c
u Less Common • Radial head or neck fracture
• Capitellum Fracture • Disrupted forearm interosseous
• Lateral Collateral Ligament Injury membrane
• Radial Head Subluxation (Nursemaid Elbow) • Unstable distal radioulnar joint
• Neoplasm, Bone • Radial Head Dislocation
• Neoplasm, Soft Tissue o Posterior dislocation
• ± Lateral ligament & common extensor
Rare but Important tendon tears
• Radial Neuropathy • ± Capitellar or coronoid fracture
• Synovial Fringe • Capsular disruption
• Hemorrhage
ESSENTIAL INFORMATION o Secondary osteoarthritis occurs late
• Capitellar Osteochondritis
Key Differential Diagnosis Issues o Focal lucency in the capitellum on
• Clinical history of trauma or overuse helpful radiographs
for directing workup o Flattened capitellar articular surface
• Presence of significant effusion favors o Loose bodies in joint
fracture (even when not visible) or an o Check for bilaterality (20%)
inflammatory etiology o Variable signal intensity on MR
Helpful Clues for Common Diagnoses • May have internal & surrounding edema
• Lateral Epicondylitis • Hyperintense fluid deep to lesion on
o a.k.a., "tennis elbow" T2WI indicates a loose fragment
o Radiographs demonstrate soft tissue o Teenage athletic patients
swelling or are normal • Capitellar Osteonecrosis
o Thickening & increased signal of the o Sclerosis of capitellum in younger patient
common extensor tendon on MR than osteochondritis
• Extensor carpi radialis brevis most o More likely to involve the entire
susceptible to tearing/degeneration capitellum than osteochondritis
• Fluid signal intensity is consistent with o Less likely than osteochondritis to have
partial thickness tearing intraarticular loose bodies
o ± Tearing & degeneration of lateral ulnar • Lateral Condylar Fracture
collateral ligament complex o Pediatric: Second most common elbow
o CT arthrography shows contrast fracture
extravasation if capsule is disrupted • Attached common extensor tendon may
• Radial Head/Neck Fracture produce distal retraction of fracture
o Joint effusion almost invariably present fragment
• Anterior fat pad elevated, "sail sign" • MR to evaluate physeal injury
• Posterior fat pad visible o Adult: Lateral condyle fracture involves
o Lucent fracture line(s) on radiographs capitellum ± lateral trochlea
o Low signal fracture line with high signal • May have disruption of lateral collateral
surrounding edema on MR ligament & common extensor tendon
III
18
LATERALELBOW PAIN
o Positive fat pad sign due to effusion o Radial head slips beneath the annular
• Common Extensor Mechanism Injury ligament, which normally lies over the
o Degeneration or tear of common extensor radial neck, becoming trapped between the
tendon components radial head & capitellum
• Extensor carpi radialis brevis has most o Clinically, the joint is held fixed in
lateral location & is injured most often pronation
o Imaging is not typically necessary for
reduction (often occurs with supination)
• Capitellum Fracture
o Fracture usually in the coronal plane
• Neoplasm, Bone
o Lesions in or near the end of bone
• Best seen on sagittal images
• Variable anterior displacement of • Giant cell tumor, chondroblastoma,
capitellar fracture fragment aneurysmal bone cyst, osteoid osteoma,
o Positive fat pad sign
chondrosarcoma, metastasis, myeloma
o Very uncommon in children
• Neoplasm, Soft Tissue
o Synovial sarcoma, nerve sheath tumors,
o Evaluate for associated radial head fracture
malignant fibrous histiocytoma
• Lateral Collateral Ligament Injury
o Components: Radial collateral ligament & Helpful Clues for Rare Diagnoses
lateral ulnar collateral ligament • Radial Neuropathy
o History of trauma or chronic overuse o Look for denervation edema or atrophy in
o Radiographs may be normal or show muscles supplied by radial nerve
malalignment to dislocation • Increased signal on T2WI
• Fractures of coronoid process, capitellum o Associated symptoms of radial tunnel
and/or radial head syndrome
o Arthrography demonstrates extravasation • Pain anterolateral proximal forearm (no
via lateral capsular defect sensation deficit or weakness)
o MR shows disruption of ligament fibers • May be an early posterior interosseous
• Radial Head Subluxation (Nursemaid nerve syndrome
Elbow) o ± Fracture of the humerus
o Radiographs are usually normal • Synovial Fringe
• Radial head subluxation or joint o Thickened triangular synovial fold (plica)
widening is uncommon between radial head & capitellum on MR
o Radiographs & CT may show associated
capite liar lucency or sclerosis
Coronal T2WI FS MR shows increased signal within a

diffusely thickened common extensor tendon origin.
NECT 3D VRT shows a fracture of the radial head and
neck •. The dominant fracture fragment. is rotated
III
at the lateral humeral epicondyle. There is no fluid signal and displaced into the lateral gutter of the joint.
within the origin to indicate (ocaltear.
19
E
~ LATERAL ELBOW PAIN
ctl
~
Ql
o
L.l.
"0
C
ctl
~ Radial Head/Neck Fracture Radial Head Dislocation
o (Left) Oblique radiograph
.0
iIi shows a comminuted
"C
fracture of the radial
Ql head/neck with
VI
C'll
lD
>.
=-
displacement and impaction
This is an Essex-Lopresti
injury. associated with a
C'll disrupted interosseous
o
C
membrane and an unstable
distal radioulnar joint. (Right)
o Lateral radiograph shows
posterior dislocation of the
radial head" There is an
obliquely oriented fracture of
the proximal ulna m. This
combination of injuries is
termed a Monteggia fracture
dislocation.
lucentregion. in the
capitellum without collapse
of the articular surface. This
area of lucency was
enlarging in a teenaged
throwing athlete. (Right)
Sagittal T1WI FS MR
patient a5 the prior image
shows the osteochondral
lesion" in the capitellum.
It is located slightly anterior
along the articular surface.
The lack of fluid extending
beneath the lesion indicates
that it is stable.
Capitellar Osteonecrosis
(Left) Coronal NECT shows
sclerosis and fragmentation
•• of the entire capitellum.
Small fracture fragments .:I
are loose in the joint.
Osteonecrosis began before
the patient was a teenager.
radiograph shows a fracture
•• involving the lateral
condyle of the humerus.
These fractures can be
difficult to detect and it can
be helpful to obtain
radiographs of the opposite
elbow.
III
20
LATERAL ELBOW PAIN C1
::l
C'l
III
'<
[II
III
Common Extensor Mechanism Injury Capitellum Fracture t/l
CD
(Left) Comnal T2WI FS MR c.
shows a focus of high signal
• in the common extensor
!:!!
rr
tendon near the origin on the o
::;:
lateral epicondyle. Fluid III
signal within the tendon :J
a.
indicates a partial thickness "Tl
tear. (Right) NEeT o
~
reformatted 3D VRT shows a CD
OJ
fracture of the capitellum
m. The dominant fracture 3
fragment .:I has flipped
anterior to the radial head.
lateral Collateral Ligament Injury Neoplasm, Bone

shows complete disruption
of both the lateral ulnar
collateral ligament as well as
the lateral collateral ligament
••. Slightly more posteriorly,
there was an extensive
part/althickness tear of the
common extensor tendon
origin. (Right) Oblique
mildly expansile lesion" in
the radial head and neck. In
an adult, the differential
diagnosis includes giant cell
lumor, metastasis, myeloma
and lymphoma.
fLeft) Axial T2WI FS MR

shows moderate edema =:I
in the supinator muscle, a
sign of denervation of the
radial nerve. This is a high
radial neuropathy likely
related to remote trauma,
with mild atrophic changes
in the supinator. (Right)
a large meniscoid structure
•• extending into the
radiocapitellar joint,
consistent with a synovial
fringe. In this case it was
symptomatic; the pain
ceased once it was surgically
removed.
III
21
§ MEDIAL ElBOW PAIN
ro
Q)
~
o
LL
DIFFERENTIAL DIAGNOSIS • Peritendon inflammation
"0
C
ro
• Epicondyle marrow edema
Common • Intermediate to bright T2WI signal
~
o • Medial Epicondylitis
..0 within tendon
W • Medial Collateral Ligament (MCL) Injury • Tendon thickening
"0
Q) • Olecranon Fracture • Medial Collateral Ligament (MCL) Injury
VI
l'Cl • Common Flexor Mechanism Injury o Chronic repetitive trauma
en • Medial Epicondyle Avulsion, Pediatric
>. o Injury to anterior bundle most common,
l'Cl • Coronoid Process Fracture most significant; anterior bundle most
<.l
c • Medial Condylar Fracture important stabilizer in valgus stress
U • Ulnar Neuropathy o Radiographs
• Little Leaguer's Elbow • Ossification late finding
• C8-Tl Radiculopathy (Mimic) oMR
• Median Neuropathy • Periligamentous edema
less Common • Bright T2WI signal within ligament
• Triceps Tendon Rupture • Ligament thickening or discontinuity
• Anconeus Epitrochlearis • Ossification
o MR arthrography
Rare but Important
• "T" sign (extension of contrast between
• Cat Scratch Disease MCL and coronoid process), though may
be normal
ESSENTIAL INFORMATION • Intraligamentous contrast or
extravasation indicative of tear
Key Differential Diagnosis Issues o US with valgus stress demonstrates
• Common mechanism is valgus stress instability with medial joint widening
o Hint: In skeletally immature athlete injury
o Avulsion of sublime tubercle
to physis most common; in adult one sees • Attachment site of anterior band of
injury to medial (ulnar) collateral ligament medial collateral ligament on coronoid
(MCL) and/or flexor-pronator muscle process
group • Olecranon Fracture
o UCL injuries and injuries to
o Fall on outstretched hand with flexed
flexor-pronator group often co-exist elbow or direct blow
• Typically present with medial elbow pain, • Triceps pull creates distraction forces at
may also have loss of grip strength fracture site & may require internal
• Usually in dominant upper extremity fixation
• Flexor-pronator group: Common tendon • Common Flexor Mechanism Injury
origin arising from the medial epicondyle o Sequelae of overuse injury and
o Flexor carpi radialis, flexor carpi ulnaris,
tendonitis/inflammation within the
flexor digitorum superficialis, palmaris flexor-pronator group
longus, pronator teres muscles o Ranges from partial to full thickness tears
Helpful Clues for Common Diagnoses oMR
• Medial Epicondylitis • Peri tendon edema
o Valgus stress overuse injury of • Intratendinous bright T2WI signal
flexor-pronator group • Discontinuity, wavy fibers, gap
• Golf, baseball, tennis o MR arthrography not useful
o Range: Acute inflammation to tendinosis o Ultrasound may identify tear
• May progress to common flexor partial • Medial Epicondyle Avulsion, Pediatric
or full thickness tear o Ossification center appears age 4-6 years
o Associated ulnar neuropathy o 50% associated with elbow dislocation
o MR: Multitude of appearances o Other mechanism: Sudden forceful
• Intermediate Tl WI signal contraction with onset of pain
III
22
MEDIAL ELBOW PAIN (")
='o
III
a Hint: When fragment displaced into joint, a Irregular ossification or overgrowth of
-<
mimics trochlear ossification center medial epicondyle apophysis; widening, tll
III
• Always identify epicondyle ossification irregularity, edema in growth plate III
<ll
center when evaluating pediatric elbow • C8-Tl Radiculopathy (Mimic) C.
• Requires transient joint widening a Degenerative disc disease, disc herniation, m

rr
a May be manifestation of Little Leaguer's impingement in neural foramina o
:E
elbow • Median Neuropathy l\l
:::l
• Coronoid Process Fracture a Tingling/aching in fingers sparing little C.
a Often seen with dislocation finger, extending proximally especially "

o
...,
a Unstable when> 50% coronoid involved base of thumb (l)
l\l
• Medial Condylar Fracture a Weakness of flexor pollicis longus, 3
a Fall with angular force or direct blow pronator teres, pronator quadratus, flexor
a Extension lateral to capitellotrochlear carpi radialis
groove leads to instability a MR changes: See ulnar neuropathy
• Ulnar Neuropathy Helpful Clues for Less Common Diagnoses
a a.k.a. tarda ulnar palsy, cubital tunnel
• Triceps Tendon Rupture
syndrome a May be post-traumatic or associated with
a Entrapment at multiple sites in elbow
underlying conditions such as rheumatoid
region: Intermuscular septum, epicondylar arthritis, hyperparathyroidism
region, ulnar groove, cubital tunnel a Tears range from small intrasubstance tears
a May complicate fracture, dislocation,
to full thickness tears with retraction
overuse injuries • Anconeus Epitrochlearis
a Clinical
a Accessory muscle: Origin medial
• Tingling elbow to hand especially fingers olecranon, insertion medial epicondyle
4 & 5, inability to abduct fingers 4 & 5, a Compresses ulnar n. in cubital tunnel
muscle atrophy
a MR: Nerve may appear normal or may be Helpful Clues for Rare Diagnoses
enlarged, have bright T2WI signal within, • Cat Scratch Disease
or perineural inflammation a Painful adenopathy following cat scratch
• Little Leaguer's Elbow a Mild constitutional symptoms

a Injury during rapid growth, age 9-14 years a Enlarged medial epitrochlear lymph node
• Has resulted in pitching restrictions in characteristic but not common
little league • MR imaging may show an enlarged
lymph node with adjacent inflammation
Medial Epicondylitis
Coronal T2WI FS MR shows edema in Ihe proximal

flexor/pronator muscle bundle III in the medial
Axial PO FSf MR shows inlermediale 10 brighl signal
indicative of moderate tendinopathy of the
III
forearm, superficial 10 Ihe ulnar collaleral ligamenl Elll =:I
flexorlpronalOr lendon origin al the medial humeral
The proximal flexor tendon origin. is intact. epicondyle.
23
E
~ MEDIAL ELBOW PAIN
ell
~
OJ
o
u..
"0
C
ell
~ Medial Collateral ligament (MCL) Injury Medial Collateral Ligament (MCLllnjury
o (Left) Coronal T2WI FS MR
.Q
W shows edema and
"0 irregularity around the
Ql humeral attachment of the
III
III anterior band of the ulnar
al collateral ligament •
~ consistent with a parUallear.
III (Right) Coronal T2WI FS MR
o
C shows poor definition of the
anterior band of the MCL
U consistent with disruption
•. There is diffuse
edema, and mild marrow
edema in the medial humeral
condyle E!ll possibly related
to chronic traction forces.
Olecranon Fracture Common Flexor Mechanism Injury

shows a fracture of the
olecranon process •.
Swelling of the olecranon
bursa HI accompanies this
injury. (Right) Coronal T2WI
FS MR shows a partial tear of
the origin of the forearm
ffexors from the medial
epicondyle aD.
Medial Epicondyle Avulsion, Pediatric Medial Epicondyle Avulsion, Pediatric

shows partial displacement
of the medial humeral
epicondylar ossification
center. from the medial
condyle !Ill There is edema
in the marrow of both
osseous structures, as well as
diffusely in the surrounding
50ft tissues E!ll (Right)
shows the apophysis of the
medial epicondyle avulsed
from the medial humeral
metaphysis and entrapped
within the joint. where it
may be misinterpreted as a
different ossification center.
III
24
MEDIAL ElBOW PAIN C"l
::J
n
Ql
-<
OJ
Ql
Coronoid Process Fracture Medial Condylar Fracture III

CD
(Leh) Sagittal bone CT shows a.
a coronoid process fracture m
•• which frequenlly results CJ
from a dislocation. The a
:;;
fragment is fairly small and OJ
the joint should remain ::J
stable. (Right) .,.,
0.
Anteroposterior radiograph a
~
shows distal humerus <1l
OJ
fracture with a large medial
condyle fragmenl •• which 3
is displaced and impacted.

mild edema in the
subcutaneous fat EiIII
adjacenl to the cubital
tunnel. The ulnar nerve. is
subluxed medially and it is
slightly enlarged in this
patient with ulnar
neuropathy. (Right) Axial
T2WI FS MR shows mild
elevated signal indicating
edema in the pronator teres
muscle" a finding due to
median nerve impingement
by a high humeral fracture.
Anconeus Epitrochlearis
(Leh) Sagittal T2WI FS MR
shows increased signal
intensity within the distal
triceps tendon as well as
retraction and surrounding
hemorrhage, consistent with
a complete tear. (Righi) Axial
T2WI MR shows large
anconeus epitrochlearis
muscle found incidenlally on
MR imaging". The muscle
overlies the cubital tunnel.
The ulnar nerve is normal in
caliber •.
III
25
Eco OLECRANON BURSITIS
~
Q)
o
LL
DIFFERENTIAL DIAGNOSIS o May see marginal, peri-articular,
"0
C
CO
nonarticular erosions which are
:: Common well-defined, with sclerotic margin &
o • Post-Traumatic
.0 overhanging edges; < 15% calcify
W • Wire/Cerclage Fixation • Rheumatoid Arthritis
"0
Q)
• Infectious Bursitis o Commonly bilateral
Ie''""
• Gout o Nodules within bursa may be palpable
>.
• Rheumatoid Arthritis o ± Arthritic changes: Uniform joint space
Less Common narrowing, marginal erosions, osteoporosis
'"
o
c • Rheumatoid Nodule (Mimic) Helpful Clues for Less Common Diagnoses
U • Tophus (Mimic) • Rheumatoid Nodule (Mimic)
• Xanthoma (Mimic) o Firm, smooth, mobile, painless
Rare but Important o May cause pressure erosions, rarely calcify
• Triceps Tendon Rupture o ± Arthritic changes
• Calcific Bursitis o MR: Nonspecific low to intermediate Tl,
bright T2, enhances, ± cystic component
• Tophus (Mimic)
ESSENTIAL INFORMATION o MR: Low to intermediate T1 WI, variable
Helpful Clues for Common Diagnoses on T2WI, diffusely enhance; ± Erosions
• Post-Traumatic • Xanthoma (Mimic)
o Acute or chronic repetitive trauma o Usually bilateral
o Dialysis elbow: Chronic repetitive trauma o Familial hypercholesterolemia,
from pressure on elbow during dialysis cerebrotendinous xanthomatosis
o With acute trauma mayor may not have o US: Hypoechoic lesions
fracture; bursitis may be hemorrhagic o MR: Stippled/speckled signal ± tendon
• Wire/Cerclage Fixation enlargement
o Irritation - bursal inflammation Helpful Clues for Rare Diagnoses
• Infectious Bursitis • Triceps Tendon Rupture
o Unilateral o Hemorrhage may extend into bursa
o Often has preceding history of trauma o Tendon fibers thickened, wavy; ± gap
• Commonly related to direct puncture • Calcific Bursitis
• Gout o Hydroxyapatite deposition disease
o Commonly bilateral o Triceps rupture uncommon complication
Post-Traumatic Infectious Bursitis
III Lateral radiograph shows soft tissue prominence =:I

over the olecranon consistent with olecranon bursitis.
Axial T2WJ MR shows inFectious olecranon bursitis with
an irregular fluid collection in the olecranon bursa III
Given the history of trauma, this likely represents and infiltrative changes in the adjacent fat Ea.
hemorrhagic bursitis.
26
C"l
OLECRANON BURSITIS
:J
n
Ql
-<
OJ
Ql
Rheumatoid Arthritis VI
tD
(Left; Sagittal T1 WI FS MR C.
shows a predominantly
[!}
fluid-signal mass posterior to CT
the olecranon __ The o
triceps tendon is seen
~
III
anteriorto the bursa. in :J
C.
this patient with olecranon 0]
bursitis secondary to gout. o
~
Marker is seen posteriorly CTl
III
Ell (Right) Lateral
radiograph shows 50ft tissue 3
swelling in the region of the
olecranonbursa.
consistent with bursitis, a
typical site of involvement in
Xanthoma (Mimic)
(Left; Lateral radiograph
shows a large sort tissue
mass posterior to the elbow
•• in this patient with
tophaceous gout. The mass
has eroded the olecranon HI
and has calcified III an
uncommon finding. (Right)
Lateral radiograph with 50ft
tissue windowing, shows a
subtle 50ft tissue mass along
the extensor surface of the
elbow Ill. This is a common
location for xanthoma (an
uncommon lesion itself,
which was proven in this
case).
Calcific Bursitis
,.
shows partial tear of the
posterior fibers of the triceps
• -:\-1. Co
< tendon with hematoma HI
interposed between the torn
III and intact III portions of
the tendon, mimicking
olecranon bursitis. (Right)
extensive dense
mineralization in the region
of the olecranonbursa.
indicative of hydroxyapatite
deposition disease.
III
27
§ NERVE ENTRAPMENT, ELBOW & WRIST
C1l
Q)
~
a
LL
"0
DIFFERENTIAL DIAGNOSIS o MR: Median nerve enlargement ±
C
C1l
flattening, t SI; flexor retinacular bowing
;:
Common o Post-operative findings
a • Carpal Tunnel Syndrome
.0 • Symptom free: Flexor retinaculum
w • Cubital Tunnel Syndrome completely disrupted with palmar
'0
ell
l/l
Less Common migration of tunnel contents
III
ell • Pronator Syndrome • Recurrent symptoms: Look for
>- • Radial Entrapment Neuropathy incomplete release, post-op scarring,
III
(,J o Radial Tunnel Syndrome nerve enlargement, tenosynovitis
C o Posterior Interosseous Nerve Syndrome • Cubital Tunnel Syndrome
(.)
• Ulnar Tunnel Syndrome o Ulnar nerve at elbow; 2nd most common
upper extremity entrapment
Rare but Important
o Symptoms
• Wartenberg Syndrome • Pain/paresthesias radiating from forearm
• Kiloh Nevin Syndrome to 4/Sth fingers & aggravated by
prolonged elbow flexion
ESSENTIAL INFORMATION o Entrapment sites
• Struthers arcade, intermuscular septum
Key Differential Diagnosis Issues medial edge, thickened arcuate ligament,
• Entrapment neuropathy: Short segment anconeus epitrochlearis, deep flexor
nerve compression at a specific site, often aponeurosis
while passing through fibroosseous tunnel, o MR: t SI & nerve enlargement; ± ulnar
muscle or fibrous tissue nerve subluxation
• Symptoms: Muscle weakness, paresthesias, o Denervation patterns: Flexor carpi ulnaris,
atrophy flexor digitorum profundus muscles;
• MR appearance: Look for nerve signal, interossei muscle wasting
course & contour (adjacent vessels may
provide landmarks); muscle signal intensity Helpful Clues for Less Common Diagnoses
(SI) & distribution • Pronator Syndrome
• Look for: Ganglia, tumors, inflammation, o Median nerve at elbow
post-trauma, scarring, edema, anomalies o Symptoms
• Muscle SI in entrapment/denervation • Volar forearm pain, worse with exercise;
o Acute « 1 month): T1 - normal; STIR- t SI; thenar muscle weakness; radial-sided (1st
enhancement: + - radial 4th fingers) paraesthesias
o Subacute (1-6 months): T1 - ± normal; STIR o Entrapment sites
- t SI; enhancement: ± • Supracondylar process, Struthers arcade,

o Chronic (> 6 months): T1 - t SI; STIR - ~ SI; lacertus fibrosis (bicipital aponeurosis),
enhancement - none pronator teres, proximal arch of flexor
digitorum superficialis
Helpful Clues for Common Diagnoses o Denervation pattern: Pronator teres, flexor
• Carpal Tunnel Syndrome carpi radialis, palmaris longus, flexor
o Median nerve at wrist; most common
digitorum superficialis
upper extremity entrapment • Radial Entrapment Neuropathy
o Symptoms o Radial nerve at elbow
• Radial-sided (1st - radial 4th fingers) o Symptoms
numbness, tingling; thenar muscle • Deep forearm pain, weakness; loss of
wasting extension at fingers & wrist
o MR & ultrasound useful but specificity
o Entrapment sites
limited • Fibrous bands arising from
o Entrapment site radiocapitellar joint
• Transverse carpal ligament (flexor • Tendinous edge of extensor carpi radialis
retinaculum) brevis (2nd most common)
III
28
NERVE ENTRAPMENT, ELBOW & WRIST n
:J
o
1\I
• Radial recurrent artery & branches (leash o Affected muscles: Palmaris brevis,
-<
of Henry) hypothenar, lateral lumbrical , interosse~, []l
1\I
• Arcade of Frohse (most common) adductor pollicis, flexor, profundus breVIS, III
nl
• Fibrous band at distal supinator muscle abductor digiti minimi 0-
o Syndromes named for symptom pattern m

Helpful Clues for Rare Diagnoses CT
o Radial Tunnel Syndrome o
• Wartenberg Syndrome ~
• Posterior interosseous nerve (PIN) o Superficial radial nerve at distal forearm;
Ql
:J
compression with sensory symptoms but known as watch strap or handcuff
0-
-n
no motor deficits neuropathy o
,
nl
o Posterior Interosseous Nerve Syndrome o Symptoms
Ql
• PIN compression with primary motor • Pain/paraesthesias around distal radial 3

symptoms forearm & dorsal radial hand
• Denervation patterns: Isolated supinator o Most commonly due to tight cast or
> > supinator & extensors postop scarring
• Ulnar Tunnel Syndrome o Entrapment sites
o Ulnar nerve at wrist; known as Guyon
• Nerve in subcutaneous tissue as it exits
canal syndrome between brachioradialis & ECR longus
o Symptoms tendons
• 4/5 digit pain & paresthesias, cold • Kiloh Nevin Syndrome
intolerance; results from blunt trauma o Median nerve, anterior interosseous
(neurologic counterpart to hypothenar branch at elbow
hammer syndrome) o Symptoms
o Compression may occur at • Pure motor deficits of flexor pollicis
• Zone 1 (proximal palmar carpal ligament longus, 2nd flexor digitorum profundus,
to ulnar nerve bifurcation) - results in pronator quadratus
combined motor/sensory deficits • Distinguished from pronator syndrome
• Zone 2 (ulnar nerve bifurcation to by complete absence of sensory deficit
hypothenar muscle fibrous arch, radial to o Entrapment sites
hamate hook) - pure motor deficits (least • Flexor muscle along interosseous
common) membrane
• Zone 3 (parallels zone 2, ulnar to hamate o Hint: Image elbow & forearm to fully
hook) - pure sensory deficits evaluate
Carpal Tunnel Syndrome
Axial T2WI F5 MR shows flexor retinaculum bowing E!lI

& perilendinous thickening • in carpal tunnel
Axial T2WI F5 MR shows carpal runnel release 11II with
palmar migration of tendons with residual scarring near
III
syndrome. Deep soft tissue edema ~ contributes to hamate hook ~ Median nerve E!lI is mildly enlarged
symptoms. Median nerve. is normal. with normal 51.
29
E
~ NERVE ENTRAPMENT, ELBOW & WRIST
I1l
~
o
U.
"0
c:
I1l
~ Carpal Tunnel Syndrome Carpal Tunnel Syndrome
o
.0
[jJ
"0
a lipoma =
within the
carpal tunnel, displacing the
Ql tendons, & median nerve
II)
III flattening 1m with
I:ll radial-sided palm & finger
~ numbness, typical of carpal
III tunnel syndrome. (Right)
.!:! Axial TlWI MR shows a
c:
carpal tunnel mass ~ due to
u fatty stroma interdigitating
with median nerve fascicles
~ This is a fibrolipomatous
hamartoma. Note tendon
displacement & retinaculum
bowing.
Carpal Tunnel Syndrome Cubital Tunnel Syndrome

shows marked flexor
tenosynovitis" with fluid
displaced proximally &
distally by pressure of the
flexor retinaculum EiIlI.
Median nerve'" is palmarly
displaced & slightly enlarged
in this mycobacterium avium
tenosynovitis. (Right) Axial
T2WI FS MR shows ulnar
nerve t 51& enlargement ••
in this cubital tunnel
syndrome resulting from
direct blow injury to the
posteromedial elbow. Note
surrounding 50ft tissue
edema EiIlI.
Cubital Tunnel Syndrome Pronator Syndrome

a large anconeus
epitrochlearis muscle ••
over the cubital tunnel. This
could create cubital tunnel
entrapment of ulnar nerve
Elil particularly when the
elbow is flexed. (Right) AP
radiograph shows a
supracondylar process
("avian spur") as a
corticated osseous
excrescence •. The
ligament of Struthers may
arise from this, creating
potential median nerve
entrapment HI as the
pronator teres contracts.
III
30
NERVE ENTRAPMENT, ElBOW & WRIST n
j
n
III
'<
tll
III
Pronator Syndrome Radial Entrapment Neuropathy t/I
(l)
(Left) Axial T2WI FS MR Q.
shows pronator teres edema
[!J
•• in a patient with pronator c-
syndrome due to median O
:E
nerve entrapment following Ql
humerus fracture. There is no :>
muscle atrophy on T1WI, ,.,
0-
suggesting a reversal o
~
neuropathy. (Right) Coronal C1l
Ql
T1WI MR shows the normal
sharp proximal margin o( the 3
supinator;, the arcade of
Frohse III under which the
radial nerve, deep branch,
~ must pass. This is a
frequent site of radial nerve
entrapment.
Posterior Interosseous Nerve Syndrome

posterior interosseous nerve
iii engulfed by a
compressive lipoma.
resulting in posterior
interosseous nerve syndrome
with motor weakness
involving the supinator &
wrist extensors. (Right) Axial
T1WI MR shows mild fatty
atrophy IIlI of the supinator,
typical of chronic posterior
interosseous nerve syndrome
due to remote trauma. There
is mild edema in this same
distribution on STIR imaging
(not shown).

shows post-lraumatic
thickening of palmar
aponeurosis III causing
ulnar tunnel syndrome with
impingement of the ulnar
nerve 11II in distal Guyon
canal. (Right) Axial TI WI MR
shows ulnar tunnel
syndrome at Guyon canal
due to hamate hook fracture
nonunion •. The fragment
III impinges on Guyon canal
lEa in zone 1, resulting in
both motor & sensory
deficits.
III
31
"0
C WRIST CliCKI NG/ClU N KING/I NSTABILITY
co
I
"0
C
co DIFFERENTIAL DIAGNOSIS • Scapholunate Ligament Tear
en o Arthrography: Visible contrast through
Common scapholunate (SL) space; ± SL widening> 4
~
"'C
• Triangular Fibrocartilage Tear mm
ell
l/)
• Scapholunate Ligament Tear o MR or CT arthrography: Sensitivity for
'"
CO • Lunotriquetral Instability complete & partial tears - 80-95%; MR
Z. • Carpal Instabilities without arthrography - 70%
o Dorsal Intercalated Segment Instability
.~
'"
c
o May have tear without malalignment or
o Volar Intercalated Segment Instability symptoms due to degenerative attrition
U o Palmar Midcarpal Instability o SL dissociation with scaphoid rotatory
• Perilunate Instability subluxation
• Osteonecrosis • Widening of SL space, scaphoid volar tilt
Less Common creates a "ring" of distal scaphoid pole
• Tendon, Injury • Lunotriquetral Instability
• Ganglion Cyst, Wrist o Lunotriquetral (LT) tear contributes to
• Fracture, Malunion several carpal instability patterns
• Hardware Complications o Arthrography: Visible contrast flow
• Distal Radioulnar Joint Instability between lunate & triquetrum
o MR or CT arthrography: Sensitivity
Rare but Important
70-90%; MR without arthrography 45%
• Carpal Translocation • Carpal Instabilities
• Madelung Deformity o Dorsal Intercalated Segment Instability
• (DlSI): Seen in SL tear, RA, CPPD,
ESSENTIAL INFORMATION scaphoid fracture
• Lunate dorsal tilt> 20°; SL angle> 70°;
Key Differential Diagnosis Issues capitolunate (CL) angle> 20°; lunate
• Instability - joint malalignment may be triangular on AP X-ray
static or dynamic o Volar Intercalated Segment Instability
• Due to trauma, chronic attenuation of • (VISI): Seen in LT tear, RA, CPPD
supporting ligaments, arthritis • Lunate volar tilt> 20°; SL angle < 30°; CL
• Click/clunk may be audible/palpable; ± angle> 20°; lunate rounded on AP x-ray
painful o Palmar Midcarpal Instability
• Imaging techniques • Distal carpal row translated volarly while
o Radiography should include neutral &
proximal row stays flexed; extreme ulnar
stress views deviation - proximal row snaps back
o Videofluoroscopy to evaluate motion of
• Failure of volar (arcuate,
proximal, distal carpal rows through range triquetrohamate, capitolunate) & dorsal
of motion (ROM) (radiotriquetral) ligaments
o Arthrography (± digital subtraction) to
o Other instability patterns:
evaluate ligament integrity Triquetrohamate, triquetrolunate related
o CT to evaluate fractures; alignment
to stabilizing ligament disruption
o MR ± arthrography to evaluate ligament,
• Perilunate Instability
tendon integrity; alignment o Fracture/dislocations disrupt key
Helpful Clues for Common Diagnoses perilunate ligaments in predictable order
• Triangular Fibrocartilage Tear o 1: SL tear ± scaphoid rotatory subluxation
o May be traumatic or attritional ranging o 2: Radiocapitate tear; perilunate
from mild wear to full tear with ulnocarpal dislocation
abutment o 3: Volar radiotriquetral, dorsal radiocarpal
o Ulnocarpal abutment: Ulnar positive (plus) tears; midcarpal dislocation
variant, triangular fibrocartilage (TFC) tear, o 4: Dorsal radiocarpal tear; lunate
lunate/triquetral edema, cyst, osteophytes dislocation
III
32
WRIST ClICKI NG/ClU NKI NG/I NSTABILITY
• Osteonecrosis o Misplacement, hardware fracture,

o Scaphoid osteonecrosis (AVN) may occur loosening
after scaphoid fracture • Distal Radioulnar Joint Instability
o Lunatomalacia (Kienbock disease) o Associated with trauma or arthritis;
associated with ulnar minus variant, associated TFC tear often present ~
::!.
trauma o Dorsal instability most common (unable to ~
o Clicking/clunking seen in advanced stage supinate); volar less common (unable to OJ
:J
AVNwith collapse resulting in proximal a.
pronate)
I
capitate migration, SL dissociation o X-ray: Prominent ulnar head ± widened OJ
:J
joint a.
o Axial CT/MR: Evaluate subtle instability
• Tendon, Injury
o Ranges from tendinosis (thickening &
• Acquire in supination & pronation to
intrasubstance t SI) to complete disruption accentuate abnormalities
(tear or avulsion) • Image both wrists simultaneously for
o Tenosynovitis results from trauma,
comparison
arthritis, infection in tendon sheath, ± Helpful Clues for Rare Diagnoses
tendon injury • Carpal Translocation
• De Quervain tenosynovitis: Abductor o Defined as ulnar shift of entire carpus
pollicis longus (APL), extensor pollicis relative to radius
brevis (EPB) inflammation o Most common: Ulnar translocation
• Extensor carpi ulnaris (ECU) associated with rheumatoid arthritis
subluxation/dislocation: Occurs with tear o Dorsal & palmar carpal translocation may
of fibrous subsheath that normally holds also occur, associated with distal radial
tendon in ulnar groove through ROM trauma
• Ganglion Cyst, Wrist • Madelung Deformity
o Thin-walled ± septations, usually solitary; o Radius: Dorsal/ulnar curvature; decreased
commonly dorsal near SL ligament radius length; triangular radial epiphysis
• Fracture, Malunion o Ulna: Dorsal subluxation, ulnar head
o Contributes to instability patterns, both at enlargement
time of injury with accompanying o Carpals wedged between radius & ulna
ligament injury & with subsequent with lunate at apex
malalignment
• Hardware Complications
Triangular Fibrocartilage Tear
Coronal T1WI FS MR arthrogram shows disruption ••

of radial aspect of TFC arUcular disc __ Contrast flows
Coronal T2* eRE MR shows triangular fibrocarUlage
lear iii with secondary osteoarthritis characterized as
III
through the disruption into both the distal radioulnar carUlage loss & subchondral cyst formation •
joint and radiocarpal joint. representing ulnocarpal abutment.
33
WRIST
[_________ CLICKING/ClUNKING/INSTABILITY
-----1
radiograph shows
scapholunate interval
widening> 4 mm ~ when
hand is fisted & radially
deviated, consistent with SL
ligament tear. (Right)
Coronal T2' CRE MR
following a radiocarpal
arthrogram shows contrast
flowing into the midcarpal
compartment through a
defect in the SL ligament _
The TFCis intact •.

shows a flap tear of the
lunate triquetralligament _
with contrast crossing from
the radiocarpal joint into the
midcarpal joint. There is also
ulnar positive variance, & an
associated TFC tear •.
shows dorsal intercalated
segmental instability, or
alternatively dorsiflexion
carpal instability. Lunate.
is dorsiflexed relative to
capitate ElII with a CL angle
which is > 20° & SL angle>
70°.
Volar Intercalated Segment Instability Perilunate Instability

shows volar intercalated
segmental instability (VIS/).
Lunate. is volar flexed
relative to capitate ElII &
scaphoid. with CL angle>
20 ° & SL angle < 30°. Note
osteopenia related to RA.
shows lunate. maintaining
normal articulation with
radius. while capitate ••
is dorsally dislocated from
the lunate. This is a
perilunate dislocation. Note
remainder of carpus moves
dorsally with capitate.
III
34
WRIST CLiCKI NG/CLU NKI NG/I NSTABI L1TY ()
::J
o
III
'<
DJ
III
Osteonecrosis Tendon, Injury VI
Cll
(Left) Coronal T1 WI MR a.
shows scaphoid
osteonecrosis III (~51 with
flattening & early collapse)
from prior midwaist
scaphoid fracture" Note
the triangular lunate contour
&II due to associated 0151
deformity. (Right) Axial PO
F5E F5 MR shows marked
tendon thickening & t 51 01
APL & EPB (1st extensor
compartment) &II with
surrounding edema, typical
of De Quervain
tendinitis/tenosynovitis. ECU
tenosynovitis. is also
present.
Tendon, Injury Ganglion Cyst, Wrist

(Left) Axial PO F5E F5 MR
shows ORUj effusion &II
with fluid in ECU tendon
sheath as well. The ECU is
torn longitudinally'" &
subluxated from the ulnar
groove'" due to disruplion
of the fibrous subsheath that
normally maintains feU
position through ROM.
(Right) Axial PO F5E F5 MR
shows a thin-walled dorsal
ganglion &II with a small tail
III directed toward the
scapholunate joint in this 14
year old who complained of
wrist clicking with joint
rotation.
Hardware Complications
bicorticalscre\1Y, used to
secure a volar plate that
stab;J;zes a distal radial
fracture. The screw extends
beyond the radial dorsal
cortex'" & impinges 2nd &
3rd extensor compartment
tendons &II during normal
ROM. (RighI) PA radiograph
shows carpal ulnar
translocation, defined as
lunate articulating> 50%
with ulna &II. Radiocarpal
joint space loss •. scaphoid
rotation & erosion EB ulnar
capping. & osteopenia are
typical of RA.
III
35
"0
C ULNAR SIDED WRIST PAIN
C1l
I
"0
C
C1l DIFFERENTIAL DIAGNOSIS • Early: Juxta-articular osteopenia, soft
en tissue swelling
Common • Later: Diffuse osteopenia, accelerated
~
• Arthritis maturation, enlarged carpals with
• Triangular Fibrocartilage Tear irregular margins (crenulation), ankylosis
• Lunotriquetral Instability • Triangular Fibrocartilage Tear
• Ulnocarpal Abutment o Traumatic: Hyperrotation, distraction or
Less Common axial loading; associated with distal
• Tendon Injury forearm fractures
• Fractures o Degenerative: Ranges from mild wear to
• Carpal Dislocations fuIl tear with ulnocarpal abutment; many
• Osteonecrosis are asymptomatic
• Infection o X-ray: Look for ulnar plus variant
o Arthrography (± digital subtraction):
Rare but Important Visible contrast flow through TFCC
• Vascular Abnormalities o MR or CT arthrography: Sensitivity
• Osseous Neoplasm 80-95%; MR without arthrography 30-45%
• Soft Tissue Neoplasm • Lunotriquetral Instability
• Madelung Deformity o Tears due to trauma with hyperextension
& radial deviation
ESSENTIAL INFORMATION o Volar intercalated segment instability
(VISI) results in volar flexed lunate,
Key Differential Diagnosis Issues scapholunate angle < 30°, capitolunate
• Ulnar & radial wrist pain etiologies often angle> 20°
overlap o Arthrography (± digital subtraction):
Helpful Clues for Common Diagnoses Visible contrast flow between lunate &
• Arthritis triquetrum
o Rheumatoid arthritis o MR or CT arthrography: Sensitivity
• Early: Symmetric swelling, juxta-articular 70-90%; MR without arthrography 30-45%
osteopenia, subtle erosions • Ulnocarpal Abutment
• Late: Diffuse osteopenia, joint space loss, o Swelling & tenderness localized to TFCC,
large erosions, ulnar carpal translocation, LT joint
ulnar capping o X-ray: Ulnar plus variant, triquetral &
• Contrast-enhanced MR: Effusions, lunate cysts, sclerosis, osteophytes
synovitis, synovial hypertrophy, active o MR: TFCC tear, triquetral & ulnar side of
(enhancing) & inactive (nonenhancing) lunate chondromalacia, edema, cysts
erosions Helpful Clues for Less Common Diagnoses
o Osteoarthritis
• Tendon Injury
• Normal bone density, joint space loss, o Ranges from tendinosis (thickening &
subchondral sclerosis, osteophytes; intra substance t SI) to complete disruption
typically due to trauma (tear or avulsion)
o Pyrophosphate arthropathy
o Tenosynovitis results from trauma,
• Multiple well-defined intraosseous cysts, arthritis, or infection in tendon sheath
radiocarpal & capitolunate joint space o Extensor carpi ulnaris (ECU)
narrowing, TFCC chondrocalcinosis tendinitis/tenosynovitis: Thickened
o Gout
tendon ± sheath fluid
• Normal bone density, soft tissue swelling o ECU subluxation: Occurs in supination
& calcifications, punched-out erosions due to ECU subsheath tear; tendon
with sclerotic borders, especially in displaced ulnarward out of ulnar groove
CMCs • Fractures
o Juvenile idiopathic arthritis o Triquetrum: Commonly fractured
III
36
ULNAR SIDED WRIST PAIN (")
:l
o
III
• Joint capsule avulsion or ulnar styloid o History of diabetes, inflammatory arthritis,
immunocompromise, puncture wounds,
-<
impaction results in small dorsal III
III
fragment best seen on lateral X-ray open fracture VI
lD
• Body fractures typically associated with o Septic joint: Extensive effusion of one or a.
other injuries, e.g., perilunate more compartments, ± carpal edema .~,
transtriquetral fracture dislocation o Osteomyelitis: Marked osteopenia; cortical ~
o Hamate loss, joint mal alignment OJ
:l
0.
• Hook: Direct blow or repetitive stress, Helpful Clues for Rare Diagnoses I
e.g., carpenters, golfers, racquet sports; • Vascular Abnormalities
OJ
:l
0.
best seen on carpal tunnel view or CT o Hypothenar hammer syndrome:
• Body: Rare; often associated with 4th, Thrombosis, spasm, or aneurysm of ulnar
5th CMC fractures artery due to repetitive trauma; may
o Ulnar styloid: Isolated or in combination
compress adjacent ulnar nerve
with other injuries o Arteriography: Narrowing, occlusion, or
• Nonunion common but rarely aneurysm of ulnar artery adjacent to
symptomatic hamate hook
• If fracture at styloid base & TFCC
• Osseous Neoplasm
disrupted, distal radioulnar joint may be o Benign: Giant cell tumor, enchondroma,
unstable osteoid osteoma
• Carpal Dislocations o Malignant: Squamous cell metastases
o Occur in combination with fractures as an
• Soft Tissue Neoplasm
ulnarward extension of scapholunate (SL) o Benign: Ganglion, GCTTS, hemangioma,
instability/trauma tendon sheath fibroma, neurogenic tumor
• Osteonecrosis o Malignant: MFH, synovial sarcoma,
o Lunate: Kienbock disease (lunatomalacia);
angiosarcoma, fibrosarcoma
associated with ulnar minus, trauma
• Madelung Deformity
o Stage 1: X-ray-normal; MR T1 ~ SI & T2 t SI
o Radius: Dorsal/ulnar curvature; decreased
o Stage 2: X-ray-sclerosis; MR T1 ~ & T2 t SI
radius length; triangular radial epiphysis
o Stage 3: X-ray-collapse, proximal capitate
o Ulna: Dorsal subluxation, ulnar head
migration, SL dissociation, scaphoid enlargement
rotatory subluxation; MR T1 & T2 ~ SI o Carpals wedging between radius & ulna
o Stage 4: X-ray-secondary osteoarthritis of
with lunate at apex
surrounding carpus MR T1 & T2 ~ SI
• Infection
Arthritis Arthritis
Posteroanterior radiograph shows rheumatoid

with diffuse osteopenia and joint space erosions
1055 ••
arthrWs Coronal T1 c+
hamate erosion HI
F5 MR shows an enhancing ulnarward
& synovitis. in this 59 year old
III
~ & carpal ulnar trans/ocaUon. Ulnar capping Ell woman with rheumatoid arthritis.
(osseous lip around distal ulna) is present.
37
"0
C ULNAR SIDED WRIST PAIN
co
I
"0
C
co
en
'C
~ Arthritis
'tl
Ql triangular fibrocartilage
III
ltI chondrocalcinosis III in this
en pyrophosphate arthropathy
.?:- as well as multiple
ltI intraosseous cysts ~. A
o scapholunate advanced
C
collapse (SLAC) wrist
U deformity is present ffi
nodular 50ft tissue
calcification surrounding
ulnar styloid E!!I (atypical for
chondrocalcinosis),
representing a gouty tophus
in this young Polynesian
man. Note the small ulnar
erosion [;8
Arthritis
radiograph shows
osteoarthritis with distal
radioulnar joint space
narrowing & a small
osteophytic ridge. along
the proximal ulnar head in
this patient with prior distal
radial fracture treated by
ORIF Ii8. (Right) Sagittal PO
FSEFS MR shows
pisotriquetral osteoarthritis
with joint space narrowing
=-
and a small osteophytic ridge
as well as joint effusion
E!!I & a small loose body ~
in the proximal capsular
recess.
radiograph arthrogram
shows typical triangular
fibrocartilage tear,
highlighted by radiocarpal
contrast flowing through the
tear ~ and filling the distal
radioulnar joint E!!I. (Right)
Coronal T2* CRE MR shows
a central triangular
fibrocartilage tear EiIl This is
well· visualized, in part due
to effusions in all three wrist
compartments _
III
38
ULNAR SIDED WRIST PAIN
Lunotriquetrallnstability Lunotriquetrallnstability
radiograph arthrogram
shows flow of radiocarpal ~
::!.
contrast between the lunate !e.
& triquetrum. intothe OJ
:::J
midcarpal compartment a.
through the lorn I
OJ
lunotriquetralligament. :::J
(Right) Coronal MR a.
arthrogram (T7 WI F5) in the
same patient shows
gadolinium extending
through the lunouiqueual
ligament. & into
midcarpal compartment. The
scapholunate ligament III &
triangular fibrocartilage E!II
are intact.
Ulnocarpal Abutment Ulnocarpal Abutment

radiograph shows ulnar plus
variance ~ (ulna longer
than radius) resulting in
impaction of ulna on lunate.
This leads to sclerosis & cyst
formation. at point of
impact. (Right) Coronal
T7WI MR shows ulnocarpal
abutment with a central
triangular fibrocartilage tear
• in combination with
ulnar plus variance. The
ulnarward lunate shows
subchondral low 51 EiIl
representing cyst &/or
sclerosis {rom impaction.
Tendon Injury Tendon Injury

(Left) Axial PO F5f F5 MR
shows a distal radioulnar
joint effusion. &
tenosynovitis. surrounding
extensor carpi ulnaris (EeU).
fCU is flattened with a
spliHype inlrasubstance tear
~ & ulnar ward tendon
subluxation. (Right) Axial T7
C+ F5 MR shows marked
synovial hypertrophy.
with small accompanying
tendon sheath effusions.
of all extensor compartments
in 33 year old woman with
new onset rheumatoid
arthritis & extensor
tenosynovitis.
III
39
Fractures Fractures
'tl
Cll shows dorsal soft tissue
VI
III swelling & a small fracture
al fragment from the dorsal
~ triquetrum •. This may
III result from capsular avulsion
o
or direct impact of the ulna
c::
on the triquetrum. (Right)
U Axial NECT shows an acute
fracture ~ of the hamate
hook Ii8 This is a
nondisplaced fracture & may
result from direct impact
during activities such as golf
(impact from club hitting the
turf).
Fractures Fractures
radiograph shows
comminuted intraarlicular
5th metacarpal base fracture
EiII with slight ulnarward
subluxation. CT (not shown)
confirmed this as an isolated
fracture. (Right)
shows a well-corticated
osseous fragment. near
the ulnar styloid"
representing a chronic
non-union. Mild
osteoarthrWs of the adjacent
distal radiocarpal joint is
present with a small
osteophytic ridge Ii8
Carpal Dislocations Carpal Dislocations

radiograph shows a
transradial, transscaphoid,
transtriquetral perilunate
fracture dislocation with
fractures of radius __
scaphoid Ei/I, & triquetrum
III as well as loss of normal
lunate contour EB (Right)
same patient confirms a
perifunate dislocation with
dorsal dislocation of the
capitate III but intact
radial-lunate articulation EiII
in this complex fracture
dislocation.
III
40
Osteonecrosis Osteonecrosis
radiograph shows increased
density of the lunate Ell with
no contour abnormality or
fragmentation. This is stage 2
Kienbock disease. (Right)
Coronal TlWI MR shows
grade 3 Kienbock disease
with partial collapse Ell of
the lunate. The scapholunate
ligament is still intact, but the
cortical fragmentation IIlI
indicates more advanced
disease.
Infection Vascular Abnormalities

shows Mycobacterium
avium septic
arthritis/osteomyelitis with
extensive erosion of the ulnar
styloid E!ll disruption of the
distal radioulnar joint. &
joint effusion with associated
synovial hypertrophy ~.
(Right) PA angiogram with
digital subtraction shows an
ulnar artery aneurysm IIEI
just distal to the hamate
hook Ell in 50 year old auto
repairman, who pounds out
fender dents with his palm.
This is hypothenar hammer
syndrome.
Osseous Neoplasm Madelung Deformity

enchondromatosis (Oilier
disease) with a markedly
foreshortened distal ulna
with chondroid calcification
of the bulbous ulnar head
Ell. Note the multiple
enchondromas III of the
fingers as well. (Right)
shows Madelung deformity
with distal radial bowing E!ll
distal radioulnar joint
dislocation _ & dorsal
displacement of the ulnar
head 11II. The carpals are
wedge-shaped.
III
41
D
c: RADIAL SIDED WRIST PAIN
ro
I
D
c:
ro DIFFERENTIAL DIAGNOSIS • Late: Diffuse osteopenia, joint space loss,
iii large erosions, ulnar carpal translocation
Common • Contrast-enhanced MR: Effusions,
~
• Fracture synovitis, synovial hypertrophy, active
• Arthritis (enhancing) & inactive (nonenhancing)
• Ganglion Cyst, Wrist erosions
• Tendon, Injury a Osteoarthritis
• Scapholunate Ligament Tear • Normal bone density, joint space loss,
Less Common subchondral sclerosis, osteophytes;
• Carpal Instabilities particularly in 1st CMC,
• Carpal Dislocations scaphoid-trapezium area
• Osteonecrosis, Wrist (Scaphoid & Lunate) • Carpal boss: Prominent dorsal ridge 2nd
• Infection CMC best seen on CT; ± symptomatic
a Pyrophosphate arthropathy
Rare but Important • Multiple well-defined carpal cysts,
• Osseous Neoplasm radiocarpal & capitolunate joint space
• Soft Tissue Neoplasm loss
• Madelung Deformity • Scapholunate advanced collapse (SLAC)
wrist: SL dissociation, lunate
ESSENTIAL INFORMATION dorsiflexion, radioscaphoid joint loss,
capitate between scaphoid & lunate
Key Differential Diagnosis Issues a Gout
• Radial & ulnar wrist pain etiologies often • Normal bone density, soft tissue swelling
overlap & calcifications, punched-out erosions
Helpful Clues for Common Diagnoses with sclerotic borders, especially in
• Fracture CMCs
a Fall on an outstretched hand (FOOSH) a Juvenile idiopathic arthritis
• 4-10: Distal radial metaphysis buckle • Early: Juxta-articular osteopenia, STS
• 11-16: Distal radius Salter II • Later: Diffuse osteopenia, accelerated
• 17-40: Scaphoid, ± triquetrum maturation, enlarged carpals, irregular
• 40: Colles fracture, distal radius margins, ankylosis
a Scaphoid: Most common carpal fracture • Ganglion Cyst, Wrist
• Early: X-ray - loss of scaphoid fat pad, a Thin-walled ± septations, usually solitary;
subtle cortical irregularity; MR - t SI commonly dorsal near SL ligament
edema; more sensitive • Tendon, Injury
• Healing: Midwaist/proximal pole fracture a Ranges from tendinosis (thickening &
complications-AVN, delayed or intrasubstance t SI) to complete disruption
non-union (tear or avulsion)
• Delayed/non-union: Sclerosis, cysts, a Tenosynovitis results from trauma,
scapholunate (SL)widening, OA arthritis or infection in tendon sheath

a Fractures of other radialward carpals rare a De Quervain tenosynovitis: Abductor
a Radial styloid: Due to ligament avulsion or pollicis longus (APL), extensor pollicis
direct blow; look for other fractures brevis (EPB) inflammation
a 1st CMC: Look for subtle volar lip a Intersection syndrome: Extensor carpi
(Bennett) fracture radialis longus/brevis inflammation at

• Arthritis musculotendinous junction; may also
a Rheumatoid arthritis involve APL/EPB
• Early: Symmetric soft tissue swelling, • Scapholunate Ligament Tear
juxta-articular osteopenia, subtle a Arthrography (± digital subtraction):
erosions Visible contrast through SL interspace; ± SL
widening> 4 mm
III
42
RADIAL SIDED WRIST PAIN n
::::l
n
III
o MR or CT arthrography: Sensitivity for • Stage 3: X-ray-collapse, proximal capitate
complete & partial tears - 80-95%; MR migration, SL dissociation, scaphoid
-<
C:J
III
without arthrography - 40-70% rotatory subluxation; MR - TI & T2 ~ Sl Ul
tD
Helpful Clues for less Common Diagnoses • Stage 4: X-ray-secondary OA; MR - T1 & Co
T2 ~ SI ~
• Carpal Instabilities ::::l.
o Volar intercalated segment instability
• Infection !e-
o History of diabetes, inflammatory arthritis, Q)
::::l
(VISI): Seen in LT tear, RA, CPPD a.
immunocompromise, puncture wounds,
• Lunate volar tilt> 200; SL angle < 300; CL I
angle> 200; lunate rounded on AP open fracture Q)
::::l
a.
o Septic joint: Extensive effusion of one or
o Dorsal intercalated segment instability
more compartments, ± carpal edema
(DISI): Seen in SL tear, RA, CPPD
o Osteomyelitis: Marked osteopenia; cortical
• Lunate dorsal tilt> 200; SL angle> 700;
loss, joint malalignment
CL angle> 200; lunate triangular on AP
• Carpal Dislocation Helpful Clues for Rare Diagnoses
o Stages due to perilunate ligament injury; • Osseous Neoplasm
look for accompanying fractures o Benign: Giant cell tumor, enchondroma,
• I: SL tear ± scaphoid rotatory osteoid osteoma
subluxation o Malignant: Squamous cell metastases
• 2: Radiocapitate tear; perilunate • Soft Tissue Neoplasm
dislocation o Benign: Ganglion, giant cell tumor of
• 3: Volar radiotriquetral, dorsal tendon sheath, hemangioma, tendon
radiocarpal tears; midcarpal dislocation sheath fibroma, lipoma
• 4: Dorsal radiocarpal tear; lunate o Malignant: MFH, synovial sarcoma,
dislocation angiosarcoma, liposarcoma, fibrosarcoma
• Osteonecrosis, Wrist (Scaphoid & Lunate) • Madelung Deformity
o Scaphoid proximal pole AVN due to o Radius: Dorsal/ulnar curvature; decreased
trauma radius length; triangular radial epiphysis
o Lunate: Kienbock disease (lunatomalacia); o Ulna: Dorsal subluxation, ulnar head
associated with ulnar minus, trauma enlargement
• Stage I: X-ray - normal; MR - TI ~ SI, T2 o Carpals wedging between radius & ulna
t SI with lunate at apex
• Stage 2: X-ray - sclerosis; MR - T1 ~ SI, T2
t SI
Fracture Fracture
Anteroposterior radiograph shows an incomplete buckle

fracture 1m of distal radial metaphysis in a 7 year who
Anteroposterior radiograph shows a subtle fracture line
1m crossing the radial styloid base & extending into the
III
fell on an outstretched hand. A subde distal ulnar radiocarpal joint in this 55 year old female who struck
fracture is also present HI her wrist against a wall.
43
RADIAL SIDED WRIST PAIN
Fracture Fracture
(Left) Coronal CT
"0
QI reformation shows midwaist
II)
ell scaphoid fracture with cystic
a:l margins. & proximal pole
~ scferosis EllIs months
ell Following acute fracture.
U
While there is not
!:
mafalignment, sclerosis
U suggests underlying AVN.
(Right) Coronal T1WI MR in
the same patient shows focaf
~ 51 ElII in the scaphoid
proximal pole on both T1 &
STIR (not shown), consistent
with osteonecrosis following
scaphoid fracture.
Arthritis Arthritis
radiograph shows
scaphoid-trapezium-trapezoid
& 1st CMC joint space
narrowing =:I & osteophytic
ridges [ig with small
subchondral cysts~. This is
cfassic osteoarthritis. (Right)
Coronal STIR MR shows
osteoarthritis with
scaphoid-crapezium-trapezoid
& 1st CMC joint space loss
• small joint effusions ElII
& subchondral reactive
marrow edema (t 51) =:I.
Arthritis
(Left) Coronal T1 C+ FS MR
shows an enhancing distal
scaphoid erosion [ig with
surrounding osteitis Ell as
well asjoint effusions. in
the midcarpal, radiocarpal &
distal radioulnar joints in 59
year old with rheumatoid
arthritis. (Right)
shows long-standing
rheumatoid arthritis with
diffuse 50ft tissue swelling
EiII, osteopenia, midcarpal &
radiocarpal joint space 1055
~ & proximal carpal row
collapse~
III
44
::l
o
III
-<
OJ
III
Arthritis Arthritis IJl
lTl
(Left) Coronal T7 C+ FS MR Co
shows scapholunate
dissociation. with capitate ~
::>.
EllI moving toward distal ~
radius, resulting in Ql
::l
scapholunate advanced a.
collapse (SLAG This I
Ql
deformity occurs in ::J
pyrophosphate arthropathy a.
or post-trauma. (Right)
shows juvenife idiopathic
arthritis with profound
diffuse osteopenia, carpal
enlargement & ankylosis 6H
Irregular/eroded distal radial
Ell & trapezium .:I cortices
are also present.

shows a ganglion cyst with a
tail. tracking to the wrist
near the lunate EllI. This
thin-walled multiseptate
mass is homogeneous t SI &
insinuates between the
extensor tendons. (Righi)
Axial T7 WI MR shows
extensor poflicis brevis
tendinosis (thickened,
mass-like) ~ & high grade
partial tears of abductor
pollieis longus III & flexor
carpi radialis (markedly
attenuated) EllI with
associated tenosynovitis •.

shows De Quervain
tenosynovitis involving both
abductor pollieis longus.
& extensor pollicis brevis HI
tendons, the first extensor
compartment. This is caused
by repetitive motion and
microlrauma. Note the
adjacent joint effusion •.
shows tenosynovitis EllI of all
extensor compartments with
enhancement of thickened
synovium in this 33 year old
female newly diagnosed with
III
45
RADIAL SIDED WRIST PAIN
Scapholunate Ligament Tear Carpal Instabilities

"0
(left) PA fluoroscopic digital
Ql subtraction radiograph
VI
III shows a needle. in the
In radiocarpal joint. with
::- injected contrast outlining
III the scaphoid EE & flowing
u
c: through the disrupted
scapholunate ligament E!I.
U (Right) Anteroposterior
radiograph shows
scaphoJunale interval
widening EE of S mm,
indicating disruption of the
scapholunale ligament.
Carpal Instabilities Carpal Instabilities

(left) Lateral radiograph
shows volar intercalated
segment instability (VIS/) in
this diffusely osteoporotic
rheumatoid arthritis patient.
The scaphoid Ell is flexed &
lunate. angled volarly.
The scapholunate angle is <
20° & capitolunate angle>
80°. (Right) Sagittal T1WI
MR shows dorsal
intercalated segment
instability (DIS/) in patient
with scaphoid fracture
nonunion & SL angle> 80°
(not shown). Dorsally tilted
lunate ~ creates a
capitolunate angle> 30°.
Carpal Dislocations Carpal Dislocations

(left) Lateralradiograph
shows a perilunate
dislocation with the lunate
HI maintaining normal
articulation with radius while
the capitate. is dislocated
dorsal to the distal lunate
articular surface. The
remainingcarpals. move
with the capitate. (Right)
midcarpal dislocation with
lunate subluxated volarly Ell
with respect to the distal
radius. as the fully
dislocated capitate 11II
moves proximally, displacing
the lunate palmarward.
III
46
:J
(1
III
'<
Osteonecrosis, Wrist (Scaphoid & OJ
III
Carpal Dislocations lunate) l/I
m
(Left) Lateralradiograph Q.
shows lunate dislocation
with the lunate Ell displaced ~
~
into the volar soft tissue & ~
the capitate" approaching III
:J
the radius articular surface Q.
•• There is an associated I
III
scaphoid (racture ffi :J
resulting in a transcaphoid a.
lunate (racture dislocation.
bone osteonecrosis related to
steroid use. There is
scaphoid sclerosis Ell with
collapse" as well as lunate
sclerosis ••
Infection Osseous Neoplasm

(Leh) Coronal T1 C+ F5 MR
shows Mycobacterium
avium septic
arthritis/osteomyelitis with
extensive erosion of
scaphoid" trapezium,
trapezoid, & ulnar styloid
ffi There is radial shaft
marrow edema (t 51)_.
Extensive joint effusion &
synovial hypertrophy ~ is
also present. (Right) AP
radiograph shows a giant cell
tumor with an expansile lytic
subchondral distal radius
lesion &I with
ps€udotrabeculations •• in
this young adult.
Soft Tissue Neoplasm Madelung Deformity

(Leh) Coronal oblique PO
F5EF5 MR shows a discrete
t 51 mass" eccentric to
but arising from median
nerve Ell This fusiform mass
was exquisitely tender to the
touch & was pathologically
proven to be a schwannoma.
radiograph shows a classic
Madelung deformity with a
shortened curved radius III
a longer (& dislocated) ulna
~ & a V-shaped radiocarpal
articulation with the lunate
Ell forming the leading edge.
III
47
.c
Ol GROIN/HIP PAIN
.c
I-
-0
c:
C1l DIFFERENTIAL DIAGNOSIS • If anterior pelvic fractures are seen, look
ci for sacral fractures
I Common o Hint: Marrow edema may mask fracture
• Fracture line; use T1 to identify fracture line
• Arthritis • Arthritis
• Osteonecrosis, Hip o Osteoarthritis
• Muscle Strain, Hip • Asymmetric joint space loss (usually
• Tendon, Injury superior), articular flattening,
• Labral Tear, Hip subchondral sclerosis & cyst formation, ±
• Bursitis loose bodies
Less Common o Inflammatory: Rheumatoid, ankylosing
• Hardware Failure spondylitis, psoriatic
• Transient Bone Marrow Edema • Uniform joint loss, ± erosions or
• Infection osteophytes, ± rice bodies
o Septic Joint o Crystalline: Gout, CPPD
o Osteomyelitis • Chondrocalcinosis, joint space loss
o Soft Tissue Abscess symmetric or asymmetric, osteophytes
• Intraosseous Neoplasm • Osteonecrosis, Hip
• Osteitis Pubis o X-rays: Focal sclerosis, crescentic
• Hip Malformation subchondral lucency (fracture), flattened
• Sciatica articular surface
o MR: Serpentine "double line" sign with the
Rare but Important
paralleling ~/t SI of reparative & necrotic
• Soft Tissue Neoplasm tissue, crescentic subcortical fluid
• Kidney Stones (fracture), flattened joint surface
• Testicular/Scrotal Pathology • Muscle Strain, Hip
• Adnexal Pathology o Muscle injury ranges from minimal fiber
• Nerve Entrapment tear (grade 1) to complete fiber disruption
(grade 3) with retraction & edema
ESSENTIAL INFORMATION o Hematoma
• Acute « 48 hrs): T1 isodense to muscle
• Subacute « 30 days): t SI on Tl & T2
• X-rays: Essential for initial evaluation (methemoglobin)
• CT: Best for bone detail • Chronic (> 30 days): Heterogeneous; ~SI
• MR: Best for marrow, soft tissues if hemosiderin deposition
• Bone scan: Useful for screening • Tendon, Injury
Helpful Clues for Common Diagnoses o Most common: Adductors, pectineus,
• Fracture obturators, hamstrings
o Avulsion: Common in skeletally immature o Range from tendinosis (thickening &
• Common locations: Adductor & intra substance signal) to complete tear
hamstring origins (tendon disruption & retraction)
• X-rays: Thin curvilinear fragment o Sports hernia: Rectus abdominus/adductor
• MR: Marrow & soft tissue edema mask aponeurosis avulsion from anterior pubis
fragment periosteum
o Stress: Abnormal stress ...•normal bone • Labral Tear, Hip
• Common locations: Medial femoral o MR arthrography with dilute gadolinium
neck, subtrochanter, symphysis (1:200) facilitates diagnosis
o Insufficiency: Normal stress ...•abnormal o Ranges from blunting of labrum through
bone intrasubstance signal & tear to detachment
• Common locations: Symphysis, pubic o Paralabral cyst indicates labral tear
rami, acetabulum, femoral head & neck • Bursitis
III
48
GROIN/HIP PAIN o
='
C'l
Ql
o t SI on fluid sensitive sequences in o Painful symphysis; related to GU surgery,
'<
potential spaces between tendons, pregnancy, infection llJ
Ql
ligaments, bony protuberances o X-ray: Irregular symphyseal cortex with VI
CD
o Common sites: Iliopsoas, obturator canal resorption, subchondral eburnation Q.

o MR: Marrow edema; ± effusion "U
CD
o Aspiration needed to exclude infection <"
• Hardware Failure (ii'
o Loosening, subsidence, foreign body • Hip Malformation I
o Malformation from developmental "0
reaction, polyethylene failure
dysplasia, 5CFE, fracture malunion, etc. Ql
:J
• Transient Bone Marrow Edema a.
o Acute onset focal pain; middle-age men results in secondary osteoarthritis, -l
abnormal gait ::r
oX-rays - osteopenia; MR - intense t 51 cO"
::r
edema without collapse or fracture • Sciatica
o Referred pain from neural impingement at
o Also known as transient osteoporosis
L2 or L3
• Infection
o Septic Joint Helpful Clues for Rare Diagnoses
• Focal osteopenia; large effusion • Soft Tissue Neoplasm
• Requires aspiration for confirmation o Benign: Lipoma, neurofibroma,
• Transient synovitis (ages 3-10) mimics hemangioma, myxoma
septic joint but noninfectious, a o Malignant: MFH, lymphoma, liposarcoma,
diagnosis of exclusion fibrosarcoma, synovial sarcoma
o Osteomyelitis • Kidney Stones, Testicular/Scrotal/Adnexal
• Cortical disruption, ± periostitis & soft Pathology
tissue involvement o Referred pain
o Soft Tissue Abscess • Nerve Entrapment
• Mass with thick, irregular walls; ± sinus o Referred pain from entrapped nerves
tracts & bone destruction or reaction including ilioinguinal, genitofemoral,
• Intraosseous Neoplasm obturator nerves
o Metastases & multiple myeloma> > > Alternative Differential Approaches
primary neoplasms
• Pubalgia
o May be lytic, sclerotic or mixed o Fracture, muscle tendon injury, osteitis
o Hint: Lesions in lesser trochanter should pubis, sports hernia, GU abnormalities,
raise the possibility of metastases ilioinguinal neuralgia
• Osteitis Pubis
Fracture
Anteroposterior
avulsion fragment =
oblique radiograph shows a small
at the adductor brevis origin in
this 14 year old soccer player,
Anteroposterior
ischial growth
radiograph shows widening of the left
plate EllI in this young patient with
chronic hamstring apophyseal stress injury.
III
49
GROIN/HIP PAIN

shows J, 51in a broad band
across the Femoral neck
which represents edema
surrounding & obscuring an
underlying subcapital
fracture.:l. (RighI) Coronal
STIR MR in a distance runner
shows an incomplete fatigue
fracture 0 51 ffi
surrounded by edema (t 51
Ell) in the basicervical
region.
Fracture Fracture
(Lefl) Coronal STIR MR in
this elderly female shows
extensive linear t 51. of a
transcervical incomplete
fracture with
insufficiency
edema 0 51~in the
femoral head. (RighI) Axial
NECT shows a non-displaced
posterior rim fracture. in
this patient who had a recent
transient posterior
dislocation. Note the small
intra capsular loose fragment
••
Arthritis Arthritis
(Left) Coronal PO F5E F5 MR
shows osteoarthritis
characterized by joint space
loss with flattening of the
articularsurface.
subchondral edema & cyst
formation HI. Note the
medial femoral neck
osteophyte" (RighI)
shows severe uniform
cartilage loss .:I & diffuse
osteopenia. Note the lack of
osteophyte development in
this patient with psoriatic
arthritis. The right 51joint
(not shown) is fused.
III
50
GROIN/HIP PAIN

shows a serpentine double
line with t 51. paralleling
! 51 ffi representing the
interface between necrotic &
reparative tissue in this 55
year old male with
prednisone~induced
osteonecrosis. (Right)
Coronal PO FSf FS MR
shows a subtle fracture(! 51
_ of the superior pubic
ramus with surrounding
marrow edema (t 51 EiII).
The obturator extern us
edema. indicatesmuscle
strain in the 65 year old.
Muscle Strain, Hip

shows extensive t 51 in an
iliopsoas partial muscle tear
(grade 2) • with associated
acute (t 51) hematoma EiII.
A posterior {emoral head
marrow contusion is present
•. (Right) Coronal STIR MR
shows bilateral
semimembranosus partial
tears with t 51of
edema/blood in the area of
disruption •. Additional
injury to the right conjoined
tendon (biceps
femoris/semitendinosus) HI
is also present.
(Left) Coronal T1 WI FS MR
shows labral tear of the
superior acetabular labrum
with contrast EiII interposed
between the acetabular rim
& the torn labrum ••.
MR shows a thin-walled
multiseptate paralabral cyst
•• tracking along the
superior acetabulum is this
patient with a small
associated anterior labral
tear (not shown).
III
51
.r: GROIN/HIP PAIN
OJ
:c
~
"0
C
ro
a.
I Bursitis Hardware Failure
(Left) Axial PO FSE FS MR
shows obturator extern us
bursitis with a multifoculate
fluid collection ••
interposed between the
obturator extemus Ell & the
ischiofemoral capsular
ligament IIIl (Right) AP CT
scanogram demonstrates
failure of a 'e(t THA with
eccentric polyethylene wear
•• & a large lytic lesion IIIIlI
in the acetabulum confirmed
to be foreign body osteolysis
at surgery.
Transient Bone Marrow Edema

shows intense right femoral
head & neck bone marrow
edema Ell in this 47 year old
male with abrupt onset of
hip pain. Attempts at
aspiration yielded no fluid.
Pain resolved over a 4 month
period. (Right)
in a middle-aged male
reveals femoral head & neck
osteoporosis Ell while the
adjacent acetabulum & joint
are normal. This is the
radiographic pattern seen in
transient bone marrow
edema syndrome.
Infection Septic Joint

(Left) AP radiograph during
arthrogram/aspiration reveals
contrast flowing into an
abscess cavity laterally Ill.
The greater trochanter has a
moth-eaten appearance of
osteomyelitis in this female
with E. Coli osteomyelitis.
radiograph shows subtle
widening of right "teardrop"
distance" in this 6 year old
with right hip pain. Septic
joint must be considered.
Aspiration yielded normal
synovial fluid & patient
recovered uneventfully from
transient synovitis.
III
52
GROIN/HIP PAIN
Intraosseous Neoplasm
(Left) Coronal TI C+ MR
shows multiloculated abscess
in the thigh IElII with adjacent
cortical reaction in the femur
•• and cellulitis_ This
patient had slowly worsening
groin pain and swelling over
several months. (Right)
shows multiple hereditary
exostoses with both
pedunculated all & sessile
••• lesions which deform the
hip contours, resulting in
mechanical impingement.
Malignant degeneration
occurs in up to 20% of
patients.
(Left) Frogleg lateral
radiograph shows an
extending to the joint
surfaces of the hip & 51joint
•. There is no internal
matrix. Cortical breakthrough
& soft tissue mass Ell are
seen medially. This is a
plasmacytoma. (Right)
intense t 51of the symphysis
pubis & bilateral superior
pubic rami" with minimal
fluid in the joint 1ElII. This is a
traumatic osteitis pubis in
this young male athlete.
Hip Malformation Soft Tissue Neoplasm

radiograph in this 75 year
old reveals the medial &
posterior rotation of a
slipped capital femoral
epiphysis'" with limb
shortening (note the lesser
trochanter position .).
shows a myxoid liposarcoma
as a heterogeneous sofl
tissue mass anterior to the
hip, containing fatty It 51
.., & myxoid I~511El11)
elements. It abuts the
neurovascular bundle ~
III
53
LATERALHIP PAIN
DIFFERENTIAL DIAGNOSIS o Complete: Complete disruption of tendon

with significant retraction &
Common edema/hematoma
en
.:; • Bursitis o Fatty atrophy of associated muscle bellies
Qj • Tendon, Injury may occur over time
a.. • Muscle Strain, Hip
"C
• Muscle Strain, Hip
Q)
en
• Arthritis o Muscle injury ranges from minimal fiber
III
co • Labral Tear, Hip tear (grade 1) to complete disruption of
>. Less Common muscle (grade 3) with retraction &
III
o • Fracture extensive t SI of edema/hemorrhage
s:: o May evolve to atrophy with fatty
• Hardware Failure
U
• Soft Tissue Hematoma infiltration with loss of muscle bulk
• Sacroiliac Dysfunction • Arthritis
• Sciatica - L4, LS o Lateral hip pain is referred
o May originate from osteoarthritis,
Rare but Important
inflammatory, crystalline or infectious
• Developmental Dysplasia of the Hip arthropathy
• Soft Tissue Abscess o Look for joint space narrowing,
• Intraosseous Neoplasm subchondral sclerosis, edema & cyst
• Soft Tissue Neoplasm formation
• Meralgia Paresthetica (Lateral Femoral
• Labral Tear, Hip
Nerve)
o May present as pain referred to lateral hip
though labral tear symptoms usually
ESSENTIAL INFORMATION include catching & clicking
o Irregular t SI in acetabular labrum ±
• Soft tissue injury is the most common o Signal may involve articular surface of
explanation for lateral hip pain labrum or extend through the fulliabral
• Hint: Don't let satisfaction of search stop thickness
you from looking for all causes of lateral hip o MR arthrography is imaging study of
pain choice
Helpful Clues for Common Diagnoses Helpful Clues for Less Common Diagnoses
• Bursitis • Fracture
o Inflammation of potential spaces between o Look for avulsion fractures
tendons, ligaments, bony protuberances • Sartorius avulsion of anterior superior
o Common hip bursae include greater
iliac spine
trochanter, subgluteus medius, subgluteus • Rectus femoris avulsion of anterior
minimus inferior iliac spine
o May have accompanying pathology such
• Gluteal avulsion of greater trochanter
as tendon/muscle tear, hematoma o Acute traumatic fracture: Look for
o May be seen in acute or chronic trauma,
appropriate mechanism of injury
arthritis, infection o Insufficiency: Look for lateral basicervical
o Results in bursal effusion, ± thickened
fracture line
synovium o Poorly reduced fractures may result in
• Tendon, Injury altered mechanics including impingement
o Most common: Gluteus maximus &
or gait alteration
medius (rotator cuff of the hip)
• Hardware Failure
o Partial: Disruption of some tendon fibers
o Look for loosening, subsidence, hardware
with minimal retraction & associated or peri prosthetic fracture, stress shielding
edema o Comparison with prior studies important
to identify early changes
III
54
LATERALHIP PAIN
• Soft Tissue Hematoma o May be difficult to distinguish from

o Intramuscular or subcutaneous necrotic neoplasm
o Acute (48 hrs): T1 isointense to muscle • Intraosseous Neoplasm
o Subacute « 30 days): t SI on T1 & T2 o Metastases & multiple myeloma are most
(methemoglobin) common neoplasms
o Chronic (> 30 days): Heterogeneous; ! SI if o Look for aggressive features including
hemosiderin cortical breakthrough, periosteal reaction I
& soft tissue mass -0.
o May evolve to a seroma, particularly in the
subcutaneous tissue superficial to tensor o Adolescent: Ewing sarcoma, osteosarcoma, Ql
::l
C-
fascia lata periosteal osteoid osteoma O;
o Adult: MFH, PNET, fibrosarcoma ::T
• Sacroiliac Dysfunction .0.
• Soft Tissue Neoplasm ::T
o Referred pain
o Sacroiliac joint pain more commonly o Appearance of neoplasms tend to be
presents as low back pain but may present nonspecific with! SI on T1 & t SI on T2
as lateral hip pain except lipomas
• Sciatica - L4, LS o Lipomas: t SI on Tl; intermediate Sl on T2;
o Referred pain follows fatty signal on all sequences
o Neural impingement in lateral recess, o Common adult tumors
neural foramina or central stenosis at L4 • Benign: Lipoma, neurogenic tumors,
&/or LS hemangioma
• Malignant: Liposarcoma, MFH,
lymphoma, synovial sarcoma,
• Developmental Dysplasia of the Hip
fibrosarcoma
o Altered hip conformation may result in
• Meralgia Paresthetica (Lateral Femoral
direct impingement or pain from 2° OA
Nerve)
o Acetabular labral pathology may
o Lateral femoral cutaneous nerve
accompany hip deformity
entrapment with anterolateral thigh
• Soft Tissue Abscess
paresthesias
o Soft tissue mass with central fluid
o May result from mass of retroperitoneal
surrounded by thickened, irregular wall; ±
space proximal to inguinal ligament or as
intralesional gas; ± sinus tract
nerve passes under ligament
o ± Involvement of adjacent bones
o Seen in diabetics, pregnancy, obesity, tight
o Surrounding soft tissue inflammation with
clothing
stranding of the fat
Bursitis
Coronal T2WI FS MR shows fluid III in the bursa

between gluteus medius EiIII & greater trochanter Ii8
Coronal T2WI FSMR demonstrates a fluid collection"
lateral to the left greater Femoral trochanter; consistent
III
There is tendinosis ••. Marrow infiftration {rom with greater trochanteric bursitis. The iliotibial band EiIII
metastatic disease is incidentally noted. is located just lateral to the inflamed bursa.
55
.r:
.2> LATERAL HIP PAIN
.r:
f-
-0
c
ro
a.
I Tendon, Injury
l/l (Left) Coronal STIR MR
"> shows thickening & partial
Qi
a.. tear of gluteus medius Ell
-0 with tendinosis of minimus
Cl> •• as well. Note fluid within
l/l
III & surrounding the hip rotator
III cuff (Right) Sagittal PO FSE
>. FS MR shows complete tear
III of the gluteus medius" &
o
C
dorsal portion of the gluteus
minimus III with retraction
U of the lOrn tendon from the
greater trochanter Ell.
Muscle Strain, Hip Arthritis

shows edema & hemorrhage
of grade 2 muscle strain in
the gluteus maximus •• &
medius Ell as well as the
adjacent fascial planes.
radiograph shows
osteoarthritis with severe
joint space loss Ell.
subchondral eburnation of
both sides of joint &
extensive cyst formation
including an Egger cyst •.
labral Tear, Hip

(Left) Coronal TI WI FS MR
shows an irregular superior
labral tear Ell with loss of the
adjacent articular cartilage
.:II. Note the accompanying
lateral femoral dysplastic
"bump".of
femoroacelabular
impingement. (Right)
Coronal bone CT shows a
subtle minimally displaced
greater trochanteric fracture
• in this osteoporotic
patient. MR (not shown)
revealed an intertrochanteric
component to this fracture,
requiring pinning.
III
56
LATERAL HIP PAIN
Hardware Failure Soft Tissue Hematoma

radiograph demonstrates 3
retracted cannulated lag
screws (Knowles pins) Ill!:I
projecting into the lateral 50ft
tissues. The pins had been
placed for subcapital
fracture, which has
collapsed, resulting in
=
femoral head/neck nonunion
proven by CT. (Right)
focal curvilinear t SI. in
subcutaneous fat superficial
to greater trochanter. This
hematoma resulted after a
recent fall on the left hip in
an anticoagulated patient.
Sacroiliac Dysfunction Developmental Dysplasia of the Hip

(Left) Oblique coronal T1WI
MR shows. 51 on both sides
of left sacroiliac joint
which enhanced with IV
=
contrast (not shown) in this
HIV patient with septic
arthritis. Sacroiliac joint
disease may present with
lateral hip pain rather than
the more usual buttock or
groin pain. (Right)
shows DOH with coxa
magna EiIl superolateral
femoral head subluxation,
medial acetabular wall
overgrowth _ & greater
trochanteric deformity 1ll!:I.
radiograph shows a mildly
expanded, partially
we/J-circumscribed lytic
lesion in the acetabulum III
without associated matrix,
which proved to be breast
metastasis. Note a slightly
more sclerotic lesion in the
ischium EiIl (Right) Axial
T2WI F5E MR shows an
intermediate 51 mass
enlarging the gluteus
minimus III & medius ~ &
displacing the maximus =.
It extends through the sciatic
notch Ell. This is a
non-Hodgkin lymphoma.
III
57
SNAPPING HIP
DIFFERENTIAL DIAGNOSIS • IPT may "catch" on iliopectineal

eminence, anteroinferior iliac spine,
Common lesser trochanter or on IP muscle medial
(/) • Tendon Impingement margin
">
Qi Less Common • Ultrasound best for dynamic evaluation
0..
't:l • Loose Bodies, Hip of IP tendon motion/restriction
Q)
(/) • Labral Tear, Hip o Iliotibial band/gluteus maxim us: Moves
III
ell • Synovial Osteochondromatosis anteriorly in flexion; snaps back over
>. • Osteochondroma greater trochanter when hip straightened
III
u o Biceps femoris: Snaps over ischial
c: Rare but Important
tuberosity
U • Osteonecrosis, Hip o Iliofemoral ligament: Snaps over anterior
• Ligamentum Teres Tear femoral head
o Bursitis & tendonitis/tenosynovitis may be
ESSENTIAL INFORMATION a cause or a result of impingement
Key Differential Diagnosis Issues Helpful Clues for Less Common Diagnoses
• Difficult to demonstrate dynamic problem • Loose Bodies, Hip
with static imaging o May be calcified, ossified or cartilaginous
o Ultrasound: Excellent dynamic imaging • Labral Tear, Hip
o Bursography: Indirect visualization o Unstable flap tear may act as loose body
o CT/MR: Soft tissue/bony abnormalities o Anterior paralabral cyst may impinge IPT
Helpful Clues for Common Diagnoses o Multiple intraarticular bodies; ± calcified
• Tendon Impingement • Osteochondroma
o Restriction due to bony prominences,
o Femoral head & neck deformities may
bursitis, cysts or masses impinge surrounding tendons
o Iliopsoas tendon (IPT)
• In flexion-abduction-external rotation, Helpful Clues for Rare Diagnoses
IPT lateral & anterior to IP muscle • Osteonecrosis, Hip
• As hip brought to neutral, IPT glides back o Look for classic serpentine "double line"
medial & posterior to IP muscle resting sign; rarely causes snapping
on superior pubic ramus • Ligamentum Teres Tear
o Best seen with joint distension, MR
arthrography
III Bursography in flexion abduction & external rotation

shows IPT position as a filling defecl ~ lateral to the
Bursography in neutral position in the same patient
shows the medial motion of the IPT EB lIS relationship
iliopectineal eminence ~ Snapping may occur in this to the iliopectineal eminence [;8 or lesser trochanter HI
area as the hip is moves to neulfal. may restrict motion.
58
SNAPPING HIP (')
:J
n
III
'<
III
III
VI
ltl
(Left) Transverse ultrasound Cl.
in flexion, abduction, -u
external rotation shows the CTl
IPT" lying lateral to the <"
en·
iliopectineal eminence RI.
Note the slightly hypoechoic I
"0
iliac muscle I!Ii:I superficial to
Q)
the tendon. (Right) :J
Transverse ultrasound in Cl.
neutral position in same -I

:::r
patient shows IPT., medial <15.
to the eminence •. :::r
Dynamic imaging shows
abrupt tendon snap as
patient moves to neutral
position. Note the iliac
muscle belly 1!Ii:I.
(Left) Coronal T2WI F5 MR

shows greater trochanteric
bursitis causing external
snapping hip syndrome.
Note the thickened iliotibial
band HI as it courses over
the greater trochanteric
bursitis III. (Right) Coronal
T2WI F5 MR shows multiple
irregular filling defects. of
intraarticular loose bodies in
this patient with advanced
osteoarthritis EiI. Hip
snapping may due to the hip
malformation or the loose
bodies.
Synovial Osteochondromatosis Osteochondroma

multiple mineralized
intra-articular bodies _ in
this 45 year old male with
advanced secondary
osteoarthritis. Synovial
osteochondromatosis was
confirmed at surgery. (Right)
shows multiple sessile 11I1 &
pedunculated fcauliflower)
= osteochondromas in this
young adult with multiple
hereditary exostoses. The
masses may impinge the
surrounding tendons through
normal range of motion.
III
59
.c THIGH PAIN
.~
.c
t-
"0
C
ro DIFFERENTIAL DIAGNOSIS o Grading of muscle injury
a. • Grade 1: Minimal fiber tear; diffuse t SI
I Common • Grade 2: Tear of < 50% of fibers; t SI in
(/) • Acute Fracture tear defect
~ • Stress Reaction
Q)
• Grade 3: Complete tear; t SI with large
0-
• Muscle Injury defect & muscle retraction
"'C
Ql o Delayed Onset Muscle Soreness o Muscle atrophy
VI
1tI o Compartment Syndrome • Decreased bulk; ± edema; ± fatty
al
~ • Hematoma infiltration
1tI • Tendon, Injury o Delayed Onset Muscle Soreness
.!:!
c • Arthritis (Hip or Knee) • Muscle soreness & tenderness occurs 1-3
u • Neurogenic Claudication days after exertion
• Sciatica • Follows a grade I muscle strain pattern
• Metastases o Compartment Syndrome
less Common • MR/CT: Swelling, loss of normal
• Hardware Complications fat/fascial planes; stranding of adjacent
• Fracture, Malunion fat planes; muscle t SI
• Osteonecrosis • May lead to myonecrosis in acute setting
• Septic Arthritis • Hematoma
• Osteomyelitis o Intramuscular or along fascial planes;
resulting from direct blow, muscle or
Rare but Important
tendon tear
• Complications of Statins o Acute « 48 hrs): T1 isointense to muscle
• Nerve Entrapment o Subacute « 30 days): t SI on T1 & T2
• Polymyositis/Dermatomyositis (methemoglobin)
• Thrombophlebitis o Chronic (> 30 days): Heterogeneous; • SI if
• Leriche Syndrome hemosiderin
• Soft Tissue Neoplasm o May evolve to heterotopic ossification
• Intraosseous Neoplasm
• Tendon, Injury
o Tendinosis: Tendon thickening, ±
ESSENTIAL INFORMATION intrasubstance t SI
o Partial tear: Partial fiber tear, t SI ±
Key Differential Diagnosis Issues surrounding edema
• Consider both primary and referred sources o Complete tear: Full fiber tear with
when evaluating thigh pain retracted tendons
Helpful Clues for Common Diagnoses o ± Associated muscle injury
• Fracture • Arthritis (Hip or Knee)
o Acute Fracture o Arthritic complaints related to hip or knee
• MR-most sensitive; CT-best bone detail may present as thigh pain
o Stress Reaction o Hint: Look for joint narrowing,
• Grade 1: X-ray -; bone scan +; MR subchondral cysts, joint effusion
periosteal edema t SI (signal intensity) • Neurogenic Claudication
• Grade 2: X-ray -; bone scan +; MR o Central spinal stenosis at L3-4 &/or L4-5
periosteal/endosteal edema t SI STIR • Sciatica
• Grade 3: X-ray ± periosteal reaction; o Possible neural impingement in lateral
bone scan +; MR t SI on T1 & STIR recesses, neural foramina, particularly at
• Grade 4: X-ray + fracture; bone scan +; L3, L4, &/or L5
MR fracture + t Sl edema • Metastases
• Hint: Edema may be so extensive that it o Hint: Look for bone marrow replacement,
obscures the underlying fracture particularly near the lesser trochanter
• Muscle Injury
III
60
THIGH PAIN (")
~
(i0
• Nerve Entrapment !!!.

o Look for mass, retraction, restriction, post III
• Hardware Complications III
surgical changes III
o Look for loosening or subsidence of ID
o Lateral femoral cutaneous nerve: Co
hardware; fractured screws or plates; subtle
Anterolateral thigh paraesthesias \l
fractures (l)
o Femoral nerve: Anterior thigh, proximal <

• Fracture, Malunion (ii'
leg dysesthesia
o Malalignment results in altered gait
o Saphenous nerve: Deep aching pain in
resulting in thigh pain or aggravate
thigh, knee
arthritis in adjacent joints/spine
o Obturator nerve: Medial thigh pain
• Osteonecrosis
o Metadiaphyseal bone infarctions may be
• Polymyositis/Dermatomyositis
o Symmetric proximal muscle weakness,
acutely painful
tenderness in adults
o History of sickle cell anemia, Gaucher
o MR: Diffuse edema, fatty atrophy
disease common
o Hint: MR limited for diagnosis; good to
o Initial: nl X-rays; t marrow edema
evaluate disease progress
o Evolves to typical circumscribed
heterogeneous lesion • Thrombophlebitis .
o Ultrasound: Distended, noncompressive
• Septic Arthritis .
o Effusion, synovial thickening, aVId
vessel lumen
o CT venography & MR: Vessel filling
enhancement of hip or knee joint
defects, distension
• Osteomyelitis
o Often associated with hardware, prior
• Leriche Syndrome
o Aortoiliac occlusive vascular disease;
trauma
vascular claudication
o Look for marrow edema, cortical loss,
periosteal reaction, enhancement • Soft Tissue Neoplasm
o Benign: Lipoma, myxoma, hemangioma,
Helpful Clues for Rare Diagnoses neurogenic tumors
• Complications of Statins 0 o Malignant: Liposarcoma, MFH, synovial
o Ranges from myalgias to rhabdomyolysis sarcoma, fibrosarcoma
• Myalgia: Pain, ± weakness; normal • Intraosseous Neoplasm
creatine kinase (CK); normal MR o Adolescent: Ewing sarcoma, osteosarcoma,
• Myositis: Pain, weakness; t CK; t SI osteoid osteoma
• Rhabdomyolysis: Pain, weakness; t CK > o Adult: Metastases, myeloma far exceed
lOx, myoglobinuria; t t SI primary tumors
Acute Fracture Acute Fracture
Anteroposterior radiograph shows a tinear longitudinal

fracture = in the distal femoral diaphysis. CT (not
Anteroposterior
transverse fracture
radiograph
_
shows
suggesting
a
high energy
displaced
Injury or
III
shown) conFirmed periosteal reaction and cortical break pathologic process. This fracture occur~ed in patient on
in this athlete. bisphosphonate treatment for osteopema.
61
.c THIGH PAIN
.2'
.c
I-
'0
C
<Il
a.
I Muscle Injury
(Left) Sagittal PO TSE FS
shows a grade 4 stress
reaction/fracture with a
cortical break and low signal
=
linear band ffi periosteal
and endosteal/medullary
edema BI. (Right) Axial PO
FSE FS MR shows
heterogeneous high signal
and swelling of a partial
(grade 2) vaslus medialis
muscle tear. This high signal
represents a combination of
edema (t 51) • and
hemorrhage (. 51) BI.
Delayed Onset Muscle Soreness Compartment Syndrome

edema of the biceps femoris
within the muscle belly
and along the
=
BI. This is typical of a grade
1 muscle injury with edema
but no definitive fiber tear.
(Right) Axial TlWI MR
shows herniation of a part of
vastus latera/is =.
Exercise-induced
compartment syndrome is
sometimes related to such
muscle herniations.
Hematoma Tendon, Injury

shows large fluid collection
BI in posterior thigh of an
80 year old male (on aspirin)
who fell while rollerblading.
In the acute phase, this
hematoma appears as simple
fluid (t 51). Note the torn
hamstring =. (Right)
Coronal STIR MR shows t 51
of edema/hemorrhage" at
the hamstring origin with a
high grade partial tear BI
and retraction of tendon
fibers. Note the subtle
edema. in the ischial
luberosity.
III
62
THIGH PAIN (")
::l
C'l
III
'<
lJl
III
Metastases Hardware Complications 1Il
(t)
(Left) Coronal T1WI MR C.
shows multiple punctate foci -U
• of marrow replacement ~
(representing breast :S.
1Il
metastases) on the
background of normal fatty I
-0
marrow. A larger lesion is
OJ
located in the left ilium Ell. ::l
(Right) NECT scanogram 0-
shows a cementless THA in -I
::T
patient with persistent thigh <5'
pain. Note eccentric femoral ::T
head position related to
polyethylene wear Ell and
subtle endosteal remodeling
•• near the femoral stem,
indicative of loosening.
Osteonecrosis Osteomyelitis
fLeft) Coronal PO FSEFS MR
shows diffuse serpentine
heterogeneoussignal. in
the bilateral metadiaphyses
(left> right), representing
medullary osteonecrosis in
patient with Gaucher
disease. (Right) Coronal STIR
MR shows a Girdlestone
arthroplasty resulting from
infection of a THA. The
metal prosthesis is removed
and replaced with
antibiotic-impregnated beads
•. There is extensive
marrow t 51 Ell of femur
and acetabulum due to
ongoing osteomyelitis.
Polymyositis/Dermatomyositis Soft Tissue Neoplasm

shows extensive, sheet-like
calcification" of muscles
and fascial planes in this
adolescent with profound
proximal muscle weakness
and dermatomyositis. (Right)
Coronal oblique T I WI FSE
MR shows a large 50ft tissue
mass displacing rather than
infiltrating the surrounding
soft tissues _ An area of
subtle t 5/11I in the mass
represents fatty tissue within
this liposarcoma.
III
63
.J:: NERVE ENTRAPMENT, LOWER EXTREMITY
OJ
.J::
t--
-0
C
<Il DIFFERENTIAL DIAGNOSIS o Entrapment site: Fibular neck or as nerve
a. pierces peroneus longus (PL)
I Common o Denervation: Leg, anterior & lateral
• Peroneal Tunnel Syndrome compartments
• Morton Neuroma • Morton Neuroma
Less Common o Interdigital nerve fibrotic nodule, 2nd or
• Sciatic Neuropathy 3rd intermetatarsal space most common
• Iliacus Muscle Syndrome o Entrapment site: Transverse metatarsal
• Meralgia Paresthetica ligament
• Saphenous Nerve Syndrome o MR: Ovoid mass centered on nerve &
• Tarsal Tunnel Syndrome plantar to transverse metatarsal ligament,
• Superficial Peroneal Nerve Entrapment Tl & T2 ~ SI, ± enhancement; ± bursitis
• Anterior Tarsal Tunnel Syndrome Helpful Clues for Less Common Diagnoses
Rare but Important • Sciatic Neuropathy
• Piriformis Syndrome o Sciatic nerve at pelvis
• Obturator Tunnel Syndrome o Symptoms: Flail leg with foot drop, loss of
• Popliteal Entrapment Syndrome ankle/toe inversion/eversion, sensory
• Sural Nerve Syndrome deficits in lateral leg, dorsal & plantar foot;
• Calcaneal Nerve Entrapment after trauma including iatrogenic (Le., hip
• Jogger's Foot surgery)
• Jogger's Heel o Entrapment site: Sciatic notch, hip
o Denervation: Anterior tibialis (AT),
peroneus longus (PL) & brevis (PB)
ESSENTIAL INFORMATION • Iliacus Muscle Syndrome
Key Differential Diagnosis Issues o Femoral nerve at pelvis
• Entrapment neuropathy: Short segment o Symptoms: Decreased hip flexion, absent
nerve compression at a specific site, often knee jerk, pain &/or paresthesias in
while passing through fibroosseous tunnel, anteromedial thigh, medial knee, calf,
muscle or fibrous tissue foot; seen after trauma including
• Symptoms: Muscle weakness, paresthesias, iatrogenic (Le., femoral artery
muscle atrophy catheterization, hip surgery)
• MR appearance: Look for nerve signal & o Entrapment site: Iliacus tunnel formed by
contour, adjacent vessels may serve as iliac bone/iliopsoas (floor) & iliopectineal
landmark; muscle signal intensity (SI) & arch/inguinal ligament (roof)
distribution o Denervation: Quadriceps, iliopsoas
• Look for: Ganglia, tumors, inflammation, • Meralgia Paresthetica
post-trauma, scarring, edema, anomalies o Lateral femoral cutaneous nerve at pelvis
• Muscle SI in entrapment/denervation o Symptoms: Burning pain, paresthesia of

o Acute « 1 mo): Tl - normal; STIR - t SI; proximal lateral thigh; seen with trauma
enhancement: + including iatrogenic (Le., iliac crest
o Subacute (1-6 mos): Tl - ± normal; STIR - t bone-graft harvest)
SI; enhancement: ± o Entrapment sites: Inguinal ligament at
o Chronic (> 6 mos): T1 - t SI; STIR - ~ SI; anterosuperior iliac spine or as nerve
enhancement: None penetrates fascia lata
o Denervation: None, purely sensory
Helpful Clues for Common Diagnoses • Saphenous Nerve Syndrome
• Peroneal Tunnel Syndrome o Femoral nerve at distal thigh
o Common peroneal at knee o Symptoms: Numbness & paraesthesias in
o Symptoms: Foot drop with loss of
medial distal thigh & knee down to medial
ankle/toe inversion/eversion, sensory leg/foot
deficits in lateral leg, dorsal & plantar foot
III
64
NERVE ENTRAPMENT, LOWER EXTREMITY
• Due to compression, masses, trauma o MR: Image pelvis for side-to-side

including iatrogenic (Le., knee comparison; look for asymmetry
arthroscopy) o Symptoms: Buttock pain, aggravated by
o Entrapment site: Adductor canal sitting, squatting, gluteal weakness
o Denervation: None, purely sensory o Entrapment site: Sciatic notch
• Tarsal Tunnel Syndrome o Denervation: Hamstrings, adductor
o Tibial nerve at ankle magnus
o Symptoms: Sharp pain worsened with • Obturator Tunnel Syndrome
activity; paraesthesia along plantar foot o Obturator nerve at pelvis
o Entrapment site: Tarsal tunnel formed by o Symptoms: Groin or medial thigh pain,
talus, calcaneus & flexor retinaculum adductor weakness, seen in trauma
o Denervation: Minimal; sensory deficits including iatrogenic (Le., hip replacement)
most common o Entrapment site: Obturator canal formed
• Superficial Peroneal Nerve Entrapment by pubic bone & obturator muscles
o Superficial peroneal nerve at distal leg o Denervation: Pectineus, gracilis, adductor
o Symptoms: Lower leg, dorsal foot longus, brevis, ± magnus
numbness, tingling • Popliteal Entrapment Syndrome
o Entrapment site: Lateral compartment o Tibial nerve at knee
fascia - 10-15 cm above ankle o Symptoms: Plantar & invertor, intrinsic
o Denervation: PL/PB foot muscles weakness; heel sensory loss
• Anterior Tarsal Tunnel Syndrome o Entrapment site: Popliteal fossa
o Deep peroneal nerve at ankle • Sural Nerve Syndrome
o Symptoms: Dorsal foot aching pain, o Tibial nerve branch at distal leg
numbness into 1st web space o Symptoms: Pain, paraesthesias, lateral foot
o Entrapment site: Superior/inferior extensor tenderness; chronic calf pain
retinaculum distal margin, extensor o Entrapment sites: Lower leg, lateral
hallucis longus (EHL) tendon malleolus
o Denervation: Extensor digitorum brevis & o Denervation: None, pure sensory nerve
longus, AT,EHL, peroneus tertius • Foot Entrapment Syndromes
o Calcaneal Nerve Entrapment: Medial
calcaneal nerve
• Piriformis Syndrome
o Jogger's Foot: Medial calcaneal nerve
o Sciatic nerve at sciatic notch
o Jogger's Heel: First branch of lateral
o Controversial; diagnosis of exclusion
plantar nerve
Peroneal Tunnel Syndrome Peroneal Tunnel Syndrome
Coronal T1 WI MR shows an elongated mass" in the

peroneal nerve Hl deviating the gastrocnemius lateral
Axial PO F5f F5 MR shows multiple heterogeneous.
masses iii of pigmented viJ/onodu/ar synovitis
51
III
head 1m. This schwannoma caused peroneal tunnel displacing the peroneal nerve III anceriorly. SymplOms
syndrome with lateral leg & (oot paresthesias. included knee pain & latera/leg numbness.
65
.c NERVE ENTRAPMENT, lOWER EXTREMITY
.Ql
.c
f--
"0
C
ro
a.
I Morton Neuroma Morton Neuroma
shows a typical Morton
neuroma. arisingbetween
the 3rd & 4th metatarsal
heads plantar to the
transverse metatarsal
ligament EllI. This. 51
nodule presented with
burning, point tender pain.
(Right) Coronal TlWI F5 MR
in the same patient, shows a
tear·drop·shaped Morton
neuroma" as • 51 with fat
suppression. There was
minimal enhancement
following gadolinium
administration (not shown).
Morton Neuroma Sciatic Neuropathy

(Left) Coronal T2WI F5 MR
shows a Morton neuroma.
at the lnd-3rd
intermelatarsal space with
slight increased 51. Note the
silastic 1st MTP prosthesis
EllI. Altered weight-bearing
may contribute to interdigital
neuroma development.
(Right) Axial PO F5f F5 MR
shows a hamstring lear with
tendon retraction III &
hematoma 11I2. Note
adjacent sciatic nerve &
surrounding soft tissues
edema EllI. This 80 year old
has acute onset foot drop
from sciatic neuropathy.
Iliacus Muscle Syndrome Tarsal Tunnel Syndrome

(Left) Coronal PO F5f F5 MR
shows intense iliacus muscle
edema" in this patient
status post left total hip
arthroplasty EllI with
decreased hip flexion and
anteromedial thigh pain,
typical of iliacus muscle
syndrome. (Right) Sagittal
TlWl F5 MR shows fluid in
subtalar joint" extending
medially & inferiorly into the
tarsal tunnel creating tunnel
constriction with resultant
venous distension" &
associated plantar neurologic
symptoms.
III
66
NERVE ENTRAPMENT, lOWER EXTREMITY
Tarsal Tunnel Syndrome Superficial Peroneal Nerve Entrapment

(Left) Coronal TlWI MR
shows that the posterior
tibial nerve ~ is enlarged &
surrounded by amorphous
scar tissue. There is atrophy
of the quadratus plantae Ii8 I
-0
& abductor digiti minimi ~
OJ
muscles innervated by lateral :::J
plantar nerve. (Right) Axial C.
TI WI MR shows superficial --i

::r
peroneal nerve thickening <5'
• in the subcutaneous fat ::r
just distal to its point of
emerging through the lower
leg fascia in this dancer with
lateral leg numbness &
tingling with exertion.
Anterior Tarsal Tunnel Syndrome

(Left) Coronal oblique T IWI
MR at the talonavicular joint
shows the normal deep
peroneal nerve, medial HI
& lateral. branches
separated by the dorsalis
pedis vessels. which serve
as a landmark for the nerve.
(Right) Axial PO FSf FS MR
shows a venous varix. at
the sciatic notch, resulting in
piriformis syndrome with left
buttock pain when sitting.
This 1/ mass If impinges the
sciatic nerve & adjacent
piriformis muscle HI
Obturator Tunnel Syndrome

shows a Fluid-filled ganglion
• in the obturator tunnel,
impinging the obturator
nerve in this patient with
persistent groin pain. Note
the mild edema in the
obturator extern us •.
Aspiration relieved the
symptoms. (Right) Axial
TI WI MR shows an enlarged
suralnerve. due to
neuroma. This nerve is
located midline & superficial
in mid calf, becoming more
posterolateral near the ankle.
Skin marker Ell caused
tingling pain.
III
67
.<: HIP PAIN, ElDERLY PATIENT
OJ
.<:
I-
"0
C
co DIFFERENTIAL DIAGNOSIS o Bone scan useful but takes up to 24 hrs to
c. be positive
I Common o Know where to look
• Fracture • Femoral head: May mimic AVN or OA;
• Arthritis look for articular surface collapse
• Tendon, Injury • Femoral neck: Subcapital, transcervical or
• Bursitis basicervical; fracture tends to propagate
• Muscle Strain, Hip from lateral to medial
• Metastases, Bone Marrow • Trochanteric: Infrequent, related to
Less Common direct blow or avulsion often due to fall;
• Osteonecrosis, Hip evaluate for intertrochanteric extension
• Hardware Failure • Intertrochanteric: Complete or
• Hematoma incomplete; single discrete fracture
• Infection without displacement or comminuted
o Septic Joint • Subtrochanteric/proximal femoral shaft:
o Osteomyelitis, Adult Atypical fractures may be seen in
o Soft Tissue Abscess patients treated with bisphosphonates
• Fracture, Malunion • Pelvis fractures: Symphysis,
• Sciatica superior/inferior pubic rami
• Osteoarthritis, Knee • Look for additional fractures in sacrum if
anterior pelvic ring fractured & vice versa
Rare but Important
• Superior acetabular: Insufficiency
• Soft Tissue Neoplasm fracture horizontal to 1 trabecula
0
• Intrapelvic Mass • Arthritis

• Testicular/Scrotal Pathology o Osteoarthritis: Asymmetric joint space
narrowing, usually superior, subchondral
ESSENTIAL INFORMATION sclerosis & cyst formation; osteophytes, ±
loose bodies
Key Differential Diagnosis Issues o Inflammatory arthritis
• Patients with painful hips tend to hold hip • Rheumatoid: Diffuse osteopenia, uniform
in flexion & external rotation joint space loss, ± erosions, ± rice bodies
• Hint: Don't let satisfaction of search keep • Ankylosing spondylitis: Uniform joint
you from seeing all abnormalities space loss, ± osteophytes, SI joint likely
Helpful Clues for Common Diagnoses fused if hip joint is involved
• Fracture o Crystalline: Chondrocalcinosis, symmetric
o Osteoporosis: Leading cause of hip or asymmetric joint space loss, osteophytes
fractures in elderly • Tendon, Injury
o Radiographs: Look for subtle trabecular o Commonly injured tendons: Hamstrings,
pattern & cortical margins hip rotator cuff, abductors, iliopsoas
• Garden classification: I-incomplete or o Injury ranges from tendinosis with
impacted; II-complete, nondisplaced; thickening & internal intermediate SI to
Ill-complete, partially displaced; complete tear of tendon with retraction &
IV-markedly displaced edema/hematoma
oCT: High resolution thin section imaging o Fatty atrophy of associated muscle
« 1 mm) essential for subtle fractures • Bursitis
o MR: Fluid sensitive sequences emphasize o Inflammation/fluid in potential space
edema (t SI) associated with fracture but between tendons, ligaments, bony
may obscure fracture lines; Tl better to protuberances
identify fracture line o t SI on fluid sensitive sequences, often
o Combining MR (to direct the search) & CT crescentic in shape
(fracture delineation) may be useful
III
68
HIP PAIN, ELDERLY PATIENT n
::J
o
III
a Commonly involved bursae: Greater a Chronic (> 30 days): Heterogeneous; ~ SI if
hemosiderin
-<
trochanteric, subgluteus medius, ll:J
III
subgluteus minimus • Infection tJI
C1l
a Look for associated tendon/muscle injury a Septic Joint Co
• Muscle Strain, Hip • Large effusion; focal osteopenia -0

(1)
a Ranges from minimal fiber tear (grade 1) to • Requires aspiration to confirm infection ;(
(jj.
complete disruption of muscle (grade 3) a Osteomyelitis, Adult
I
with retraction • Cortical disruption, ± periostitis & soft
a Fatty atrophy of associated muscle tissue involvement "::J
Cll
• Metastases, Bone Marrow a Soft Tissue Abscess Co

--i
a Metastases & multiple myeloma common • Mass with thick, irregular walls; ± sinus ::r
<£5.
in this age group tracts & bone involvement ::r
a Radiographs: Lytic, sclerotic or mixed; ± • Fracture, Malunion
cortical disruption a Malunion results in abnormal gait,
a MR: Typically ~ SI on T1WI, t SI on fluid mechanics
sensitive sequences; ± cortical disruption • Sciatica
a Referred pain
a Lateral recess, neural foramina or central
• Osteonecrosis, Hip
a Radiograph: Focal sclerosis; crescentic
stenosis at L3, L4, LS, or Sl
subchondral lucency (fracture); flattened • Osteoarthritis, Knee
a Referred pain
joint surface
a MR: Serpentine heterogeneous Helpful Clues for Rare Diagnoses
wedge-shaped lesion; crescentic • Soft Tissue Neoplasm
subchondral fluid (fracture); flattened joint a Benign: Lipoma, neurofibroma, myxoma,
surface schwannoma, hemangioma
• Hardware Failure a Malignant: Lymphoma, MFH, liposarcoma,
a Loosening, subsidence, foreign body fibrosarcoma, MPNST
reaction, polyethylene failure • Intrapelvic Mass
• Hematoma a Referred pain from mass arising from
a Develop with relatively little trauma uterine or adnexal pathology
a Acute (48 hrs): T1 isointense to muscle • Testicular/Scrotal Pathology
a Subacute « 30 days): t SI on T1 & T2 a Referred pain from testicular or scrotal
(methemoglobin) pathology including inguinal hernia
Fracture Fracture
Coronal STIR MR shows the linear t 5/ in the lateral

femoral neck. of an incomplete (Garden type /)
Anteroposterior radiograph shows a transcerv;cal
femoral neck fracture with subUe disruption of medial &
III
fracture in this 77 year old female. Note diffuse edema lateral coruces • This is a Garden 11/ fracture with
of the femoral head EilI. valgus aHgnment across the fracture.
69
.r:. HIP PAIN, ELDERLY PATIENT
.2'
.r:.
~
"0
C
ro
a.
I
(/)
.;; (Leh) Coronal TlWI MR
Qi
shows a comminuted
a.. femoral head fracture with
"0 subcapital & femoral head
GI •• components. TI WI
(/)
ro allows for better fracture line
III conspicuity as surrounding
~ marrow edema may obscure
the fracture. Note the slight
'"
u
articular surface flattening
c
III (Right) Coronal TI WI
U MR shows an incomplete
intertrochanteric fracture ~
originating at the greater
trochanter & extending
distally across the
intertrochanteric line.
Fracture
fractures sustained in ground
level fall including left
symphysis, inferior pubic
ramus Ell & acetabulum ffi
as well as a vertical right
sacral body fracture ••
(Right) Coronal bone CT
shows bilateral subacute
transverse incomplete
subtrochanteric fractures.
in this 70 year old female
being treated with
bisphosphonates for
osteopenia. This site is
typical for bisphosphonate
related Fractures.
Arthritis
radiograph shows superior
joint space loss •.
subchondral sclerosis, &
femoral head flattening Ell.
as well as acetabular
osteophytes •. along with
diffuse osteopenia in this
elderly patient with
osteoarthritis. (Right)
typical MR appearance of
osteoarthritis with bilateral
superior joint space loss from
subtle cartilage thinning ••
& acetabular subchondral
cysts Ell. There is a minimal
right hip effusion •.
III
70
(")
HIP PAIN, ELDERLY PATIENT
~
C"l
III
-<
to
III
Arthritis III
It)
radiograph shows ankylosing -U
spondylitis with fusion of ~
bilateral 51 join15 EiIIl Note :S.
(f)
the rather uniform joint
space na"owing of the left
hip •. (Right)
after a hip arthrogram
(needle in place Ell! in a
patient with known
rheumatoid arthritis. Uniform
cartilage 1055 ~ is
accompanied by large
acetabular & femoral
erosions •. Osteophytes •
represent secondary
osteoarthritis.

shows partial left hamstring
tear with t 51 & disruption of
the semimembranosus
portion of the tendon. in
this 76 year old male with
acute onset pain. Note the
ischial marrow edema HI
(Right) Axial STIR MR shows
complete iliopsoas tendon
tear in this 86 year old
female. There is retraction of
tendon fibers & associated
edema/hematoma E£I near
the tendon insertion.
Bursitis Muscle Strain, Hip

shows small crescentic fluid
collections in the subgluteus
minimus • & subgluteus
medius bursae Ell. There is
mild thickening of the
gluteus minimus tendon near
the trochanteric insertion •.
shows t 51 in the central
iliopsoas muscle belly
representing a grade I muscle
strain. in this 77 year old
patient after injury during a
yoga class.
III
71
.£
.gl HIP PAIN, ElDERLY PATIENT
.£
f-
"0
C
m
a.
:r:
IJ) (Leh) Anteroposterior
'S; radiograph shows sclerosis of
a;
Cl. the lesser trochanter with
"0 cortical disruption" in this
QI elderly patient with prostate
IJ)
metastasis. A more subtle
'"
al lesion is located in the
>- ischium ~ (Right) Coronal
TlWI MR shows multiple
'"
.5:1 small ~ 51lesions in the
c
proximal femurs" with a
u larger lesion in the left ilium
E!lI in this patient with breast
metastases.
Osteonecrosis, Hip Osteonecrosis, Hip

shows the classic serpentine
heterogeneous focus of
femoral head avascular
necrosis HI with surrounding
edema (~ 51) o( the head &
neck". There is no
articular collapse. (Right)
Coronal STIR MR shows a
circumscribed subchondral
focus of ~ 51 (osteonecrosis)
• with surrounding edema
E!lI in the right femoral head
with a smaller but similar
lesion in the left femoral
head •.
Hardware Failure Hematoma

(Left) Coronal CT
reformation shows a lucency
•• in the periprosthetic ilium
& acetabulum related to
foreign body osteolysis from
polyethylene wear
characterized by slight
narrowing of polyethylene
liner ~ (Right) Axial T2WI
Fs MR shows a crescentic
heterogeneous If mass" Ell
superficial to the left gluteus
maximus in this elderly
patient who takes aspirin &
recently sustained a fall. This
was an acute hematoma &
completely resolved with
time.
III
72
HIP PAIN, ELDERLY PATIENT ()
::J
"
III
'<
III
III
Septic Joint Osteomyelitis, Adult III
11l
(Left) Coronal STIR MR Q.
iI~' . ..
.,.~ shows early MR appearance \J
_~Il'/~' .--~.:!(.. of septic arthritis of the hip 11l

with a joint effusion. and <
(ii'
edema •. Aspiration
_."
Joo..:.• '."'Y.... ~•• '~'I?-'
.,4&t,
_"
..... 0
.>. confirmed infection in this 80

.• ~ \.
'j.'.-::>~' . :..<' .
year old male. (Right) Axial
bone CT shows right
"
~. -~_.._
.
'-"'. ,••- ;,'
.!'C. .• '., I·," ., .' p
n.
acetabulum
destruction.
cortical
with soft
tissue swelling EiII in this BS
. _ ' ':.f' '. '
"~' ' '~
'.:' ...
year old female who had
~.~- . - .,
"'~ .. '
increasing hip pain several
months following hip
~~l.>"- . ~ . arthroplasty. This proved to
be osteomyelitis at surgery
.;.
Soft Tissue Abscess Soft Tissue Neoplasm

(Left) Coronal CT scanogram
obtained following
arthrogram demonstrates
extensive soft tissue contrast
collections EiII within the
multiple soft tissue abscesses
resulting from an E. coli
inFection. Note the
associated sinus tract III
shows a 50ft tissue mass in
the right groin. which
infiltrates the obturator
intemus. It is • SI T7 WI (not
shown) & f SI T2WI in a
nonspecific pal/ern & proved
to be lymphoma at biopsy.
Intrapelvic Mass Testicular/Scrotal Pathology

large cystic adnexal mass.
representing primary ovarian
carcinoma in this 65 year old
female who presented with
hip pain. Extensive 50ft tissue
density tumor is noted along
the dependent surfaces of
the perilOneal cavity •.
shows a large left inguinal
hernia. with loops of small
bowel EiII & peritoneal fat ~
within the hernia in this 83
year old male with left hip
pain.
III
73
.r: PAINFUL HIP REPLACEMENT
.Ql
.r:
I-
"0
<=
co DIFFERENTIAL DIAGNOSIS • Choose landmarks to measure for
Cl.
superior or inferior subsidence of either
I
Common component
• Arthroplasty Loosening • Arthroplasty Dislocation
• Arthroplasty Dislocation o Femoral head dislocation is obvious; must
• Component Malposition look for component malposition as
• Septic Joint underlying etiology (see Component
• Arthroplasty Component Wear Malposition below)
• Particle Disease/Massive Osteolysis • Component Malposition
• Stress Shielding (Mimic) o May result in pain and/or dislocation
• Heterotopic Ossification o Lateral opening of cup should be 400 ± 100;
Less Common excess in either direction puts at risk for
• Arthroplasty Hardware Failure dislocation
• Periprosthetic Fracture o Limb lengths should be equal (usually
• Iliopsoas Bursitis assessed by measuring distance of lesser
trochanter to transischialline and
comparing to contralateral side)
ESSENTIAL INFORMATION • If component placement results in
Key Differential Diagnosis Issues over-lengthening, at risk for spasm and
• Total hip arthroplasty (THA) complications dislocation
are common but may be subtle initially • If component placement results in
• To avoid missing subtle complications, must shortening, muscles are inefficient
compare image with both o Cup should be anteverted 150 ± 100; this is
o Index radiograph (initial post-operative evaluated on groin lateral radiograph
image) • Retroversion puts patient at risk for
o Most recent comparison radiograph dislocation
• Make use of transischialline as baseline for • Excessive anteversion puts patient at risk
measuring angulation of acetabular for dislocation
component & relative limb length (generally o Cup should not be placed excessively
compare level of lesser trochanters) laterally; if center of rotation is lateral to
iliopsoas tendon as it crosses joint, flexion
Helpful Clues for Common Diagnoses places it at risk for dislocation
• Arthroplasty Loosening • Septic Joint
o For cemented components, 2 mm lucency o Usually no radiographic signs; if septic
at bone-cement interface surrounding joint is suspected, must aspirate
component is diagnostic o Rarely, serpiginous tracking and periosteal
o For cementless components, 2 mm lucency reaction are seen (late findings)
at bone-component interface (usually with o Occasionally fluffy, amorphous
surrounding sclerotic line) surrounding heterotopic bone formation heralds
component is diagnostic infection
o For any component, change in position is • Arthroplasty Component Wear
diagnostic o Wear generally occurs in polyethylene
• Positional change may be a new tilt or liner
angulation of component o Wear is on most frequent weight-bearing
• Acetabular components tend to subside portion of liner (superolateral)
superiorly o Wear is visualized by femoral head
• Femoral components tend to subside placement within the cup; if the head is
inferiorly down shaft asymmetric and superolateral, that
o To evaluate subtle change in position, indicates polyethylene liner wear
compare with index radiograph and use • Particle Disease/Massive Osteolysis
transischialline as reference
• Measure angle of lateral cup opening
III
74
PAINFUL HIP REPLACEMENT
o Debris of a critical size triggers cascade • Heterotopic Ossification

effect o Frequent around femoral neck
• Inflammatory reaction with macrophage o Matures into normal bone
and foreign body giant cells - osteolysis • Rarely is massive enough to cause
- loosening or fracture obstruction or significant symptoms
o Debris may be of multiple origins Helpful Clues for Less Common Diagnoses
• Most frequent: Polyethylene particles • Arthroplasty Hardware Failure
from wear (particles not directly o Femoral stem may fracture; generally
visualized) subtle since non-displaced
• Metallic beads from component surface o Cup may fracture, but generally only when
may abrade and stimulate massive there is already failure due to loosening
osteolysis o Liner rarely may displace from cup
• Less commonly, osseous or cement • Periprosthetic Fracture
debris may contribute to osteolysis o Most frequently femoral shaft
o Degree of lysis may be impressive;
• Watch for fracture extending from tip of
differential includes metastasis, femoral component
plasmacytoma, or primary bone tumor • Do not confuse with nutrient artery
• Hint: With lytic lesion adjacent to THA, • Most likely with a long-stem revision
look for possible sources of particles femoral component: The long stiff stem
• Stress Shielding (Mimic) fractures through the anteriorly bowed
o With altered weight-bearing on THA, some
femoral cortex (visualize on lateral view)
areas of proximal femur have less stress
o Fractures around acetabulum less frequent,
• Bone is resorbed, leading to an
though with loosening or lysis, medial
osteopenic region which may be
wall may erode
confused with osteolysis
o Regions of osteolysis or stress shielding are
• Most frequent region affected is proximal
at risk for pathologic or insufficiency
femoral metaphysis, particularly in
fracture; watch these carefully
region extending into greater trochanter
• Iliopsoas Bursitis
o Identify by location and fact that bone is
o Large hip effusion may decompress into
resorbed rather than destroyed
the iliopsoas bursa
• This will avoid misdiagnosis of massive
o Presents as a hard anterior groin mass
osteolysis or tumor
o May be drained through large bore needle;
o Because of bone resorption, bone is at risk
generally very gelatinous
for insufficiency peri prosthetic fracture
AP radiograph shows a wide lucency at the

bone-component interface III surrounding most of the
AP radiograph shows superior subsidence of the
acetabular component (subsided over the distance
III
femoral shaft prosthesis. Endosteal & periosteal bone between .:I). Additionally, there is abnormal tilt of the
production HI indicates toggling at tip. (tMSK Req). cup ffi another indication of gross loosening.
75
.J:: PAINFUL HIP REPLACEMENT
.Ql
.J::
I-
"0
C
ro
a.
I Arthroplasty Loosening
en (Left) AP radiograph shows a
~ wide bone-component
Ql
a.. interface lucency. Note
"0 that the femoral component
Ql has subsided inferiorly by
II)
ro approximally 2 em.
CD Subsidence, even without
~ the obvious lucency at the
Cll component interface,
o
c: indicates loosening. (Right)
AP radiograph shows 2 mm
U bone-component interface
lucency surrounding the
acetabular cup" There is
also a 3 mm lucency at the
bone-cement interface of the
femoral component ElII. Both
are loose.

dislocation of the total hip.
There ;5 no obvious
malalignment of the
components predisposing to
the dislocation. (Right) Groin
lateral radiograph of the
same hip as previous image,
following relocation, shows
retroversion of the cup •. A
retroverted acetabular
component puts the patient
at risk for dislocation, as in
this case. Note that this
malposition is seen only on
this view.
Arthroplasty Dislocation Arthroplasty Dislocation

dislocation of the IOtalhip.
Although the cup does not
have an abnormal lateral
opening angle, it does show
significant opening in the
antero-posterior plane (note
the anterior & posterior rims
delineated by.). (Right)
Groin lateral radiograph on
image, shows exaggerated
anteversion of the cup _
Although retroversion ;s a
greater concern, excessive
anteversion a/50 predisposes
to dislocation.
III
76
PAINFUL HIP REPLACEMENT n
j
o
III
'<
OJ
III
Arthroplasty Dislocation III
CD
no loosening, but dislocation -U
o( the component. Note the (l)
prominent lateral opening of 5

III
the cup _ this puts the hip
at risk for dislocation. (Right)
AP postoperative radiograph
shows abnormally decreased
lateral opening of the cup
•. This puts the hip at risk
for dislocation since the neck
of the shaft may catch and
torque on the lateral cup.
Component Malposition Septic Joint

total hip placed with
asymmetric lengthening of
the limb. Note the position
of the lesser trochanter IIlI
on the left relative to the
right and to the
intertrochanteric line.
Abnormal length predisposes
to dislocation. (Right) AP
radiograph shows irregular
serpiginous lucency
throughout the acetabulum
.:II. This indicates septic joint
with osteomyelitis.
Septic Joint Arthroplasty Component Wear

irregular and prominent
lucency about the tip of the
femoral component ••.
Additionally, there is focal
and very thick endosteal and
periosteal reaction HI. The
appearance is too irregular
for simple loosening and
represents infection. (Right)
AP radiograph shows offset
of the femoral head within
the cup. Note that the
distance between head and
edge of cup superiorly" is
significantly less than
inferiorly HI. indicating wear
of the polyethylene.
III
77
.c. PAINFUL HIP REPLACEMENT
.2>
.c.
I-
"0
C
ell
a.
I Particle Disease/Massive Osteolysis Particle Disease/Massive Osteolysis
en (Left) AP radiograph shows
.;;;
offset of the head within the
Qi
Il. cup, indicating polyethylene
wear. Additionally, there is
"en
CI>
III
surrounding bone". This
aJ osteolysis develops due to
>- polyethylene particles.
III (Right) AP radiograph shows
l.l
U
C
acetabulum =-
polyethylene wear.
There is no
However. there are tiny

metallic microspheres ••
which have rubbed off the
cup: they are of the optimal
size to cause osteolysis.
Stress Shielding (Mimic)

(Left) CT coronal reformat
shows polyethylene wear
(note offset of femoral head
in cup) & extensive
osteolysis, not only in the
acetabulum III but in the
proximal femur as well. CT
can be a valuable asset in
determining bone stock.
lucency in the proximal
metaphysis III due to stress
shielding. The focal loss of
bone density is secondary to
altered weight-bearing and is
considered normal. Note a
subtle insufficiency fracture
1!IllI.
Arthroplasty Hardware Failure

fluffy heterotopic ossification
(HO) III surrounding an
arthroplasty. HO frequently
forms superolaterally without
consequence. In this case,
there is air HI in the soft
tissues a5 well, indicating
infection. (Right) Frogleg
lateral radiograph shows
metallic wedges III which
have loosened from the
polyethylene liner,
representing cup failure.
There is also fracture of the
component Ell and resultant
dislocation of the hip.
III
78
PAINFUL HIP REPLACEMENT n
::l
C'l
Ql
-<
OJ
Ql
Arthroplasty Hardware Failure Arthroplasty Hardware Failure VI
(1)
(Leh) AP radiograph shows Q.
(racture of the femoral -U
component". The femur (1)
shows massive osteolysis and ~

(f)
loosening; this can put the
hardware at risk for fracture. I
1:l
<ll
gross loosening of the cup ::l
HI with subsidence. This Q.
loosening has resulted in -i

:r
fracture of the acetabular <5.
component. :r
Periprosthetic Fracture Periprosthetic Fracture

wide lucency at the
bone-cement interface. in
this femoral component,
indicating loosening. With a
grossly loose component, the
osteopenic bone is put at risk
for fracture, as has occurred
here •. (Right)
Post-operative lateral
radiograph shows a
long-stem femoral prosthesis
to have Fractured the anterior
femoral car/ex". Longer
stems put the femur at risk
for periprosthetic fracture
because of the normal
anterior bowing of the femur.
Iliopsoas Bursitis
radiograph shows total hip
without malposition.
However. lucency is seen,
thinning the iliac wing •.
Concern was for a
destructive lesion. (Right) CT
in the same patient, above
the level of the arthroplasty
shows significant thinning of
the iliac wing. explaining
the radiographic appearance
of a "lytic lesion". Aspiration
of the iliac bursal mass (note
needle in position) showed
thick synovial fluid,
decompressed from the
arthroplasty.
III
79
Ol
<I) ANTERIOR KNEE PAIN
-'
"0
C
CIl
<I) DIFFERENTIAL DIAGNOSIS • Arthritis
<I)
C
o Osteoarthritis: Cartilage loss, subchondral
~ Common cysts, osteophytic ridging, ± osteopenia
"0
CIl
• Patellofemoral Syndrome o Crystalline
III
CIl • Meniscal Tear • Pyrophosphate arthropathy:
llJ • Meniscal Cyst
Z. Chondrocalcinosis, cartilage loss -
01 • Arthritis patellofemoral > tibiofemoral, ±
,!:!
c Less Common osteopenia
u • Transient Patellar Dislocation • Gouty arthropathy: Patellar erosion, ±
• Patellar Fracture osteopenia
• Patellar Malalignment o Inflammatory: Effusion, synovial
o Patellar Subluxation hypertrophy, osteopenia
o Patella Alta Helpful Clues for Less Common Diagnoses
o Patella Baja • Transient Patellar Dislocation
• Bursitis o Medial patella & anterolateral femoral
• Patellar Tendon Tears & Tendinosis bone bruise
• Quadriceps Tendon Tear o Look for impaction or avulsion fractures
• Infection o May sprain medial retinaculum or sprain
• Medial Plica Syndrome vastus medialis
• Pigmented Villonodular Synovitis (PVNS) • Patellar Fracture
• Post-Operative Fibrosis o Fracture patterns: Transverse, marginal,
Rare but Important osteochondral, vertical
• Synovial Osteochondromatosis o Evaluate articular surface congruity,
• Intraarticular Chondroma extensor mechanism
• Osgood-Schlatter Disease o Distinguish normal variants
• Sinding Larsen Johansson Disease • Bi- or multipartite patella; dorsal defect

• Hoffa Disease • Typically superolateral; overlying
• Lipoma Arborescens, Knee cartilage intact
• Intraosseous Neoplasm • Patellar Subluxation
• Soft Tissue Neoplasm o Lateral subluxation: Common
o Related to patellar tendinopathy; patella or
trochlea dysplasia; arthritis
ESSENTIAL INFORMATION o Patellar tracking difficult to assess in static
Helpful Clues for Common Diagnoses imaging
• Patellofemoral Syndrome • Patella AIta
o Patellar &/or femoral trochlea cartilage o High-riding patella
damage; ± patellar tracking abnormalities o Lateral radiograph: Tendon length
o Radiograph/CT: Subchondral irregularity, (TL)/patellar length (PL) ratio> 1.2
sclerosis o Sagittal MR: TL/PL > 1.S
o MR: Cartilage damage, subchondral • Patella Baja
edema, cyst formation o Low-riding patella
o Chondromalacia grading o Lateral radiograph: TL/PL < 0,8
• I: Swelling & softening o Sagittal MR: TL/PL < 0,74
• II: Fissuring • Bursitis

• III: Deeper, broader damage o Synovial-lined potential space irritation
• IV: Full thickness loss from trauma, infection, arthropathy
• Meniscal Tear o Prepatellar: Housemaid knee from kneeling
o Anterior horn lateral> medial in a forward position
• Meniscal Cyst o Infrapatellar: Parson's knee from kneeling
o Multiloculated cysts arise from meniscal in upright position
tear • Patellar Tendon Tears & Tendinosis
III
80
ANTERIOR KNEE PAIN n
='
(")
III
o Tendon thickening & t 51; ± tendon fiber o Synovial metaplasia resulting in multiple
-<
tear; ± distal patellar edema small ovoid intraarticular bodies ± Dl
III
o Jumper's knee: Proximal tendinopathy in ossification VI
C1l
jumping athletes • Intraarticular Chondroma 0-
• Quadriceps Tendon Tear o Ossifying cartilaginous metaplasia in Hoffa A
o Occurs with eccentric quad contraction fat pad ='

Cll
Cll
with planted foot, flexed knee o Heterogeneous mass with cartilage (t 51)& III
o Predisposition: Degenerative tendon; calcification/ossification 0 51) ='

0-
r
Cll
co-existing disease such as chronic renal • Osgood-Schlatter Disease <0
failure, diabetes, RA, SLE,steroids o Traction apophysitis at tibial tubercle in

o MR best defines extent of tear adolescents
• Infection o Fragmentation at apophysis with soft
o Septic arthritis: Effusion, synovial tissue swelling ± bone edema
thickening ± osteopenia, bone marrow • Sinding Larsen Johansson Disease
edema o Traction apophysitis at inferior patella in
o Osteomyelitis: Osteopenia, cortical loss, adolescents
bone marrow edema, effusion o Fragmentation at apophysis with soft
• Medical Plica Syndrome tissue swelling ± bone edema
o Thickened media plicae impinges medial • Hoffa Disease
femoral condyle; due to trauma, o Inflammation of Hoffa fat pad from acute
inflammation or repetitive trauma
• Pigmented ViIlonodular Synovitis (PVNS) o Results in hemorrhage & edema; may
o Focal or diffuse villonodular synovial evolve to fibrosis
thickening; effusion; ± bone erosion; • Lipoma Arborescens, Knee
variable enhancement o Villous synovial proliferation with
o ± ~51due to hemosiderin deposition lipomatous hypertrophy; predilection for
• Post-Operative Fibrosis suprapatellar pouch
o Hoffa fat pad scarring with linear ~ 51 o Hint: Synovial hypertrophy is "fatty" signal
stranding & retraction of normal fat pad on MR sequences
contours • Intraosseous Neoplasm
o Giant cell tumor, chondroblastoma,
osteoblastoma, SBC, hemangioma
o Synovial sarcoma, MFH, hemangioma
Patellofemoral Syndrome Patellofemoral Syndrome
Axial T2WI MR shows full thickness cartilage loss along

the lateral patellar facet with adjacent subchondral
reactive marrow edema III as well as edema in the
=
Sagittal PO FSf FSMR shows full thickness cartilage loss
with subchondral cyst formation & adjacent
subchondral edema.
III
lateral femoral sulcus Ill.
81
Ol
Q) ANTERIOR KNEE PAIN
....J
"0
C
m
Q)
Q)
C
~
Patellofemoral Syndrome Meniscal Tear
"0
Ql (Left) Sagittal PO FSEMR
=
shows a chondral fracture
III
CO
III ElII with undercutting of
~ the surface, creating a
co chondral flap. (Right) Sagittal
u PO FSEMR shows a
c macerated tear" of the
U lateral meniscus anterior
horn. Note the adjacent
femoral trochlear cartilage
loss ElII.
Meniscal Cyst Arthritis

(Left) Axial PO FSEMR
shows a multilobulated
parameniscal cyst. arising
from a lateral meniscus
anterior horn lear HI and
extending into Hoffa fat pad
11II. (Right) Lateral
radiograph shows erosion ElII
of patella and a small
osteophytic ridge" There
is chondrocalcinosis in the
menisci (not shown). The
pattern of predominant
patellofemoral disease
(mixed erosive/productive)
and chondrocalcinosis is
arthropathy.
Arthritis Transient Patellar Dislocation

(Left) Merchant view
radiograph shows marked
prepatellar soft tissue
swelling Ell a joint effusion
=:I & ventral erosions
with a poorly-defined
-=
pathologic fracture of the
lateral patella ~ (Right)
Axial PO FSEFS MR shows
the typical bone bruise of a
transient lateral patellar
dislocation, involving lateral
femoral condyle" & medial
patella ElII. Note the
irregularity of the patellar
surface due to impaction
fracture.
82
ANTERIOR KNEE PAIN C"l
:J
(')
III
-<
OJ
III
(Left) Sagittal PO FSE FS MR

'"
CD
Co
shows a horizontal fracture /\
HI of the patella and :J
(1)
articular cartilage. Note (1)
effusion extending into OJ

:J
horizontal 11:I and vertical Co
clefts •• in Hoffa fat pad r
(1)
(Right) Axial PO FSE FS MR to
shows lateral patellar
subluxation with associated
articular cartilage damage
HI and subchondral reactive
marrow edema _
Patella Alta Patella Baja

shows patella alta with an
elongated tendon" and
high-riding patella HI due to
prior trauma. The TUPL is >
1.2. (Right) Sagittal PO FSE
MR shows patella baja EilI in
this patient status post ACL
reconstruction" The TUPL
is < 0.74. Note Hoffa
post-operative fibrosis [;8
which may contribute to the
tendon shortening.
Bursitis Bursitis
shows a well-circumscribed
fluid collection EilI contained
within the bursa superficial
to the patella resulting from a
fall S months earlier.
Aspiration revealed sterile
sero-sanguinous fluid. (RighI)
Sagittal PO FSEFS MR shows
fluid in the deep infrapatellar
bursa ElIl resulting from
recent trauma.
III
83
OJ
CIl ANTERIOR KNEE PAIN
-l
"0
C
ro
CIl
CIl
C
~
Patellar Tendon Tears & Tendinosis
"0
Ql
(Left) Sagittal PO FSEMR
l/I shows thickening of the
III
III proximal patellar tendon Ell
~ with high tendon signal.
III in this young volleyball
o player, consistent with
C
patellar tendinosis (jumper's
U knee). (Right) Sagittal PO
FSEMR shows a high grade
partial tear of the quadriceps
tendon with minimal
retraction. There is fluid Ell
in the gap created by the
tendon fiber disruption •.
Medial Plica Syndrome Pigmented Villonodular Synovitis (PVNS)

(Left) Sagittal MRA shows a
thickened medial plica.
which snaps & pops, causing
pain, particularly when
climbing stairs, as it catches
on the anteromedial femoral
condyle Ell. (Right) Sagi!!al
T1 C+ FS MR shows a
suprapatellar minimally
enhancing synovial nodule
_ There is a large effusion
with thickened synovium Ell.
The mass is biopsy-proven
PVNS & is atypical in that it
has minimal hemosiderin.
Synovial Osteochondromatosis Intraarticular Chondroma

shows synovial
osteochondromatosis,
presentinga conglomerate of
small faintly calcified bodies
•. in the suprapatellar
pouch just above the patella
•. (Right) Sagittal T1WI FSE
MR shows a rounded
heterogeneous mass III
expanding & displacing
Hoffa fat pad. This is an
intraarticular chondroma.
Radiographs (not shown)
reveal rounded fat pad
calcifications, corresponding
to low signal areas _
84
(")
ANTERIOR KNEE PAIN
:l
C'l
III
'<
OJ
III
Osgood-Schlatter Disease Sinding larsen Johansson Disease
'"
(1)
Q.
shows libial tubercle A
fragmentation III & sofl :::J
(1)
tissue swelling Ell (1)
corresponding to the area of OJ

:::J
tenderness in Ihis 13 year old 0.
male with Osgood-Schlalter r
ctl
disease. (Right) Sagittal PO (Q
FSf FS MR shows edema in
Ihe dislal palella III and
adjacentlendon as well as
Hoffa fal pad Ell in Ihis /2
year old with acute onset
pain al the inferior patella
without known trauma.
lipoma Arborescens, Knee lipoma Arborescens, Knee

(Leh) Sagittal PO FSf FS MR
shows numerous
suprapatellar pouch filling
defects III in a moderate
joint effusion. These are, in
fact, villous in nature and are
low signal with fal
suppression. (Right) Sagillal
T1 WI MR in the same patient
as previous image, shows the
"filling defects" III /0 be
fatty on T1 WI, typical of
villous synovitis and
subsynovial fat hypertrophy
of lipoma arborescens.
Soft Tissue Neoplasm

(Leh) Laleral radiograph
shows giant cell tumor
presenting as a lytic patellar
lesion III withoul effusion,
cortical disruption or matrix.
(RighI) Sagillal STIR MR
shows a cystic mass
involving Hoffa fal pad III as
well as the prepatellar
subculaneous fal E!illt is
somewhal tubular and
multi-septate, proving to be a
cavernous hemangioma at
excision.
III
85
Ol
Q) MEDIAL KNEE PAIN
--'"0
C
co Pellegrini Stieda: Ossification at femoral
Q) DIFFERENTIAL DIAGNOSIS o
Q)
c origin; indicates prior injury
:.:: Common • Medical Meniscus Tear
"0
Ql
• Medial Collateral Ligament Sprain o Medial tears are most common
Vl
ro • Medial Meniscus Tear o Orientations: Horitzontal, horizontal
aJ o Medial Meniscal Cyst
.2- oblique, radial, vertical longitudinal
ro • Arthritis • Medial Meniscal Cyst
u o Osteoarthritis
c o Medial parameniscal cysts are most
o Rheumatoid Arthritis common
U
o Pyrophosphate Arthropathy o Typically multiloculated mucin-filled cyst
• Insufficiency Fracture o Look for the associated meniscal tear
• Acute Trauma, Fracture • Arthritis
• Hardware Failure, Post-Operative o Osteoarthritis: Cartilage loss, subchondral
less Common cysts, osteophytic ridging, loose bodies, ±
• Pes Anserine Bursitis osteopenia
• Medial Collateral Ligament Bursitis • Loose bodies range in size, shape,
• Osteochondritis Dissecans appearance
• Osteonecrosis o Inflammatory arthritis: Effusion, synovial
• Medial Plica Syndrome hypertrophy, osteopenia, rice bodies
• Septic Joint • Rice bodies are small, regular
• Pigmented Villonodular Synovitis (PVNS) o Crystalline arthritis: Effusion, subchondral
• Synovial Osteochondromatosis edema, soft tissue chondrocalcinosis,
• Hip Pathology usually not osteopenic until endstage
• Insufficiency Fracture
Rare but Important
o Acute pain with no trauma; osteopenia
• Soft Tissue Neoplasm o Linear low signal subchondral band
• Intraosseous Neoplasm parallels articular surface with extensive
• Nerve Impingement (Saphenous Neuritis) surrounding edema
o May be located at mid femoral condyle
ESSENTIAL INFORMATION (formerly discussed as spontaneous
osteonecrosis of knee)
Key Differential Diagnosis Issues o May be located at medial proximal tibial
• Diagnoses may occur in combination condyle
• Hint: Don't let satisfaction of search keep • Acute Trauma, Fracture
you from looking for all the possible causes o Appropriate mechanism of injury
of medial knee pain o Look for associated injuries in ligaments,
Helpful Clues for Common Diagnoses menisci, cartilage
• Medial Collateral Ligament Sprain • Hardware Failure, Post-Operative
o Most commonly injured ligament o Look for lucency at
o Composed of deep & superficial layers bone-cement-prosthesis interfaces;
• Superficial layer originates from medial fractures; ± effusion
femoral epicondyle; inserts tibial Helpful Clues for less Common Diagnoses
metaphysis 4-5 cm distal to joint line • Pes Anserine Bursitis
• Deep layer attaches to medial meniscus o Bursa between MCL & distal sartorius,
body with meniscofemoralligament gracilis, semitendinosus tendons as they
proximally & meniscotibialligament insert on anteromedial tibia
distally o Seen in distance runners
o Ligament sprain grading
• Medial Collateral Ligament Bursitis
• 1: Few torn fibers; structurally intact o Bursa between deep & superficial MCL
• 2: Incomplete tear; no joint laxity layers
• 3: Complete tear; joint laxity
III
86
(")
MEDIAL KNEE PAIN
::l
C'l
III
Vertical elongate fluid collection o Multiple small ovoid intra-articular bodies
o -<
paralleling superficial MCL ± ossification [Jl
III
• Osteochondritis Dissecans • Hip Pathology IJI
~
o Fragmentation ± separation of a part of o Referred pain pattern Co
;:<:
articular surface Helpful Clues for Rare Diagnoses :J
<l>
o Most common in the lateral aspect of • Soft Tissue Neoplasm <l>
III
medial femoral condyle o May be difficult to distinguish benign :J
a.
o May be cartilage, cartilage & bone, or bone from malignant r
<l>
alone o Evaluate patient age, tumor size, location, to
• Osteonecrosis imaging characteristics, enhancement
o Serpentine, demarcated heterogeneous patterns
lesions in metadiaphysis may extend to o MR/CT allows delineation of involved
subchondral epiphyses anatomy, especially the neurovascular
o Look for risk factors: Steroids, alcohol,
bundle
sickle cell anemia, Gaucher disease, trauma • Intraosseous Neoplasm
• Medial Plica Syndrome o Pain tends to be gradual and insidious
o Thickened medial plica results from
o Acute onset pain, look for pathologic
fibrosis & impinges the medial femoral fracture
condyle causing pain with normal range of o Benign
motion • Epiphyseal/subchondral: Giant cell
o Due to inflammation from trauma, OCD,
tumor, chondroblastoma
inflammatory arthritis • Metaphyseal: Enchondroma, exostosis,
• Septic Joint nonossifying fibroma, fibrous dysplasia
o Effusion, synovial thickening, avid
o Malignant
enhancement
• Secondary neoplasm is most common &
• Pigmented Villonodular Synovitis (PVNS) includes metastasis, multiple myeloma
o Focal or diffuse villous &/or nodular
• Primary neoplasm is less common &
synovial thickening; effusion; bone
includes osteosarcoma, chondrosarcoma,
erosion
Ewing sarcoma
o May have marked low signal due to
• Nerve Impingement (Saphenous Neuritis)
hemosiderin deposition
o May result from impingement at the
o Heterogeneous enhancement
adductor canal
o Mimics medial meniscus tear or arthritis
o Cartilaginous metaplasia
Medial Collateral Ligament Sprain
Coronal PO FSf FS MR shows a grade

with minimal fiber disruption. Edema outlines the
I MCL sprain Coronal
retraction
PO FSf MR shows
of the superficial
a grade 3 MCL tear with
fibers [;8 as well as complete
III
superficial fibers 11II & is interposed between the tears of the meniscofemoral ~ & meniscotibial III
ligament's deep & superficial layers Ell as well. portions of the deep fibers.
87
OJ
Q) MEDIAL KNEE PAIN
....J
"0
C
ro
Q)
Q)
c
:.::
Medial Collateral Ligament Sprain Medial Meniscus Tear
"0
C1l
III radiograph shows
1Il
al ossification EiII of the MCL at
~ the femoral origin. This
1Il ossification, termed
o Pellegrini·Stieda, ;5 indicative
C of MCL sprain at some time
U in the past. (Right) Coronal
PO FSEMR through the mid
knee shows a truncated
medial meniscus" resulting
in bucket handle tear with a
large fragment EiII displaced
into the intercondylar notch.
Medial Meniscus Tear Medial Meniscal Cyst

(Left)Coronal PO FSEFS MR
shows a typical
nondisplaced horizontal
oblique tear E!II of the medial
meniscus body, extending to
the inferior articular surface.
(Right) Coronal STIR MR
shows a t/lin-walled
multi/obulated cystic mass
E!II arising from the capsular
surface of a horizontal
medial meniscus tear.
just posterior to the MCL •.
Osteoarthritis Rheumatoid Arthritis

radiograph shows joint space
narrowing Ell subchondral
eburnation. & osteophytic
ridging III typical of
osteoarthritis. Osteoarthritis
often, but not invariably,
presents in the medial
compartment of the knee.
Diffuse osteopenia ;s present
due to patient age & gender.
a large erosion EiII of the
medial tibial plateau in this
patient with long-standing
RA. Note the accompanying
osteopenia & diffuse
narrowing of joint space.
III
88
MEDIAL KNEE PAIN n
::l
(")
III
-<
llJ
III
en
<D
(Left) AP radiograph shows a.
chondrocalcinosis ••
~
normal bone density, & a ::l
(1)
large subchondral cyst within (1)
the medial tibial condyle •• OJ

::l
in a patient with 0-
pyrophosphate arthropathy. r
(1)
(Right) Coronal STIR MR co
shows medial femoral
condy~rsubchond~1
insufficiency fracture. in a
72 year old female with
acute onset medial joint line
tenderness. Note the
extensive bone edema. This
fracture may remain
radiographically occult until
it develops collapse.
Acute Trauma, Fracture Hardware Failure, Post-Operative

(Left) Coronal PO FSEMR
shows an impaction fracture
•• of the medial tibial
plateau with minimal
displacement of the fragment
in this /5 year old soccer
player. Such fractures may
be radiographically occult.
radiograph shows a total
knee arthroplasty
complicated by a fracture ••
along the medial femoral
condyle with resultant
loosening of the femoral
component.
Pes Anserine Bursitis Pes Anserine Bursitis

shows fluid in the pes
anserine bursa Ell
paralleling distal sartorius &
gracilis. This bursa is located
anterior & medial to the
usual Baker cyst location.
Note the unassociated
medial meniscus body tear
••. (Right) Coronal PO FSE
FS MR in the same patient,
shows a crescent-shaped
medial fluid collection ••
intimate with the medial
tibial cortex typical of pes
anserine bursitis.
III
89
Ol
Q)
...J
"0
c:
[- MEDIAL KNEE PAIN
ro
Q)
Q)
c:
~
Medial Collateral Ligament Bursitis Osteochondritis Dissecans
'tl (Left) Coronal STIR MR
Ql
fJl shows fluid" interposed
III
al between the superficial
~ portion of the MCL HI & the
III adjacent proximal tibial
U metaphysis, representing
c: medial collateral ligament
U bursitis. (Right) Sagittal PO
FSf MR shows a medial
OCO lesion HI in a 14 year
old. The discrete fragment is
covered by intact cartilage
lI:I & does not appear loose,
though the cystic changes at
the margin are concerning.
Careful scrutiny in multiple
planes is important.
Osteochondritis Dissecans Osteonecrosis

shows an OCO in the typical
lateral aspect of the medial
femoral condyle with fluid
•• between the fragment &
the condyle, indicating a
loose fragment in this S2
year old. (Right) Coronal PO
FSf MR shows a
heterogeneous tibia/lesion
medial tibial plateau in this
Gaucher patient. This
osteonecrosis has the typical
serpentine margin.
demarcating the extent of the
bone infarction.
Medial Plica Syndrome

(Left) Axial T I C+ FS MR
shows a slightly thickened
medial plica III in a 42 year
old who reports pain &
snapping when extending
knee. The plica impinges on
HI. (Right) Axial TI C+ FS
MR shows thickened, avidly
enhancing synovitis HI with
adjacent reactive femoral
condylar osteitis" in this
patient with gram positive
cocci septic arthritis.
III
90
()
MEDIAL KNEE PAIN
::l
(')
Ql
-<
to
Ql
Pigmented Villonodular Synovitis (PVNS) III
<1l
(Leh) Coronal T2" CRE MR a.
shows nodular synovial ~
thickening" in this 13 year ::l
<ll
old with a large joint <ll
effusion. On CRE, the OJ
::l
nodules are low signal with 0-
"blooming" artifact, typical r
<ll
o( hemosiderin deposit & <0
classic for PVNS. (Right)
Sagiual PO FSEMR shows a
discrete intracapsular slightly
heterogeneous mass ElIII. This
is biopsy proven PVNS but
without the typically more
prominent hemosiderin
deposition.
Synovial Osteochondromatosis Soft Tissue Neoplasm

(Leh) Axial PO FSE FS MR
shows a large effusion with
innumerable small round
bodies. particularly in
Ho(fa fat pad, corresponding
to ossific densities on
radiograph (not shown). The
appearance is typical o(
synovial chondromatosis.
(Right) Coronal T1WI MR
shows an extraarticular soft
tissue mass ~ along the
medial joint line. This is a
synovial sarcoma in this
young adull. Age and
location should suggest the
diagnosis.
radiograph shows an
eccentric lytic geographic
lesion, typical (or giant cell
tumor III. The lesion is
metaphyseal, approaches the
subchondral bone & expands
the medial cortex. (Right)
epiphyseal lesion =
nonaggressive malrix·forming
in the
posteromedial tibia which is
Jow signal intensity on T2
MR (not shown). Note the
associated periosteal
reaction III incited by this
chondroblaslOma.
III
91
Ol
Q) CALF PAIN
-l
-0
C
<Il
Q) DIFFERENTIAL DIAGNOSIS o Baker cyst most common; arises from
Q)
C
posterior medial capsule between
~ Common semimembranosus & gastrocnemius
"tl
Q)
• Fracture (medial head) tendons
l/l
Rl • Popliteal Cyst o Simple or complex with multiple
III
• Muscle Injury septations; ± loose bodies
~ o Muscle Strain
Rl o May decompress into surrounding soft
l.l
o Compartment Syndrome tissues with symptoms mimicking DVT
C
o Calcific Myonecrosis o DVT may co-exist in - 10% of
U
• Hematoma symptomatic patients
• Arthritis of Knee or Ankle • Muscle Injury
• Sciatica o Muscle Strain
• Neurogenic Claudication • Ranges from mild edema (grade 1) to
Less Common complete fiber disruption (grade 3) with
• Tendon, Injury retraction
• Vascular Abnormalities o Compartment Syndrome
o Arterial Insufficiency • Elevated pressure in confined space may
o Deep Venous Thrombosis irreversibly damage muscle & nerves
o Venous Insufficiency • MR or CT: Swelling, edema, loss of
• Infection normal muscle markings
• Fracture, Malunion o Calcific Myonecrosis
• History of trauma; residua of
Rare but Important
compartment syndrome & nerve injury;
• Intraosseous Neoplasm anterior compartment most common
• Soft Tissue Neoplasm • Fusiform mass with plaque-like
• Nerve Entrapment amorphous calcifications
• Hematoma
ESSENTIAL INFORMATION o Acute « 48 hours): T1 isointense to muscle
o Subacute « 30 days): t SI on T1 & T2
Helpful Clues for Common Diagnoses (methemoglobin)
• Fracture o Chronic (> 30 days): Heterogeneous; ~ SI if
o May result from high energy trauma or
hemosiderin present
repetitive stress (abnormal stress on • Arthritis of Knee or Ankle
normal bone) or from insufficient bone o Referred pain
(normal stress on abnormal bone)
• Sciatica
o Radiographs/CT delineate fracture
o Referred pain; neural impingement at L4,
alignment, healing & potential LS &/or Sl
complications • Neurogenic Claudication
o Bone scintigraphy useful for identifying
o Referred pain from central stenosis at L4,
injury but poor resolution LS or S; typically bilateral & symmetric
o MR sensitive to early stress response,
pain
surrounding soft tissue injury
o Stress response grading Helpful Clues for Less Common Diagnoses
• Grade 1: Periosteal edema; t SI T2/STIR • Tendon, Injury
• Grade 2: Endosteal/periosteal edema; t SI o Most common: Achilles, plantaris
T2/STIR o Range from tendinosis (thickening &
• Grade 3: Endosteal/periosteal edema; t SI intrasubstance signal) to complete tear
T2/STIR & ~ SI T1 (tendon disruption & retraction) with
• Grade 4: Discrete cortical fracture associated hematoma
perpendicular to long bone surface • Vascular Abnormalities
• Popliteal Cyst
III
92
CALF PAIN n
::l
o
III
o Duplex ultrasound (Duplex = 2D US • MR will better delineate osseous & soft
tissue involvement
-<
combined with Doppler flow detection) CD
III
highly sensitive to vessel disease o Brodie abscess VI
(l)
o Radiograph: Look for arterial calcification, • Subacute osteomyelitis, variable Q.
phleboliths presentation; classic appearance = A

::l
o CT/MR angiography highly sensitive with discrete, lytic metaphyseal lesion; ± <1l
<1l
advanced imaging techniques periostitis Q)
::l
o Arterial Insufficiency o Soft tissue abscess a.
r
• Artery occlusion from peripheral vascular • Mass with thick, irregular walls; ± sinus <1l
CD
disease or direct vessel impingement tracts & bone destruction
• Angiography remains gold standard for • Fracture, Malunion
evaluation vessel disease/obstruction o Abnormal alignment (including rotation
• Popliteal entrapment: Artery malalignment) may alter gait, limb length
impingement from extrinsic source such Helpful Clues for Rare Diagnoses
as aberrant muscles or cystic adventitial
• Intraosseous Neoplasm
disease
o Pain tends to be gradual, insidious
o Deep Venous Thrombosis
o Benign: Enchondroma, exostosis, fibrous
• US: Look for incompressibility of vessels, dysplasia, Paget disease
loss of flow augmentation when vessels
o Malignant: Lymphoma, osteosarcoma,
distal to obstruction are compressed,
chondrosarcoma, Ewing sarcoma
intraluminal mass or obstruction
• US of vessels distal to popliteal artery is o Benign: Hemangioma, fibromatosis,
less sensitive
neurofibroma, myxoma
• CT/MR venography used for direct
o Malignant: Synovial sarcoma, MFH,
visualization of intraluminal defect
liposarcoma, MPNST
o Venous Insufficiency
• Nerve Entrapment
• Radiographs: ± Phleboliths, varicosities
o May be entrapped by mass, hardware,
as elongate masses, long bone periosteal
scarring
thickening
o Commonly entrapped nerves
• Infection
• Common peroneal
o Osteomyelitis
• Tibial nerves
• X-ray: Lytic, permeative with cortical
disruption, ± periostitis & soft tissue
edema; ± sinus tracts
Fracture Fracture
Coronal TlWI MR shows.

diaphyseal medullary space ~
51 in the proximal dbial
at the area of point
Coronal 5T1R MR in the same padent shows t 51 of
extensive medullary E!II & periostea/III edema which
III
tenderness in this 40 year old distance runner with a extends far beyond the primary focus ~ of developing
grade 3 stress response. fracture seen in T 1WI.
93
Ol
Q) CALF PAIN
-l
"
C
<tl
Q)
Q)
C
~ Fracture Fracture
"tl (Leh) Axial STIR MR shows
=
C1l
Ul subtle t 51 of the periosteum
<tl
CD & a crescent of t 51 in
~ the endosteum Ell of the mid
<tl tibia in this athlete with
o intermittent "shin" pain. This
C is a grade 2 stress injury.
radiograph shows an
incomplete insufficiency
fracture of the proximal
medial tibial meta diaphysis
with sclerosis. at the
fracture site & adjacent
subtle periostitis Ell due to
healing.

shows typical multiseptate
synovial cyst Ell tracking
along the semimembranosus
tendon =. It follows the
gastrocnemius (medial head)
~ as well as dissecting into
its muscle belly" (Right)
Sagittal PO FSE FS MR shows
a discrete thin-walled cyst
which has partially
decompressed. into the
adjacent subcutaneous soft
tissues Ell along the
gastrocnemius. Note the
small loose body ~ in the
popliteal cyst.
Muscle Strain
(Leh) Two contiguous
longitudinal views of the
posterior medial knee!ca/f
demonstrate a farge,
thin-walled multiseptate Ell
chronic Baker cyst with
dissection along the
superficial fascial of the
gastrocnemius ~ (Right)
Axial STIR MR shows a
typical case of gastrocnemius
soleus strain with a pattern of
diffuse muscle edema.
without clear pattern of
myofibril disruption,
consistent with grade 7
muscle strain.
III
94
CALF PAIN C'l
:l
C'l
III
0<:
OJ
III
Compartment Syndrome Calcific Myonecrosis III
CD
(Lefl) Axial Tf C+ FS MR Co
shows patchy enhancement A
(t 51) o( the swollen anterior :l
CD
tibialis ~ & extensor hallucis CD
longus ~ with interosseous III
OJ
membrane bowing fa in this Co
compartment syndrome. The r
CD
enhancement suggests some to
remaining viability of the
injured muscle. (RighI)
shows calcific myonecrosis
of lower leg anterior
compartment with diffuse
amorphous plaque-like
calcifications II] in areas of
necrosis & prior hemorrhage.
Hematoma Tendon, Injury

(Lefl) Coronal STIR MR
shows a complex mass in
right medial gastrocnemius.
t 51of edema !J::l surrounds
a mass of intermediate & • 51
typical of subacute/chronic
hemorrhage with
methemoglobin SI &
hemosiderin ~. (RighI)
plantaris tendon rupwre E±I
with {Deal heterogeneous
mass between deep &
superficial posterior
compartments, representing
hematoma. Grade 1 soleus
strain a is also present.
Arterial I nsufficiency
(Lefl) Sagittal 5T1R MR
shows complete Achilles
tendon rupture =
at
with acute hemorrhage (t
51) SI & retraction of
muscle. There is underlying
tendinosis with marked
thickening & heterogeneity
!J::l. (RighI) CT angiogram
(aortic runoff) shows
occlusion of left popliteal
artery ~ with extensive
distal collateral flow !J::l in
this 82 year old with
intermittent claudication.
Note normal right leg runoff
~.
III
95
OJ
Q) CALF PAIN
-'
-0
C
ctl
Q)
Q)
c
:>::: Arterial Insufficiency Arterial Insufficiency
"tl (Leh) Axial T2WI FSf MR
CIl
l/I shows popiteal artery
<a
tll entrapment due 10 a large
~ aberrant slip of the medial
<a head of gaslrocnemius =:I
o lateral to popliteal
l: neurovascular bundle 81 & a
U smaller slip !:ll medial 10 the
vessels. (RighI) Coronal MRA
shows deviation of the
popliteal artery C12; the
medial displacement results
from an aberrant slip of the
medial head of the
gastrocnemius. The patient
had symplOms of
claudication in the calf.
Deep Venous Thrombosis Venous Insufficiency

(Lefl) Transverse ultrasound
shows distended posterior
tibial veins ~ which do not
compress with applied
pressure 81. Note the
adjacent slightly
compressible posterior tibial
artery =:I. (RighI) Lateral
radiograph shows chronic,
calcified venous thrombus
with a serpentine calciFied
calf mass =:Icorresponding
to a previously documented
venous thrombus. Signs of
venous insufficiency
including varicose veins E2
& phleboliths !:ll are also
present.
Infection
(Lefl) Coronal STIR MR
shows a Brodie abscess in
this skeletally immature
patient with a
meta-epiphyseal t SI
well-defined fluid-filled lesion
1:]1 with intense surrounding
edema 81 including
periosteal edema !:ll. (RighI)
Sagittal T7 C+ FS MR shows
avidly enhancing anterior
subperiosteal soft tissue !:ll
lifting the periosteum =:I.
Adjacent intramedullary
edema ~ is present as well
as a soft tissue abscess with a
thickened, shaggy rim 81.
III
96
CALF PAIN (")
::l
(i'
ll>
'<
OJ
ll>
Infection VI
Infection <l>
shows tuberculosis A
osteomyelitis with an :J
ill-defined Iylic lesion
the proximal tibial
in= <tl
<tl
metaphysis with minimal soft '"

:J
C.
tissue swelling !I:!Jl. r
<tl
Mineralization is normal. (Q
in the same patient, shows
the true extent of this
tuberculosis osteomyelitis.
There is heterogeneous
interosseous enhancement
e:I surrounding necrotic
bone =. There is also a sofl
tissue abscess with thickened
irregular walls !I:!Jl.
(Left) Sagittal CT reformation
shows a permeative distal
fibular lesion
diagnosed
=originally
as stress fracture.
However, delayed healing
with aggressive periostitis ~
led to biopsy, confirming
lymphoma. (Right)
shows an aggressive lytic
lesion of the proximal Fibular
metaphysis with extensive
periosteal reaction There
is bone expansion, cortical
breakthrough Ell & a large
50ft tissue mass =. This is
Ewing sarcoma.
Soft Tissue Neoplasm Soft Tissue Neoplasm

a lesion in the gastrocnemius
(lateral head) of a child who
had spasm of the calf
muscles. The heterogeneous
mass = reveals multiple
serpentine channels with
interdigitating fat, Iypical of a
hemangioma. (R;gl1t) Axial
T1 C+ MR shows a
helerogeneous • 51 mass
which is tender to palpation.
=
lIS signal !I:!Jl suggests fibrous,
mineralized or hemorrhagic
content. This was a low
grade malignant peripheral
nerve sheath tumor at
biopsy.
III
97
OJ
Q) PAINFUL KNEE REPLACEMENT
....J
"0
C
ctl
Q) DIFFERENTIAL DIAGNOSIS • If medial and lateral collateral ligaments
Q)
c are stretched, may use a wider
~ Common polyethylene spacer on tibial tray to
"0
CIl
• Arthroplasty Loosening eliminate soft tissue slack
I/)
01 • Knee Instability • Stability also conferred by concave shape
[Q
• Component Malpositioning of polyethylene spacer, which partially
~
01 • Arthroplasty Dislocation conforms to the femoral component
U
C
• Septic Joint • Component Malpositioning
U
• Stress Shielding (Mimic) o TKAplacement designed to duplicate the
• Arthroplasty Component Wear normal knee
• Particle Disease/Massive Osteolysis • Femoral component placed without
• Arthroplasty Hardware Failure angulation on distal femur
• Periprosthetic Fracture • Tibial component positioned to produce
Less Common
0
7 ± 3 valgus angulation overall
0
• Quadriceps Tendon Tear • Mechanical axis through center knee

0
• Soft Tissue Impingement • On lateral, expect to see 10 posterior tilt
• Stress Fracture of Fabella on tibial side, mimicking normal tibial
• Peroneal Nerve Injury tilt (may be provided either by tibial tray
tilt or a differential thickness of
polyethylene liner)
ESSENTIAL INFORMATION • Patellar button centrally placed
Key Differential Diagnosis Issues o Watch for malrotation of tibial component
• Many abnormalities are subtle & must be relative to femoral component
carefully sought; index radiographs for • Arthroplasty Dislocation
comparison are essential o Dislocation of patella may occur with soft
tissue imbalance
o Dislocation of polyethylene occurs; may be
• Arthroplasty Loosening more subtle to note
o Of all the components, tibial is most likely
• Tibial polyethylene dislocation: Watch
to show loosening
for lucency with concave shape displaced
o Usually begins at medial portion of tibial
in any direction; with dislocation, may
tray, with lucency at bone-cement or develop gapping of joint, mimicking soft
bone-component interface tissue imbalance
• Following lucency, bone may show • Patellar button dislocation: Watch for
impaction & component may shift (tilt) lucency with convex shape dislocated
• Eventual subsidence, usually into medial relative to patella; may carry cement or
tibial cancellous bone part of metal backing with the
• Eventually, lucency surrounding polyethylene
component, > 2 mm at interface o With polyethylene dislocation, there may
• Progression may be subtle; may need to be abrasion of the adjacent metal
compare with multiple earlier
• Abraded metal often shifts within joint
radiographs, not just the most recent to line either synovium or polyethylene
o Patellar button may subside superiorly
• Linear collections of abraded metal
o Femoral component rarely loosens
termed "metallosis"
• Knee Instability
• Septic Joint
o TKAusually not hinged or mechanically
o Radiographic manifestations of septic joint
constrained; stability depends on (other than large effusion) are rare
• Posterior cruciate usually retained • Clinical manifestations are generally
• Medial and lateral soft tissue constraints obvious and diagnosis made before
are retained and may be tightened osseous destruction occurs
o Diagnosis made by aspiration of joint
98
(")
PAINFUL KNEE REPLACEMENT
:J
o
III
• Stress Shielding (Mimic) • Arthroplasty Hardware Failure
o Fracture of femoral or tibial hardware rare
-<
o Weight-bearing through knee is altered CJ
III
with TKA,with less anteriorly and more o Fracture of metal-backed patellar buttons VI
C1l
posteriorly through femoral metaphysis may occur & may contribute to metallosis C.
• With less anterior weight-bearing, bone • Peri prosthetic Fracture A

:J
o Patella is at great risk for fracture CD
is resorbed anteriorly in femur CD
• With more posterior weight-bearing, • Generally transverse; may displace or not III
:J
a.
bone is produced along a line from • Risk increased because of osteotomy for r
preparation of button placement: Patella CD
posterior cortex across to posterior co
femoral component or peg; linear is thinned & vascular supply altered
sclerosis is seen o Tibial periprosthetic fractures are subtle
• Lucency and sclerosis may be progressive • Watch for thin linear sclerosis
o Resorption anteriorly in femur is so • Increased risk with osteoporosis
prominent that it might be mistaken for (rheumatoid arthritis; patients on
osteolysis or osseous lytic lesion steroids)
o Not associated with pain, loosening, or • Increased risk when patient has had prior
other complication tibial apophyseal transfer
o Pattern is constant; recognize as normal
• Arthroplasty Component Wear • Quadriceps Tendon Tear
o Wear occurs in tibial polyethylene liner;
o Occurs in patients at risk for this injury
need to observe joint line in tangent to • Rheumatoid arthritis or connective tissue
evaluate thinning disease, especially on steroids
• Particle Disease/Massive Osteolysis • End stage renal disease
o Source of particles is polyethylene, metal
• Soft Tissue Impingement
(bead shedding), and less frequently, o Generally a clinical diagnosis
fractured cement or bone • Stress Fracture of Fabella
o Particle disease seen most frequently in
o Subtle complication; may be detected on
patella or tibia radiograph, but CT more reliable
• If tibial component has screws extending • Peroneal Nerve Injury
into cancellous bone, particles may track o If the pre-operative knee is in severe
through screw holes & develop osteolysis chronic valgus & the position is corrected
which appears separate from the TKA by TKA, the peroneal nerve is stretched
o CT useful in determining extent of lysis &
and patient may develop foot-drop
visualizing associated pathologic fractures
AP radiograph shows a 2 mm lucency at the

bone-component interface •. This represents early
AP radiograph shows impaction at the medial tibial
plateau" where there is progressive loosening. Even
III
loosening, and is likely to progress. or the three without gross lucency at the site, progressive impaction
components, the tibialis the most likely to loosen. and shift of the component indicates loosening.
99
Ol
-J
"0
C
ell
Q)
Q)
C
~
Knee Instability
"0
Ql (Left) Lateralradiograph
III shows posterior subluxation
ell
[Q of the tibia relative to the
~ femur. This indicates
ell posterior cruciate ligament
o insufficiency, and a deficit of
C one of the important
U stabilizers of a knee
arthroplasty. (Right)
shows the femoral
component to be in normal
position, but the tibial
component is malposilioned.
It is rotated relative to the
femoral component. The
patient cannot achieve full
extension.

shows a lucent body located
inferior to the patella _.
This lucency is the
polyethylene patellar
"button 1/, which has
dislocated from the patella.
(Right) Sunrise view shows
the lucent polyethylene
patellar "button". with its
cement, which has
dislocated laterally from the
patella. The patellar
component is the most
frequent of the three to fail.

radiograph shows gapping at
the medial joint line.
While instability with medial
collateral insufficiency might
initially be considered the
diagnosis, the answer is seen
on the lateral view (next
image). (Right) Lateral
radiograph shows the tibial
polyethylene liner. to
have dislocated anteriorly
from the tibial tray. The
polyethylene can be seen if
the radiograph is carefully
scrutinized.
III
lOa
PAINFUL KNEE REPLACEMENT (")
:l
o
Dl
-<
OJ
Dl
Stress Shielding (Mimic) Stress Shielding (Mimic) Ul
CD
(Leh) Lateral radiograph a.
shows a relative lucency in ;,.;;
the anterior metaphysis Ell :l
<ll
of this patient who is not <ll
symptomatic. This is III
:l
expected in knee a.
arthroplasties, and should be r
<ll
followed as stress shielding. <0
the same patient 1 year later,
shows more pronounced
lucency Ell and increased
bone density streaming
posteriorly from the femoral
peg to the posterior cortex
_ Stress shielding occurs
because of altered
weight-bearing.
Arthroplasty Component Wear Arthroplasty Component Wear

radiograph shows a
unicondylar arthroplasty,
with metal-on-metal, due to
complete wearing down of
the polyethylene component
which should be seen on the
tibial tray. This component
should normally be visible.
radiograph shows thinning of
the medial portion of the
polyethylene component.
compared with the lateral
•. indicating asymmetric
wear. Note that, additionally,
there is osteolysis" related
to particle disease.
Particle Disease/Massive Osteolysis Particle Disease/Massive Osteolysis

(Leh) Sunrise radiograph
shows a patellar button
which demonstrates bead
shedding" along with
severe osteolysis Ell. The
metallic beads are of the size
required to produce this
massive osteolysis. (Right)
shows massive osteolysis
involving the tibia _ The
particles, likely from
polyethylene wear, have
moved down the medial
screw to elicit the reactive
osteolysis.
III
101
Ol
-l
"'0
c:
ro
Q)
Q)
c:
~
Particle Disease/Massive Osteolysis Particle Disease/Massive Osteolysis
"C (Left) Coronal CT reformat
CIl
1/1
III
[JJ
>.
osteolysis =
shows the extent of massive
in this patient
who had polyethylene wear.
III The large region of osteolysis
U puts the patient at risk for
c: fracture. (Right) Coronal CT
U reformat in the same patient,
obtained more posteriorly,
shows healing attempt of
pathologic fracture. due
to the large region of
osteolysis. The fracture was
not seen on radiographs.
Arthroplasty Hardware Failure Arthroplasty Hardware Failure

metallic patellar button to be
breaking up and dissociating
from the patella =.The
patellar hardware is the most
likely of the components to
have metallic failure. (Right)
Lateralradiograph shows an
angular deformity at the
superior patellar button.
where it has fractured.
Additionally, free metal
particles line the
polyethylene component IIlII;
this has been termed
,)metal/osis".
Arthroplasty Hardware Failure Arthroplasty Hardware Failure

radiograph shows a ring of
metal. located superior to
the patella, corresponding to
a portion of the patellar
button which has fractured
and displaced. (Right)
Lateralradiograph shows a
button =
metallic ring of the patellar
which has
fractured and displaced.
III
102
(')
PAINFUL KNEE REPLACEMENT
:l
n
III
-<
III
III
Peri prosthetic Fracture VI
Periprosthetic Fracture lD
shows fracture of the ;:>\
superior pole of the patella :J
C1l
•. It is important to protect C1l
this patella, so that it does OJ
:J
not displace. (Right) Lateral 0-
radiograph shows fracture r
C1l
and displacement of the (Q
superior pole of the patella

••. Note that, at this point,
the patellar bullon can still
be seen to be allached
normally" to the
remainder of the patella.
Periprosthetic Fracture
sclerosis. indicating
subacute fracture.
Periprosthetic fractures are
subtle but important to
identify. Note the screws __
located in a position which
indicates that the patient had
a tibial tubercle transfer.
shows linear sclerosis of a
periprosthetic fracture III in
a patient who had a prior
tibial tubercle transfer. That
procedure reportedly places
the patient at additional risk
for fracture.
Peri prosthetic Fracture

sclerosis" typical of an
incomplete periprosthetic
fracture. Note the patient's
osteoporosis, resuWng from
underlying rheumatoid
arthritis, placing her at risk
for fracture. (Right)
shows an angular deformity
•• in the femoral
metaphysis. This is not
normal, and was changed
relalive to prior exams. It is
the only indication in this
patient of a periprosthetic
fracture.
III
103
oo ANTERIOR ANKLE PAIN/IMPINGEMENT
LL
-0
C
ro DIFFERENTIAL DIAGNOSIS o Anterior tibiofibular ligament thickened or
Ql
:>2c discontiouous
Common
« • Injury may extend into interosseous
"C
• Anterior Impingement ligament
ell
f/) • Anterolateral Impingement
01
• Syndesmosis Sprain Helpful Clues for less Common Diagnoses
aI
~ • Stress Fracture, Tibia & Talus
01
less Common o Insufficiency fractures: Poor quality bone
o • Stress Fracture, Tibia
C such as osteoporosis, normal stress
U
• Stress Fracture, Talus o Fatigue fractures: Normal bone, excessive
• Tibialis Anterior Tendinosis stress such as overuse
• Tibialis Anterior Tendon Tear o MR appearance can be divided into stress
• Avascular Necrosis (AVN) of the Talus response & stress fracture
• Osteochondral Lesion of the Talus • Stress response: Focal area of marrow
• Navicular Fractures edema in typical location & appropriate
• Loose Body history; may have generalized linear
• Talus Fractures configuration
• Stress fracture: Low signal fine line
ESSENTIAL INFORMATION within focus of marrow edema; sequence
on which the line is visible varies
Key Differential Diagnosis Issues between patients
• Difficult to differentiate on physical o Radiographs show ill-defined, somewhat
examination thickened, linear region of sclerosis
• Clinical history will help narrow the o Periostitis not seen on talus, rarely seen on
differential diagnosis distal tibia
• Begin imaging evaluation with radiographs o Tibia
• MR preferred for advanced imaging • Fatigue fracture at base of medial
Helpful Clues for Common Diagnoses malleolus
• Anterior Impingement • Insufficiency fracture occurs in distal
o Symptoms worse in dorsiflexion metaphysis
o Result of chronic repetitive trauma with • Tibialis Anterior Tendonosis
talus impinging upon anterior tibia o Pain with dorsiflexion
• Repetitive impingement leads to o Overuse injury, especially in runners

o MR: Thickened tendon with intermediate
osteophyte formation along anterior
tibia signal
o Osteophytes best seen on lateral view and • Tibialis Anterior Tendon Tear
in sagittal plane o Inability to coordinate normal foot
o MR may show marrow edema at impaction motion, especially dorsiflexion (major
sites function) & inversion
o Mechanism
• Anterolateral Impingement
o Chronic pain • Laceration (most common mechanism)
• Pain over lateral gutter & anterior • Sudden onset of pain after forced
talofibular ligament (ATFL) plantarflexion
o History of inversion injury (acute sprain) o MR: Tendon usually thickened with
o Injury leads to inflammation, thickening heterogeneous bright signal

of ATFL& formation of meniscoid lesion • May be discontinuous, wavy, retracted or
• Meniscoid lesion: Hyalinized tissue have longitudinal split
extending into joint from talofibular • Avascular Necrosis (AVN) of the Talus
o Multitude of causes including previous
ligament
• Syndesmosis Sprain talar neck fracture
o Chronic pain, history of ankle sprain
III
104
ANTERIOR ANKLE PAIN/IMPINGEMENT
o May occur entirely within body or extend • Loose Body

to talar dome with subsequent articular o Pain, locking
surface fragmentation & collapse o Underlying conditions include
o MR: Range from nonspecific marrow osteochondral injury, osteoarthritis,
edema to typical serpiginous low signal trauma
periphery, central fat o Fragments reside in anterior & posterior
• Osteochondral Lesion of the Talus recesses of joint or in osteochondral defect
o Pain worse with activity o Synovial osteochondromatosis
o History of inversion injury • Leads to multiple osteocartilaginous
o Equal distribution between medial & bodies of uniform size
lateral talar dome • Many but not all will be "loose"; others
o Evaluate stability with CT arthrography, remain attached to synovium
MR or MR arthrography • Talus Fractures
o Stable: Overlying articular cartilage intact o Pain, swelling, difficulty bearing weight
o Unstable: Displaced fragment, contrast or o History of trauma
fluid signal at margin of fragment o Neck: Most common site
• See Loose Body below • May lead to AVN
• Navicular Fractures • Hawkins sign (lucency beneath talar
o Avulsion fractures most common, most dome) excludes AVN
from superior surface o Body: Includes lateral process, posterior
• If acute, donor site may be visible, process, dome, central body
margin of avulsed fragment ill-defined & • Posterior & lateral process fractures
not corticated, overlying soft tissue unlikely to cause anterior pain
swelling • Central body fracture results from high
• If remote, fragments well-corticated; impact injury such as MVA or fall from
need to continue search for acute source height; coronally oriented; commonly
of pain have associated dislocation
o Body fractures often radiographically • Dome: See Osteochondral Fracture above
occult; orientation is sagittal; moderate o Head: Includes small avulsion fractures
energy trauma • Most common from superior surface
o Tuberosity fractures coronally oriented • Avulsions: See Navicular Fractures above
• Result from forefoot abduction with
avulsion of posterior tibial tendon
insertion
Anterior Impingement
Sagittal NEeT shows a case of anterior impingement

due to prominent tibia/ Elland ta/arIII osteophytes.
Sagittal T2W/ FS MR shows anterior ankle impingement
due to a large osteophyte. arisingfrom the anterior
III
edge of the dista/tibia. Adjacent mallow edema III and
soh tissue edema are present.
105
o
o
u..
"0
C
Cll
Q)
32
c
«
"0 (Left) Axial T2WI FS MR
C1l shows a typical example of a
/J)
III men;scoid lesion in the
al anterolateral gutter of the
~ ankle 11:I deep to the
III talofibular ligament" in
.!:! this patient with anterolateral
c
impingement. (Right)
u Oblique PO FSEFS MR
shows typical appearance of
an isolated, anterior, inferior,
tibiofibular ligament
disruption. A small remnant
of the ligament is visible •.
Extension of fluid beyond the
anterolateral corner of the
tibia is an indicator of
disruption of this ligament.
Stress Fracture, Tibia Stress Fracturer Talus

radiograph shows an
insufficiency type of stress
fracture of the distal tibia.
The fracture appears as an
ill-defined, sclerotic, linear
abnormality in the
metaphysis •. (Right)
Sagittal T1 WI MR shows
discrete fracture lines within
the neck of the talus" and
adjacent bone marrow
edema" in this patient
with a stress fracture.
Tibialis Anterior Tendinosis

(Left) Axial STIR MR shows a
subtle MR appearance of
anterior tibialis tendinosis
11:I. The tendon is slightly
enlarged without intrinsic
signal abnormality. (Right)
Sagittal PO FSEMR shows a
rupture of the tibialis anterior
tendon" The tendon
fibers are wavy and
thickened with diffuse
intermediate signal.
III
106
Avascular Necrosis (AVN) of the Talus Osteochondral Lesion of the Talus

shows a classic case of
subchondral bone collapse
• Following avascular
necrosis of the talus. Note
the extensive sclerosis
throughout the talar dome
•. (Right) Sagillal bone CT
shows an osteochondral
lesion with small osseous
Fragments within the deFect
•. The margin of the deFect
is sclerotic with small cysts
••
Osteochondral Lesion of the Talus Navicular Fractures

shows a rounded lesion.
located posteromedially on
the dome of the talus which
has the typical appearance
of an osteochondral injury.
There is no overlying
articular cartilage defect or
ossiFic Fragment. (Right)
vertical navicular body
fracture •. The fracture was
nO! visible on the AP or
lateral views.
Loose Body Talus Fractures

radiograph shows an ossiFic
body projecting along the
medial aspect of the joint
•. This body is the result of
an unstable osteochondral
injury. On the lateral view it
was still partially located
within the deFect. (Right)
Sagillal STIR MR shows a
typical appearance of a
coronally oriented talar body
fracture" Thisparticular
Fracture is complicated by a
non-union of the fracture
fragments.
III
107
(5 MEDIAL ANKLE PAIN
o
LL
"0
C
ro DIFFERENTIAL DIAGNOSIS • Imaging shows fluid restricted to one
Q)
:;;:: portion of tendon sheath
c Common • Osteochondral Lesion of the Talus
«
"0
• Tendon, Injury o Entity is traumatic or atraumatic
Q)
l/l • Tenosynovitis (including osteochondritis dissecans,
l'll
III • Osteochondral Lesion of the Talus thought to be due to ischemic necrosis)
~ • Arthritis • Trauma history in 85%; often with
l'll
• Fracture ligament laxity
C" Less Common o Represents variable articular cartilage &
(,)
• Hardware Failure subchondral bone fracture injury
• Infection o Staged as follows
• Tarsal Coalition • Stage 1: Articular cartilage injury only
• Os Trigonum Syndrome • Stage 2: Cartilage injury + subchondral
• Tarsal Tunnel Syndrome fracture
• Stage 3: Detached (but nondisplaced)
Rare but Important fragment
• Transient Bone Marrow Edema • Stage 4: Detached & displaced fragment
• Osteonecrosis • Stage 5: Subchondral cyst formation
• Deltoid Ligament Sprain • Arthritis
• lntraosseous Neoplasm o Osteoarthritis: Joint space narrowing,
• Soft Tissue Neoplasm osteophytes, subchondral sclerosis & cysts,
± effusions
ESSENTIAL INFORMATION o Rheumatoid arthritis: Juxta-articular
osteoporosis, symmetric joint space
Helpful Clues for Common Diagnoses narrowing, erosions, effusions
• Tendon, Injury o Gout: Corticated erosions, soft tissue
o Tendinopathy: Intrasubstance signal,
masses, relatively normal mineralization
thickening, central or delaminating o Neuropathic: Joint dissolution, debris,
o Tear patterns may seen on ultrasound (US)
dislocation, subluxation, distention; occurs
&MR in diabetics
• Type 1: Partial with contour hypertrophy • Fracture
• Type 2: Partial with contour attenuation o Traumatic: Look for appropriate
• Type 3: Complete with retraction mechanism of injury
o Medial (flexor) tendons: Posterior tibialis
o Insufficiency: Osteoporosis, fracture line
(PTT), flexor hallucis longus (FHL), flexor perpendicular to major trabeculae/cortex
digitorum longus (FDL), anterior tibialis o Symptomatic accessory navicular
(ATT) synchondrosis: Edema/inflammation due
o May see marrow edema (t SI) at or near
to PIT traction or direct impingement
tendon attachments (ill-fitting shoes, etc.)
• Tenosynovitis
o Inflammation due to trauma, arthritis or Helpful Clues for Less Common Diagnoses
infection in tendon sheath ± visible • Hardware Failure
tendon pathology o Look for lucency surrounding hardware,
o Small amount of fluid normal in tendon loosening & withdrawal, failure of fusion
sheaths or fracture healing
o FHL communicates with tibiotalar joint & • Infection
may have fluid related to joint effusions; o Osteomyelitis
look for t fluid volume out of proportion • Lytic lesions, cortical loss, periosteal
to joint fluid reaction, ± sinus tracts
o Stenosing tenosynovitis o Septic arthritis
• Due to adhesions between sheath and

tendon; limits tendon movement
III
108
MEDIAL ANKLE PAIN
• juxta-articular osteopenia, effusion, o Transient osteopenia involving a single

synovial thickening, + synovial tarsal; may involve other tarsal bones over
enhancement, ± sinus tracts time
o Soft tissue abscess o Patchy or diffuse bone marrow edema of
• Often have thickened, irregular walls & an isolated tarsal with recovery of normal
multiple sinus tracts signal over time; second episode likely
• Look for foreign body involves a different bone
• Tarsal Coalition • Osteonecrosis
o Most common: Calcaneonavicular & o Look for underlying cause: Trauma,
talocalcaneal (medial facet) alcoholism, steroids, sickle cell anemia,
o Look for broad, flat, irregular articular Gaucher disease, etc.
surfaces; may be osseous, fibrous or o Regional sclerosis ± articular collapse;
cartilaginous; 20% are bilateral serpentine t / ~ Sllesion most common in
o May develop secondary signs such as talar talus, navicular
beak, horizontal sustentaculum, • Deltoid Ligament Sprain
ball-and-socket tibiotalar joint o Strongest capsuloligament complex;
• Os Trigonum Syndrome medial malleolus usually fractures before
o Seen in athletes with extreme plantar deltoid fails
flexion movements, (e.g., ballet) oEdema ± discrete disruption of deep or
o Irregular synchondrosis margins, marrow superficial ligaments
edema of talus & os trigonum, FHL • Intraosseous Neoplasm
tenosynovitis ± stenosis o Benign: Lipoma, osteoid osteoma, SBC,
• Tarsal Tunnel Syndrome ABC, osteoblastoma, chondroblastoma
o Tibial nerve compression at ankle flexor o Malignant: Chondrosarcoma, Ewing
retinaculum sarcoma, osteosarcoma
o Pain & paresthesias in medial ankle & foot • Soft Tissue Neoplasm
o Look for ganglion, venous or other o Benign: Lipoma, hemangioma,
vascular malformation, mass, bony neurofibroma, chondroma, fibromatosis
prominence, prior trauma o Malignant: Synovial sarcoma, clear cell
Helpful Clues for Rare Diagnoses sarcoma, fibrosarcoma,
• Transient Bone Marrow Edema dermatofibrosarcoma protuberans, MFH,
o Diagnosis of exclusion; abrupt onset pain liposarcoma
Tendon, Injury
Axial PO FSEFSMR shows marked lhickening and t S/

in poslerior libialtendon (PIT) •• as il passes behind
Sagillal T / WI MR in lhe same paUent shows the grade 7
inlrasubslance parlial tear with "hypertrophy" of the
III
the medial malleolus EilI. NOle lhe normally conloured lendon conlour". The normally contoured FOL 11:I is
adjacenl flexor digilorum longus tendon Ill. proximal & posterior 10 PIT.
109
<5o MEDIAL ANKLE PAIN
u..
"0
C
CIl
Ql
:i:
c
<l: Tenosynovitis Tenosynovitis
Cll shows FHL tenosynovitis.
III
III Fluid (t Sf) •. surrounds the
al normally contoured tendon
;., Ell. Fluid volume in the
III tendon sheath is out of
.!:!
c proportion to volume of fluid
in the joint •. (Right) Axial
u PO FSf FS MR shows ATT
tenosynovitis with excessive
tendon sheath fluid Ell
encircling the normal
tendon. Note the
constriction of tendon as it
passes under the extensor
retinaculum ••
Tenosynovitis
(Left)Sagittal PO FSf FS MR
shows FHL• tenosynovitis
with a large volume of
tendon sheath fluid Ell Note
tendon sheath constriction
•• at the calcaneocuboid
joint representing stenosing
tenosynovitis. (Right)
medial talus osteochondral
lesion" with lucency
surrounding a detached but
nondisplaced fragment
(stage 3).
Osteochondral lesion of the Talus

(Left) Sagittal CT reformation
shows typical talar
osteochondral lesion with
cartilage disruption" &a
fracture fragment surrounded
by small osseous cysts ffi
There ;5 no articular surface
flattening. (Right) Coronal
STIR MR shows a small t SI
area in the medial talar
subchondral bone" with
subtle hyaline cartilage
irregularity Ell representing
osteochondral lesion of the
talus at stage 2.
III
110
MEDIAL ANKLE PAIN (")
::l
n
III
'<
OJ
III
Arthritis Arthritis VI
m
(Left) Sagittal CT reformation Co
shows marked posterior
~
subtalar join! space :J
narrowing Ell with small
subchondral cysts. &
'"
r0-
ll)
osteophytic ridging 11II as :J
a.
well as profound osteopenia -n
in this posttraumatic o
osteoarthritis. (Right) Sagittal ~
T1 C+ FS MR shows a
moderate join! effusion _
joint space narrowing with
an enhancingerosion. &
periarticular bone marrow
edema. in rheumatoid
arthritis. The contralateral
ankle had similar findings.
Arthritis Arthritis
shows a large & radiodense
soft tissue mass. in the
tibiota/ar joint representing
tophaceous gout with large
associated erosions HI in the
tibiotalar, subtalar &
intertarsal joints. (Right)
typical neuropathic
(Charcot) joint in a diabetic
patient with distention ••
disorganization EB debris
•. & joint dislocation Ell
(talonavicular). Aspiration
may be necessary to exclude
infection.
Fracture Fracture
shows a nondisplaced
vertical navicular fracture
•. The lateral & AP
radiographs (not shown)
appeared completely
normal. This may occur in
athletes in jumping &
sprinting sports. (Right)
Coronal oblique T1 WI MR
shows an incomplete
insufficiency fracture Ell of
the posterior medial plantar
calcaneus with surrounding
edema. in this 39 year old
anorexic female runner.
III
111
oo MEDIAL ANKLE PAIN
u..
"0
c:
CO
Q)
~
c:
<t: Hardware Failure
Gl shows a symptomatic
'"
nl
aJ
accessory navicular with t Sf
in both the navicular .:II &
~ the accessory navicular HI
nl with a small amount of fluid
.~ in the synchondrosis _.
c:
(Right) Sagittal CT
(,)
reformation shows a
dome-shaped metal
trabecular ingrowth implant
EiIl initially placed to
fac;J;tate tibiotafar
arthrodesis. Instead, the
metal has become a
wedge-inhibiting fusion ~
and requires removal.
Infection Tarsal Coalition

(Left) Coronal CT
reformation shows failed
tibiotalar arthrodesis due to
infection. Lucency at the
screw·bone interface HI
periosteal reaction
=
indicates loosening. Note the
&
swelling III'I. (Right) Axial

NECT shows talocalcaneal
tarsal coafWon, which is one
of the most common
coalition patterns. Note
widened & slightly irregular
left middle subtalar facet 11II
compared to the normal
right facet iii. (tMSK Req).
Os Trigonum Syndrome Os Trigonum Syndrome

shows an irregular & sclerotic
(~ Sf) as trigonum iii & the
adjacent talus with a small
subtalar joint effusion. This
young woman is a ballerina
with pain when in plantar
flexion. (Right) Axial PO FSE
FS MR in the same patient
shows edema (t Sf) in the
talus & as trigonum" with
FHL tenosynovitis (fluid out
of proportion to joint
effusion) IIIll in this instance
of 05 trigonum syndrome.
III
112
MEDIAL ANKLE PAIN n
:::l
n
III
'<OJ
III
VI
Tarsal Tunnel Syndrome Transient Bone Marrow Edema ClI
(Left) Axial TlWI FS MR C.
shows a ganglion cyst III in
the tarsal tunnel, deep to the
»
:::l
flexor retinaculum, impinging '"
10
on the neurovascular bundle III
III with resultant pain in the :::l
C.
medial ankle. (Right) Sagittal "Tl
PO FSEFS MR shows mild o
diffuse navicular edema •. ~
The patient has had similar
episodes of isolated edema
in the talus & medial
cuneiform, which
spontaneously resolved. This
represents transient regional
bone marrow edema.
Osteonecrosis
shows heterogeneous
serpentine t 51 (edema) ••
& ~ 51 (preserved marrow
fat) ~ throughout the talus
& subtle articular surface
flattening Ell. This patient's
primary risk factor for
osteonecrosis was alcohol
abuse. (Right) Coronal STIR
MR shows edema (t Sf)
within the posterior UbiotaJar
Ell & tibiocalcaneal ~
portions of deltoid ligament
as well as medial malleolar
marrow edema III resulting
from an acute pronation
eversion injury.
Intraosseous Neoplasm Soft Tissue Neoplasm

shows an intracorticaf nidus
(I Sf) III surrounded by
intense edema Ell in the
talus in this /4 year old
soccer player with an osteoid
osteoma. (Right) Axial PO
FSEMR shows a discrete t 51
mass EllI medial & superficial
to the abductor hallucis
muscle _ Fat suppression
(not shown) confirmed this
mass to be a lipoma. While a
lipoma does not typically
cause pain, this patient's
medial ankle was painful due
to pressure from her shoes.
III
113
oo LATERALANKLE PAIN
LL
"0
r:::
C'O
DIFFERENTIAL DIAGNOSIS o Jones (dancer's) fracture: Transverse thru
(l)
~ proximal shaft, nonunion common
r::: Common
« • Traumatic Fracture, Fibula
"C
• Anterior Talofibular Ligament Tear a Weber classification aids in surgical
Ql
III • Fracture, Base 5th Metatarsal decision making
<ll
CO • Traumatic Fracture, Fibula • Weber A: Below tibiotalar joint, typically
~ • Fracture, Anterior Process Calcaneus avulsion of tip of lateral malleolus
<ll
o • Cuboid Fracture • Weber B: At level of the tibiotalar joint
c: • CaIcaneofibular Ligament Tear • Weber C: Above the tibiotalar joint
U • Peroneal Tendinosis/Tear/Tenosynovitis • Fracture, Anterior Process Calcaneus
• Subtalar Arthritis a Avulsion of bifurcate ligament
• Insufficiency Fracture, Fibula a Seen on lateral view
• Osteochondral Lesion of the Talus • Cuboid Fracture
• Extensor Digitorum Brevis Avulsion a Usually small fractures from lateral margin
Less Common • Direct blow or nutcracker fracture

• Tarsal Coalition resulting from forefoot abduction
• Anterolateral Impingement • Calcaneofibular Ligament Tear
• Tillaux Fracture a Tear in association with ATFL tear more
• Peroneal Tendon Subluxation common than isolated tear
• Sinus Tarsus Syndrome a Tear usually midsubstance
• Fracture, Lateral Process of Talus • Peroneal Tendinosis/Tear/Tenosynovitis
a Tendinosis: Tendon thickened,
Rare but Important
intermediate internal signal
• Peroneus Quartus Muscle o Tear: Tendon thinned, wavy, or
• Syndesmosis Sprain discontinuous
• Syndesmotic Impingement • Peroneus brevis split: Longitudinal tear
or tendon fraying
ESSENTIAL INFORMATION • Peroneus longus tear usually transverse
a Tenosynovitis: Fluid signal surrounding
Key Differential Diagnosis Issues tendon, small amounts of fluid are within
• Common features to many of the entities realm of normal
a Chronic pain, varying degrees instability
• Subtalar Arthritis
a History of inversion injury, "ankle sprain"
a Causes include previous trauma,
a Typical sequence of injury in ankle sprain:
osteoarthritis, rheumatoid arthritis
Anterior talofibular ligament (ATFL), • Insufficiency Fracture, Fibula
caIcaneofibular ligament, posterior a Normal stresses on poor quality bone
talofibular ligament a Radiographs may show ill-defined linear
Helpful Clues for Common Diagnoses sclerosis
• Anterior Talofibular Ligament Tear a MR appearance ranges from stress response
a Weakest of lateral ankle ligaments to stress fracture
a Ligament thick, thin, wavy or • Stress response: Focal area of marrow
discontinuous edema, may have linear configuration
a Adjacent edema if acute • Stress fracture: Fine low signal intensity
• Fracture, Base 5th Metatarsal line within area of marrow edema,
a May mimic ankle sprain sequence which demonstrates line is
• Base of fifth metatarsal should always be variable
included on ankle films • Osteochondral Lesion of the Talus
a Tuberosity avulsion by peroneus brevis: a Equal distribution between medial &
Longitudinal or oblique orientation of lateral talar dome
fracture a Evaluate stability with CT arthrography,
MR, MR arthrography
III
114
LATERAL ANKLE PAIN
o Stable: Overlying articular cartilage intact o Trauma most common cause, also gout,
o Unstable: Displaced fragment, bright signal osteoarthritis
or contrast at fragment margin o MR shows sinus edema/inflammation
• Extensor Digitorum Brevis Avulsion o Talocalcaneal & cervical ligaments may be
o Small flake of bone from lateral margin of edematous or disrupted
calcaneus near anterior process o Late findings are subchondral sclerosis &
o Seen on AP,mortise views cysts in adjacent talus
• Fracture, Lateral Process of Talus
Helpful Clues for LessCommon Diagnoses
o Commonly seen in snowboarders
• Tarsal Coalition
o Best seen on mortise view
o Flatfoot, pain especially after activity
o Vertically oriented fracture
o Talocalcaneal or calcaneonavicular
o Fragment of variable size
o Fibrous, cartilaginous, or osseous
• May involve subtalar articular surface
o Lateral pain due to spasm of peroneals
• Anterolateral Impingement Helpful Clues for Rare Diagnoses
o Injury leads to inflammation, thickening • Peroneus Quartus Muscle
of ATFL,formation of meniscoid lesion o Variable origin & insertion
• Meniscoid lesion: Hyalinized tissue o Crowds peroneus longus, brevis in
extending into joint from ATFL retromalleolar groove leading to
• Tillaux Fracture tendinosis, tears, subluxation
o Avulsion of anterior tibiofibular ligament • Syndesmosis Sprain
from anterior tibia o Abduction, external rotation, dorsiflexion
• Variant: Wagstaffe-LeFort fracture, o Anterior tibiofibular ligament thickened or
avulsion of ligament from fibula discontinuous
o Juvenile Tillaux: Salter III tibial fracture o Injury may extend into interosseous
occurs at stage where medial physis closed, ligament
lateral physis open, around age 14 o Adjacent edema if acute
• Peroneal Tendon Subluxation • Syndesmotic Impingement
o Creates snapping sensation o Sequelae of syndesmotic sprain
o Retinaculum avulsion from posterolateral o ATFL,posterior tibiofibular ligament,
margin of lateral malleolus may create interosseous membrane involved in
small osseous fragment isolation or combination
• Sinus Tarsus Syndrome o Ligamentous thickening, synovial
proliferation responsible for symptoms
Anterior Talofibular Ligament Tear
Axial T2WI FSMR shows acute traumatic rupture of the

anterior talofibular ligaments near its talar attachment
Lateral radiograph shows a nondisplaced fracture
=
through the base of the fifth metatarsal following an
III
III. Extensive surrounding edema E!I is consistent with inversion injury.
an acute injury. 115
(5 LATERAL ANKLE PAIN
o
u..
"0
C
CO
Q)
3<
c
<l: Fracture, Anterior Process Calcaneus Fracture, Anterior Process Calcaneus
"0 (Left) Sagittal PO FSf FS MR
Ql shows bright signal at the
VI
CO anterosuperior process of the
al calcaneus. consistent with
>. a small anterosuperior
III process avulsion by the
u
C bifurcate ligament. (Right)
Sagittal NfCT shows a
o fracture through the anterior
process of the calcaneus ••.
The posterior third of the
fracture appears healed •.
Cuboid Fracture Cuboid Fracture

shows cortical irregularity of
the cuboid on this oblique
radiograph. consistent
with a nondisplaced fracture.
shows marrow edema within
the cuboid •. Close
inspection reveals irregularity
of the cortex EiII and a small
osseous fragment III
indicative of a fracture.
Calcaneofibular Ligament Tear Calcaneofibular Ligament Tear

(Left) Coronal PO FSf MR
shows acute traumatic
rupture of the
calcaneofibular ligament •.
The ligament is
discontinuous and
abnormally oriented. (Right)
Axial PO FSf FS MR shows a
classic case of partial tear of
the calcaneofibular ligament.
A few intact ligament fibers
are present but the majority
of the ligament is replaced
by increased signal. in the
typical position of the
ligament between the
calcaneus and the adjacent
peroneal tendons.
III
116
LATERAL ANKLE PAIN
Peroneal Tendinosis/Tear/Tenosynovitis Peroneal Tendinosis/Tear/Tenosynovitis

shows a typical case of the
peroneus brevis split form of
tendon tear. The peroneus
brevis tendon (typically the
more anterior tendon) is
divided. and wraps
around the peroneus longus
tendon III. (Right) Sagittal
T2WI FS MR shows focal
inflammatory change in the
peroneus longus tendon.
and marrow edema within
the as peroneum ••• in this
patient with peroneus longus
tendonitis and painful as
peroneum syndrome.
Subtalar Arthritis
(Left) Coronal reformatted
CT shows significant
degenerative change at the
posterior (latera/) facet of the
subtalar joint •. Note the
associated sort tissue
swelling ElIIl centered distal
to the fibula. (Right)
shows moderately severe
osteopenia in this patient
with rheumatoid arthritis. An
insufficiency fracture is
present in the fibular
diaphysis •.
Osteochondral Lesion of the Talus Extensor Digitorum Brevis Avulsion

shows a classic appearance
of an oSleochondrallesion or
the talus with cyst formation
E!ll adjacent edema _ and
ill-definition of the overlying
subchondral bone and
articular cartilage. (Right) AP
radiograph shows an osseous
fragment adjacent to the
anterolateral portion of the
calcaneus. with
associated soft tissue
swelling. This extensor
digitorum brevis avulsion
may also be seen on an AP
view of the ankle, 2 cm distal
to the tip of fibula.
III
117
oo LATERAL ANKLE PAIN
u..
"0
c
<0
Q)
:i:
c
< Tarsal Coalition Tarsal Coalition
"0 (Left) Coronal PO FSEFS MR
Q)
shows typical MR
III
Ol appearance of a
III talocalcaneal coalition. The
~ middle facet is hypoplastic
Ol HI and the joint ;5 narrowed
U
c without definite osseous
bridging _ (Right) Lateral
U
talar beak EilI which results
from constant traction by the
talonavicular ligament. The C
sign is a continuous curve
from the talar dome to the
sustentaculum tali =-
It is
an insensitive but specific
sign of talocalcaneal
coalition.
Anterolateral Impingement Tillaux Fracture

anterolateral impingement
with marked thickening and
intra substance intermediate
signal of the anterior
talofibular ligament EilI and
intermediate signal in the
anterolateral gutter
representing synovitis _
a juvenile Tillaux fracture
resulting from injury du,;ng a
specific stage of physeal
maturation with closure
medially and incomplete
fusion laterally.
Peroneal Tendon Subluxation Sinus Tarsus Syndrome

shows a split in the peroneus
longus, with subluxation of
the anterior fibers of the split
III located lateral to the
fibula, while the posterior
fibers Ell are in a normal
position, posterior to the
fibula. The superior peroneal
retinaculumis stretched.
(Right) Sagittal PO FSEFS
MR shows extensive soft
tissue edema replacing
normal fat signal typically
seen in the sinustarsus. &
ill-definition of the cervical
ligament EilI in this patient
with sinus tarsus syndrome.
118
LATERAL ANKLE PAIN
Fracture, lateral Process of Talus Peroneus Quartus Muscle

(Left) Anteroposterior,
mortise view radiograph
shows a fracture of the
lateral process of the talus
with a small nondisplaced
fragment _ (Right) Axial
T2WI FSE MR shows a
peroneus quartus muscle _.
The peroneus brevis tendon
has a normal appearance HI
and the peroneus longus
tendon is seen divided into
two fragments by a
longitudinal split tear III.

shows a typical case of injury
to the anterior tibiofibular
ligament. The ligament is
thickened with intermediate
signal within. and
edema. (Right) Coronal STIR
MR shows a typical MR
appearance of an acute
syndesmotic sprain. The
injury not only involved the
anterior tibiofibular ligament
but extended up into the
interosseous ligament =.

bony impingement of the
anterior aspect of the distal
tibiofibular syndesmosis.
There is anterior subluxation
of the fibula, with resultant
narrowing anteriorly and
frank bony impingement of
the tibia and fibula •.
shows synovitis and chronic
fibrosis around an old tear of
the anterior inferior
tibiofibular (syndesmotic)
ligament •.
119
(5 HEEl PAIN
o
LL
"0
C
CO
DIFFERENTIAL DIAGNOSIS • Avulsed posterior tubercle of calcaneus
<ll
32 • May see associated vascular calcifications
c Common • Calcaneal Stress Fracture
<l:
"tl
• Plantar Fasciitis o Similar appearance as calcaneal
Cll
III • Calcaneal Insufficiency Fracture insufficiency fractures
ro
OJ • Calcaneal Stress Fracture o Differentiate by clinical presentation
>- • Calcaneal Fracture, Traumatic
ro • Stress fx: Younger patient, overuse
.!:!
• Achilles Tendon Tear & Tendinopathy • Insufficiency fx: Older, osteopenic
c • Osteomyelitis
U
• Calcaneal Fracture, Traumatic
less Common o Several classification schemes; Sanders
• Retrocalcaneal or Retro-Achilles Bursitis classification most often used
• Plantar Fascia Rupture o Key features for classification
• Tarsal Tunnel Syndrome • Intraarticular or extraarticular
• Haglund Syndrome • Extension into subtalar joint
• Foreign Body • Number of fracture fragments in subtalar
• Heel Pad Atrophy joint on coronal images
• Chronic Reactive Arthritis (CRA) • Medial to lateral location of the subtalar
• Rheumatoid Arthritis joint fractures
• Sever Disease • Achilles Tendon Tear & Tendinopathy
• Psoriatic Arthritis (PSA) o Tendon thickening appears as round
configuration on axial images
Rare but Important
o Increased signal on Tl WI & T2WI
o Watershed area 2-6 cm proximal to
• Sarcoidosis
calcaneal insertion is prone to tear
• Neoplasm, Bone
o Location of tear, cross-sectional area
involvement & extent are important for
• Paget Disease surgical planning
• Traumatic Neuroma
• Osteomyelitis
• Bone Infarct
o Abnormal bone marrow edema &
• Hemophilic Pseudotumor
enhancement on MR
• Radiation Osteonecrosis
o Progressive destruction of bone seen on
serial radiographs
ESSENTIAL INFORMATION o Look for abscess or sinus tract extending
from skin surface to bone
• Plantar Fasciitis Helpful Clues for less Common Diagnoses
o Intermediate to high signal in the • Retrocalcaneal or Retro-Achilles Bursitis
normally low signal plantar fascia o Focal collections of fluid around the
o Continuum from thickening & calcaneus & Achilles tendon
degeneration to partial thickness tear o Retrocalcaneal bursa located at
o Most commonly involves the medial band posterosuperior aspect of calcaneus,
plantar fascia near calcaneal attachment dorsally bordered by Achilles tendon
o May have reactive edema in the calcaneus o Retro-Achilles bursa located dorsal to
& surrounding soft tissue edema Achilles tendon, deep to subcutaneous fat
• Calcaneal Insufficiency Fracture • Plantar Fascia Rupture
o Oriented perpendicular to the bone o High signal, fluid-filled gap along the
trabeculae/long axis of bone course of plantar fascia
o Most common location: Posterior tubercle o Rupture at proximal or mid portion
o Second most common location parallels • Tarsal Tunnel Syndrome
the subtalar joint o Mass or scar along course of posterior tibial
o Variant: Diabetic calcaneal insufficiency nerve, deep to flexor retinaculum
avulsion fracture o Edema in tarsal tunnel on MR
120
HEEl PAIN
o Associated clinical findings of pain & Helpful Clues for Rare Diagnoses
muscle weakness
• Sarcoidosis
• Haglund Syndrome o Bilateral heel pain with or before arthritis
o Enlarged calcaneal tuberosity
• Neoplasm, Bone
• a..k"a., pump bump " o Some neoplastic entities are not painful
o Retrocalcaneal & retro-Achilles bursitis
unless bone cortex is traversed or
• Foreign Body associated with pathologic fracture
o Wide variety of foreign bodies may be
o Simple bone cyst, intraosseous lipoma,
embedded in heel during walking Ewing sarcoma, metastases,
o Foreign object may not be visible on
chondroblastoma, chondrosarcoma,
imaging, especially organic material osteosarcoma
o Surrounding edema on MR
• Heel Pad Atrophy o Talocalcaneal or calcaneonavicular may
o Atrophy of the subcutaneous fat
cause hindfoot pain
o May have history of steroid injections
o Bony, cartilaginous or fibrous fusion
o Associated with plantar fascia rupture
• Paget Disease
• CRA, PSA, IBD Arthritis o Sclerotic stage has thickened cortex &
o Calcaneus involved in 50% of cases CRA
coarsened trabeculae
o Erosions & reactive spurring at Achilles
o Calcaneal involvement in 3-10% of cases
tendon and plantar aponeurosis
• Traumatic Neuroma
• Rheumatoid Arthritis o Focal mass along course of nerve
o Erosions involving the calcaneus are
o Area of amputation or trauma
located near the plantar aponeurosis &
• Bone Infarct
Achilles tendon attachments o Serpiginous sclerosis within bone
o Look for classic rheumatoid erosions in
o Predilection for posterior half of the
metacarpal & metatarsal heads calcaneus
• Sever Disease • Hemophilic Pseudotumor
o Calcaneal apophysitis in preteen patients
o Calcaneus one of 3 top locations
o Sclerosis & fragmentation of the calcaneal
• Radiation Osteonecrosis
apophysis on radiographs is somewhat o Delineated by location of radiation port
unreliable due to anatomic variation o Mixed lytic and sclerotic changes in bone
o Calcaneal apophysis edema on MR
may mimic an aggressive entity
Plantar Fasciitis
Sagittal T2WI FS MR shows thickening and increased

signal in the medial head of the plantar faSCIa__ With
Sagittal T1 WI MR shows an oblique low intensity
fracture III extending posterosuperior to anteromfeflor
III
surrounding soft tissue edema and marrow edema m across the posterior calcaneus, perpendicular to the
the calcaneal origin HI. primary trabecular struts.
121
"0 HEEl PAIN
o
LL
"0
C
ro
Q)
:><
c
~ Calcaneal Insufficiency Fracture Calcaneal Stress Fracture
"tl (Left) Lateral radiograph
Q) shows a calcaneal
l/l
insufficiency avulsion
aI'" fracture of the calcaneus in a
~ diabetic patient. Note the
vascular calciFication iii.
'"
.!:!
The fracture pattern is across
c
u calcaneus =.
the posterior tubercle of the
with the
Achilles tendon elevating the
fracture fragment. (Right)
Sagittal Tl WI MR shows an
incomplete, low signal
intensity fractureline. is
present in the body of the
calcaneus, with mild
surrounding bone marrow
edema.
Calcaneal Fracture, Traumatic Achilles Tendon Tear & Tendinopathy

calcaneal shear fracture,
divided into anteromedial.
and posterolateral EllI
fragments. The anteromedial
fragment maintains
alignment with the talus,
while the posterolateral
fragment is angulated and
depressed •. (Right)
Sagittal T2WI FS MR shows
marked thickening,
increased signal and partial
thickness tearing of the distal
Achilles tendon •. A mild
amount of fluid is present in
the retro-Achilles bursa 11II.
Achilles Tendon Tear & Tendinopathy Osteomyelitis

shows a thickened distal
Achilles tendon 11II.
Intermediate signal is
consistent with
tendinopathy. Bursal fluid is
present in both
retrocalcaneal. and
retro-Achilles EllI regions.
(Right) Coronal TlWI FS MR
shows extensive
enhancement within the
marrow of the calcaneus
A sinus tract. is clearly
=.
depicted extending to bone.
There is loss of the cortical
margin where the sinus tract
abuts the calcaneus.
III
122
HEEL PAIN
Plantar Fascia Rupture Tarsal Tunnel Syndrome

shows disruption in the
plantar (ascia •• with mild
surrounding 50ft tissue
edema. The torn fascia ends
are thickened either due to
the tear with mild retraction
or due to pre-existing plantar
(asciitis. (Right) Sagittal T2WI
FS MR shows a round Ouid
signal mass in the tarsal
tunnel. located just
posterior to the tibial nerve
•. This is a ganglion cyst in
the tarsal tunnel which
resulted in clinical tarsal
tunnel syndrome.
Foreign Body
shows tremendous
thickening o( the distal
Achilles tendon _ There is
an enthesophyte arising at
the tendon insertional site iii
and an increased amount of
fluid within the
retrocalcaneal bursa •.
shows a subtle linear lucency
•• in the soft tissues of the
heel. The round skin
entrancesite. of the
embedded golf tee is beller
seen.
Chronic Reactive Arthritis (CRA) Chronic Reactive Arthritis (CRA)

shows dense reactive change
with" enthesopathy and
effacement o( the normal
pre-Achilles fat pad. This is
not pathognomonic o(
chronic reactive arthritis, but
that is the most likely
diagnosis (or this
appearance. (Right) Lateral
erosive disease of the
posterior calcaneus in a
patient with chronic reactive
arthritis _ Note the normal
bone density. eRA may be
erosive, productive, or
mixed, depending on stage.
III
123
15 HEEL PAIN
o
LL
-0
C
ro
Q)
:;;<
c
«
"0
Ql shows severe erosive disease
f/l
•. as well as soft tissue
'"
CD swelling & obliteration of the
~ pre-Achilles fat pad. Though
this could represent any
'"
o
c inflammatory arthritis, it is
rheumatoid arthritis in this
U case. (Right) Lateral
radiograph shows erosions
•• involving the plantar
aspect of the calcaneus
adjacent to the attachment
of the plantar aponeurosis,
as well as 50ft tissue
inflammation III all
secondary to rheumatoid
arthritis.
Sever Disease
(LehJ Sagittal T2WI FS MR
shows inflammatory change
with edema in the calcaneal
apophysis ElII and
metaphysis •.
Retrocalcanealbursitis.
and retro-Achilles edema are
present in this child with
Sever disease, or calcaneal
apophysitis. (Right) Lateral
radiograph shows mixed
erosive" and productive
•• change involving the
posterior calcaneus. This
patient has psoriatic arthritis
with involvement of the heel.

(IBD) Neoplasm, Bone
shows subtle filling in of the
pre-Achilles fat pad •.
indicating an inflammatory
process in this child who
refuses to walk and had a
several month history of
diarrhea. This represents
inflammatory bowel disease
arthropathy. (Right) Sagittal
T2WI FS MR shows a mass
•• involving the posterior
calcaneus. The normal low
signal marrow is obliterated.
Both primary and malignant
tumors should be considered
in this region. Biopsy showed
metastatic melanoma.
III
124
HEEL PAIN
Neoplasm, Bone
(Left) Sagittal T1 C+ FS MR
shows rim-enhancement
around a unicameral bone
cyst •. This is a common
location for this lesion; it
becomes painful if a
pathologic hacture develops.
(RighI) Lateral radiograph
shows a lytic lesion EiIII
involving the portion of the
calcaneus typically seen with
intraosseous lipoma or
unicameral bone cyst. The
central calcific density.
proves the former diagnosis.
This lesion may be
asymptomatic unless it
develops pathologic fraclure.
Tarsal Coalition Bone Infarct

shows extensive coalition at
the talocalcaneal,
talonavicular, and
calcaneocuboid joints. This
results in a painful hindfoot
and ball-and-socket tibiotalar
joint. (Right) Lateral
serpiginous bone infarcts in
the calcaneus and distal tibia
__ This patient had no
known risk for infarction.
Hemophilic Pseudotumor Radiation Osteonecrosis

shows a bubbly appearance
replacing the entire
calcaneus. This young male
has hemophilia and this
lesion has developed slowly
over the course of several
years. It developed
secondary to subperiosteal
and intra osseous bleeds.
shows a port-like distribution
of mixed lytic & sclerotic
bone density involving the
entire calcaneus and the
plantar portion of the talus.
The patient was trealed 10
years earlier for PNET.
III
125
(5 PAIN IN THE BALLOF THE FOOT
o
LL
"C
ell
DIFFERENTIAL DIAGNOSIS o Especially phalangeal, MT neck fractures
OJ
32 • Stress Fracture
c Common o Especially 2, 3, 4 metatarsals
<l:
't:l
• High Impact Activities • Sesamoids less commonly involved
Ql
Vl • Obesity o Radiographs, CT may be negative
'"
lD • Improperly Fitting Shoes o MR shows soft tissue & marrow edema ±
~ • High Heel Shoes fracture line
'"
l.l • Osteoarthritis • Hallux Valgus Deformity & Other
c • Aging Malalignment Deformities
C,)
• Acute Trauma o Requires weight-bearing views to diagnose
• Stress Fracture o Hallux valgus angle: Angle between long
• Hallux Valgus Deformity & Other axis 1st metatarsal & 1st proximal
Malalignment Deformities phalanx, abnormal> 15°
• Morton Neuroma o Associated bunion, 1st MTP osteoarthritis,
• Vascular Insufficiency sesamoid subluxation
• Gout • Bunion: Bone proliferation or bursa over
• Cellulitis/Ulcer/Abscess medial eminence 1st metatarsal head
• Osteomyelitis & Septic Arthritis o Morton toe: Short 1st metatarsal, long 2nd
• Diabetes: MSK Complications toe alters mechanics
• Bursitis o Hammertoe: MTP neutral/extended, PIP
Less Common flexion
o Claw toe: MTP extension, PIP & DIP
• Freiberg Infarction
• Rheumatoid Arthritis (RA) flexion
• Sesamoiditis • Morton Neuroma
o Perineural fibrosis plantar digital nerve
• Foreign Body
o Intermittent pain
• Plantar Plate Rupture
o Common site is third web space
• Neuralgia
o MR: Low to intermediate on Tl & T2WI,
• Psoriatic Arthritis
most conspicuous on Tl, diffusely
• Chronic Reactive Arthritis
enhances
• High Arch
• Plantar Fibromatosis • Gout
o Synovitis in acute phase, early disease
• Heel Cord Contracture
o May develop 2° osteoarthritis
Rare but Important o Tophi: Soft tissue or intra-osseous
• Coalition • Create erosions which may be marginal,
peri-articular, nonarticular; have sclerotic
ESSENTIAL INFORMATION margins, overhanging edges; < 15%
calcify
Key Differential Diagnosis Issues • MR intermediate to low on Tl WI,
• Underlying factors include excessive activity, variable on T2Wl, diffuse enhancement
abnormal forces or altered foot mechanics • Cellulitis/Ulcer/Abscess
• Many entities on the list are clinical only, o Diabetics: Vascular insufficiency
may cause pain without imaging o Cellulitis: Subcutaneous edema
abnormality or may predispose to other o Ulcer: Soft tissue defect, may contain air
conditions with imaging abnormalities o Abscess: Rim-enhancing fluid collection
Helpful Clues for Common Diagnoses • Osteomyelitis & Septic Arthritis
o Diabetics: Vascular insufficiency
• Osteoarthritis
o Especially 1st MTP & sesamoids o Direct spread from soft tissue infection
o Joint space narrowing, subchondral o Over pressure points especially 1st, 5th
sclerosis, cysts, osteophytes metatarsal heads

• Acute Trauma
III
126
PAIN IN THE BALL OF THE FOOT
o Radiographs: Osteopenia, bone • Plantar Plate Rupture

destruction, joint space narrowing, air o 2-5 MTP joints (particularly 2nd); F > M
o MR: Marrow & soft tissue edema, bone o Radiographs, CT normal
destruction, effusion, sinus tract o MR: Edema base metatarsal head; edema,
• Diabetes: MSK Complications thinning or discontinuity of plate
o Changes related to infection, vascular o Turf Toe: 1st MTP hyperextension injury
insufficiency or Charcot disease, may lead • Male, kicking on artificial turf
to other deformities such as hammer toe • Complete rupture may result in
• Bursitis malpositioned sesamoids
o Intermetatarsal, plantar surface metatarsal • Psoriatic Arthritis
heads, within bunion o Bilateral asymmetric erosive arthritis,
Helpful Clues for Less Common Diagnoses periostitis, ankylosis
o DIP, PIP, MTP joints
• Freiberg Infarction
o Sausage digit
o 2nd & 3rd MT heads; common in women
o Ivory digit (distal phalanx great toe)
o Radiographs: Subchondral fracture,
o Hands more common than feet
fragmentation, articular surface flattening
o MR • Chronic Reactive Arthritis
o Imaging identical to psoriasis
• Early: Nonspecific edema
o Feet more common than hands
• Late: Dark on fluid sensitive sequence
• Rheumatoid Arthritis (RA) • High Arch
o Cavus deformity on weight-bearing view
o Bilateral symmetric erosive arthritis,
o Increases pressure on ball of foot
peri-articular osteopenia, MTP joints
common • Plantar Fibromatosis
o Variable size soft tissue mass(es) arise in
• Sesamoiditis
o Causes the following
plantar fascia
o Pain not common
• Periosteal inflammation
o MR: Intermediate to low Tl, variable
• AVN: Dark marrow signal T1 & T2WI
• Fracture: Trauma or stress; high rate of mainly intermediate T2
nonunion; medial> lateral Helpful Clues for Rare Diagnoses
• Foreign Body • Coalition
o US, CT, MR for nonradiopaque objects o Isolated or with other anomalies
o Soft tissue edema, foreign body • Midfoot rare relative to hindfoot
granuloma, osseous pseudotumor
Anteroposterior radiograph shows classic osteoarthritis

of the first MTP joint with joint space narrowing,
Coronal T2WI FS MR shows degenerative arthritis of the
hallux-sesamoid joint. The carlilage space is narrowed
III
subchondral sclerosis and osteophyte formation. and subchondral signal changes are present in the
metatarsal. and the tibial sesamoid 11I:I.
127
(5 PAIN IN THE BAll OF THE FOOT
o
U.
-0
c
ro
Q)
:;;:
c
« Acute Trauma StressFracture
-0 (Leh) Axial STIR MR shows
Q) marrow edema in the base of
III
OS the second metatarsal •.
III The Lisfranc ligament is
~ disrupted near its medial
III
<.l cuneiform attachment = in
C this patient with a Lisfranc

dislocation. Note the lateral
U subluxation of the second
metatarsal Ell. (Right)
second & fourth metatarsal
stress fractures with marrow
edema lID and adjacent 50ft
tissue edema Ell. Cortical
thickening of the second
metatarsal. is also present.
Hallux Valgus Deformity & Other Hallux Valgus Deformity & Other
Malalignment Deformities Malalignment Deformities
radiograph shows a hallux
valgus deformity. Bone
proliferation is present on the
medial eminence of the 1st
metatarsal head consistent
with bunion lID. Altered
mechanics has lead to
Freiberg infarction of the 2nd
metatarsal head Ell. (Right)
shows a Morton toe
configuration. The first
metatarsal is short and the
second toe is longer than the
first. A mild hallux valgus
deformity is present as well.
Morton Neuroma Morton Neuroma

shows an intermediate signal
bulbous 50ft tissue mass 11:I
between the third and fourth
metatarsal heads extending
slightly plantarward. Slight
widening between the third
and fourth metatarsals is a/so
present in this patient with a
Morton neuroma. (Right)
typical example of a Morton
neuroma appearing as a
mass with heterogeneous
enhancement. between
the third and fourth
metatarsals.
III
128
(')
PAIN IN THE BAll OF THE FOOT
:;]
o
III
-<
OJ
III
Gout VI
Gout <l>
changes of gout in the foot.
»
:;]
Osseous erosions from tophi
~
CD
are seen within the articular III
::J
surface of the proximal n.
phalangeal head and along .,.,
the shaft B. The 3rd toe is o
also involved E!!I. (Right)
~
Sagittal T2WI MR shows
severe circumferential
destruction of the neck of
the 1 st metatarsal with an
B. The mass shows low
signal on this T2 weighted
image, typical of a tophus.
Cellulitis/Ulcer/Abscess Osteomyelitis & Septic Arthritis

(Left) Coronal T7 C+ MR
shows soft tissue abscess
formation along the dorsum
of the foot IIllI complicating
septic arthritis of the great
toe in this diabetic patient.
Note the extensive phlegmon
surrounding the metatarsal
neck E!!I. (Right) Oblique
periarticular osleopenia,
osseous destruction along
the articular surfaces of the
proximal and distal phalanx
Ell in this patient with
diabetes complicated by
septic arthritis and
osteomyelitis.
Diabetes: MSK Complications Bursitis

shows typical case of 50ft
tissue infection with gas
forming organism and
associated Charcot changes.
Extensive soft tissue air is
present and the articulation
between the navicular and
the medial cuneiform is
disrupted r=. (Right)
Coronal TI C+ MR shows a
large bursa beneath the first
MTP joint r=. No
enhancement is seen within
the wall. The mass had been
present for several months
and was becoming
increasingly painful.
(5 PAIN IN THE BAll OF THE FOOT
o
LL
"0
c::
III
Q)
32
c::
<l: Freiberg Infarction Rheumatoid Arthritis (RA)
"0 (Left) Anteroposterior
Q) radiograph shows Freiberg
III
<II infraction involving both the
CD second and third metatarsal
.?:- heads __ Findings include
<II subchondral fracture and
U
c:: articular surface collapse.
(Right) Axial inversion
U recovery FSf MR shows
erosion involving the fifth
metatarsal head" and
surrounding synovitis Ell in
this young patient with
newly diagnosed rheumatoid
arthritis. The 5th metatarsal
is often the earnest site of
involvement in the foot by
RA.
Sesamoiditis Sesamoiditis
shows an acute fracture of
the medial sesamoid. Diffuse
marrow edema is present in
the tibial sesamoid E!iI. The
fracture line was seen on
other images. (Right)
avascular necrosis of the
lateral hallux sesamoid __
with sclerosis and resultant
low signal intensity of the
marrow on all imaging
sequences.
Foreign Body Plantar Plate Rupture

(Left) Coronal T1 C+ FS MR
shows low signal foreign
bodies .:II surrounded by
inflammatory reaction. This
patient had stepped on glass,
but the foreign bodies were
not demonstrable by
radiograph. (Right) Coronal
bone CT demonstrates
widening between the first
metatarsal head and the
tibial sesamoid __ The
sesamoids are laterally
subluxated which can only
result from loss of the
stabilizing medial collateral
ligament and medial portion
of the plantar plate.
130
(")
PAIN IN THE BAll OF THE FOOT
::::l
n
III
0<:
CJ
III
Psoriatic Arthritis VI
Plantar Plate Rupture tD
(Leh) Sagilfal T2WI FS MR C.
shows disruption of the
plantar plate of the great toe
»
::::l
with discontinuity" and
~
Cll
diffuse internal signal HI A III
joint effusion is also present :J
C.
_ (Right) Anteroposterior
radiograph shows diffuse "!?
o
MTP erosive change, with
early pencil-in-cup erosions
typical of psoriatic arthritis.
Note the periostitis; psoriatic
arthritis often shows mixed
erosive and productive
changes.
Chronic Reactive Arthritis High Arch

radiograph shows
predominantly erosive
change at the IP joint of the
great toe" with adjacent
whiskering in this patient
with chronic reactive
arthritis. (Right) Lateral
radiograph shows pes
cavovarus in a patient with
Charcot Marie Tooth. This
malalignment may result in
added pressure on the ball of
the foot resulting in pain.
Plantar Fibromatosis Coalition

shows a small mass with
intermediate signal arising
from the plantar fascia ••.
The mass had intermediate
signal on all sequences
consistent with plantar
fibromatosis. (Right) Oblique
radiograph shows a
cubocuneiform coalition ••
accompanied by a
hypoplastic 4th metatarsal
Ell This is an uncommon
form of tarsal coalition.
131
<5o PES PLANO VALGUS (FLATFOOT)
U.
"0
C
<Il
<ll
:;;: • Pes Planus (Mimic)
C Common
« o "Low arch foot"
"0
• Pes Planus (Mimic)
o Not synonymous with unstable
Q)
VI • Pes Planovalgus (Flexible Flatfoot)
ItS
• Tibialis Posterior Tendon Tear hypermobile pes valgus deformity
CD
~ • Diabetic Foot o Not necessarily a pathologically pronating
ItS
• Traumatic Lisfranc Ligament Disruption foot & may have no other morphological
.!:!
c abnormalities
u
Less Common o Generally does not require treatment
• Tarsal Coalition • Pes Planovalgus (Flexible Flatfoot)
• Congenital Vertical Talus (Rocker Bottom o Common abnormality
Foot) o Requires weight-bearing radiographs to
Rare but Important make the diagnosis
• Marfan Syndrome • Hindfoot shows valgus deformity
• Ehlers Danlos (increased talocalcaneal angle on both
• Rheumatoid Arthritis AP and lateral weight-bearing
radiographs)
• Forefoot shows pronation/valgus
ESSENTIAL INFORMATION deformity (on lateral, metatarsals are
Key Differential Diagnosis Issues superimposed, with ~ inclination angle
• Terminology of "flatfoot deformity" is 1st MT; on AP, ~ convergence at bases of
variable & confusing metatarsals
o Pes planus, pes valgus, congenital • No equinus
hypermobile flatfoot, talipes o Flexible (non-fixed) deformity:
calcaneovalgus, compensated talipes Non-weight-bearing radiographs are
equinus, collapsing pes valgo planus completely normal
• Multiple etiologies are recognized & even • Tibialis Posterior Tendon Tear
more are theorized o Most common etiology of new onset
• Clinically, the foot is recognized as having flatfoot deformity in middle-aged to
some or all of the following elderly women
o Everted heel o Tibialis posterior tendon characteristics
o Abduction of forefoot on hindfoot leading to flatfoot deformity
o Collapse of medial column • Tibialis posterior tendon has the longest
o Flexibility of foot with reducibility of lever arm & is the most efficient
deformity supinator of foot
• Support of arch depends on several factors, • Arch-stabilizing effect also attributed to
both dynamic & static its extensive ligamentous support
o Osseous architecture provided by its many deep insertions
o Intrinsic & extrinsic musculature/tendons • Damaged tendon prevents normal
o Fascia & ligaments resupination of foot when walking -
• Basic definitions and measurements leads to pronated foot & flexible pes
o Hindfoot valgus: t Talocalcaneal angle planovalgus
• On lateral, T-C angle normally 25-55° o MR appearance of tear may be variable
• On AP,T-C angle normally 15-40° • Complete rupture w/retraction is unusual
o Calcaneal pitch angle: 20-30° • Altered morphology: Usually
o Forefoot pronation: On AP, metatarsals do enlargement of the tendon, but may be
not converge at bases thin (note, tibialis posterior tendon is
o Forefoot pronation on lateral: Angle of normally twice as large in diameter as
inclination decreases for metatarsals 1-4 flexor digitorum)
• Increased signal within tendon
• Diabetic Foot
132
PES PLANO VALGUS (flATFOOT) (")
::l
n
III
o Neuropathic joints generally result in • Indirect sign of coalition: Talar beak -<
collapse of longitudinal arch • Indirect sign of calcaneonavicular OJ
III
• Lisfranc (tarso-metatarsal joints) coalition: "Anteater" extension of VI
~
• Mid-tarsal joints anterior calcaneus on lateral a.
• Chopart articulation (midfoot-hindfoot: • Indirect sign of talocalcaneal coalition: »
::l
Calcaneocuboid & talonavicular) "C" sign of subtalar sclerosis on lateral '"en
o Associated abnormalities radiograph Ql
::l
• Congenital Vertical Talus (Rocker Bottom a.
• Vascular calcifications
"
• Fragmentation & dislocation of joints
• Large fluid collections
• Traumatic Lisfranc Ligament Disruption
Foot)
o Rigid flatfoot deformity
o Four required abnormalities
-
o
o
o If Lisfranc ligament disruption is not • Plantarflexed talus, dislocated from

detected and treated navicular
• Progressive disruption of the • Hindfoot valgus (increased talocalcaneal
tarso-metatarsal joints angle on both AP and lateral)
• Develops pronation of forefoot, with • Forefoot pronation & valgus (lateral
collapse of the longitudinal arch shows superimposition of metatarsals,
with angle of inclination significantly
decreased for first MT; AP shows
decreased convergence at bases of MTs)
o Also termed "spastic peroneal flatfoot"
o Most common etiology of painful flatfoot
• Hindfoot equinus
in 2nd & 3rd decades Helpful Clues for Rare Diagnoses
o Most frequent coalitions are talocalcaneal • Madan Syndrome
and calcaneonavicular o Ligamentous laxity results from defect in
o Coalition decreases motion in hindfoot; in collagen synthesis
turn, other tarsal joints increase their o Foot structure stretches & relaxes; develops
motion to retain flexibility hypermobility
o "Flatfoot" occurs due to spastic peroneal • Ehlers Danlos: Similar to Marfan
contraction, pulling the forefoot/midfoot • Rheumatoid Arthritis
into pronation o As in the hand, ligamentous stretching &
o Watch for disruption may result in abnormal motion
• Direct sign of calcaneonavicular at the osseous articulations, with collapse
coalition: Seen on oblique radiograph of the arch
Pes Planovalgus (Flexible Flatfoot)
U1teralradiograph shows a low arch, but no evidence of U1teral weight-bearing radiograph shows a valgus
hindfoot valgus and no suggestion of pronation. This is hindfoot (t talocalcaneal angle) and pronated forefoot
the full extent of the abnormalities in this patient, and (superimposed metatarsals, decreased metatarsal
does nol need surgical treatment. inclination angle). This is a flexible flatfoot deformity.
133
o
o PES PLANO VALGUS (FLATFOOT)
u..
"0
c
ro
Q)
:;;;::
c
« Pes Planovalgus (Flexible Flatfoot) Pes Planovalgus (Flexible Flatfoot)
"0 (Left) AP weight-bearing
Q)
radiograph shows increased
Ul
ell talocalcaneal angle,
CO indicating valgus hindfoot.
Z. The metatarsals do not show
ell normal convergence at the
.!:!
c bases/ indicating pronation.
(Right) AP
u non-weight-bearing
patient, taken on the same
day as the prior image,
shows the flexible nature of
this deformity. The hindfoot
valgus as well as forefoot
pronation have completely
reduced.
Tibialis Posterior Tendon Tear Tibialis Posterior Tendon Tear

shows a mild valgus
hindfoot, with early collapse
of the midfoot. Note that the
articulations of the talus;
navicular & cuneiform
articular surfaces are not as
parallel as expected ••.
the tibialis posterior tendon
to be enlarged ElIlI relative to
flexor digitorum 11II. It also
contains central high signal.
These morphologic changes
indicate tendon tear.
Diabetic Foot Diabetic Foot

shows collapse and
resorption of the talus,
deformity of the calcaneus,
and subluxation of the
Chopart (hindfoot-midfoot)
articulation, resulting in los5
of the normal longitudinal
arch. This patient is diabetic
and the findings result from
Charcot joint changes.
(Right) AP radiograph of the
same patient confirms the
destruction at the
calcaneocuboid joint and
talonavicular dislocation,
typical of neuropathic
Chopart joint.
134
(")
PES PLANO VALGUS (FLATFOOT)
:J
o
Cll
'<
OJ
Cll
Traumatic Lisfranc Ligament Disruption Traumatic Lisfranc Ligament Disruption
(Leh) AP weight-bearing
'"
CD
Co
radiograph shows a chronic »
untreated Lisfranc disruption. :J
Note particularly the offset at '"
m
the second Ell and third. t\)
tarsometatarsal joints. There :J
Co
is also significant pronation; -n
note the lack of overlap at o
the metatarsal bases. (Right) ~
same patient shows collapse
of the midfoot" a typical
long-term effect of untreated
Lisfranc injury. The forefoot
is pronated; note the
abnormal MT inclination
angles.
Tarsal Coalition
(Leh) Lateral weight-bearing
radiograph shows flattening
of the longitudinal arch.
There is prominence &
elongation of the anterior
process of the calcaneus III
termed the "anteater sign",
indicating calcaneonavicular
coalition. (Right) Oblique
confirms the
calcaneonavicufar coalition
Ell Tarsal coalition results in
flatfoot deformity due to
peroneal muscle spasticity &
resultant pronation.
Congenital Vertical Talus (Rocker

Bottom Foot) Marfan Syndrome
(Left) Lateral weight-bearing
radiograph shows
plantarflexed talus III
dislocated from the
navicular, as well as hindfoot
equinus, valgus, and forefoot
valgus/pronation. This is
typical of congenital vertical
talus. (Right) AP radiograph
shows valgus hindfoot
(increased talocalcaneal
angles) and valgus, pronated
forefoot (lack of
convergence of metatarsal
bases), bilaterally. There is
also arachnodactyly; the
patient has Marfan
syndrome.
135
"0 CAVUS FOOT DEFORMITY
o
LL
"0
C
co DIFFERENTIAL DIAGNOSIS • Increased talocalcaneal angle (high
Ql
32 calcaneal pitch)
c Common • Unusual profile view of talus
«
"C
• Idiopathic • Mid talus-first metatarsal lines form
Q)
IJl • Charcot-Marie-Tooth Disease angle with apex upward (first ray
III
al • Cerebral Palsy plantarflexed)
~ • Fracture, Malunion • Hindfoot varus or valgus (less common)
III
U • Muscular Dystrophy • Claw toe deformities
C
• Spina Bifida • Pes cavus & hindfoot varus are commonly
U
Less Common associated findings
• Stroke • Findings are typically due to imbalance of
• Compartment Syndrome intrinsic & extrinsic muscles ± contraction
• Thermal Injury, Burns of plantar fascia & soft tissues
• Spinal Cord Injury Helpful Clues for Diagnoses
• Spinal Cord Tumor • Charcot-Marie-Tooth Disease
• Syringomyelia o Classic neuromuscular cause of pes cavus
• Meningocele o Forefoot pronation, first metatarsal
• Friedreich Ataxia pronation & plantar flexion
• Polio • Fracture, Malunion
• Spinal Dysraphism o Hindfoot-midfoot deformity
• Arthrogryposis o Talar neck fracture malunion with varus
Rare but Important rotation of talar head
• Bound Foot • Compartment Syndrome
o Deep posterior compartment of calf
• Muscle atrophy & calcification
ESSENTIAL INFORMATION o May occur in foot after calcaneal fracture
Key Differential Diagnosis Issues o May have evidence of prior tibia, fibula,
• Radiographic findings are diagnostic but hindfoot or midfoot fracture
nonspecific as to cause • Polio
o Anteroposterior view = normal or forefoot o Increased calcaneal pitch angle due to
adduction & supination gastrocnemius-soleus complex weakness
o Lateral view, standing o ± Normal forefoot alignment
Charcot-Marie- Tooth Disease
III Lateral radiograph shows an abnormally

longitudinal arch •• of the foot Hindfoot varus
high Lateral radiograph shows a cavus foot with excessive
calcaneal dorsiflexion •• and forefoot varus" This
produces the nonstandard appearance of the talus •• combination suggestsspasticity
136
CAVUS FOOT DEFORMITY ('")
::l
(:;'
III
-<
llJ
III
Cerebral Palsy Muscular Dystrophy VI
CD
shows valgus and mild
equinus of the hindfoot _.
»
::l
The forefoot shows ~
CD
supinationand varus. III
which is quite severe. The ::l
C.
combination of varus and
valgus is usually seen in a
spastic foot, and is not
o"
Sl.
otherwise specific. (Right)
cavus foot deformity and
diffuse osteopenia. Note the
high calcaneal pitch _ and
atrophied 50ft tissues in this
child with muscular
dystrophy.
Meningocele
shows a high arch and claw
toe Ell deformities. Note that
the talonavicular and
calcaneocuboid joints
appear stacked 11:I and
almost the entire subia/ar
joint 1m is visible. (Right)
shows foot asymmetry due
to an occult inlrasacral
meningocele with tethered
spinal cord. In addition to
the smaller size of the foot,
the metatarsals are mildly
adducted 1m due to forefoot
varus and claw toe
deformities are present 1m.
Polio Bound Foot

shows cavus with a valgus
hindfoot It talocalcaneal
angle) • flattened midfoot
Ell & varus forefoot 1m. This
odd combination is only
seen in spastic feel, here due
to polio. (Right) Lateral
radiograph shows cavus in a
Chinese bound foot. Note
the indentation of soft tissue
_ where the foot was
folded upon itself. These
patients are at risk for
infection from tissue necrosis
developed during the
deforming procedure.
ItMSK Req).
III
137
oo CONGENITAL FOOT DEFORMITY
u..
"cro DIFFERENTIAL DIAGNOSIS • On lateral radiograph, metatarsals

<l)
:>2 normally are moderately superimposed,
c Common with 5th in plantar-most position; angle
«
• Metatarsus Adductus of inclination of metatarsals gradually
"Ql
l/)
CO
• Pes Planovalgus (Flexible Flatfoot) increases from 5° for the 5th to 20° for
aI • Club Foot (Talipes Equinovarus) the 1st
~ • Tarsal Coalition • On AP radiograph, metatarsals normally
CO
o Less Common show moderate convergence of the bases
c • Varus forefoot: Inversion and supination;
• Congenital Vertical Talus (Rocker Bottom
<..> on lateral, decreased superimposition of
Foot)
• Pes Cavus (Mimic) metatarsals (ladder-like) with 5th MT in
• Polio (Mimic) plantar-most position; on AP, increased
• Cerebral Palsy (Mimic) overlap of MT bases
• Valgus forefoot: Eversion & pronation;
Rare but Important on lateral, increased superimposition of
• Metaphyseal Bar metatarsals with 1st MT in plantar-most
position; on AP, decreased convergence
ESSENTIAL INFORMATION of MT bases
• Hint: Most congenital foot deformities
Key Differential Diagnosis Issues match the type of hindfoot & forefoot
• Hint: Do not attempt to diagnosis foot deformities
deformities without weight-bearing films o Varus hindfoot with varus forefoot
• Hint: Most congenital foot deformities can o Valgus hindfoot with valgus forefoot
be diagnosed by evaluation of three • Hint: If hindfoot and forefoot deformities
relationships are unmatched (Le., varus hindfoot and
o Hindfoot equinus or calcaneus valgus forefoot or valgus hindfoot and varus
• On lateral radiograph, normal angle forefoot), it is usually due to a spastic foot
between lines bisecting calcaneus and
tibia ranges between 60° and 90° Helpful Clues for Common Diagnoses
• Hindfoot equinus: Tibiocalcaneal angle> • Metatarsus Adductus
o Most common structural foot abnormality
90° (excessive plantarflexion of
calcaneus) of infants
o Adduction of metatarsals; normal hindfoot
• Hindfoot calcaneus: Tibiocalcaneal angle
< 60° (excessive dorsiflexion of o Rarely imaged, since it is a flexible
calcaneus); also termed "cavus" deformity and self-correcting
o Hindfoot varus or valgus
• Pes Planovalgus (Flexible Flatfoot)
o Common (4% of population)
• On lateral radiograph, normal angle
o Note: It is flexible; non-weight-bearing
between lines bisecting talus and
calcaneus ranges between 25° and 55° radiographs are normal
o Abnormalities on weight-bearing
(termed Kite angle, or lateral
talocalcaneal angle) radiographs
• On AP radiograph, normal angle between • Hindfoot valgus
lines bisecting talus and calcaneus ranges • Forefoot valgus
between 15° and 40° • No equinus
• Varus hindfoot: Decreased talocalcaneal • Club Foot (Talipes Equinovarus)
o Incidence 1:1,000 births
angle (bones approach parallel), < 25° on
o Male> female 2-3: 1
lateral and < 15° on AP
o Constant structural abnormalities
• Valgus hindfoot: Increased talocalcaneal
angle (bones diverge): > 55° on lateral • Hindfoot equinus
and> 40° on AP • Hindfoot varus
o Forefoot varus or valgus • Forefoot varus
III
138
CONGENITAL FOOT DEFORMITY
o Painful flatfoot: Persistent or intermittent o Isolated, or part of several syndromes

spasm of peroneal muscles (frequently associated with
o Usually secondary to congenital lack of meningomyelocele)
segmentation of bones of hindfoot o Constant structural abnormalities
o Symptoms begin in late first or second • Hindfoot equinus
decade • Hindfoot valgus
o Secondary signs • Plantarflexed talus, dislocated from
• Talar beak: Due to excessive motion at navicular
talonavicular joint because of rigid • Forefoot valgus
subtalar joint • Pes Cavus (Mimic)
• "Ball and socket" tibiotalar joint: o Multiple etiologies; none are strictly
Conversion of this hinge joint to a congenital, hence the "mimic" designation
rounded articulation; generally due to an • Upper motor neuron lesions (Friedrich
unusually extensive subtalar coalition ataxia)
o Calcaneonavicular coalition • Lower motor neuron lesions
• Anterior process of calcaneus extends (poliomyelitis)
and broadens at the union with • Vascular ischemia
navicular • Charcot Marie Tooth
• Directly visualized on oblique radiograph • Chinese bound foot
o Talonavicular coalition • Polio (Mimic) & Cerebral Palsy (Mimic)
• Generally mid subtalar joint o Spastic abnormalities, often with
(sustentaculum tali) and not directly mismatch of hindfoot and forefoot
visualized abnormalities (varus-valgus)
• Diagnosed by CT or MR where this o Soft tissues show muscle atrophy
portion of subtalar joint is directly Helpful Clues for Rare Diagnoses
visualized on radiographs
• Metaphyseal Bar
• Rarely will involve posterior and/or
o Rare congenital link between the proximal
anterior subtalar facets
and distal epiphyses of the first metatarsal
o 25% bilaterality
o Link is on the medial side, resulting in a
Helpful Clues for Less Common Diagnoses curved 1st MT, concave medially
• Congenital Vertical Talus (Rocker Bottom o Clinical appearance is of metatarsus
Foot) adductus, but the deformity is rigid
o Rigid flatfoot
Pes Planovalgus (Flexible Flatfoot) Pes Planovalgus (Flexible Flatfoot)
Lateral radiograph shows increased plantarflexion of the AP radiograph, same patient, shows a wide Fe angle
III
talus III forming hindfoot valgus. There is also
pronation of the forefoot, with superimposition of the
metatarsals & decreased inclination angle of MT 1-]=. metatarsal bases =
(hindfoot valgus), with lack of convergence at the
(forefoot pronation/valgus). The
abnormalities reduce on non-weightbearing.
139
"0 CONGENITAL FOOT DEFORMITY
o
u...
-0
c
<tl
<Il
:;;<
c Club Foot (Talipes Equinovarusl
Club Foot (Talipes Equinovarus)
<
-0 (Left) AP radiograph shows
Q) near superimposition of talus
Ul
<tl •• & calcaneus III
tQ (decreased talocalcaneal
~ angle, hindfoot varus). There
<tl is increased convergence at
o
C
the bases of the metatarsals
Bl typical of forefoot
U supination/varus. (Right)
same paUent, shows equinus
of the calcaneus •. The
calcaneus & talus are nearly
parallel, confirming hindfoot
varus. The forefoot shows
metatarsals =
severe supination, with the
appearing
stacked, typical of clubfoot.

shows the "anteater sign'! of
an elongated anterior
process of the calcaneus •.
This long process extends to
the navicular and is highly
suggestive of
calcaneonavicular coalition.
In this case there is no talar
beak. (Right) Oblique
radiograph confirms the
calcaneonavicular coalition
=. This type of coalition
can usually be diagnosed
with oblique radiograph. If
there is further question, CT
is confirmatory.

shows a large talar beak _
a secondary sign of tarsal
coalition. The coalition itself
is not seen, but there is a
sclerotic "C sign" in the
=
region of the subta/ar joint
which is highly
suggestive. (Right) Angled
axial bone CT shows the
broad and sclerotic
talocalcaneal coalition at the
middle facet _ compared
with the normal left side Bl
Talocalcaneal coalitions most
frequently involve this
portion of the subtalar joint.
III
140
CONGENITAL FOOT DEFORMITY
Congenital Vertical Talus (Rocker Congenital Vertical Talus (Rocker

Bottom Foot) Bottom Foot)
shows all the elements of
congenital vertical talus,
including calcaneal equinus
•• & hindfoot valgus. Note
the severe plantarflexion of
the talus _ contributing to
the valgus. The forefoot is
severely pronated HI
(Right) AP radiograph in
same patient shows t
talocalcaneal angle, with
severe medial angulation of
the talus 1lIII. There is
pronation/valgus of the
forefoot, with lack of
convergence at the MT bases
••
Pes Cavus (Mimic) Polio (Mimic)
shows abnormal dorsiflexion
of the calcaneus. and
varus deformity of the
Forefoot. This cavovarus
pattern is typically seen in
Charcot Marie Tooth, as in
this case, but may be seen
with other spastic conditions
as well. (Right) Lateral
radiograph shows a mixed
pattern of hindfoot valgus
(increased talocalcaneal
angle) and forefoot
varus/supination. This
unusual combination is seen
in spastic conditions,
incfuding polio.
Cerebral Palsy (Mimic) Metaphyseal Bar

shows equinus of the
calcaneus, valgus hindfoot,
and supinated forefoot. This
is another pattern of a spastic
rOOl, this time in a patient
with cerebral palsy. (Right)
Axial T7 WI MR shows
bridging bone extending
from the proximal to distal
epiphysis, across the
diaphysis of the first
metatarsal HIlt is bilaterally
symmetric, and causes
bowing and shortening of
the bone. It results in overall
fixed metatarsus adductus.
III
141
ao DIABETIC FOOT COMPLICATIONS
l.L.
"0
C
ctl
Q)
:;;:: • Ulceration/Cellulitis/Soft Tissue Abscess
c Common
« • Ulceration/Cellulitis/Soft Tissue Abscess
a Plantar aspect, or at the site of any
"0 deformity of foot
Q)
<Jl • Osteomyelitis, Adult
ctl a May have foreign bodies present without
co • Charcot, Neuropathic
• Insufficiency Fracture, Tarsal & Metatarsal patient's knowledge
~
ctl a Air seen in sinus tract, outlined by
o • Calcaneal Insufficiency Fracture
c enhancing tissue
o a Surrounding cellulitis is common, as are
ESSENTIAL INFORMATION soft tissue abscesses
Key Differential Diagnosis Issues • Osteomyelitis, Adult
a If sinus tract is demonstrated extending to
• All complications of the diabetic foot are
osseous destruction, diagnosis is secure
common
a Otherwise, may have reactive osseous
• Watch for vascular calcification in foot as a
hint of underlying diabetic condition edema to adjacent soft tissue abscess or
ulceration which is not truly osteomyelitis
• Many may be subtle; knowledge of expected
• "Confluent" rather than "reticulated" low
sites of complication should allow early
signal on T1 imaging may help
detection
differentiate osteomyelitis from reaction
a Charcot sites in foot: Lisfranc (tarsal
• Either osteomyelitis or osseous reaction
metatarsal) > talonavicular> Chopart
will be hyperintense and enhance with
(hindfoot/midfoot)
contrast; again, confluence of MR
a Insufficiency fractures (isolated, not
abnormality may make osteomyelitis a
associated with Charcot) most frequently
stronger consideration
seen in metatarsals & posterior calcaneal
tubercle; tarsals less common • Charcot, Neuropathic
a Fragmentation, debris (though may be
• Ulcers and cellulitis are common
atrophic in diabetic foot), large soft tissue
a Must differentiate from osteomyelitis
fluid collections, disruption of joint
a Osseous structures may show reactive
a Because of abnormal mechanics, there is
edema which simulates osteomyelitis
osseous hyperintensity & enhancement
• It may not be possible to distinguish an
a May be impossible to differentiate
uncomplicated Charcot joint from one
uncomplicated from infected Charcot joint
complicated by osteomyelitis; both may
have similar features
Ulceration/Cellulitis/Soft Tissue Abscess
III Sagittal T1 WI MR shows air in a sinus tract EillI

extending towards a calcaneus (deformed from surgery
Coronal
tract EiI
T1 c+ FS MR shows enhancement of the sinus
(same patient). There is reactive edema in the
several years earlier). There is fine reticulated Jaw signal calcaneus III but no confluence of signal; this was soft
within the calcaneus IIIbut no confluence of signal. tissue abscess without osteomyelitis.
142
DIABETIC FOOT COMPLICATIONS
Osteomyelitis, Adult Osteomyelitis, Adult

shows low signal in a sinus
tract with surrounding
edema 11II. There is
confluent low signal
occupying the majority of
the calcaneus III this
confluent pattern is highly
suspicious for osteomyelitis.
(Right) Coronal T1 C+ FS
MR shows air within the
sinustract. (same patient)
extending from the plantar
aspect of the heel, all the
way to the calcaneus. The
calcaneusenhances.
diffusely, indicating
osteomyelitis.
Charcot, Neuropathic Charcot, Neuropathic

neuropathic joint at the
Chopart joint
(hindfoot/midfoot junction).
Destruction & fragmentation
is seen at the
calcaneocuboid joint __ as
well as dislocation at the
talonavicular joint Ell. Air ;5
seen in an adjacent ulcer •.
shows large fluid collections
•• tenosynovitis, &
enhancement of the distal
tibia 11II. Patient had Charcot
joint but was not infected;
the metallic artifact is due to
failed subta/ar arthrodesis.
Insufficiency Fracture, Tarsal &

Metatarsal Calcaneal Insufficiency Fracture
(Left) Sagittal T1 C+ FS MR
shows an insufficiency
fracture of the talar body lEI
with surrounding edema.
There is also a
wedge-shaped unenhanced
region of the posterior talus
• which represents
avascular necrosis. (Right)
fracture of the posterior
tubercle of the calcaneus,
with proximal displacement
of the fragment. This is a
fracture which is typically
seen only in diabetic
patients. /t does not heal
well.
III
143
<ll
c: PAINFUL SCOLIOSIS
"0.
(f)
"0
DIFFERENTIAL DIAGNOSIS o See "Presentation" above
ell
• Variable neurologic manifestations
co''"" Common include incontinence, paralysis
>.
• Degenerative o Radiographs, CT, nuclear medicine studies
'"
o
c:
• Vertebral Body Osteomyelitis negative in early & isolated disease
• Epidural Abscess o MR preferred imaging examination
U
• Iliopsoas Abscess • Epidural mass with rim-enhancement
• Osteoid Osteoma • Difficult to identify without gadolinium
• Epidural Hematoma • Mass effect not always present
• Asymmetric Vertebral Body Fracture • Iliopsoas Abscess
Less Common o Usually 2° vertebral osteomyelitis
• Spinal Fatigue Syndrome • See "Presentation" above
• Paraspinal Muscle Injury o Typically unilateral, may be bilateral
o MR preferred, CT may be useful
• Ewing Sarcoma
• Osteoblastoma • Rim enhancing fluid-filled mass
• Intraspinal Tumors • Near infected disc
• Metastases, Bone Marrow • Osteoid Osteoma
• High Thoracic Scoliosis: Neurofibromatosis o Pain worse at night, after activity, relieved
by aspirin
Rare but Important o Commonly located in posterior elements
• Septic Facet Joint • Most lesions based in cortex
o Radiographs & CT
ESSENTIAL INFORMATION • Sclerotic pedicle, non-rotational scoliosis
• Central lucent nidus, variable central
Key Differential Diagnosis Issues mineralization
• Hint: Lesion along concavity of the curve • Nidus may only be seen on CT or MR,
• Hint: In adult history is critical; infection, rarely greater than 1.5 cm
trauma, long standing (degenerative) o Intense uptake on bone scan
• Hint: Child, osteoid osteoma most common o MR: Nidus: Isointense Tl WI, slightly more
Helpful Clues for Common Diagnoses intense T2WI
• Degenerative • Peripheral low signal rim all sequences
o Long history of pain • Adjacent marrow & soft tissue edema
o Most common cause in adult • Epidural Hematoma
• Vertebral Body Osteomyelitis o Surgical emergency
o Presentation o Focal back pain ± radiculopathy,
• Acute onset, severe unrelenting pain incontinence
• Fever, chills, elevated WBC • May rapidly progress to paralysis
• No neurologic deficits unless associated o History often includes anticoagulation or
epidural abscess recent spine procedure
o Radiographs & CT negative early in disease • Trauma usually has fractures
• Late: Adjacent end plate edema & • Underlying AVM may be cause
destruction, cysts, sclerosis; differentiate o Radiographs, nuclear scans not helpful
from mechanical disc destruction o CT limited: Epidural soft tissue mass
o Gallium scans preferred to labeled white o MR preferred imaging modality
cell scans • Tl WI: Epidural soft tissue mass, diffuse
o MR preferred imaging modality bright signal if acute, peripheral bright
• Endplate marrow edema & soft tissue rim if subacute
edema, gadolinium enhancement of disc • Asymmetric Vertebral Body Fracture
o May have iliopsoas and/or epidural abscess o History of trauma with lateral compression
• Epidural Abscess Helpful Clues for Less Common Diagnoses
o Isolated or 2° vertebral body osteomyelitis
• Spinal Fatigue Syndrome
III
144
PAINFUL SCOLIOSIS
o Underlying idiopathic scoliosis o Variable neurologic symptoms especially

o Due to paraspinal muscle strain paresthesias
o Position dependent, relieved by rest o Associated scoliosis more common in child
o No imaging findings, image to exclude o Commonly astrocytoma, adult also may
other causes have ependymomas
• Paraspinal Muscle Injury o Radiographs & CT likely negative
o Trauma, surgery (retractor injury) • May see interpediculate widening or
o Radiographs, CT, bone scan negative posterior vertebral body scalloping
o MR: Bright intramuscular signal T2WI o MR: Enlarged spinal cord, syrinx, mass
• Ewing Sarcoma with variable enhancement
o Less common in axial than appendicular • Metastases, Bone Marrow
skeleton, but a relatively common tumor o Pain ± radiculopathy
o Asymmetric vertebral body destruction o Solitary or multiple lesions
results in scoliosis o Lytic or sclerotic
• OsteobIastoma o Breast, lung, prostate, multiple myeloma
o Pain, weak association with activity • High Thoracic Scoliosis:
o Some consider giant osteoid osteoma but Neurofibromatosis
• Slightly older patient o Angular deformity commonly convex right
• Milder pain, not relieved by aspirin o Foraminal widening, posterior vertebral
• Larger lesions (over 2 cm), less sclerosis body scalloping, neurofibromas, Lisch
o Most common in spine, especially sacrum nodule, mesodermal dysplasia, optic
• Posterior elements glioma
o Variable radiographic & CT appearance
from aggressive lysis to expansile well
• Septic Facet Joint
corticated heavily mineralized lesion o Presentation similar to vertebral body
• Classic appearance is expansile lytic osteomyelitis (see above)
lesion with well-defined margins and o Risk factor: Steroid injection
irregular mineralization o Radiographs likely negative
• Soft tissue mass common o CT shows joint effusion, destruction (late)
o MR appearance: See osteoid osteoma
o Bone scan: Nonspecific, identifies site
o Aggressive variant acts like osteosarcoma
o MR: Joint effusion, subchondral edema &
• Intraspinal Tumors destruction, edema adjacent paraspinal
o Long history of pain, worse at night
muscles, enhancement
Vertebral Body Osteomyelitis Epidural Abscess
Sagittal T1 C+ MR shows diffuse enhancement within

the disc space •• enhancement within the adjacent
Sagittal T2WI MR shows a ventral epidural high signal
intensity collection consistent with epidural abscess III
III
vertebra and an epidural phlegmon" in this paUent extending from C2 into upper thoracic spine
with vertebral body osteomyelitis & scoliosis. compressing the cord posteriorly.
145
Q)
c PAINFUL SCOLIOSIS
'0.
U)
'tl
Q)
III
CO
ell
Iliopsoas Abscess Osteoid Osteoma
2:- (Left) Axial TI C+ MR shows
CO
o rim enhancing abscesses in
c both psoas muscles ElIl
U Enhancement is present
within the adjacent disc
space indicative of vertebral
body osteomyelitis. (Right)
shows a long thoracolumbar
scoliosis, convex left, without
associated rotation. This;s
the classic curve associated
with osteoid osteoma. The
lytic nidus may be
impossible to identify on
radiograph, so suspicion
must be high.
Epidural Hematoma
classic location of osteoid
osteoma" in the pedicle
with ill-defined sclerosis in
the adjacent bone EllII. This
caused a painful scoliosis;
concave on the side with the
osteoid osteoma nidus.
shows lentiform-shaped mass
•• which creates moderate
canal stenosis. The mass is
diffusely bright, indicative of
an acute epidural
hematoma. This may be a
surgical emergency,
depending on location &
extent.
Ewing Sarcoma
shows diffuse edema within
the paraspinal musculature
• with associated
hematoma. in thispatient
with paraspinal muscle injury
resulting from motor vehicle
accident. Painful splinting
creates a scoliosis. (Right) AP
radiograph shows a mild
scoliosis concave left. There
is destruction of a pedicle ••
and asymmetric compression
of the vertebral body due to
a lytic lesion. This 13 year
old proved to have Ewing
sarcoma.
III
146
PAINFUL SCOLIOSIS C)
:J
o
III
'<
III
III
Osteoblastoma Osteoblastoma VI
<D
radiograph shows (j)
destruction of the right '2.
vertebral body cortex and :J
<ll
pedicfe. in this patient
with an asteoblastoma. Note
the location of the lesion
along the concavity of a mild
leftward curve. (Right)
osteoblastoma Ell of the
right L2 lamina along the
concavity of a 'eftward
curve. The lesion is a
heterogeneous moderately
enhancing mass expanding
the lamina.
Intraspinal Tumors Metastases, Bone Marrow

radiograph demonstrates a
leftward lumbar curve in chis
child with back pain. No
focal osseous lesion is seen.
MR revealed spinal cord
astrocytoma. (Right) Axial
NECT from a patient with
renal cell carcinoma and
severe back pain reveals and
expansile lytic metastases
within the right pedicfe •.
Large soft tissue mass nearly
fills the spinal canal EiII. The
patient presented with a
painful scoliosis.
High Thoracic Scoliosis:

Neurofibromatosis Septic Facet Joint
radiograph shows focal
rightward curve at
cervicothoracic junction in a
patient w/neurofibromalosis
type 1. (Right) Axial T1 WI
MR shows destruction of left
facet joint, with
inflammatory soft tissue
extending into adjacent
paraspinaJmusculature.
as a result of facet joint
septic arthritis. It is not
surprising that the
presentation is with a painful
scoliosis secondary to
splinting towards abnormal
side.
III
147
<ll
en ARTHRITIS IN A TEENAGER
ro
<ll
.!!1
o • Enlarged metaphyses & epiphyses
.502
E ("balloon joints") due to overgrowth
<ll Common secondary to hyperemia from
U;
>. • Juvenile Idiopathic Arthritis OIA)
(f) inflammatory process
"0 • Ankylosing Spondylitis • Cartilage narrowing & widened notches
Cl>
en • Psoriatic Arthritis related to pannus formation & erosion
III
In • Septic Joint • Often asymmetric
~ • Pigmented Villonodular Synovitis (PVNS) o Other distinguishing features
III
.!:! • Femoral Acetabular Impingement (FAI) • Periostitis may be first manifestation in a
c: • Developmental Dysplasia of the Hip young child
u
Less Common • Fusion frequently occurs in the carpals
• Hemophilia: MSK Complications • Interbody fusion in the cervical spine
• Synovial Osteochondromatosis limits growth of vertebral bodies, giving
• Legg-Calve-Perthes, Secondary Changes the "waisted" appearance
• Chronic Reactive Arthritis • Ankylosing Spondylitis
• Inflammatory Bowel Disease Arthritis o Earliest manifestations (clinical &
• Osteoid Osteoma of Hip, 2° Changes radiographic) occur during teenage years
o Spinal manifestations initiate the
Rare but Important
radiographic disease process
• Congenital Insensitivity/Indifference to Pain • Osteitis at the anterior corners of
vertebral bodies
ESSENTIAL INFORMATION • SI joint widening & erosions; may be
asymmetric initially
• Teenagers normally have wide Sl joints
• Surprising number of arthridities originate with indistinct cortices; do not overcall!
during childhood or teenage years o Appendicular disease most frequently is in
• Early & accurate diagnosis is important to large proximal joints, particularly hips;
initiate treatment & avoid later debilitating may be erosive or productive
joint disease o Inflammatory Bowel Disease Arthritis
Helpful Clues for Common Diagnoses • Less frequent, but manifestations are
• Juvenile Idiopathic Arthritis OIA) similar to AS
o May have one of several manifestations • Psoriatic Arthritis
• 5% appear indistinguishable from adult o 30-50% of psoriatic patients develop
rheumatoid arthritis (RA): Most become spondyloarthropathy
seropositive • Bilateral asymmetric erosive disease; may
• 40% are pauciarticular, affecting the eventually fuse
knee, elbow & ankle most frequently; o 20% of psoriatic patients develop
seronegative; 25% develop iridocyclitis arthropathy prior to skin and nail changes
• 20% have Still disease: Acute systemic o Distinguishing features
disease with fever, anemia, • May have sausage digit with periostitis
hepatosplenomegaly; 25% of these have • DIP disease predominates; hands> feet
polyarticular destructive arthritis, • Aggressive erosive disease (pencil-in-cup)
affecting small and large joints alike & eventual fusion
• 25% have seronegative polyarticular o Chronic Reactive Arthritis
disease, symmetric & widespread in adult • Rare compared with psoriatic arthritis;
distribution; no systemic complaints & appendicular manifestations usually
seronegative foot/ankle
o Specific features generally distinguishing • Septic Joint
JIA from other teenage arthridities o Monostotic; cartilage damage and osseous
deformity eventually leads to secondary
OA
III
148
(')
ARTHRITIS IN A TEENAGER
::I
n
III
o If longstanding & slow process in a child o Similar appearance to JIA, with "balloon"
overgrowth of epiphyses/metaphyses due
-<
(especially tuberculous or fungal septic III
III
joint), hyperemia leads to overgrowth of to hyperemia Ul
CD
epiphyses & metaphyses: "Balloon" joint o Pauciarticular; knee> elbow> ankle a.
• Pigmented Villonodular Synovitis (PVNS) o Hemosiderin deposits lead to low signal on (J)
'<
o Monoarticular; nodular mass or nodules MR, blooming on GRE sequence Ul
en
lining synovium • Osteoid Osteoma of Hip, 2° Changes 3
()"
o Causes erosion if longstanding o Intraarticular 00 elicits synovitis ~ o
o Large effusion; iron deposition results in subluxation of joint ~ altered weight Ul
CD
III
foci of low signal which bloom on GRE bearing & development of osteophytes Ul
CD
• Femoral Acetabular Impingement (FAI) Alternative Differential Approaches
o Often bilateral abnormalities, though
• Consider number of joints involved (some
complaints usually begin unilaterally diagnoses belong in more than one)
o Morphologic abnormalities of femoral
o Monoarticular
head, neck, or acetabulum ~ impingement
• Septic joint
• Lateral femoral neck "bump", limiting • Pigmented villonodular synovitis (PVNS)
the normal head/neck cutback: Cam type • Synovial osteochondromatosis
• Acetabular rim overgrowth or • Osteoid osteoma of hip, 2° changes
retroversion: Pincer type o Pauciarticular
• Multiple etiologies: Trauma, DDH, SCFE • Juvenile idiopathic arthritis alA)
• ~ Labral tear & cartilage damage; ~ early • Ankylosing spondylitis
osteoarthritis
• Psoriatic arthritis
• Onset of complaints 2nd or 3rd decade • Femoral acetabular impingement (FAI)
• Developmental Dysplasia of the Hip • Developmental dysplasia of the hip
o Multiple types of dysplasia
• Hemophilia: MSK complications
• Shallow acetabulum • Legg-Calve-Perthes, secondary changes
• Femoral varus or valgus • Chronic reactive arthritis
• Acetabular or femoral retroversion • Inflammatory bowel disease arthritis
o Develop labral hypertrophy; with shear
• Congenital insensitivity/indifference to
stress, the labrum tears; eventual cartilage pain
damage & early osteoarthritis o Polyarticular
Helpful Clues for Less Common Diagnoses • Juvenile idiopathic arthritis OIA)
• Hemophilia: MSK Complications • Psoriatic arthritis
Juvenile Idiopathic Arthritis (jlA)
AP radiograph shows a combination of overgrowth of

lhe radial epiphysis _ and erosions wilh fusion althe
AP radiograph shows bilateral widening & erosion of lhe
sacroiliac joinls Eill as well as a small oSleophyle on lhe
III
carpometacarpal joint •. This combination indicates femoral neck". This 18 year old male has had back
hyperemia plus an inflammalory arthrilis, lypical of JIA. pain for 3 years; findings are lypical of AS.
149
Q)
(/) ARTHRITIS IN A TEENAGER
ro
Q)
(/)
(5
.~
E
Q)
iil Psoriatic Arthritis
>- (Left) AP radiograph shows
(j)
near complete loss of
"0
Q) cartilage in this 17 yo
(/)
nl female's hip" with mild
co erosive change. There were
~ hand and foot erosions, but
nl a/50 one site of periostitis
.!:! and unilateral sacroiliitis. The
c: patient developed psoriatic
u skin changes within a year.
a chronic septic hip. in a
teenager with L2 paraplegia
and chronic decubitus ulcer
leading to the hip joint
There is complete cartilage
destruction, with associated
osseous deformity_

shows a huge glenoid
erosion 11II in a 15 yo. Also
note nodular synovial masses
scallered throughout joint
ElII. Appearance is typical for
PVNS, proven at biopsy.
a bump at the lateral femoral
junction of the head and
neck. eliminating the
normal cutback at this site.
This configuration puts
patient at risk for cam-type
FA/; this 20 yo already had a
labral tear and cartilage
damage, despite minimally
abnormal appearance.
Hemophilia: MSK Complications

(Leh) AP radiograph in a 15
yo shows severe DOH, with
a shallow acetabulum,
superolateral subluxation of
the femoral head, and coxa
magna deformity Patient is
developing a painful arthritis.
shows a large dense effusion
•. There is erosive change
throughout the joint. Note
the overgrowth of the
epiphyses, particularly the
femoral condyles and
patella. This overgrowth is
due to chronic hyperemia
from multiple hemophilic
bleeds.
III
150
(")
ARTHRITIS IN A TEENAGER
::J
(1
III
-<
to
III
Synovial Osteochondromatosis <II
(!)
shows multiple loose bodies (J)
within a distended elbow '<
<II
joint of a 12 yo. Note the CD
bodies distending the 3
anterior III as well as (1
posterior. fat pads. 9

<II
Synovial Ctl
osteochondromatosis is OJ
<II
unusual in children, but not Ctl
rare. (Right) Coronal T2WI
FS MR in this 15 yo with LCP
shows findings of secondary
arthritis, with a large labral
tear ElIl subchondral cysts,
and diffuse cartilage loss.
This is a severely damaged
hip
Chronic Reactive Arthritis Inflammatory Bowel Disease Arthritis

shows early erosion of the
posterior calcaneus _.
There is a/so soft tissue
inflammatory change which
obliterates the pre-Achilles
fat pad. These are early heel
changes in a /9 yo with
(Right) Lateral radiography
shows soft tissue swelling
and inflammatory change at
the posterior calcaneus. in
a 10 yo who had diarrhea for
3 months. The heel is so
painful that he cannot walk.
This is inflammatory bowel
disease arthropathy.
Congenital Insensitivity/Indifference to
Osteoid Osteoma of Hip, r Changes Pain
(Left) AP radiograph in a 17
yo shows surprising findings
of femoral neck osteophytes
• & calcar buttressing HI.
These relate to the chronic
synovitis developed in
conjunction with an
intraarticufar osteoid
neck =-
osteoma, faintly seen in the
(t MSK Req)
(Right) Lateral radiograph in
a 16 yo shows severe
destruction of the foot &
ankle. He had congenital
indifference to pain; (he felt
pain with ambuJation, but
continued to walk on it,
destroying the joints).
III
151
Q)
f/l ANEMIA WITH MUSCULOSKELETAL MANIFESTATIONS
ro
Q)
.!!1
o o Associated findings of renal
.~ DIFFERENTIAL DIAGNOSIS
E osteodystrophy
Q) Common • Rugger jersey spine
1ii
>-
en • Iron or Vitamin Deficiency Anemia • Osteosclerosis or osteopenia
'0 • Chronic Renal Disease o Associated findings of
4)
VI • Anemia of Chronic Disease hyperparathyroidism
IV
l:Il • Sickle Cell Anemia • Subperiosteal bone resorption
~ • Cortical thinning
IV Less Common
U
• Lead Poisoning • Erosion of end plates, sacroiliac joints,
c:
• Myelofibrosis en theses
o
• Thalassemia • Brown tumors
• Hypothyroidism • Anemia of Chronic Disease
• Polycythemia Vera o Any chronic disease may produce anemia
• Aplastic Anemia • Rheumatoid arthritis, HIV, cirrhosis,
malignancy
Rare but Important
o Musculoskeletal findings are specific to the
• Osteopetrosis underlying disease & unrelated to anemia
• Down Syndrome (Trisomy 21) unless inducing red marrow reconversion
• Erythroblastosis Fetalis • Sickle Cell Anemia
• Engelmann Disease (Engelmann-Camurati) o Bone infarcts = serpiginous low signal on
• Fanconi Anemia Tl WI & high signal on T2WI
o Avascular necrosis = double line around
ESSENTIAL INFORMATION necrotic region in weight-bearing region
• Femoral head & humeral head are most
Key Differential Diagnosis Issues commonly involved
• Musculoskeletal findings are often unrelated o Red bone marrow reconversion = fatty
to anemia but are associated with the marrow signal replaced by low signal on
underlying disease state, thus are helpful for TlWI
imaging differential diagnosis o "H-shaped" vertebral body = collapse of
Helpful Clues for Common Diagnoses central portion of vertebral end plates
• Iron or Vitamin Deficiency Anemia o Autosplenectomy = absent spleen allows
o Most common cause of anemia bowel to collect in left upper quadrant of
o Red bone marrow reconversion involves abdomen
central to peripheral skeleton o Dactylitis = periosteal reaction can mimic
• Can be confluent, patchy or mass-like osteomyelitis
o Reconverted red marrow tends to preserve
some fatty marrow signal producing • Lead Poisoning
higher signal than muscle on T1 WI o Anemia caused by a variety of mechanisms
o Red marrow shows signal drop out on
o Musculoskeletal findings unrelated to
opposed phase imaging anemia
o Red marrow lower signal than
o Dense metaphyseal lines at ends of bones
intervertebral disc on T1 WI • Involvement of the fibula favors lead
o Gadolinium enhancement not definitive poisoning over physiologic dense
for differentiating benign from malignant metaphyseal bands
bone marrow infiltration since both have o May identify ingested flakes of lead paint
variable enhancement on abdominal imaging
• Chronic Renal Disease o Erlenmeyer flask deformities
o Deranged erythropoietin production o Undertubulation of bone diaphyses, late
o Musculoskeletal findings are related to the o Separation of cranial sutures
disease state, not the anemia • Myelofibrosis
III
152
ANEMIA WITH MUSCULOSKElETAL MANIFESTATIONS (')
:]
r;'
l\l
o Osteosclerosis from replacement of the o Skeletal manifestations are related to the .;;:
fatty marrow with fibrous tissue cause of aplastic anemia OJ
l\l
• Lower marrow signal intensity on Tl WI • Chemotherapy, infection, radiation, VI
C1l
than red marrow toxic exposure C.
o No cortical thickening Helpful Clues for Rare Diagnoses

(f)
'<
VI
o Extramedullary hematopoiesis en
• Osteopetrosis
• Thalassemia 3
o Autosomal recessive types are associated 0'
o "Squaring" of bones due to marrow o
with hematological derangement (jj'
packing • Increased fractures & infections CD
Ql
o Hair-on-end appearance of skull
• Malignant infantile type = death at VI
CD
o Thinning of the endosteal cortex young age without bone marrow
o Coarse trabecular pattern
transplant
o Obliteration of paranasal sinuses
o Autosomal dominant forms do not cause
o Biconcave vertebral bodies are rare
anemia & may be entirely asymptomatic
o Extramedullary hematopoiesis
• Hypothyroidism o Atlantoaxial subluxation
o Congenital hypothyroidism findings are
o Short humerus & femur
unrelated to anemia o Flared iliac wing
• Kyphosis o Flattened acetabular roof
• Flattened vertebral bodies o Absent or hypoplastic nasal bone
• Wedge or hook shape upper lumbar • Erythroblastosis Fetalis
vertebral body - "sail vertebra" o Transverse metaphyseal bands
• Increased intervertebral disc spaces o Diffuse diaphyseal sclerosis
o Associated with autoimmune diseases
• Fanconi Anemia
• Rheumatoid arthritis, lupus, ulcerative o Short stature
colitis, IDDM o Absent, malformed or hypoplastic thumbs
• Polycythemia Vera o Absent or hypoplastic radius
o Myelofibrosis may be precursor to
o Dysplastic ulna
polycythemia o Microcephaly
o Red marrow reconversion
o Micrognathia
• Apophyseal regions more resistant to o Scoliosis
reconversion o Developmental hip dysplasia
• Aplastic Anemia o Malformed toes
Chronic Renal Disease
Sagittal T1WI FS MR shows areas of increased signal in

the distal femoral and proximal tibial marrow space due
Lateral radiograph shows dense lines at the vertebral
endplat€s 11III due to osteoblastic activity, which occurs
III
to red bone marrow reconversion • in this young, in addition to osteoclastk activity, producing the 50
anemic female patient. called rugger jersey appearance.
153
Q)
ANEMIA WITH MUSCULOSKELETAL MANIFESTATIONS
'"
co
Q)
.!!1
o
.~
EQ)
U; Anemia of Chronic Disease Sickle Cell Anemia
en>- (Left) Sagittal T1WI MR
shows diffuse low signal in
'tl
Q) the marrow in a patient with
'"
III
llJ
HIV. Gther sequences did
not suggest infiltrating tumor.
.?:- HIV may have a dysplasia
III affecting one of the blood
.!:! eel/lines resulting in anemia.
<:
U shows normal vertebral body
height in the anterior and
posterior aspects but an
abrupt loss of height" in
the mid portion of the body,
producing the classic
"H-shape" III There is
biconcavity of the remaining
vertebral bodies.
Sickle Cell Anemia Sickle Cell Anemia

the serpiginous pattern of
avascular necrosis in the
anterosuperior portions of
both femoral heads" The
infarcts are surrounded by
edema and the remainder of
the bone marrow has low
signal red marrow
reconversion. (Right)
shows a change in density
and slight periosteal reaction
involving the first metacarpal
=. The remaining bones are
normal. The appearance is
equivocal for infection vs.
dactylitis.
Lead Poisoning Myelofibrosis

radiograph shows classic
dense bands" involving
the diaphyses. This is due 10
deposition of radiodense
lead. Involvement of the
fibula favors lead poisoning
over a normal variant.
(Right) Axial NEeT shows
diffuse sclerosis" involving
the marrOw space of the
pelvis and sacrum. The bone
cortex is not thickened.
Osteopetrosis can have a
similar appearance but does
not produce anemia in the
adult form of the disease.
III
154
ANEMIA WITH MUSCULOSKELETAL MANIFESTATIONS (")
:J
c;'
III
.:c:
OJ
III
Thalassemia VI
Myelofibrosis CD
radiograph shows diffuse en
medullary space '<
VI
osteosclerosis. that CO
involved the axial skeleton as 3
well as the tubular bones. o'
The lack of thickening of the o
VI
endosteal cortex is typical of (1)
myelofibrosis. (Right) Lateral Dl

VI
radiograph shows dense (1)
striations in a much widened

diploic space of the cranium,
giving the "hair on end"
appearance m. Note also
that the paranasal sinuses are
obliterated secondary to
marrow hyperplasia ElIlI.
shows a paravertebral mass
•. This mass is a site of
extramedullary
hematopoiesis and is found
in the most common
location for this occurrence.
obliteration of the maxillary
sinuses" Thisobliteration
is a result of marrow
hyperplasia. Generalized
expansion of the sinuses is
present. This expansion leads
to a distortion of the facial
features which is typical of
thalassemia and is known as
rodent facies.
Thalassemia Osteopetrosis
radiograph shows "squaring"
•• involving the bones of
the hand, or loss of their
normal tubular morphology
due to marrow packing.
There is associated thinning
of the endosteal cortex.
radiograph of severe
autosomal recessive
osteopetrosis shows the
bones to be diffusely and
densely sclerotic. Note that
the long bones are
undertubulated with relative
widening of the proximal
humerus •.
III
155
Q)
VI AVASCULAR NECROSIS
ro
Q)
.!!1
o • Watch for soft tissue calcifications
E suggesting dermatomyositis
Q)
Common • Watch for staple lines of ileoanal
tl
>- • Steroids
(jJ pull-through and sacroiliitis suggesting
"C • Hip Dislocation inflammatory bowel disease, requiring
Ql
VI • Femoral Neck Fractures steroid use
ltl
lrl • Post-Traumatic, Wrist • Watch for uniform cartilage narrowing &
~ • Alcohol Abuse erosive disease suggesting rheumatoid
ltl
o • Sickle Cell Anemia arthritis, commonly treated with steroids
l::
• Radiation Osteonecrosis o Systemic steroid use increases size of fat
U
• Systemic Lupus Erythematosus cells; in sites at risk for AVN, these
Less Common compromise blood flow
• Slipped Capital Femoral Epiphysis • Particularly femoral head, humeral head,
• Legg-Calve-Perthes talus, vertebral bodies
• Post-Traumatic, Ankle (Talus & Navicular) o Direct intraarticular injection of steroids
• Developmental Dysplasia of the Hip may result in both AVN and intraarticular
• AIDS Drug Therapy calcification
• Chemotherapeutic Drugs • Hip Dislocation
• Idiopathic o Because of tenuous blood supply to
femoral head, a hip which remains
Rare but Important
dislocated> 12 hours is at significant risk
• Gaucher Disease of developing AVN
• Cushing Disease • Femoral Neck Fractures
• Embolic Disease o In adults, artery of ligamentum teres is no
• Pancreatitis longer patent; femoral head depends on
• Caisson Disease circumflex artery at femoral neck
• Osteomyelitis, Pediatric o Subcapital fracture puts artery & blood
supply at risk; basi cervical or
ESSENTIAL INFORMATION intertrochanteric fractures do not have a
comparable risk of AVN
• Displaced subcapital fracture is at greater
• Though "idiopathic" is found at the top of risk for AVN than non-displaced
the list for etiology of AVN in many • Post-Traumatic, Wrist
discussions, in the author's experience, o Scaphoid fractures
another etiology can usually be found • Waist or proximal pole fractures are at
o Hint: Watch for clues in the soft tissues &
risk for AVN; distal pole fractures are not
bones to discover the etiology of AVN at similar risk
• Hint: The most frequent etiologies of AVN • AVN may be difficult to evaluate in
in developed countries includes steroid use, scaphoid fracture; relative increase in
alcohol use, sickle cell disease, and trauma radiographic or CT density alone may
• Hint: Bones which are mostly covered by not signify the fragment is avascular
cartilage are particularly at risk for • T1 and post-contrast MR is most reliable
developing AVN means of predicting fragment viability
o Femoral head, humeral head, scaphoid,
o Lunate injuries
lunate, talus, navicular • Direct fracture is rarely a cause of lunate
Helpful Clues for Common Diagnoses malacia
• Steroids • Most frequent traumatic cause of lunate
o Multiple reasons for steroid use; these may AVN is ulnar negative variance, which
sometimes be noted on the images results in shift of weight-bearing through
• Watch for reniform soft tissue mass in lunate from being shared by ulna to
iliac fossa, indicating renal transplant entirely radial
III
156
AVASCULARNECROSIS n
::l
o
III
• Repetitive microtrauma results in AVN • Post-Traumatic, Ankle (Talus & Navicular)
-<
• Alcohol Abuse o Body of talus at risk for AVN following lJl
III
o Common cause of AVN; patients must be neck fracture; watch for Hawkins sign VI
(l)
asked directly how much alcohol they suggesting viability Q.
consume daily to ascertain the truth o Muller-Weiss: Bilateral (usually) AVN of CIl
'<
VI
o Other possible hints on radiograph: navicular, related to stress fracture en
Pancreatic calcifications • Developmental Dysplasia of the Hip 3
C'i"
• Sickle Cell Anemia o Infrequently develops AVN o
o Sickled cells sludge in small vessels, • AIDS Drug Therapy iii"
<1>
Q)
causing occlusion o Antiretroviral therapy results in low MR (J)
<1>
o Femoral head and humeral head are at signal throughout osseous structures
significant risk o Rarely, AVN is also seen
o Vertebral body endplates are at risk • Chemotherapeutic Drugs
• Small vessels form terminal loops o Cytotoxic therapy rarely results in bone
beneath vertebral endplates, at risk for infarcts & AVN
sludging by abnormal red blood cells Alternative Differential Approaches
• Once endplates lose vascularity, they • AVN with diffusely abnormal marrow
collapse, often in "H-shaped" o Sickle cell anemia: Diffuse bone infarcts
configuration; may also be biconcave o Systemic lupus erythematosus: May show
o Watch for other signs of sickle cell anemia
diffuse osteoporosis
• Diffuse increased bone density from o Steroids: Marrow may show diffuse
diffuse infarcts osteoporosis
• Small or auto-infarcted spleen o AIDS drug therapy: Diffuse low marrow
• Gallstones signal
• Pulmonary infarcts; increased lung o Chemotherapeutic drugs: Diffuse infarcts
vascularity from anemia o Cushing disease: Diffuse osteoporosis
• Radiation Osteonecrosis • AVN with focally abnormal marrow (beyond
o Port-like region of sclerotic bone indicates
necrotic site)
focal region of osteonecrosis related to RT o Radiation osteonecrosis: Port-like
Helpful Clues for Less Common Diagnoses abnormal marrow in adjacent bones
• Slipped Capital Femoral Epiphysis o Gaucher disease: Shows marrow
o Usually only develop coxa magna replacement at other sites (spine, distal
deformity, but occasionally AVN femora)
Steroids Steroids
heads =
AP radiograph shows end stage AVN of the femoral
due to steroid use. The paUent had a renal
fIanspJanl; note the reniform so(t Ussue mass in the iliac
AP radiograph shows AVN of the left hip 1IIlI. Other
findings include staple lines (from ileoanal pull-through
&I), & bilateral sacroiliac joint disease •. The patient is
III
fossa E!il along with the surgical clips. on steroids for inflammatory bowel disease.
157
Q)
AVASCULAR NECROSIS
'"
OJ
Q)
o'"
.~
E
Q)
iii Hip Dislocation Hip Dislocation

en>- (Left) AP radiograph shows
sclerosis and flattening of the
"0
Q) femoral head, with
'"
III
aI
secondary osteoarthritis. This
is a young man who was
Z. involved in a rollover motor
III vehicle accident one year
U
earlier; the accident was not
c: discovered for several hours.
U (Right) AP radiograph
obtained in the same patient
in the emergency room
following his accident shows
the femoral head
superimposed on the
superior acetabulum III
typical of posterior hip
dislocation.
Femoral Neck Fractures Femoral Neck Fractures

(Left) AP radiograph in a
young man shows three
cannulated screws crossing a
healed subcapital fracture.
Though the fracture healed,
the femoral head developed
AVN, now with flattening &
secondary osteoarthritis •.
radiograph shows a pinned
subcapital fracture in an 80
year old. Though treated
appropriately, she developed
AVN with collapse III a
known complication of this
fracture.
Post-Traumatic, Wrist Post-Traumatic, Wrist

(Left) Sagittal N fCT shows
sclerosis of the proximal pole
of scaphoid. concerning
for AVN in this patient with
scaphoid fracture. The
fragments have developed a
humpback deformity III a
common complication.
shows edema within the
lunate III indicating early
AVN in a patient with ulnar
minusvariance" this
variance has been associated
with Kienbock disease. The
edema in the capitate III
may relate to altered
weight-bearing.
III
158
AVASCULAR NECROSIS (")
:J
o
III
'<
OJ
III
Alcohol Abuse Alcohol Abuse
'Co"
n>
shows subchondral fracture (f)
• indicating AVN. The '<
(f)
patient was clinically in
diagnosed as femoral 3
acetabular impingement? but o·
upon questioning, admitted o
(f)
to excessive alcohol use. <1>
(Right) Lateral radiograph tll
(f)
shows air within a fractured <1>
vertebral body _. This
represents AVN as the
etiology of the fracture. Most
frequently this is seen in
patients with rheumatoid
arthritis on steroids, but in
this case is due to alcohol
abuse.

AVN with collapse _ in a
patient with diffuse osseous
sclerosis. The bone density is
typical of diffuse infarction in
this patient with sickle cell
disease. (Right) Lateral
mid-endplate vertebral body
collapse _ which has been
termed "H-shaped". This
represents AVN of the
vertebral bodies, a pattern
typical of sickle cell.
Radiation Osteonecrosis Radiation Osteonecrosis

radiograph AVN _ in this
11 year old. Note the
increased density in the
adjacent iliac wing III. The
femoral neck shows sclerosis
& abnormal morphology Ell.
The other bones are normal;
this is a radiation port.
AVN, with collapse, of both
the acetabulum _ and the
femoral head Ell. The bone
abnormality is in a port·/ike
configuration, proving
radiation as the etiology. The
clips indicate lymph node
dissection. (t MSK Req).
III
159
CIl
(J) AVASCULAR NECROSIS
ro
CIl
(J)
is
.2
E
CIl
en>- Systemic Lupus Erythematosus
U) (Left) Coronal T1WI MR
shows the serpiginous
"t:l
CIl pattern of multiple bone
(J)
infarcts, as well as AVN of
'"
llJ both femoral condyles and
>- tibial condyles. This patient
has 5LEas the underlying
'l::"
U
disease, and is being treated
with steroids. (Right) AP
U radiograph shows AVN of
both the lunate" and the
scaphoid Ell in a patient
with 5LE. There was no
trauma to suggest another
etiology
Slipped Capital Femoral Epiphysis

high grade AVN IIIin a
patient who had been
treated for slipped capital
femoral epiphysis. Note the
linear /ucencies in the
femoral neck" indicative
of stabilizing pins which
have been removed. (Right)
collapse and fragmentation
of the left femoral capital
epiphysis" compared with
the normal right There is
early development of coxa
magna, with short, broad,
head and neck. This is
typical Legg-Perthes.
Developmental Dysplasia of the Hip

radiograph shows normal
right hip, but fragmentation
of the left femoral capital
epiphysis". This could be
due to Legg-Perthes, but the
accompanying radiograph
demonstrates the true
etiology (Right)
shows superolateral
dislocation of the left hip III
of an infant, the same child
depicted in the previous
image. Although treated
appropriately with reduction
and stabilization, the patient
developed AVN
III
160
AVASCULAR NECROSIS (")
::l
n
01
-<
lJl
01
AIDS Drug Therapy VI
C1l
(Leh) Coronal STIR MR 0-
shows typical appearance of
en
AVN in the hips of an AIDS '<
VI
patient on anliretroviral
therapy. The right hip has
m
3
more advanced disease. n
plus effusion III the left hip o
V>
BI is asymptomatic. (Right) C1l
Coronal T2WI FS MR shows OJ
V>
multiple bone infarcts Cll
throughout the hip.
including femoral head AVN.
This process appeared
following chemotherapy for
non-Hodgkin lymphoma & is
presumed secondary to
cytotoxic injury.
Gaucher Disease Gaucher Disease

grade IV AVN of the hip with
secondary osteoarthritis. The
etiology is not clear on chis
coned down view. However,
this was part of an
abdominal image which
shows the underlying disease
process. (Right) AP
patient as previous image
shows organomegaly. Note
the enlarged liver BI and
spleen" with the bowel
gas compressed between.
This patient has Gaucher
disease.
Cushing Disease Caisson Disease

([eh) AP radiograph shows
sclerosis in both femoral
heads typical of AVN • in a
young woman with Cushing
disease and endogenous
steroid production. There is
also severe osteoporosis,
typical of this disease.
classic AVN of the shoulder
_ The contralateral
shoulder and both hips were
involved as well in this
patient with Caisson disease.
This is a rare etiology of
AVN. Note the secondary
osteoarthritis which has
developed •.
III
161
Q)
(f)
HETEROTOPIC OSSIFICATION
ro
Q)
(f)
o • Imaging appearance of HO is predominantly

E the same regardless of cause
Q)
Common o Area of calcification developing into
iii
>-
(j) • Trauma peripherally matured bone on radiographs
"0 • Post-Operative &CT
CIl
en • Spine Injury o Low signal ossified rim around mass on
aI'" • Thermal Injury, Burns MR
>- • Brain Injury • Variable enhancement of mass &
'"
U • Infection surrounding edema
C
• Neurologic Infection o History & any associated injury is most
U
Less Common helpful for suggesting etiology of HO
• Dermatomyositis (Mimic) Helpful Clues for Common Diagnoses
• Progressive Systemic Sclerosis (Mimic) • Trauma
• Calcific Myonecrosis (Mimic) o Blunt trauma, muscle hematoma, joint
Rare but Important dislocation
• Systemic Lupus Erythematosus (Mimic) o Injury may not always be remembered or
• Fibrodysplasia Ossificans Progressiva reported by the patient
• Progressive Osseous Heteroplasia o Cases of heterotopic ossification without
identified cause are often presumed to be
due to trauma
ESSENTIAL INFORMATION • Post-Operative
Key Differential Diagnosis Issues o Very common after hip replacement
• Heterotopic ossification (HO) = development • 2-90% depending on definition
of bone in the soft tissues o Clinically significant in < 5%
o Muscle • Reduced range of motion, mechanical
o Tendon impingement, ankylosis
o Ligaments • Pre-operative CT to assess location &
o Subcutaneous fat extent
o Periosteum o Uncommon after knee or shoulder
• a.k.a., myositis ossificans (due to common arthroplasty
location in muscle) • Spine Injury
o Heterotopic ossification is a more inclusive o HO occurs in 20-25% of patients
term • Most common around hips, knees &
• Differentiate heterotopic ossification from ankles
bone-forming malignancy by presence of • More likely to limit joint mobility than
more mature periphery than center post-operative causes
• Be suspicious for malignancy if central o May have additional findings of fusion or
calcification or ossification is present in a widening of sacroiliac joints
soft tissue mass • Thermal Injury, Burns
o Heterotopic ossification may attach to o Additional findings of soft tissue
native bone or be separated by a cleavage contractures, acroosteolysis
plane • Brain Injury
o Fibrous plane between heterotopic o History of closed head injury, coma,
ossification and soft tissue is difficult to cerebrovascular accident
appreciate on imaging o HO occurs in 10-20% of patients
o Remember that myositis ossificans consists • Infection
of calcification, not ossification, at o Early surgical intervention for a septic
approximately 1 month post insult joint is more likely to have associated HO
• Ossification appears later as the lesion than intervention for a chronically
matures infected joint
• Neurologic Infection
III
162
HETEROTOPIC OSSIFICATION n
;:,
0"
III
o Poliomyelitis, tetanus, Guillain-Barre • Short femoral neck
'<
Helpful Clues for Less Common Diagnoses • Small cervical vertebral bodies + large III
III
posterior elements l/l
• Dermatomyositis (Mimic) (1)
o Focal or generalized soft tissue calcification

• Progressive Osseous Heteroplasia Co
o Genetic cause of heterotopic ossification C/l

o Dominant involvement of proximal thighs '<
o Dense sheet-like calcification is typical
that is less severe than fibrodysplasia l/l
<P
o May have concurrent mixed connective
ossificans progressiva 3
0"
o Ossification of skin & subcutaneous tissues o
tissue disorder iii"
• Progressive Systemic Sclerosis (Mimic) primarily, progressing superficial to deep CD
III
o Globular or sheet-like calcification
• Hemimelic distribution l/l
CD
o Findings begin in infancy
o Most common in hands
o Lacks skeletal malformations of FOP
o Acroosteolysis & soft tissue atrophy
• Calcific Myonecrosis (Mimic) Other Essential Information
o History of compartment syndrome or • Clinical findings including pain, swelling &
severe pain after trauma warmth are common
o Peripheral calcification & muscle atrophy • Early imaging appearance can mimic
in single muscle compartment sarcoma
• Lower extremity most common • Radionuclide bone scan, 3-phase
o Early (2 weeks-l month) = increased
• Systemic Lupus Erythematosus (Mimic) uptake all phases
o Intermediate (1-3 months) = increased
o Rare manifestation of lupus produces
linear & nodular calcification uptake on 3rd phase
o Late (> 3 months) = decreasing 3rd phase
o Involves subcutaneous & deep soft tissues
• Fibrodysplasia Ossificans Progressiva uptake
o Chronic (6-12 months) = normal
o Genetic cause for predictable pattern of
ossification • Complications of HO include restriction of
• Cranial to caudal movement, nerve impingement, blood
• Axial to appendicular vessel impingement, fracture
o Very rare malignant transformation to
o Ossification begins at about 3 years of age
o Associated skeletal malformations
osteosarcoma
• Short great toe or thumb • Biopsy may induce changes similar to
• Malformed phalanges aneurysmal bone cyst
• Short metacarpals & metatarsals
Sagittal NEeT shows an oval region of ossification. in

the musculature of the anterior distal thigh. The mature
Sagittal STIR MR in the same padent as prior image
shows markedly high signal in and around the oval
III
periphery of the lesion is typical for heterotopic region of ossification •. This benign entity has an
ossification (a.k.a., myositis ossificans). aggressiveappearance on MR.
163
Ql
(/) HETEROTOPIC OSSIFICATION
ro
Ql
(/)
o
.~
E
Ql
1ii Trauma Trauma
>- (Left) Axial T2WI FS MR in
en
-g
the same patient as prior
Ql shows that the oval focus of
(/)
III heterotopic ossification.
10 has intermediate to high
>- signal, with a suggestion of a
III fluid-fluid level, and
(.)
prominent surrounding
c: edema" (Right) Axial T1
U C+ FS MR in the same
patient shows
inhomogeneous
enhancement of the lesion
_ The MR appearance of
heterotopic ossification can
suggest an aggressive
process due to enhancement
and edema.
radiograph shows
heterotopic ossification ••
forming between the clavicle
and coracoid due to
disruption of the
coracoclavicular ligaments in
this grade /II
acromioclavicular dislocation
Ell. (Right) Anteroposterior
radiograph shows an osseous
mass .:II which is moderately
mature. The mass is most
mature at its periphery. The
MR showed nonspecific low
T1 and high T2 signal, but
the radiograph is diagnostic
of myositis o5sificans.
Trauma
shows development of
heterotopic ossification. in
the antecubital fossa. This is
a common location for
myositis, particularly
fof/owing elbow dislocation.
Note that the bone formation
is amorphous. suggesting
an injury 4-8 weeks earlier.
shows a mature osseous
mass, with a very distinct
and smooth outer cortex.
but less defined center.
There is a cleavage plane
between the mass and the
underlying humerus.
III
164
HETEROTOPIC OSSIFICATION (")
::::l
C:;'
III
'<
III
III
Trauma Post-Operative /II
CD
radiograph shows en
heterotopic ossification. '<
VI
extending from the ischial CD
tuberosity to the proximal 3
femur, corresponding to the 0'
location of the quadratus o
femoris muscle, This is likely
iii'
CD
due to a remote injury. OJ
VI
(Right) Anteroposterior CD
heterotopic ossification.
surrounding a noncemented
right total hip prosthesis,
Heterotopic ossification after
hip arthroplasty is very
common, but rarely causes
significant clinical symptoms.
radiograph shows a sheet of
heterotopic bone. anterior
to the left hip, Neurologically
injured patients, especially
paraplegics, are at high risk
for developing heterotopic
ossification, especially
around the hips, (Right)
shows a pin tract. through
the distal femoral diaphysis,
related to pinning for
suspension of the burned
extremity. There is classic
heterotopic o5s;{;cation =
surrounding the pin tracl.
Fibrodysplasia Ossificans Progressiva

radiograph shows the typical
extensive 50ft tissue
heterotopic ossification. in
the arms and chest of a
patient with fibrodysplasia
ossificans progressiva.
shows mature oss;{icalion
within the soft tissues of the
anterior thigh., The
patient was treated with a
chelator to resorb the
dystrophic bone, which
caused resorption of normal
bone. in a rickets-like
pattern (widened provisional
zone of calcification).
III
165
<ll
(/)
RICKETS& OSTEOMALACIA
ro
<ll
.!!1
o • Bone resorption: Subperiosteal,
.~
E subchondral, subligamentous,
<ll Common subtendinous, cortical tunneling
Ui
>-
en • Renal Failure (Renal Tubular Disease) • Brown tumors, osteoporosis
"C
• Chronic Liver Disease o Osteosclerosis, Rugger jersey spine
Ql
VI • Chronic Pancreatitis o Atrophic kidneys, dialysis catheter
ro
llJ Less Common • Chronic Liver Disease & Chronic
~ Pancreatitis
ro • Intestinal Malabsorption
l.l
• Rickets of Prematurity o No differentiating radiographic features
c:
• Aluminum Toxicity o History essential to diagnosis
U
• Vitamin D Deficiency • Intestinal Malabsorption
• Oncogenic Osteomalacia o Underlying disorders include gluten
• Dilantin sensitive enteropathy, sprue, regional
• Phenobarbital enteritis, scleroderma, obesity surgery,
• Vitamin D Dependent Rickets short gut syndrome, partial gastrectomy
• Hypophosphatemic Rickets (X-Linked) o Regional enteritis; seronegative
• Hypophosphatasia (Mimic) spondyloarthropathy including spinal
• Pseudohypoparathyroidism / fusion, SI joint ankylosis, enthesopathy
Pseudo-pseudohypopara thyroidism o Scleroderma: Soft tissue calcification,
• Atypical Axial Osteomalacia acroosteolysis, polyarthritis (most
• Metaphyseal Chondrodysplasia (Mimic) common is co-existent rheumatoid
arthritiS)
• Rickets of Prematurity
ESSENTIAL INFORMATION o s 1,000 gm; s 28 weeks EGA
Key Differential Diagnosis Issues • Aluminum Toxicity
• Radiographic manifestations common to all o In past main source of aluminum was
o Osteopenia dialysate, now it is oral phosphate binders
o Coarse, ill-defined trabecula o Features which may help differentiate from
o Looser's zones, pseudofractures renal osteodystrophy
o Cortical tunneling • Less pseudofractures, bone resorption,
o Rickets osteosclerosis
• Metaphyseal cupping & fraying • Increased incidence of infarction
• Growth retardation, short stature following renal transplantation
• Bowing, protrusio & other deformities 2° Helpful Clues for Rare Diagnoses
to "soft bones" • Vitamin D Deficiency
• Changes most pronounced in wrists & o Nutritional rickets uncommon in US today
knees • Consider in immigrant populations &
• More severe than adult onset disease individuals in poverty conditions
• Pertinent laboratory values: Serum calcium, • May be seen with limited exposure to
serum phosphate, serum alkaline sunlight
phosphatase o Decreased serum calcium & phosphate,
Helpful Clues for Common Diagnoses elevated alkaline phosphatase
• Renal Failure (Renal Tubular Disease) • Oncogenic Osteomalacia
o Decreased serum calcium, elevated o Hemangiopericytoma most common
phosphate is unique finding underlying tumor
o Associated hyperparathyroidism o Also hemangioma, giant cell tumor,
• Soft tissue calcium deposits nonossifying fibroma, osteoblastoma
o Osteomalacia resolves after tumor
resection
• Dilantin & Phenobarbital
III
166
RICKETS & OSTEOMALACIA (")
::I
n
III
o No distinguishing radiographic features • Decreased serum calcium, elevated serum 0<:
o History essential to diagnosis phosphate, parathyroid hormone OJ
III
• Vitamin D Dependent Rickets elevated III
CD
o Manifests in infancy • Obesity, developmental delay Co
o Decreased serum calcium & phosphate, • Dental hypoplasia (f)

'<
III
elevated alkaline phosphatase • Premature physeal fusion leads to short ro
• Hypophosphatemic Rickets (X-linked) stature 3
o'
o a.k.a. vitamin D resistant rickets • Bone resorption changes of HPTH may o
(jj'
o Serum calcium normal, low serum be seen CD
Ql
phosphate, elevated alkaline phosphatase, • Soft tissue calcifications/ossifications: III
CD
PTH normal to slightly elevated Calcification plaque-like, ossification
o Presents late infancy, early toddler years, peri -articular
mainly difficulty walking/weight bearing • Short metacarpals & metatarsals,
o Abnormal dentition especially 4th & 5th metacarpals, also
o Calcification in tendon & ligaments, short distal phalanx of thumb
enthesopathy • Coned epiphyses
• Mimics DISH, ankylosing spondylitis • Small exostoses located on diaphysis
o Adults: Increased bone density in spine • Basal ganglia calcification
o May see changes of hypervitaminosis D o Pseudo-pseudohypoparathyroidism
• Hypophosphatasia (Mimic) • Biochemically normal
o Normal serum calcium & phosphate, • Phenotype mimics
decreased alkaline phosphatase pseudoh ypopara thyroid ism
o Early loss of decidual teeth is common • Atypical Axial Osteomalacia
o Perinatal form lethal o Confined to spine & pelvis
o Infantile form o No pseudofractures, Looser's zones
• Radiolucent lines extending into o Described only in men
metaphyses • Metaphyseal Chondrodysplasia (Mimic)
o Adult form o Abnormal enchondral bone formation
• Fractures, chondrocalcinosis, tendon & • No Looser's zones, pseudofractures,
ligament calcification, enthesopathy cortical tunneling
• Pseudohypoparathyroidism / o Mental retardation, exophthalmos,
Pseudo-pseudohypoparathyroidism contractu res
o Pseudohypoparathyroidism
Renal Failure (Renal Tubular Disease)
Anteroposterior
oSleodyslJophy
radiograph shows
There is metaphyseal
severe renal
cupping and
l.iJteral radiograph shows dense lines at the endplates of
the vertebral bodies" which create the appearance
III
fraying •. The femoral capital epiphysis" is smal/, known as Rugger Jersey spine in this patient with renal
indicaUve of delayed skeletal maturaUon. osteodystrophy.
167
Ql
l/) RICKETS & OSTEOMALACIA
ro
Ql
l/)
o
.~
E
Ql
(;) Chronic Liver Disease
en>- (Left) Anteroposterior
"tl
Ql changes of renal
l/)
III osteodystrophy.
aJ Radiographic findings
~ include osteopenia,
III ill-defined trabecula and
o dysmorphic femoral necks &
c: trochanters Ell. (Right)
o Anteroposterior radiograph
rickets in a child with biliary
atresia. Abnormal
metaphyses" are present
with cupping and fraying.
radiograph shows
enlargement of femoral and
tibial metaphyses _ This
finding contributes to the
enlarged knees seen on
physical examination in
patients with rickets such as
this child with biliary atresia.
pseudofracrure ••.
Pseudofracture is a
nonspecific radiographic
abnormality of osteomalacia
a5 seen in this patient with
regional enteritis.
Vitamin D Deficiency Oncogenic Osteomalacia

changes of nutritional
deficiency rickets. The
rachitic rosary is due to
unmineralized osteoid
accumulation at the
costochondral junctions ••.
(Right) Axial NEeT shows a
large soft tissue mass with
phleboliths •• and
tremendous reactive bone
formation both at the tibia
and fibula Ell. The findings
are indicative of a vascular
tumor which in this patient
proved to be a
hemangiopericyroma.
III
168
RICKETS & OSTEOMALACIA (")
:;,
o
01
-<
CD
01
Dilantin Vitamin D Dependent Rickets tIl
(1)
(Left) Axial NEeT shows the C.
coarse iII-delined trabecula Ul
of anti-convulsant associated '<
(fJ
osteomalacia. Note poor CD
definition between cortical 3
and medullary bone in part o·
due to cortical tunneling. o
(fJ
(Right) Anteroposterior (1)
radiograph of a patient with Ol

(fJ
vitamin 0 resistant rickets (1)
demonstrates the prominent

enthesopathy III associated
with high doses of vitamin D.
Both femurs have been
instrumented for fixation of
fractures related to bone
softening from unmineralized
osteoid.
Hypophosphatasia (Mimic) Hypophosphatasia (Mimic)

changes of
hypophosphatasia with
osteopenia, & deformities
secondary to "soft bones"
including acetabular
protrusio & bowing of the
femurs. (Right) AP
diffuse osteopenia and
ill-defined trabecula. The
small exostoses III along the
diaphysis is characteristic of
hypophosphatasia. This is a
less severe (tarda) form
compared with the previous
image.
Pseudo hypoparathyroidism / Pseudohypoparathyroidism /

Pseudo-pseudohypoparathyroidism Pseudo-pseudohypoparathyroidism
radiograph demonstrates 50ft
tissue calcification III and a
short first metatarsal HI. This
combination of findings is
typical of
or pseudo-
radiograph shows shortening
of all metacarpals and
epiphyseal abnormalities
from coned epiphyses. These
features are typical of
or pseudo-
III
169
Q)
en SOFT TISSUE CONTRACTU RES
'"
Q)
en
o
.~
E
Q)
Common Key Differential Diagnosis Issues
U5
>-
(j) • Immobility • Soft tissue contractures have a relatively
"0 • Dupuytren Contracture nonspecific appearance on imaging
Q)
en • Trauma • Correlation with history is most useful:
ra
a:l • Post-Operative Contracture Immobility, trauma, burns, radiation,
~ • Thermal Injury, Burns inflammatory process, syndromes
ra
u • Volkmann Ischemic Contracture Helpful Clues for Diagnoses
t:
• Rheumatoid Arthritis • Complex Regional Pain Syndrome
U
• Juvenile Idiopathic Arthritis o Three phase bone scan useful for diagnosis
• Complex Regional Pain Syndrome
• Cerebral Palsy
• Radiation-Induced Non-Neoplastic Soft o Pseudoacetabulum, femoral head
Tissue Abnormalities deformity, hip subluxation or dislocation,
Less Common thoracic kyphosis, lumbar lordosis,
• Cerebral Palsy scoliosis, comma-shaped patella, foot
• Infection equinus
• Myelomeningocele • Parsonage-Turner Syndrome, Late
• Marfan Syndrome o MR in acute setting shows high signal in
• Diabetes: MSK Complications muscles on T2WI without tendon tear
• Parsonage-Turner Syndrome, Late o Joint contractures may occur late in the
• Fibromatosis Colli process without physical therapy
Rare but Important • Fibromatosis Colli
o Ultrasound is imaging modality of choice
• Nephrogenic Systemic Fibrosis
to evaluate torticollis in neonate; compare
• Arthrogryposis
with unaffected side
• Linear Morphea
• Fibrodysplasia Ossificans Progressiva • Nephrogenic Systemic Fibrosis
o Skin thickening & tendon fibrosis
o Bone scintigraphy shows radiotracer
uptake in extremity soft tissues
• Holt-Oram Syndrome
• Camptodactyly • Leprosy
o Linear calcification of peripheral nerves
• Leprosy
can be visible on radiographs & CT
• Myotonic Dystrophy
Immobility Dupuytren Contracture
III Laleral radiograph shows a marked flexion deformity.

of the knee. The musculalUre is atrophic and the bones
Axial T1WI MR shows diffuse, irregular thickening of the
palmar fascia _ which resulted in flexion deformities
are severely osteoporotic in this quadriplegic patient. of the third through fifth digits.
170
SOFT TISSUE CONTRACTU RES o
::;,
(")
III
-<
I:D
III
Trauma Juvenile Idiopathic Arthritis l/l
(1)
(Left) Sagittal T2WI MR a.
shows separation of the (f)
flexor profunda and '<
l/l
superficialis tendons. from CD
the proximal interphalangeal 3
joint. indicating rupture o·
of the A2 and A3 pulleys. o
l/l
This represen15 flexor annular CD
pulley tears from remote ClJ
en
lrauma. (Right) CD
shows flexion deformities.
carpal fusion Ell and erosive
changes _ Note that the
patient is still skeletally
immature, despite her age of
22 years.
Cerebral Palsy Fibromatosis Colli

forefoot to be supinated with
a varus deformity, which is
quite severe. The hindfoot
was in valgus. The
combination of varus and
valgus is usually seen in a
spastic foot, and is not
otherwise specific. (Right)
Transverse ultrasound shows
focal enlargement of the left
sternocleidomastoid muscle
• in this neonate with
torticollis. The contralateral
right sternocleidomastoid
muscle was normal.
Arthrogryposis
radiograph shows a fixed
abducted right hip. and
chronically dislocated left
hip al. Note that the hip
capsules are relatively dense.
Arthrogryposis represents a
heterogeneous group of
disorders which have in
common fixed joint
contractu res. (Right)
shows mature bone bridging
the soft tissue between the
lumbar spine and pelvis EiIII
cage and pelvis

in loss of motion.
=
as well as between the rib
resulting
III
171
Q)
en SHORT LIMB, UNILATERAL
ell
Q)
en
o • Component (cup, femoral head, femoral
E neck) may be mis-sized, resulting in
Q) Common relative shortening
ii)
>-
(/)
• Physeal Fractures, Pediatric o Arthroplasty loosening with subsidence of
"C • Arthroplasty Malpositioning components results in relative shortening
Ql
VI • Osteomyelitis, Pediatric • Cup subsides superiorly, femoral stem
l'tl
m • Legg-Calve-Perthes subsides into shaft
>- • Slipped Capital Femoral Epiphysis
III
• Osteomyelitis, Pediatric
••• • Juvenile Idiopathic Arthritis o Metaphyseal osteomyelitis may result in
c: • Developmental Dysplasia of the Hip slipped epiphysis & resultant shortening
U • Fibrous Dysplasia o Epiphyseal osteomyelitis may result in
Less Common epiphyseal destruction, hyperemia and
• Meningococcemia early physeal fusion - shortening
• Embolic Disease, During Infancy • Legg-Calve-Perthes
• Neurofibromatosis o AVN in child results in flattening of
• Congenital Pseudarthrosis Tibia femoral capital epiphysis - shortening

• Radiation-Induced Growth Deformities o LCP often results in coxa magna
• Compartment Syndrome, Insult Prior to deformity, with short broad femoral neck
Skeletal Maturity as well as head, further contributing to
• Hemophilia shortening
• Oilier Disease • Slipped Capital Femoral Epiphysis
• Maffucci Syndrome o Capital femoral epiphysis slips posteriorly
• Amniotic Band Syndrome and medially, resulting in shortening of

the head
Rare but Important o SCFE often results in coxa magna
• Proximal Femoral Focal Deficiency deformity, with short broad femoral neck
• Polio as well as head, further contributing to
shortening
ESSENTIAL INFORMATION • Juvenile Idiopathic Arthritis OIA) &
Hemophilia
Key Differential Diagnosis Issues o Hyperemia in both processes leads to early
• There are few congenital abnormalities physeal fusion - shortening of limb
leading to a unilateral short limb • Developmental Dysplasia of the Hip
• Many etiologies of insults to the physes may o Uncorrected DDH results in
result in modest limb length discrepancies pseudarthrosis, with femoral head
Helpful Clues for Common Diagnoses articulating with the iliac wing rather than
• Physeal Fractures, Pediatric acetabulum
o Salter III, IV, and V physeal fractures are at • Results in significant relative shortening
high risk for early bony bridging across site and lurching gait
• May bridge uniformly across physis, o Reduced DDH often develops coxa magna
leading to early cessation of growth deformity, with short broad femoral neck
• May bridge non-uniformly, leading to as well as head, - shortening of limb
both shortening and malalignment o DDH occasionally is complicated with
• Arthroplasty Mal positioning AVN, resulting in mild shortening
o Limb length following total hip • Fibrous Dysplasia
arthroplasty (THA) may be decreased, o Dysplastic bone develops microfractures,
related to positioning resulting in bowing deformities
• Acetabular component may be placed • Shepherd's crook deformity (varus) of
high femoral neck
• Osteotomy for femoral component may • Anterolateral bowing of femur and tibia
be cut low
III
172
SHORT LIMB, UNILATERAL n
::J
o
l\I
o Fibrous dysplasia generally is unilateral, • Polio
o Muscle atrophy and disuse - relative
-<
resulting in shortening of one limb [Jl
l\I
Helpful Clues for LessCommon Diagnoses shortening (fl

<1l
Q.
• Meningococcemia; Embolic Disease, Alternative Differential Approaches
en
During Infancy; Compartment Syndrome, • May divide into congenital abnormalities '<
(fl
Insult Prior to Skeletal Maturity; and versus dysplastic abnormalities versus insults m
3
Amniotic Band Syndrome to growth centers o'
o Each of these entities results in ischemia of o Congenital limb length abnormalities o
en'
the involved limb, either from embolic • Developmental dysplasia of the hip <1l
l\I
(fl
disease or vascular compression • Proximal femoral focal deficiency <1l
o Physes are particularly at risk for vascular o Dysplastic abnormalities leading to limb
insult - flattening and shortening of limb length discrepancies
• Neurofibromatosis & Congenital • Fibrous dysplasia
Pseudarthrosis Tibia • Neurofibromatosis
o Dysplastic tibia (and occasionally fibula) • Congenital pseudarthrosis tibia
results in bowing and/or non-healing • Ollier disease
fractures and pseudarthrosis - shortening • Maffucci syndrome
o Generally unilateral process o Insults to growth centers
• Radiation-Induced Growth Deformities • Physeal fractures, pediatric
o Radiation (RT) causes vascular compromise • Osteomyelitis, pediatric
• In a skeletally immature patient this • Legg-Calve-Perthes
results in AVN and early physeal fusion • Slipped capital femoral epiphysis
- shortening of limb • Juvenile idiopathic arthritis
• Oilier Disease & Maffucci Syndrome • Meningococcemia
o Both diseases are a dysplasia, affecting the • Embolic disease, during infancy
metaphyses, with cartilage lesions which • Radiation-induced growth deformities
do not grow appropriately • Compartment syndrome, insult prior to
o Unilateral involvement - short limb skeletal maturity
Helpful Clues for Rare Diagnoses • Hemophilia
• Proximal Femoral Focal Deficiency • Amniotic band syndrome
o PFFD: Unilateral congenital absence of
portions of femoral head, neck and
proximal diaphysis
Physeal Fractures, Pediatric Physeal Fractures, Pediatric
Sagittal bone CT shows osseous bridging IIIlI at the

cent,al portion of the physis in this child, a result of a
AP radiograph shows evidence of an old Salter IV lateral
condylar fracture, with the fracture crossing the
III
high grade Saller injury. Bone growth ceases with this metaphysis _ through the physis, and across the
bridging, resulUng in a short limb. epiphysis 1EiI. The malunion results in limb shortening.
173
Q)
<I) SHORT LIMB, UNILATERAL
ro
Q)
<I)
o
.~
E
Q)
iil Arthroplasty Malpositioning

"0
ell sized femoral component,
<I)
ro which has subsided down
CD the shaft by 2 em, leaving
~ the limb relatively short.
ro Mal-sized or malpositioned
o components can result in
c: limb length discrepancies.
radiograph shows left THA
placed with the components
too long. Note the level of
the left lesser trochanter
compared with right _ This
leaves a relatively short right
limb, but also puts the left at
risk for dislocation.
legg-Calve-Perthes
(Left)AP radiograph shows
obvious metaphyseal
destruction. in a child
with staphylococcus
osteomyelitis. The infection
has crossed the physis,
showing subtle epiphyseal
destruction _ This may
result in growth disturbance
and shortening of the limb.
radiograph shows Lei>;
which results in a coxa
magna deformity: Short,
broad femoral head III as
well as short, broad femoral
neck HI. This results in limb
shortening.
Slipped Capital Femoral Epiphysis Slipped Capital Femoral Epiphysis

radiograph shows medial
and posterior slip of the left
capital femoral epiphysis _
This slip results in shortening
of the limb; note the level of
the left lesser trochanter.
relative to the normal right
side. (Right) AP radiograph
shows a left SCFE. which
was pinned; unfortunately.
the patient developed
chondrolysis _ This
resulted in fixed abduction,
and the patient now has a
relatively shortened limb and
pelvic tilt. (The right hip was
prophylactically pinned.)
III
174
SHORT LIMB, UNILATERAL C"l
:l
(')
III
-<
OJ
III
t/l
Juvenile Idiopathic Arthritis CD
(Left) AP radiograph shows e-
severe erosion of the right en
hip in a patient with j/A. '<
t/l
Besides erosions, limb length in
may be affected by 3
premature closure of (i'
epiphyses secondary to o
iii'
chronic hyperemia in this (1)
Q)
disease process. (Right) AP t/l
radiograph shows DOH on (1)
the right. Note the shallow

acetabulum, coxa magna
deformity of the femoral
head and neck, and
shortening of the right
compared to left (compare
level of lesser trochanters 11II
and not pelvic tilt).
Meningococcemia
bilateral involvement with
fibrous dysplasia. Note the
pelvic tilt and the differential
levels of the lesser
lrochanlers •. This is due to
the shepherd's crook
deformity of the right femoral
neck _ resulting in a
shortened femur. (Right) AP
radiograph shows signiFicant
deformity of the left femoral
metaphysis & epiphysis EiIl
with short varus neck. This is
due to thrombotic disease in
meningococcemia. The left
limb is short (compare lesser
trochanter levelsllli.
Embolic Disease, During Infancy Embolic Disease, During Infancy

AVN of femoral head" &
shortening of left femoral
neck relative to right
(compare levels of lesser
trochanters). Insult occurred
at younger than expected
age for Legg-Perthes; another
etiology must be sought.
(Right) AP radiograph of
knees of same patient shows
a coned epiphysis" at left
distal {emu,", and irregularity
at left proximal epiphysis.
These, along with hip,
contribute to a short limb,
due to emboli from umbilical
artery catheter.
III
175
Q)
(/) SHORT LIMB, UNILATERAL
III
Q)
.!!1
o
u
E
Q)
Vi Neurofibromatosis Congenital Pseudarthrosis Tibia
radiograph shows significant
"0
Ql bowing of both the tibia and
(/)
III fibula" in a patient with
lD neurofibromatosis. In this
~ disease, these bones are
III frequently dysplastic, which
o can result in bowing
c: deformities or
U pseudarthroses. (Right)
shows fracture of both the
tibia and fibula IIIat the
distal 7/3 of the leg, with
smooth, tapered ends. This is
a congenital pseudarthrosis,
and results in limb
shortening.
Radiation-Induced Growth Deformities Radiation-Induced Growth Deformities

humerus to be short relative
to the thorax. There is diffuse
bone sclerosis, limited to the
humerus; this confirms that
the patient had whole bone
radiation. There is also a
radiation-induced sarcoma
•. (Right) Anteroposterior
radiograph shows a port-like
distribution of osseous
hypoplasia, including the
sacrum and iliac wings in this
patient who had pelvic RT as
a child. There is asymmetric
hypoplasia of the left hip,
giving a mild pelvic tilt

shows irregularity and
shortening of the talus" as
well as the distal tibial
physis. These deformities
resulted from compartment
syndrome and associated
ischemia several years
earlier. The limb is slightly
short. (Right) Lateral
erosive disease and a large
denseeffusion. in a
hemophilic The limb was
short, in part because of the
joint destruction, but also
due to hyperemia resulting in
early physeal closure.
III
176
SHORT LIMB, UNILATERAL C'l
:J
(i.
III
-<
OJ
III
Oilier Disease Oilier Disease en
CO
shows short ulna with en
enchondroma Ell and '<
en
associated dislocation of the CD
radial head Ea. This 3
combination is seen in Oilier (l
disease, and is usually 9

en
unilateral, resulting in a short CO
limb. (Right) Anteroposterior III
en
radiograph shows striated CO
both metaphyses
of multiple
=-
expanded lytic lesions in
typical
enchondromatosis. The
disease is usually unilateral,
resulting in a short limb. The
plate and screws are from a
limb lengthening procedure.
Maffucci Syndrome Amniotic Band Syndrome

short humerus undergoing
lengthening procedure, with
external fixator in place. The
metaphysis is broad and
striated, typical of
enchondroma, and there is a
50ft tissue hemangioma m
making the diagnosis
Req). (Right) PA radiograph
shows absent thumb E!Il and
amniotic
=
multiple coned or abnormal
epiphyses due to
band (not shown
here). By restricting blood
supply, amniotic bands can
cause limb shortening.
Proximal Femoral Focal Deficiency Polio

radiograph shows an absent
proximal femur;, including
head and neck. The mid
femur is bowed, and limb
extremely short. This is
typical PFFD.(Right)
shows pelvic tilt and relative
hypoplasia of the right
hemipelvis and lower limb.
Note the increased density
on the left, indicating
significantly greater muscle
mass on that side. Findings
are typical of polio with short
right limb.
III
177
Q)
rJ) HEMIHYPERTROPHY
l\l
Q)
.!!1
o o Overstimulation during development
.>< DIFFERENTIAL DIAGNOSIS
E o Focal gigantism more common
Q)
Common • Vascular Malformation (Mimic)
U;
>-
(fJ
• Idiopathic/Congenital o Tangled dilated vessels, phleboliths, no
"0 • Neurofibromatosis discrete mass, ± intra-osseous extension
Q)
rJ) • Lipomatosis (Mimic)
ltl Helpful Clues for Less Common Diagnoses
[0 • Hyperemia, Any Cause
~ • Vascular Malformation (Mimic) • Lymphangioma (Mimic)
ltl o Soft tissue mass with multiple cyst spaces
U
c: Less Common • Beckwith-Wiedemann Syndrome
U • Lymphangioma (Mimic) o Macroglossia, enlarged abdominal organs,
• Beckwith-Wiedemann Syndrome umbilical hernia, Wilms tumor
• Neurocutaneous Syndrome, Uncommon • Tuberous Sclerosis
o Tuberous Sclerosis o Seizures, mental retardation, cutaneous
o Sturge- Weber Disease abnormalities
o Von Hippel-Lindau Disease o Facial angiofibromas, subungual fibromas,
Rare but Important shagreen patches, ash leaf spots, cortical
• Klippel-Trenaunay-Weber Syndrome tubers, subependymal nodules
• Sturge-Weber Disease
o Seizures, mental retardation, glaucoma,
ESSENTIAL INFORMATION port wine stain, leptomeningeal angioma
Helpful Clues for Common Diagnoses • Von Hippel-Lindau Disease
• Idiopathic/Congenital o Angiomatosis especially retinal, renal cell
o Increased risk childhood cancer carcinoma, neuroendocrine tumors
• Wilms tumor most common Helpful Clues for Rare Diagnoses
o Associated renal disorders • Klippel-Trenaunay-Weber Syndrome
o Leg-length discrepancy is mild form o Capillary hemangioma, varicose veins,
• Neurofibromatosis gigantism, ± arteriovenous malformation
o Plexiform neurofibromas & mesodermal • Focal gigantism more common
dysplasia, cafe-au-lait spots, optic glioma,
Other Essential Information
Lisch nodule
• Hemihypertrophy: Enlargement of one side
• Lipomatosis (Mimic)
o Diffuse increase adipose tissue
of body or one extremity vs. focal gigantism
(macrodactyly) with enlarged
• Hyperemia, Any Cause
digit(s)/portion of extremity
Neurofibromatosis
III Anteroposterior radiograph shows congentiaJ

hypertrophy of the right leg. The right femur is longer
Coronal T2WI FSf MR shows a spectacular example of
hemihypertrophy due to neurofibromatosis. On the
and wider and the thigh musculature is enlargedEil right there ;s a giant plexiform neurofibroma Ia
extending from the sciatic notch to the fool.
178
HEMIHYPERTROPHY (")
;,
o
III
-<
III
III
Neurofibromatosis Vascular Malformation (Mimic) III
(l)
(Leh) Anteroposterior Q.
radiograph shows (J)
asymmetric increased soft '<
III
tissue of the right lower CO
extremity" along with mild 3
limb length discrepancy, n
right leg slighlly longer than o
III
the left. This patient's (l)
hemihypertrophy is QJ
III
secondary to (l)
neurofibromatosis. (Right)
shows bulky soft tissues of
the forearm and hand" in
this one day old with a large
soft tissue hemangioma.
Vascular Malformation (Mimic) Vascular Malformation (Mimic)

lobulated high T2WI signal
mass with diffuse
enhancement. This patient
has a hemangioma which
clinically mimics
hemihypertrophy. The
adjacent musculature and
humerus are normal in size.
(Right) Sagittal T1 C+ MR
shows a tangle of vessels in
the forearm with multiple
large flow voids ••
consistent with an
arteriovenous malformation
simulating hemihypertrophy.
Lymphangioma (Mimic)
from a patient with a large
lymphangioma shows a high
signal mass with multi
septate cysts involving the
left chest waif and upper
extremity _ (Right)
Anteroposterior CT
scanogram shows left leg
hemihypertrophy with
enlargement of the bones
and soft tissues of the left leg
(compared to the right) in
this patient with
Klippel-Trenaunay-Weber
syndrome.
III
179
Q)
(/) FOCAL GIGANTISM/MACRODACTYLY
ro
Q)
.!!?
o o Other disease manifestations
.>! DIFFERENTIAL DIAGNOSIS
E • Monoarticular to polyarticular disease
Q) Common • Small joints, hands, feet; also wrist,
Ul
>-
(fJ
• juvenile Idiopathic Arthritis (Epiphyses) elbow, knee, shoulder, ankle
"C
• Hemangioma, Soft Tissue • Peri-articular osteoporosis
Ql
VI • Arteriovenous Malformation • Marginal erosions
III
III • Lymphangioma • Periosteal new bone formation
J?:- • Neurofibromatosis • Uniform joint space narrowing
III
l.l
Less Common • Hemangioma, Soft Tissue
c:
• Macrodystrophia Lipomatosa o Soft tissue mass
U
• Klippel-Trenaunay-Weber Syndrome (KTW) • Phleboliths
• Oilier Disease (Phalanges) • Variable amount of fatty stroma
• Maffucci Syndrome (Phalanges) o Osseous changes variable
• Hemophilia (Epiphyses) • Overgrowth 2° hyperemia

• Hyperemia, Any Cause • Periosteal new bone
o Chronic Osteomyelitis • Cortical thickening
o Fracture During Childhood • Pressure erosions
o Tuberculosis o Cutaneous changes
• Skin discoloration
Rare but Important • Prominent veins
• Epidermal Nevus Syndrome • Cutaneous hemangiomas
• Proteus Syndrome • Arteriovenous Malformation
o Soft tissue mass
ESSENTIAL INFORMATION • Phleboliths
• Tangled dilated vessels, no discrete mass
Key Differential Diagnosis Issues o Intra-osseous extension may be seen
• Key features to aid in differentiation o Cutaneous changes absent
o Overgrowth: Osseous, soft tissue, both
• Dilated vessels may be visible beneath
o Cutaneous manifestations
skin
• Hint: Macrodystrophia lipomatosa, • Lymphangioma
neurofibromatosis, KTW, Maffucci have o Soft tissue mass with multiple cystic spaces
similar appearance o No osseous overgrowth
o Soft tissue and osseous involvement o No cutaneous changes
• Hint: Hyperemia underlying cause with • Neurofibromatosis
osseous overgrowth only o Gigantism may be bilateral
o juvenile idiopathic arthritis o Involved digits may not be contiguous
o Hemophilia o Most severe involvement at any site along
o Chronic osteomyelitis digit
o Tuberculosis o 2° plexiform neurofibroma (soft tissue) and
o See hyperemia, any cause below mesodermal dysplasia (osseous)
• Hint: juvenile idiopathic arthritis and o Cutaneous changes: Cafe-au-lait spots
hemophilia have similar appearance o Other disease manifestations
o Osseous overgrowth only
• Neurofibromas
• Ballooned epiphyses • Mesodermal dysplasia: Bowing,
• Widened intercondylar notch pseudoarthrosis, abnormal healing,
• Knee (femoral condyles), elbow periosteal abnormalities
(capitellum) overgrowth common • Optic glioma, Lisch nodule (iris nevi)
Helpful Clues for Common Diagnoses Helpful Clues for Less Common Diagnoses
• Juvenile Idiopathic Arthritis (Epiphyses) • Macrodystrophia Lipomatosa
o Overgrowth mainly knee, elbow o Unilateral; one or more contiguous digits
o No cutaneous changes o Most severe involvement along distal digit
III
180
(")
FOCAL GIGANTISM/MACRODACTYlY
::;,
o
III
o Volar surface more affected than dorsal o Typically one joint suffers repeated .:c
surface creating dorsal bowing deformity hemorrhage which leads to hyperemia Cll
III
o 2nd and 3rd digits most common then osseous overgrowth III
tI)
o Overgrowth soft tissue & bone • Commonly affects knee (femoral a.
• Prominent adipose overgrowth condyles), elbow (radial head) w
'<
III
o Neural enlargement o Associated arthritic changes
ro
• Secondary to adipose infiltration • Peri-articular osteoporosis 3
0'
• Median nerve> plantar nerve • Uniform joint space narrowing o
o No cutaneous changes iij.
• Dense effusion tI)
Ql
• Klippel-Trenaunay-Weber Syndrome • Subchondral cysts III
tI)
(KTW) • Secondary osteoarthritis
o Unilateral soft tissue and osseous • Hyperemia, Any Cause
overgrowth o Osseous overgrowth
• Gigantism ranges from macrodactyly to o Random sites of involvement
hemihypertrophy • Typically one site or multiple sites in one
o Lower extremity more common than extremity
upper extremity o Hyperemia prior to skeletal maturation,
o Syndrome: Capillary hemangiomas (port often from fracture healing
wine), varicose veins, local gigantism Helpful Clues for Rare Diagnoses
• ± Arteriovenous malformations
• Epidermal Nevus Syndrome
• OIlier Disease (Phalanges) o Soft tissue and osseous overgrowth
o a.k.a., echondromatosis
o No typical site of involvement
o Gigantism hands/feet only
o Cutaneous changes: Multiple nevi
o Osseous involvement only: Multiple
o Variable other manifestations including
enchondromas of phalanges
cerebral atrophy
• Expansile lytic ± ground-glass matrix
• Proteus Syndrome
• Bilateral asymmetric distribution o Syndrome has protean manifestations
• Maffucci Syndrome (Phalanges)
• Focal gigantism and lymphangiomatous
o Ollier disease plus soft tissue hemangiomas
hamartomas are consistent features
o Hemangiomas
o Soft tissue and osseous overgrowth
• Phleboliths o No cutaneous changes
• Any site throughout body o Osteochondroma-like osseous lesions
• Hands, feet especially involved o Skull, face, spine abnormalities common
• Hemophilia (Epiphyses)
Juvenile Idiopathic Arthritis (Epiphyses)
Anteroposterior radiograph shows a cfassic example of

severe juvenile idiopathic arthritis with overgrowth of
Lateral radiograph of this patient with juvenile idiopathic
arthritis reveals overgrowth of the capitellum •
III
the femoral condyles especially medially and widening secondary to hyperemia. rtMsK Req).
of the intercondylar notch.
181
Q)
FOCAL GIGANTISM/MACRODACTYlY
'"
ro
Q)
'"
(5
.~
E
Q)
(i) Hemangioma. Soft Tissue Arteriovenous Malformation
en>- (Left) Lateral radiograph
shows bulky soft tissues of
"C
Cll the forearm and hand"
'"ro
!Xl
secondary to soft tissue
hemangioma. Associated
>. overgrowth of the first and
CV second digits was present
••• but is not seen on this image.
c: (RighI) Anteroposterior
U radiograph shows focal
overgrowth of the second
digit of the left foat _ The
overgrowth was due to
hyperemia from a vascular
malformation.
Arteriovenous Malformation Macrodystrophia lipomatosa

(Left) Axial T2* GRE MR
shows multiple flow void
from the enlarged vessels in
this arteriovenous
malformation Ell; the
adjacent osseous structures
showed overgrowth. (RighI)
shows focaf giantism
secondary to
macrodystrophia lipomatasa,
involving a single ray of the
hand". The osseous and
soft tissues are both
involved.
Macrodystrophia lipomatosa Oilier Disease (Phalanges)

shows a normal hindfoat and
midfoot with giantism of
both the soft tissues and
osseous structures of the
forefoot in this patient with
macrodystrophia Iipomatosa.
radiograph of the hand of a
patient with Oilier disease
demonstrates multiple
enchondromas ••.
III
182
FOCAL GIGANTISM/MACRODACTYlY n
::s
o
III
«:
Cl
III
tIl
Oilier Disease (Phalanges) Maffucci Syndrome (Phalanges) (l)
(Left) Oblique radiograph Q.
shows a skeletally immalure (j)
child with mulliple '<
tIl
enchondromas. consistent CD
with Oilier disease. The 3
lesions are expansile o
especially in the fifth o
tIl
metacarpal. (Right) PA C1l
radiograph shows bizarre Cl
tIl
expansion of all the bones of C1l
the hand, associated with
multiple phleboliths. The
diagnosis is Marucci
syndrome, but clinically it
manifests as focal gigantism
of the hand.
Maffucci Syndrome (Phalanges)

radiograph shows a classic
case of Maffucci syndrome
with mulliple enchondromas
in the phalanges and
multiple soft tissue
hemangiomas with
phleboliths =. (t MSK Req).
radiograph shows
enlargement of the femoral
condyles and widening of
the intercondylar notch in
this patient with hemophilia.
Hemophilia (Epiphyses)
radiograph shows capitellar
overgrowth" in this patient
with hemophilia. Associated
changes include subchondral
cyst formation and joint
space narrowing. (Right)
Axial radiograph shows
left patella=
relative overgrowth of the
compared to
the right Ell resulting from a
patellar fraclure which
occurred prior to skeletal
maturation.
III
183
Q)
en DWARFISM WITH MAJOR SPINE INVOLVEMENT
ctl
Q)
.!!1
o • Spondyloepiphyseal Dysplasia
E o Ovoid or pear-shaped vertebrae in infancy
Q) Common o Central, anterior vertebral body beak
U5
>- • Achondroplasia o Odontoid hypoplasia
en
-c • Thanatophoric Dwarf • Hypothyroidism, Child (Mimic)
C1l
VI • Spondyloepiphyseal Dysplasia o Congenital vertebral anomalies:
ctl
al less Common Hemivertebrae, abnormal rib-vertebral
Z.
l'Cl • Hypothyroidism, Child (Mimic) articulations, platyspondyly
U
• Noonan Syndrome • "Sail vertebrae" = upper lumbar vertebra
c:
• Morquio Syndrome with wedge or hook shape
U
• Hurler Syndrome • Noonan Syndrome
• Hunter Syndrome o Klippel-Feil anomaly
o Scoliosis & kyphosis
Rare but Important
• Morquio Syndrome
• Progeria o Extensive vertebra plana
• Hypochondroplasia o Central, anterior vertebral body beak
• Metatropic Dwarfism o Diminutive or disappearing dens of axis
• Diastrophic Dwarfism • Hurler Syndrome
• Kniest Dysplasia o Anterior inferior vertebral body beak
• Camptomelic Dysplasia o Oval to biconvex vertebral bodies
• Osteoglophonic Dysplasia o Absent dens -+ atlantoaxial subluxation
• Dyssegmental Dysplasia • Hunter Syndrome
o Inferior beak similar to Hurler syndrome
ESSENTIAL INFORMATION o Posterior vertebral body scalloping
• Progeria
Helpful Clues for Diagnoses o Infantile central notching retained
• Achondroplasia • Hypochondroplasia
o Short, flat vertebral bodies; decreasing
o Decreased interpediculate distance L1 -+ LS
interpediculate distance L1 -+ LS • Kniest Dysplasia
o Posterior vertebral body scalloping
o Platyspondyly with narrow interpediculate
o Hypoplastic upper lumbar vertebral bodies
distance
• Thanatophoric Dwarf o Coronal vertebral body clefts, infants
o Platyspondyly with rounded anterior
• Camptomelic Dysplasia
vertebral bodies o Hypoplastic cervical vertebrae
Achondroplasia Achondroplasia
III Sagittal T2WI MR shows posterior vertebral scalloping

ffi anterior beaking •• as well as hypoplasia of LI
and L2. This resullSin a focal kyphosis HI.
Anteroposterior radiograph shows
narrowing of the interpediculate distance =
progressive
lower lumbar spine, typical of achondroplasia.

in the
184
DWARFISM WITH MAJOR SPINE INVOLVEMENT n
::l
o
!!!.
-<
OJ
III
Thanatophoric Dwarf
'"
<II
Co
shows the classic en
platyspondyly" with '<
(/)
widened intervertebral disk ro
spaces" Thus, the normal 3
truncal length is maintained o
despite the flat vertebral o
bodies. This is a lethal form
of dwarfism. (RighI)
'"
<1l
Ql
(/)
Anteroposterior radiograph <1l
shows universal
platyspondyly and scoliosis.
Images of the extremities
showed severely deformed
epiphyses. The combination
of findings helps make the
diagnosis.
Morquio Syndrome
shows a Klippel-Feil anomaly
that is typical in Noonan
syndrome but is also seen
incidentally, as in this
patient. The cervical
vertebral bodies are small
and fused" and there is an
adjacent omovertebral bone
•. (RighI) Lateral
of the odontoid =-
radiograph shows hypoplasia
This
anomaly can contribute to
atlantoaxial subluxation in
these patients.

shows dorsolumbar kyphosis
•. flattened vertebral
bodies and central, anterior
beaking of the vertebral
bodies" (RighI) Lateral
dorsolumbar kyphosis =-
oval vertebral bodies and
typical anterior inferior beaks
•. The
mucopolysaccharidoses,
including Morquio, Hunter
·and Hurler syndrome all
have variably short, rounded
vertebral bodies with
anterior beaks.
III
185
Q)
rn DWARFISM WITH SHORT EXTREMITIES
ro
Q)
.~
o • Chondrodysplasia Punctata
E o Punctate calcifications in cartilage &
Q)
Common periarticular regions
en>-
(f)
• Achondroplasia • Dyschondrosteosis
"t:l • Pseudoachondroplasia o Madelung deformity of forearms
Q)
rn • Achondrogenesis o Beaking of medial tibial metaphysis
'"
CC • Chondrodysplasia Punctata • Mesomelic Dysplasia
2- • Dyschondrosteosis o Hypoplastic fibula
'"
o • Mesomelic Dysplasia • Multiple Epiphyseal Dysplasia
c: • Multiple Epiphyseal Dysplasia o Marked epiphyseal ossification delay
U
Less Common o Small, fragmented epiphyses
• Hypochondroplasia o Femoral head avascular necrosis
• Chondroectodermal Dysplasia (Ellis-van • Hypochondroplasia
Creveld) o Shortened long bones with wide diaphyses
• Camptomelic Dysplasia o Brachydactyly
Rare but Important
Creveld)
• Thanatophoric Dwarf o Short, heavy tubular bones
• Asphyxiating Thoracic Dystrophy of ]eune o Spur at medial distal humeral metaphysis
• Kniest Dysplasia o Cone-shaped epiphyses of middle
phalanges & polydactyly
ESSENTIAL INFORMATION • Camptomelic Dysplasia
o Fifth digit clinodactyly
Helpful Clues for Diagnoses
• Thanatophoric Dwarf
• Achondroplasia o Short, bowed limbs, "French telephone
o Short, thick tubular bones with flared
receiver femurs"
metaphyses o Flared metaphyses
o Hemispheric femoral head
• Asphyxiating Thoracic Dystrophy of
o Overgrown fibulae
Jeune
• Pseudoachondroplasia o Hands with cone-shaped epiphyses
o Splayed, fragmented, irregular metaphyses
o Handlebar clavicles
• Achondrogenesis • Kniest Dysplasia
o Short tubular bones & long bones
o "Swiss cheese" cartilage dysplasia
o Non-ossified sacrum & pubis
o Short, dumbbell-shaped long bones
Pseudoachondroplasia
Anleroposlerior radiograph of the lower legs shows Anteroposterior radiograph shows delayed skeletal
flaring of the lower femoral metaphyses _ The fibulae maturation, with abnormal epiphyses • resulting in
III are longer than the tibiae, a reversal of the normal shorl, stubby long bones. Note the excrescences arising
relationship. from lhe metaphyses Ill.
186
(")
DWARFISM WITH SHORT EXTREMITIES
::::J
(")
III
.:c
Chondroectodermal Dysplasia (Ellis-van lJl
III
Creveld) VI
Chondrodysplasia Punctata lTl
(Left) Anteroposterior C.
radiograph shows diffuse (f)
stippling" in the pelvis and '<
VI
epiphyses of the lower en
extremities. These patients 3
also have long fibulae with (")
respect to the shortened 9

VI
tibiae. (Right) (1)
Q)
Anteroposterior radiograph VI
shows flared iliac wings with (1)
a trident deformity of the

acetabulum 111. The knees
lack epiphyseal ossification
centers ••. Each fibula is
very short relative to the tibia
HI
Thanatophoric Dwarf
radiograph of the pelvis and
legs shows the short, bowed
tubular bones III. These
have been likened to
telephone receivers (the old
fashioned, pre-cell phone
types) (Right)
shows short, bowed tubular
bones". Flaringof the
metaphyseal regions is a
typical finding This infant
died shortly after birth. On
prenatal ultrasound, the
femurs may appear short or
curved.
Asphyxiating Thoracic Dystrophy of

Jeune
radiograph of the lower
extremities shows shortened
long bones that have normal
tubulation. The lower legs
•• are shorter than the
upper legs (mesomelic
shortening). Premature
femoral head ossification is
commonly present (Right)
shows markedly splayed
metaphyses" and
epiphyses compared with
the diaphyseal diameter HI.
The epiphyseal regions ••
are squared and have
irregular ossification.
187
Ql
If) DWARFISM WITH SHORT RIBS
<1l
Ql
.!i1
o • Mucopolysaccharidoses
E o Oar-shaped, short ribs
Ql Common o Short clavicles
UJ
>. • Achondroplasia
Cf) o Morquio syndrome = thin posterior
"tl
Ql
Less Common portion of rib
II)
III • Cleidocranial Dysplasia • Thanatophoric Dwarf
aJ o Short ribs with cupped costochondral
>.
III
Creveld) junctions
<J o Long trunk with small chest
'c Rare but Important
U
• Mucopolysaccharidoses Jeune
• Thanatophoric Dwarf o Horizontal, short ribs with bulbous ends
• Asphyxiating Thoracic Dystrophy of Jeune o Bell-shaped thoracic cage
• Camptomelic Dysplasia o Handlebar clavicles
• Achondrogenesis • Camptomelic Dysplasia
• Mucolipidosis II and III o Bell-shaped thorax
• Otopalatodigital Syndrome o 11 pairs of shortened ribs
• Short-Rib Polydactyly Syndrome o Hypoplastic cervical vertebrae
• Achondrogenesis
ESSENTIAL INFORMATION o Short tubular bones & long bones
o Minimal mineralization of vertebral bodies
Helpful Clues for Diagnoses
• Mucolipidosis II and III
• Achondroplasia o Short, wide ribs similar to
o Short trunk with short, wide ribs that do
mucopolysaccharidoses
not extend around the chest
• Otopalatodigital Syndrome
• Cleidocranial Dysplasia o Ribs are short, wavy & angled
o Cone-shaped chest with short ribs due to
o Long scapular bodies
long cartilaginous segments o Precocious fusion of sternum
o Hypoplastic clavicles
o Sloped clavicles
o Small scapulae
• Short-Rib Polydactyly Syndrome
• Chondroectodermal Dysplasia (Ellis-van o Very short, horizontal ribs
Creveld) o Deformed, elevated clavicles
o Short, heavy tubular bones (including ribs)
o Small scapulae
o Handlebar clavicles
o Polydactyly
Achondroplasia Cleidocranial Dysplasia
Anteroposterior radiograph shows a short tJunk with

wide, short ribs III. Additional findings include scoliosis
and a narrow media/areral dimension of the spinal canal
both clavicles=
Anleroposterior radiograph shows short ribs, absence
!III. A midline
or
as well as hypoplasUc glenoid fossae
defecl was also present at lhe pubic
in the lumbar region EiII. symphysis.
188
DWARFISM WITH SHORT RIBS ("')
::l
n'
III
-<
OJ
Mucopolysaccharidoses III
Mucopolysaccharidoses CIl
Cl>
(Leh) Anteroposterior Co
radiograph shows wide, (IJ
short, paddle-shaped ribs 11II '<
(f)
with relatively small
intercostal spaces in this
m
3
patient with Morquio o'
syndrome. (Right) o
Anteroposterior radiograph en'
CD
shows wide ribs 11II with OJ
(f)
narrow intercostal spaces. CD
Additional findings include
humeral neck varus and
short thick clavicles, which
are typical skeletal findings
of Hurler syndrome.
Thanatophoric Dwarf Thanatophoric Dwarf

radiograph shows very short
ribs 11II with cupped
costochondral junctions. The
vertebral bodes are flat with
the widened intervertebral
disk spaces maintaining the
normal truncal length.
radiograph shows
platyspondyly but
maintenance of normal trunk
length by means of widened
intervertebral disk spaces.
Note the very short ribs 11II
that do not encircle the
chest.
Asphyxiating Thoracic Dystrophy of Asphyxiating Thoracic Dystrophy of

Jeune Jeune
radiograph shows short ribs
11II with bulbous ends. The
chest has a mild bell shape
and the clavicles show
"handlebar" deformities Ea.
(Right) Anterior radiograph
shows a narrow chest with
short ribs" Handlebar
clavicles HI are also evident.
Other commonly seen
assodated skeletal anomalies
include a small pelvis with a
trident acetabular margin, a
femoral head ossification
center present at birth and
mesomelic limb shortening.
III
189
l1> DWARFISM WITH HORIZONTAL ACETABULAR ROOF
'"l1>
ro
i:5'" o Short ribs

El1> o Minimal mineralization of vertebral bodies
Common o Short iliac wing
iii
>, • Achondroplasia
en lOn-OS We sacrum & pu is
"lJ Less Common • hondrodysplasia Punctata
l1>
'"
III • Achondrogenesis hart long bone
lD
• Chondrodysplasia Punctata Punctate calcifj ations in cartilage &
~ periarticular region
III
o Rare but Important
oronal cleft of vertebral bodi s
'c • Thanatophoric Dwarf
u
D layed brain myelination, cortical
• Asphyxiating Thoracic Dy trophy of Jeune atrophy
• Chondroectodermal D splasia (Ellis-van
• Thanatophoric Dwarf
Creveld)
Large cloverleaf skull with mall face
• Caudal Regression frontal bossing
• Hypochondroplasia Long trunk with small chest
• Down Syndrome (Mimic) hart ribs with upp d costochondral
• Nail Patella Syndrome (Fang) (Mimic) junctions
o h r , bowed limbs, " rench telephon
ESSENTIAL INFORMATION receiver femurs"
o Flared metaphyses
Helpful Clues for Diagn se
Platy pondyly with rounded anterior
• Achondroplasia vertebral bodie
o Short, thick tubular bone
Short, mall iliac bone with horizontal
o Short trunk with short ribs
acetabular roof
o Large skull with narrow foramen magnum
Lethal shortly after birth
o Short, flat vertebral bodi lacking normal
widened interpediculate distance caudally Jeune
o Posterior vertebral body calloping
Bell- haped thoracic age
o Square iliac wing with horizontal
Handlebar clavi Ie
acetabular roof
Horizontal, short ribs with bulbous end
o Hemispheric femoral head
o Short iliac bone with spur of cia tic notch
o Overgrown fibulae
Horizontal acetabular roof trid nt
• Achondrogenesis acetabular margin
o Short tubular bones 1 ng bones
Hands with can - haped epiphy es
Achondroplasia Chondrodysplasia Punctata
wings =
Anteroposterior radiograph shows short, wide iliac
and horizontal acetabular roofs with the inner
margin of the pelvis EllI resembling a champagne glass.
in the pubic =. hip =
Anteroposterior radiograph shows stippled calcification
and sacral EllI regions that is
typical for chondrodysplasia punctata. Each acetabular
There is coxa valga with short {emoral necks. roof has a horizontal orientation.
190
()
DWARFISM WITH HORIZONTAL ACETABULAR ROOF
j
n
III
'<
Asphyxiating Thoracic Dystrophy of OJ
III
Thanatophoric Dwarf Jeune
'0-"
a>
radiograph shows short, m
small iliac bones ffi '<
C/l
horizontal acetabular roofs CD
• "French telephone 3
receiver" shaped femora •. o·
and bowed long bones with o
C/l
irregular (Iared metaphyses Cll
Q)
HI. (Right) Anteroposterior C/l
radiograph shows short, CD
flared iliac wings EiIlI and
horizontal acetabular roofs
• with a trident margin due
to an inferolateral spur along
the scialic notch •.
Chondroectodermal Dysplasia (Ellis-van

Creveld) Caudal Regression
radiograph shows iliac wings
that are flared and
hypoplastic •. Acetabular
roofs are somewhat
horizontal. and have a
trident configuration Eill The
femoral heads are
prematurely ossified ffi
radiograph shows agenesis of
the lumbar vertebrae. and
dysplastic, fused iliac bones
with horizontal acetabular
roofs •. Hip dislocation is a
common finding.
Down Syndrome (Mimic) Nail Patella Syndrome (Fong) (Mimic)

radiograph shows broad iliac
wings, narrow sacrosciatic
notch _ and horizontal
acetabular roorla seen in a
patient with Down
syndrome. Although Down
patients are not dwarfs, this
appearance of the pelvis,
along with delayed skeletal
maturation, may mimic
dwarfism. (Right)
shows horizontal acetabular
roofs •. The cfassic finding
is the presence of symmetric,
bilateral, central-posterior,
iliachoms.
191
INDEX
A
Abscess, soft tissue supra-acetabular iliac destruction, 1:330-333
anechoic mass vs., 11:194, 195 Achilles tendon
ball of foot pain related to, 111:126, 129 idiopathic ossification, tendon and ligament
cystic masses vs., 11:160, 163 ossification vs., 11:100, 101
diabetic foot complications vs., 111:142 repair (mimic), calcaneal erosions, posterior
epidural abscess, painful scoliosis vs., 111:144, tubercle vs., 1:377, 379
145 retro-Achilles bursitis, heel pain related to,
extraarticular popliteal mass vs., 1:363, 365 111:120
groin/hip pain related to, 111:49,53 tear/tendinopathy
hip pain in elderly patients related to, 11I:69, 73 heel pain related to, 111:120, 122
iliopsoas abscess, painful scoliosis vs., 111:144, retrocalcaneal bursitis vs., 1:380
146 thickening/enlargement vs., 1:374
intermuscular edema vs., 11:180, 182 tendinitis, calcaneal erosions, posterior tubercle
knee fluid collections vs., 1:357, 360 vs., 1:377, 379
lateral hip pain related to, IIl:55, 57 thickening/enlargement, 1:374-375
medial ankle pain related to, 11I:109 Achondrogenesis
shoulder fluid collections vs., 1:223, 225 dwarfism with horizontal acetabular roof vs.,
soft tissue lesions with f1uid/fluid levels vs., 111:190
11:155, 157 dwarfism with short extremities vs., 111:186
soft tissue mass of finger vs., 1:240 dwarfism with short ribs vs., 111:188
soft tissue mass of foot vs., 1:382, 386 Achondroplasia
subcutaneous mass vs., 11:168 bullet shaped vertebra/anterior vertebral body
subperiosteal, long bone surface (juxtacortical) beaking vs., 1:282
lesion vs., 1:61, 65 dwarfism with horizontal acetabular roof vs.,
Abutment, ulnar. See Ulnar abutment. 111:190
Accessory muscle, soft tissue mass of foot vs., 1:383, dwarfism with major spine involvement vs.,
387 111:184
Accessory ossicle, ossification/calcification anterior dwarfism with short extremities vs., 1Il:186
to C1 vs., 1:274, 275 dwarfism with short ribs vs., 111:188
Accessory soleus (mimic), Achilles tendon genu varum (bow leg deformity) vs., 1:373
thickening/enlargement vs., 1:374 homozygous, childhood platyspondyly vs.,
Acetabulum 1:284
dwarfism with horizontal acetabular roof, long bone metaphyseal cupping vs., 1:30, 31
111:190-191 long bone undertubulation vs., 1:97,99
dysplasia, hip labral tear related to, 1:341, mimic, long bone overtubulation vs., 1:103, 105
342-343 short metacarpal/metatarsal bones vs., 1:261,
femoral acetabular impingement 263
arthritis with preserved cartilage space vs., symphysis pubis widening vs., 1:327
1:167, 169 Acral myxoinflammatory fibroblastic sarcoma, soft
in teenagers, 111:149, 150 tissue mass of finger vs., 1:241
ossification of rim, hip labral tear related to, Acromegaly
1:341,344 bone within bone appearance vs., II:77
protrusio acetabuli, 1:334-337 cortical tunneling vs., 11:92
differential diagnosis, 1:334-337 discalmineralization vs., 1:271
hip labral tear related to, 1:341 generalized osteoporosis vs., 11:83
secondary, hip labral tear related to, 1:341, long bone diffuse cortical endosteal thickening
344 vs., 1:91
retroverted, hip labral tear related to, 1:340, 342 spinal osteophytes vs., 1:298
INDEX
>< widened joint space related to, 1:171, 175 carpal cystic/lytic lesions vs., 1:232,233
QJ
"'0 Acromioclavicular joint separation discal mineralization vs., 1:27]
r:::: mimic, distal clavicular resorption vs., 1:212, erosive arthritis vs., 1:147, 150
213 generalized osteoporosis vs., 11:83, 86
rotator cuff symptoms vs., IIL5, 7 interphalangeal-predominant arthritis vs., 1:195,
Acroosteolysis, 1:246-249 197
Acroosteosclerosis, 1:250-25 1 intraarticular low signal material vs., 11:191, 193
Adamantinoma long bone epiphyseal/apophyseal/subchondral
long bone aggressive diaphyseal lesion vs. lytic lesion vs., 1:22, 25
adult, 1:71 patellar lytic lesions vs., 1:348, 350
child, 1:75, 77 phalangeal cystic/lytic lesions vs., 1:253, 257
long bone cortically based lytic diaphyseal shoulder fluid collections VS., 1:223
lesion vs., 1:85, 87 soft tissue lesions with predominately low Tl &
long bone cortically based metaphyseal lesion T2 signal vs., 11:151
vs., 1:57,59 soft tissue target lesions vs., 11:158, 159
solitary geographic lytic lesions vs., 11:15, 19 soft tissue uptake on bone scan vs., 11:198,200
tibial bowing vs., 1:353, 355 solitary geographic lytic lesions vs., 11:14-15, 18
tibial metadiaphyseal cortically based lesion vs., tarsal cystic/lytic lesions vs., 1:390
1:94,95 Amyotrophic lateral sclerosis, muscle atrophy vs.,
Adenopathy, subcutaneous mass vs., 11:166 II: 177
Adhesive capsulitis, rotator cuff symptoms vs., Anconeus epitrochlearis, medial elbow pain related
111:5,7 to, 111:23,25
Adipocytes Anechoic mass, 11:194-195
radiation-induced increase, increased marrow Anemia
fat vs., 11:136-137, 139 abnormal epiphyseal marrow signal vs., 11:132-
steroid-induced increase, increased marrow fat 133,135
vs., 11:136-137, 138 aplastic
Adrenocortical tumor/hyperplasia, advanced bone anemia with musculoskeletal manifestations
age vs., 11:102 vs., 111:153
Aging, normal, increased marrow fat vs., 11:136, superscan vs., II:204
137 bone marrow hyperplasia vs., 11:140, 141
AIDS drug therapy, avascular necrosis related to, Fanconi anemia, 111:153
11I:157, 161 iron or vitamin deficiency, ]11:152, 153
Air musculoskeletal manifestations, 111:152-155
intraarticular (mimic), meniscal size alteration of chronic disease, 11I:152, 154
vs., 1:367 sickle cell. See Sickle cell anemia,
soft tissue lesions with predominately low Tl & musculoskeletal complications.
T2 signal vs., 11:150, 152 Aneurysm
Alcohol abuse, avascular necrosis related to, 11I:157, linear and curvilinear calcification vs., 11:116,
159 118
Alkaptonuria. See Ochronosis. mimic, anechoic mass vs., 11:194
ALPSA (anterior labroligamentous periosteal sleeve popliteal artery
avulsion), anteroinferior labral/capsule injury extraarticular popliteal mass vs., 1:363, 365
vs., 111:12,13 knee fluid collections vs., 1:357, 361
Aluminum toxicity, rickets and osteomalacia soft tissue lesions with predominately low Tl &
related to, 111:166 T2 signal vs., 11:150
Aminopterin fetopathy, long bone metaphyseal soft tissue mass of foot vs., 1:383
bands and lines vs., 1:27 soft tissue target lesions vs., ]]:158, 159
Amniotic band syndrome Aneurysmal bone cyst
acroosteolysis vs., 1:247,249 benign osseous lesions with aggressive
unilateral short limb related to, 111:173, 177 appearance vs., 11:51, 53
Amputation, acroosteolysis vs., 1:246 bone lesions with fluid/fluid levels vs., 11:144
Amyloid deposition flat bones with focally expanded or bubbly
arthritis with large subchondral cysts vs., 1:155, lesion vs., 1:2, 4
157 lesions originating in posterior vertebral
arthritis with osteopenia vs., 1:139, 141 elements vs., 1:306, 307
arthritis with preserved cartilage space vs., 1:167 long bone diaphyseal cortically based lytic
lesion vs., 1:85,87
II
INDEX
long bone metaphyseal lesions vs. arthritis with preserved cartilage space vs., 1:168
bubbly, 1:44,46 arthritis with productive changes vs., 1:143, 144
cortically based, 1:57, 59 calcaneal erosions, posterior tubercle vs., 1:376,
eccentric 378
aggressive, 1:53, 55 discal mineralization vs., 1:270-271, 273
non-aggressive, 1:48, 50 effusions, shoulder fluid collections vs., 1:222,
mimic 223
bizarre horizontal periosteal reaction vs., enthesopathy vs., 11:96-97, 98
1:123 erosive arthritis vs., 1:146, 148
long bone surface (juxtacortical) lesion vs., generalized osteoporosis vs., 11:82,85
1:60,63 groin/hip pain related to, 111:48
nonarticular clavicular lesions vs., 1:208,210 hip pain in elderly patients related to, 111:68,71
patellar lytic lesions vs., 1:349 in teenagers, 1lI:148, ]49
phalangeal cystic/lytic lesions vs., 1:252, 254 linear ossification along anterior spine vs., 1:280,
solitary geographic lytic lesions vs., 11:14, 16 281
supra-acetabular iliac destruction vs., 1:331, 332 long bone metaphyseal bands and lines vs.,
target lesions of bone vs., II:41 1:27,29
tarsal cystic/lytic lesions vs., 1:394 mixed erosive/productive arthritis vs., 1:152, 153
thin bone painful or enlarged sternoclavicular joint vs.,
long bone central diaphyseal non-aggressive 1lI:2, 3
lesion vs., 1:67, 68 post-traumatic, pseudoarthrosis vs., 11:94, 95
long bone central metaphyseal non- protrusio acetabuli vs., 1:334, 336
aggressive lesion vs., 1:35, 38 regional osteoporosis vs., 11:89, 9]
Angiomatoid fibrous histiocytoma rotator cuff symptoms vs., 111:5
soft tissue lesions with fluid/fluid levels vs., sacroiliitis vs.
11:154 bilateral asymmetric, 1:320, 32]
subcutaneous mass vs., II:171 bilateral symmetric, 1:3]6, 3]7-3]8
Angiomatosis unilateral, 1:322, 323
bacillary, cortically based lytic diaphyseal lesion squaring of one or more vertebra vs., 1:290, 292
vs., 1:85,89 symphysis pubis widening vs., 1:326, 328
cystic symphysis pubis with productive changes/
adult polyostotic lesions vs., 11:2-3, 6 fusion vs., 1:324, 325
flat bones with focally expanded or bubbly tendon and ligament ossification vs., 11:100, 101
lesion vs., 1:3, 5 Ankylosis, 1:176-179
soli tary rib lesion vs., 1:313 Anorexia
Angiosarcoma, osseous generalized osteoporosis vs., 11:82,84
adult polyostotic lesions vs., 11:3, 6 increased marrow fat vs., 11:137, 139
aggressive periostitis vs., 1:113, 115 Anterior cruciate ligament reconstruction, cyclops
flat bones with permeative lesions vs., 1:7, 11 lesion associated with, intraarticular mass vs.,
long bone central metaphyseal aggressive lesion 1:202,204
vs., 1:41,43 Anti-viral drug effect, bone marrow hyperplasia vs.,
long bone diaphyseal aggressive adult lesion vs., 11:141, 143
1:71 Anus, imperforate, symphysis pubis widening vs.,
tarsal cystic/lytic lesions vs., 1:391, 395 1:327,329
Ankle. See also Achilles tendon; Talus; Tarsal Aorta
entries. calcification, linear ossification along anterior
anterior pain/impingement, 1l1:104-1O7 spine vs., 1:280
arthritis obstruction, low, inferior rib notching vs., 1:308
calf pain related to, 1lI:92 Aortic coarctation, thoracic
medial ankle pain related to, 1Il:108, ]]] inferior rib notching vs., 1:308-309
lateral pain, 111:114-119 superior rib notching vs., 1:310
medial pain, 111:108-113 Aplastic anemia
post-traumatic, avascular necrosis related to, anemia with musculoskeletal manifestations vs.,
111:157 111:153
Ankylosing spondylitis superscan vs., 11:204
ankylosis vs., 1:177, 178 Aponeurotic fibroma, juvenile, bizarre horizontal
arthritis with osteopenia vs., 1:138, 140 periosteal reaction vs., 1:123, 124
III
INDEX
)( Arachnodactyly, 1:238-239 genu valgum (knock knees) vs., 1:370
QJ
""0 congenital contractural, 1:238 medial knee pain related to, 111:86
r::: Arch, high, ball of foot pain related to, 111:127, 131 metacarpophalangeal-predominant, 1:192-193
Armillifer armillatus infection, linear and mixed erosive/productive, I: 152-153
curvilinear calcification vs., II:1l7 monoarthritis, I: 198-201
Arterial insufficiency, calf pain related to, 111:93, mutilans, 1:162-163
95-96 protrusio acetabuli vs., 1:334
Arteriosclerosis, linear and curvilinear calcification psoriatic. See Psoriatic arthritis.
vs., II:Il6, Il7 rheumatoid. See Rheumatoid arthritis.
Arteriovenous fistula, soft tissue lesions with sesamoiditis vs., 1:258, 259
predominately low T1 & T2 signal vs., 11:150, subchondral edematous-like signal vs., 11:130,
152 131
Arteriovenous malformations. See also Vascular subtalar, lateral ankle pain related to, 111:117
malformations. tenosynovitis/tenosynovial fluid vs., 11:184, 185
focal gigantism/macrodactyly related to, 11/:180, thigh pain related to, 11I:60
182 tuberculosis-related, atrophic joint destruction
inferior rib notching vs., 1:308 vs., 1:159, 161
soft tissue lesions with predominately low T1 & with large subchondral cysts, 1:154-157
T2 signal vs., 11:151, 152 with normal bone density, 1:134-137
soft tissue mass of finger vs., 1:241, 245 with osteopenia, 1:138-141
Arthritis. See also Ankylosing spondylitis; Chronic with preserved cartilage space, 1:166-169
reactive arthritis; Inflammatory bowel with productive changes, 1:142-145
disease arthritis; Juvenile idiopathic arthritis; wrist pain related to
Osteoarthritis; Psoriatic arthritis; Rheumatoid radial-sided, 11I:42, 44-45
arthritis; Septic joint. ulnar-sided, 11I:36, 37-38
Achilles tendon thickening/enlargement vs., Arthritis mutilans, 1:162-163
1:374 Arthrogryposis
ankle abnormal radiocarpal angle vs., 1:236
calf pain related to, m:92 long bone overtubulation vs., 1:103, 104
medial ankle pain related to, II1:108, 111 muscle atrophy vs., 11:177
bone marrow edema syndromes vs., II: 126, 127 soft tissue contractu res related to, 111:171
erosive, I:146-1 5 1 Arthropathy. See also Osteoarthropathy.
fungal crystalline. See Crystalline arthropathy.
atrophic joint destruction vs., 1:159, 161 hemophilic, intraarticular low signal material
monoarthritis vs., 1:199, 201 vs., 11:191, 193
genu varum (bow leg deformity), 1:372 inflammatory, shoulder instability related to,
groin/hip pain related to, 11I:48, 50 111:9, 11
heel pain related to, 111:121, 124 Jaccoud
hip mimic, metacarpophalangeal-predominant
lateral hip pain related to, m:54, 56 arthritis vs., 1:192
pain in elderly patients related to, 111:68, ulnar deviation of MCP joints vs., 1:264
70-71 neuropathic, non-diabetic, arthritis with normal
HIV-related bone density vs., 1:135, 137
arthritis with osteopenia vs., 1:139 pyrophosphate. See Pyrophosphate arthropathy.
erosive arthritis vs., 1:150 silastic implant, arthritis with preserved
interphalangeal-predominant arthritis vs., cartilage space vs., 1:167, 169
1:195, 196 Arth roplasty
swelling and periostitis of digit (dactylitis) adjacent metastasis/primary neoplasm,
vs., 1:266, 267 arthroplasty with lytic/cystic lesions vs.,
in teenagers, 111:148-151. See also Juvenile 1:206,207
idiopathic arthritis. infection, arthroplasty with lytic/cystic lesions
interphalangeal-predominant, 1:194-197 vs., 1:206,207
juvenile idiopathic. See Juvenile idiopathic prior lucencies in revision, arthroplasty with
arthritis. lytic/cystic lesions vs., 1:206, 207
knee shoulder, mechanical impingement on, medial
anterior knee pain related to, 111:80,82 metaphyseal erosion of proximal humerus
calf pain related to, 11I:92 vs., 1:214
with lytic/cystic lesions, 1:206-207
IV
INDEX
Arthroplasty components. See also Hardware. dwarfism with short ribs vs., 111:188, 189
hardware failure nonarticular clavicular lesions vs., 1:209,211
hip pain related to, 111:75,78-79 Atrophic joint destruction, 1:158-161
knee pain related to, Ill:99, 102 Avascular necrosis, 11I:156-161
instability, painful knee related to, 1lI:98, 100 differential diagnosis, 1Il:156-161
loosening and dislocation talar, anterior ankle pain/impingement related
arthroplasty with lytic/cystic lesions vs., to, 111:104-105, 107
1:206 Avulsion
hip pain related to, IJl:74, 75-77 epicondylar, medial, pediatric, medial elbow
knee pain related to, 111:98,99, 100 pain related to, IIl:22-23, 24
mimic, target lesions of bone vs., 11:41, 43 extensor digitorum brevis, lateral ankle pain
supra-acetabular iliac destruction vs., 1:330 related to, 11I:115, 117
malposition humeral avulsion of glenohumeral ligament,
painful hip related to, 1lI:74, 77 anteroinferior labral/capsule injury vs.,
painful knee related to, 11I:98, 100 1Il:12, 13
unilateral short limb related to, 1Il:172, 174 labroligamentous periosteal sleeve avulsion,
massive osteolysis anterior, anteroinferior labral/capsule injury
arthritis with large subchondral cysts vs., vs., llI:12, 13
1:154-155, 156 tibial stress syndrome/adductor insertion
arthroplasty with lytic/cystic lesions vs., avulsion syndrome, cortically based,
1:206 sclerotic diaphyseal lesion vs., 1:80, 82
hip pain related to, 1Il:74-75, 78 Avulsion fractures
knee pain related to, 111:99,101-102 early, nodular calcification vs., 11:110, 113
peri prosthetic fracture intraarticular, calcified intraarticular body/
hip pain related to, 11I:75, 79 bodies vs., 1:180, 182
knee pain related to, 111:99,103 ossification/calcification anterior to C1 vs.,
photopenic lesions and false negative scans vs., 1:274,275
11:196 pelvic (mimic), enthesopathy vs., 11:97, 99
stress shielding (mimic) Axial osteomalacia
arthroplasty with lytic/cystic lesions vs., atypical, rickets and osteomalacia vs., 111:167
1:206,207 vertebral body sclerosis vs., 1:293
hip pain related to, Ill:75, 78 Axillary nerve injury, shoulder instability related
knee pain related to, 111:99,101 to, 111:9
wear/particle disease
arthritis with large subchondral cysts vs.,
1:154-155, 156 B
arthroplasty with lytic/cystic lesions vs., Baastrup disease, enthesopathy vs., 11:96
1:206 Bacillary angiomatosis, long bone diaphyseal
benign osseous lesions with aggressive lesion vs., cortically based, lytic, 1:85, 89
appearance vs., 1I:50, 52 Ball of foot pain, II1:126-131
erosive arthritis vs., 1:147, 149 Bankart lesion, anteroinferior labral/capsule injury
hip pain related to, 1lI:74-75, 77-78 vs., 111:12-13
knee pain related to, 111:99,101-102 Beckwith-Wiedemann syndrome,
long bone eccentric metaphyseal non- hemihypertrophy related to, 111:178
aggressive lesion vs., 1:49, 50 Biceps labral complex, types 1-3, anterosuperior
phalangeal cystic/lytic lesions vs., 1:252, 255 labral variations/pathology vs., 1:219,221
solitary geographic lytic lesions vs., 11:14, 17 Biceps tendon tear, shoulder instability related to,
supra-acetabular iliac destruction vs., 1:330, 111:9,11
332 Bicipital tenosynovitis, shoulder fluid collections
Artifact, photopenic lesions and false negative vs., 1:222
scans vs., 11:196 Bisphosphonates
Ascites, malignant, soft tissue uptake on bone scan complications, childhood platyspondyly vs.,
vs., 11:202 1:285,287
Askin tumor, solitary rib lesion vs., 1:313,315 osteonecrosis related to, sequestration vs., 11:37,
Asphyxillting thoracic dystrophy of Jeune 39
dwarfism with horizontal acetabular roof vs., Bladder ex trophy, symphysis pubis widening vs.,
111:190, 191 1:327
dwarfism with short extremities vs., 111:186, 187 Blount disease
v
INDEX
genu varum (bow leg deformity) vs., 1:372, 373 bone marrow edema syndromes vs., 11:126-
long bone growth plate widened physis vs., 127, 128
1:109, 110 groin/hip pain related to, I1I:49, 52
mimic, long bone epiphyseal overgrowth/ medial ankle pain related to, 111:109,] 13
ballooning vs., 1:16, 17 Bone marrow edema syndromes (proximal femur),
tibial bowing vs., 1:352, 354 11:126-129
Bone age differential diagnosis, II:126- ]29
advanced,II:102-103 transient, subchondral edematous-like signal
delayed, 11:104-105 vs., 11:130
Bone bruise Bone marrow metastases
abnormal epiphyseal marrow signal vs., 11:132 abnormal epiphyseal marrow signal vs., 11:135
subchondral edematous-like signal vs., 11:130 bone marrow edema syndromes vs., 11:126, ]28
Bone cysts. See Aneurysmal bone cyst; Unicameral flat bones with permeative lesions vs., 1:6, 7
bone cyst. generalized increased bone density vs., adult,
Bone density, generalized increased, adult, 11:60-63 11:60,61
Bone graft hip pain in elderly patients related to, 111:69,72
failed, pseudoarthrosis vs., 11:94,95 lesions originating in posterior vertebral
mimic, hypertrophic callus formation vs., 11:74, elements vs., 1:306
75 long bone central metaphyseal lesions vs.
Bone infarct aggressive, 1:40, 41
bone within bone appearance vs., 11:76-75, 79 non-aggressive, [:35, 37
heel pain related to, 111:121,125 long bone diaphyseal lesions vs.
long bone central diaphyseal non-aggressive aggressive
lesion vs., 1:69 adult, 1:70, 71
long bone central metaphyseal non-aggressive child, 1:74, 76
lesion vs., 1:34,36 cortically based
long bone eccentric metaphyseal non-aggressive lytic, 1:84, 85
lesion vs., 1:48, 50 sclerotic, 1:8]
matrix-containing bone lesions vs., 11:44,46 long bone eccentric metaphyseal aggressive
multiple sclerotic bone lesion vs., 11:26,28 lesion vs., 1:52, 54
sclerotic bone lesion with central lucency vs., long bone epiphyseal/apophyseal/subchondral
11:32,34 lytic lesion vs., 1:23, 24
solitary sclerotic bone lesion vs., 1I:20, 22 medial metaphyseal erosion of proximal
target lesions of bone vs., 1I:40, 42 humerus vs., 1:2]4, 215
Bone island. See Enostosis (bone island). painful scoliosis vs., 1II:145, 147
Bone lesions patellar lytic lesions vs., 1:349
with bright T1 signal, 11:146-149 polyostotic lesions vs.
with fluid/fluid levels, 1I:144-145 adult, 11:3
Bone marrow childhood,lI:ll
failure, increased marrow fat vs., 11:137, 139 sequestration vs., 11:36,38
hyperplasia, 11:140-143 solitary geographic lytic lesions VS., 11:14,16
increased fat, II:136-139 solitary sclerotic bone lesion vs., 11:23
Bone marrow edema supra-acetabular iliac destruction vs., [:330,331
abnormal epiphyseal signal, 11:132-135 target lesions of bone vs., 11:40,42
peritumoral reactive tarsal cystic/lytic lesions vs., [:391, 395
bone marrow edema syndromes vs., 11:127, Bone neoplasms. See also Intraosseous neoplasms.
129 adjacent to arthroplasty, arthroplasty with Iytic/
subchondral edematous-like signal vs., cystic lesions vs., 1:206, 207
11:130,131 epiphyseal marrow signal vs., abnormal, 11:133,
reactive 135
abnormal epiphyseal marrow signal vs., fish (biconcave) or H-shaped vertebra, 1:288, 289
11:132, 133 heel pain related to, 1II:121, 124-125
subchondral edematous-like signal vs., intermuscular edema vs., 11:181, 183
11:130, 131 intraarticular mass, 1:202-205
transient lateral elbow pain related to, 111:19,21
abnormal epiphyseal marrow signal vs., metastatic, 11:56-59
11:132, 134 osteopenia vs., 11:80,81
VI
INDEX
polyostotic aggressive, periostitis of multiple olecranon bursitis vs., 1II:26
bones in children vs., 1:130, 132 intermuscular edema vs., H:180, 182
protrusio acetabuli vs., 1:335, 337 knee, anterior knee pain related to, 111:80, 83
shoulder fluid collections vs., 1:223, 225 medial collateral ligament
wrist pain related to knee fluid collections vs., 1:356, 359
radial-sided, 1II:43, 47 medial knee pain related to, 1lI:86, 90
ulnar-sided, III:37, 41 olecranon, III:26-27
Bone scan, soft tissue uptake on, 11:198-203 patellar, anterior, knee fluid collections vs.,
Bone within bone appearance, 11:76-79 1:356,358
Bound foot, cavus foot deformity vs., 1II:137 pes anserine
Brain infarct, soft tissue uptake on bone scan vs., medial, knee fluid collections vs., 1:356, 359
11:201 medial knee pain related to, m:86, 89
Brain injury retro-Achilles, heel pain related to, 1II:120
heterotopic ossification vs., 1II:162 retrocalcaneal, 1:380-381
hypertrophic callus formation vs., 11:74 Achilles tendon thickening/enlargement vs.,
Breast carcinoma 1:374,375
metastatic differential diagnosis, 1:380-381
bone cancer vs., 11:56, 57 heel pain related to, 1Il:120
photopenic lesions and false negative scans semimembranous tendon
vs., 11:196 extraarticular popliteal mass vs., 1:363, 364
soft tissue uptake on bone scan vs., 11:198, 201 knee fluid collections vs., 1:357, 361
Brodie abscess, long bone cortically based sclerotic shoulder fluid collections vs., 1:222
diaphyseal lesion vs., 1:81, 83 soft tissue lesions with fluid/fluid levels vs.,
Brown tumor. See Hyperparathyroidism, with 11:155, 157
brown tumor; Renal osteodystrophy, with soft tissue mass of foot vs., 1:382, 383-384
brown tumor. subacromial, rotator cuff symptoms vs., 1II:4, 6
Buford complex, anterosuperior labral variations/ surrounding osteochondroma, knee fluid
pathology vs., 1:219, 221 collections vs., 1:357, 360
Burns
acroosteolysis vs., 1:246, 248
heterotopic ossification vs., 111:162, 165 c
linear and curvilinear calcification vs., H:117, Caffey disease
120 long bone diffuse cortical endosteal thickening
long bone growth plate premature physeal vs., 1:91, 93
closure vs., 1:106, 107 long bone undertubulation vs., 1:97, 101
long bone metaphyseal fraying vs., 1:32 mimic, generalized increased bone density in
muscle atrophy vs., II: 177 child vs., [[:65, 67
nodular calcification vs., 11:111 nonarticular clavicular lesions vs., 1:209
periarticular calcification vs., 1:187 periostitis of multiple bones in children vs.,
Bursitis 1:131, 133
anechoic mass vs., H:194 solid periostitis vs., 1:117
ball of foot pain related to, 1Il:127, 129 Caisson disease, avascular necrosis related to,
calcific 1II:161
nodular calcification vs., 11:110, 112 Calcaneal nerve entrapment, lower extremity nerve
olecranon bursitis vs., 1Il:26, 27 entrapment vs., 1II:65
periarticular calcification vs., 1:186, 188 Calcaneofibular ligament tear, lateral ankle pain
cystic masses vs., [[:160-161, 163 related to, 1II:114, 116
hip Calcaneus
groin/hip pain related to, 1ll:48-49, 52 apophysitis (Sever disease), retrocalcaneal
lateral hip pain related to, 111:54, 55 bursitis vs., 1:380, 381
pain in elderly patients related to, 1II:68-69, erosions, posterior tubercle, 1:376-379
71 fractures
iliopsoas, painful hip replacement related to, anterior process, lateral ankle pain related to,
[[1:75, 79 111:114, 116
iliotibial, knee fluid collections vs., 1:357, 360 insufficiency
infectious diabetic foot complications vs., m:143
knee fluid collections vs., 1:357, 361 heel pain related to, Ill:120, 121-122
VII
INDEX
retrocalcaneal bursitis vs., 1:380,381 soft tissue lesions with fluid/fluid levels vs.,
stress, heel pain related to, 111:120, 122 11:154, 156
traumatic, heel pain related to, 111:120, 122 soft tissue mass of finger vs., 1:240,244
retrocalcaneal bursitis, 1:380-381 soft tissue mass of foot vs., 1:383
Achilles tendon thickening/enlargement vs., Calcium deficiency, generalized osteoporosis vs.,
1:374,375 11:83
differential diagnosis, 1:380-381 Calcium pyrophosphate deposition disease,
Calcific bursitis ossification/calcification anterior to C1 vs.,
nodular calcification vs., 11:110, 112 1:274
olecranon bursitis vs., 1Il:26, 27 Callus formation
periarticular calcification vs., 1:186, 188 early, matrix-containing bone lesions vs., 11:45,
Calcific myonecrosis 47
calf pain related to, 11I:92, 95 hypertrophic, 11:74-75
mimic, heterotopic ossification vs., 111:163 Camptomelic dysplasia
nodular calcification vs., 1!:l11, 115 dwarfism with major spine involvement vs.,
Calcific tendinitis 111:184
nodular calcification vs., 11:110, 112 dwarfism with short extremities vs., 111:186
periarticular calcification vs., 1:186, 187 dwarfism with short ribs vs., 111:188
Calcification forearm deformity vs., 1:229
central mass, soft tissue target lesions vs., 11:158, Capitellar fracture, lateral elbow pain related to,
159 III :21
dense soft tissue lesions with predominately low Capitellar osteonecrosis, lateral elbow pain related
1'1 & T2 signal vs., 11:150 to, 1I!:l8, 20
dystrophic Capsular laxity, shoulder instability related to, 111:8,
soft tissue neoplasms with calcification vs., 10
11:125 Capsule/labral injury, anteroinferior, 111:12-13
soft tissue sarcoma, periarticular calcification Carcinoid, metastatic, multiple sclerotic bone
vs., !:l87, 190 lesion vs., 11:31
soft tissue uptake on bone scan vs., 11:199, Carpal bones
202 coalition, ankylosis vs., !:l77, 179
infection, soft tissue lesions with predominately cystic/lytic lesions, 1:232-233
low 1'1 & T2 signal vs., 11:151 dislocations
linear and curvilinear, 11:116-121 radial-sided wrist pain related to, 1Il:43,
metastatic 46-47
nodular calcification vs., 11:111, 115 ulnar-sided pain wrist related to, 111:37,40
painful or enlarged sternoclavicular joint vs., instability
1Il:2 dorsal intercalated segment, 11I:32
soft tissue uptake on bone scan vs., U:199 dorsal midcarpal, 111:32
neoplastic, soft tissue uptake on bone scan vs., palmar midcarpal, 111:32
11:200,201 radial-sided wrist pain related to, 111:43,46
ossification/calcification anterior to C1, 1:274- volar intercalated segment, 111:32
275 wrist clicking/clunking/instability related to,
paravertebral ossification and calcification, 111:32
1:276-279 translocation, wrist clicking/clunking/instability
periarticular, 1:186-191 related to, 111:33,35
soft tissue neoplasms, 11:122-125 Carpal tunnel syndrome
Calcified intraarticular body/bodies, 1:180-183 elbow/wrist nerve entrapment vs., 111:28,29-30
Calcinosis enlarged peripheral nerves vs., 11:186, 187
soft tissue uptake on bone scan vs., U:199 Cast, hanging, glenohumeral malalignment related
tumoral to, 1:216
idiopathic, periarticular calcification vs., Cat scratch disease, medial elbow pain related to,
1:187, 191 111:23
nodular calcification vs., 1!:l11, 115 Caudal regression syndrome
painful or enlarged sternoclavicular joint vs., dwarfism with horizontal acetabular roof vs.,
1Il:2 111:191
paravertebral ossification and calcification long bone overtubulation vs., 1:103, 105
vs., 1:276-277, 278 Cavernous hemangioma, soft tissue lesions with
VIII
INDEX
predominately low T1 & T2 signal vs., 11:151 spinal, neuropathic osteoarthropathy vs., 1:164,
Cavus foot deformity, 111:136-137 165
Cellulitis tarsal cystic/lytic lesions vs., 1:390,393
ball of foot pain related to, 111:126, 129 ulnar deviation of MCr joints vs., 1:264
in diabetic foot complications, 1lI:142 with syphilis, neuropathic osteoarthropathy vs.,
Cement and bone fillers 1:165
long bone epiphyseal sclerosis/ivory vs., 1:18, 20 with syringomyelia
mimic atrophic joint destruction vs., 1:158, 160
bone within bone appearance vs., 11:77, 79 neuropathic osteoarthropathy vs., 1:164
soft tissue ossification vs., 11:106, 108 Chemical ingestion, long bone metaphyseal bands
vertebroplasty cement, discal mineralization and lines vs., 1:26, 28
vs., 1:270, 272 Chemotherapeutic drugs
paravertebral ossification and calcification vs., avascular necrosis related to, 111:157, 161
1:276,277 complications, periostitis of multiple bones in
photopenic lesions and false negative scans vs., children vs., [:131
11:196 long bone metaphyseal bands and lines vs., 1:26
solitary sclerotic bone lesion vs., 1J:21, 24 Child abuse
target lesions of bone vs., 11:40, 42 metaphyseal fracture
Cerebral palsy long bone metaphyseal cupping vs., 1:30
cavus foot deformity related to, 111:137 long bone metaphyseal fraying vs., 1:32, 33
long bone overtubulation vs., 1:102, 103 mimic, generalized increased bone density in
mimic, congenital foot deformity related to, child vs., 11:64, 66
1J1:139, 141 periostitis of multiple bones in children vs.,
shoulder instability related to, 111:9 1:130,131-132
soft tissue contractu res related to, 111:170, 171 Chondroblastoma
Cervical carcinoma, metastatic, bone cancer vs., bone lesions with fluid/fluid levels vs., 11:144,
11:57 145
Cervical vertebrae flat bones with focally expanded or bubbly
ossification/calcification anterior to Cl, 1:274- lesion vs., 1:3, 5
275 long bone epiphyseal sclerosis/ivory vs., 1:18,
radiculopathy, rotator cuff symptoms vs., 111:4 20-21
Charcot joint, neuropathic long bone epiphyseal/apophyseal/subchondral
ankle, medial ankle pain related to, 111:108, III lytic lesion vs., 1:22, 23
arthritis mutilans vs., 1:162 long bone metaphyseal bubbly lesion vs., 1:45,
benign osseous lesions with aggressive 47
appearance vs., 11:55 matrix-containing bone lesions vs., 11:49
calcified intraarticular body/bodies vs., 1:181, mimic, long bone eccentric metaphyseal non-
182-183 aggressive lesion vs., 1:49, 51
cavus foot deformity vs., 111:136 patellar lytic lesions vs., 1:348
diabetic, 111:142, 143 solid periostitis vs., 1:116, 119
arthritis with osteopenia vs., I: 138, 139 solitary geographic lytic lesions vs., [1:14, 17
atrophic joint destruction vs., 1:158, 160 supra-acetabular iliac destruction vs., 1:331
effusions, shoulder fluid collections vs., 1:222, target lesions of bone vs., 11:41,43
224 tarsal cystic/lytic lesions vs., 1:391,394
enlarged peripheral nerves vs., 11:187, 189 Chondrocalcinosis, 1:184-185
genu varum (bow leg deformity) vs., 1:373 bone lesions with bright T1 signal vs., 11:147
intraarticular steroid therapy, neuropathic calcified intraarticular body/bodies vs., [:180-
osteoarthropathy vs., 1:165 181, 182
mimic, erosive arthritis vs., 1:147, 149 differential diagnosis, [:184-185
monoarthritis vs., 1:198-199, 200 idiopathic, 1:185
muscle atrophy vs., 11:177 linear and curvilinear calcification vs., 11:116,
paravertebral ossification and calcification vs., 118
1:276,278 meniscal size alteration vs., 1:367,368
periarticular calcification vs., 1:187, 190 Chondrodysplasia punctata
sequestration vs., 11:37, 39 dwarfism with horizontal acetabular roof vs.,
shoulder instability related to, 11I:9, 11 111:190
soft tissue mass of foot vs., 1:382, 386 dwarfism with short extremities vs., 11[:186, 187
IX
INDEX
)( irregular or stippled long bone epiphysis vs., flat bones with focally expanded or bubbly
Q.I
"'0 1:13,15 lesion vs., 1:2-3, 4
c: metaphyseal flat bones with permeative lesions vs., [:6, 9
long bone metaphyseal fraying vs., 1:32 lesions originating in vertebral body vs.,
mimic, rickets and osteomalacia vs., 11I:167 [:301,305
tibial bowing vs., 1:353 long bone central metaphyseal lesion vs.
nodular calcification vs., 11:111 aggressive, 1:40, 42
short metacarpal/metatarsal bones vs., 1:261 non-aggressive, 1:34-35, 36
symphysis pubis widening vs., 1:327 long bone diaphyseal lesion vs., aggressive
Chondroectodermal dysplasia (Ellis-van Creveld adult, 1:71, 73
syndrome) child, 1:75, 77
abnormal radiocarpal angle vs., [:235, 237 with endosteal thickening, 1:78, 79
dwarfism with horizontal acetabular roof vs., long bone metaphyseal bubbly lesion vs.,
111:191 1:45,46
dwarfism with short extremities vs., 111:186, 187 matrix-containing bone lesions vs., 11:45,47
dwarfism with short ribs vs., 111:188 paravertebral ossification and calcification
Chondrolysis vs., 1:277, 279
idiopathic, protrusio acetabuli vs., 1:335 parosteal, long bone surface (juxtacortical)
post-traumatic lesion vs., 1:61
atrophic joint destruction vs., 1:159,161 soft tissue mass of finger vs., 1:241
monoarthritis vs., 1:199, 201 solitary geographic lytic lesions vs., II: 14, 17
Chondroma solitary rib lesion vs., 1:313, 315
in traarticula r target lesions of bone vs., II:41, 43
anterior knee pain related to, 111:81, 84 tarsal cystic/lytic lesions vs., 1:391, 394
calcified intraarticular body/bodies vs., 1:181, vertebral body sclerosis vs., 1:293, 297
183 mesenchymal, soft tissue neoplasms with
intraarticular mass vs., 1:203,205 calcification vs., 11:125
soft tissue neoplasms with calcification vs., synovial
11:123, 124 calcified intraarticular body/bodies vs., 1:181
periosteal intraarticular mass vs., 1:203
long bone surface (juxtacortical) lesion vs., Chordoma
[:60,62 lesions crossing disc space vs., 1:268, 269
matrix-containing bone lesions vs., 11:48 lesions originating in vertebral body vs., 1:301,
medial metaphyseal erosion of proximal 305
humerus vs., 1:215 paravertebral ossification and calcification vs.,
mimic, soft tissue neoplasms with 1:277,279
calcification vs., 11:122, 124 sequestration vs., 11:37, 39
periarticular calcification vs., 1:187, 189 target lesions of bone vs., 11:41, 43
soft tissue vertebral body sclerosis vs., 1:293,296
soft tissue mass of finger vs., [:241, 245 Chronic disease
soft tissue neoplasms with calcification vs., anemia related to, 1lI:152, 154
11:122-123,124 delayed bone age vs., 11:104
Chondromatosis, tenosynovial, soft tissue mass of long bone metaphyseal bands and lines vs., 1:26
finger vs., 1:241, 245 rickets and osteomalacia related to, 111:166, 168
Chondromyxoid fibroma Chronic reactive arthritis
flat bones with focally expanded or bubbly ankylosis vs., 1:177, 179
lesion vs., 1:3, 5 arthritis mutilans vs., 1:163
long bone eccentric metaphyseal non-aggressive arthritis with normal bone density vs., 1:135,
lesion vs., 1:49, 51 137
long bone metaphyseal bubbly lesion vs., 1:45, arthritis with osteopenia vs., 1:139, 140
47 arthritis with preserved cartilage space vs., 1:169
matrix-containing bone lesions vs., 11:49 arthritis with productive changes vs., 1:143, 145
solitary geographic lytic lesions vs., 11:15, 19 ball of foot pain related to, 111:127, 131
Chondrosarcoma calcaneal erosions, posterior tubercle vs., 1:376,
clear cell, long bone epiphyseal/apophyseal! 378
subchondral lytic lesion vs., 1:23 enthesopathy vs., 11:97, 99
conventional erosive arthritis vs., 1:147, 150
x
INDEX
heel pain related to, 111:121, 123 lateral, injury of, lateral elbow pain related to,
in teenagers, 11I:148, 151 111:19,21
interphalangeal-predominant arthritis vs., medial
1:194-195,196 bursitis
linear ossification along anterior spine vs., 1:280 knee fluid collections vs., 1:356, 359
mixed erosive/productive arthritis vs., 1:152, 153 medial knee pain related to, 1II:86-87, 90
paravertebral ossification and calcification vs., injury, medial elbow pain related to, 111:22,
1:276,278 24
periostitis of multiple bones/acropachy vs., sprain, medial knee pain related to, III:86,
1:127, 129 87-88
sacroiliitis vs. Common extensor tendon mechanism injury,
bilateral asymmetric, 1:320, 321 lateral elbow pain related to, 111:19, 21
bilateral symmetric, 1:317, 319 Common flexor mechanism injury, medial elbow
unilateral, 1:322 pain related to, 111:22,24
"sausage digit," swelling and periostitis of digit Compartment syndrome
(dactylitis) vs., 1:266, 267 calf pain related to, III:92, 95
solid periostitis vs., [:116, 120 cavus foot deformity vs., 111:136
squaring of one or more vertebra vs., 1:290 enlarged muscle vs., 11:173, 174
Chronic recurrent multifocal osteomyelitis. See intermuscular edema vs., 11:181, 183
Osteomyelitis, chronic recurrent multi focal. thigh pain related to, II1:60, 62
Chronic repetitive trauma. See Repetitive trauma, unilateral short limb related to, 111:173, 176
chronic. Complex regional pain syndrome
Claudication, neurogenic bone within bone appearance vs., 11:77
calf pain related to, 11I:92 cortical tunneling vs., 11:92, 93
thigh pain related to, 111:60 regional osteoporosis vs., 11:88, 90
Clavicle soft tissue contractures related to, 111:170
distal resorption, 1:212-213 Compression fracture, acute, vertebral body
fracture, nonarticular clavicular lesions vs., sclerosis vs., 1:292,294
1:208,209-210 Condylar fracture
ischemic necrosis, painful or enlarged lateral elbow pain related to, 111:18, 20
sternoclavicular joint vs., 11I:2 medial elbow pain related to, 111:23,25
nonarticular lesions, 1:208-211 Connective tissue disease, mixed, nodular
osteitis condensans calcification vs., 11:110-111
nonarticular clavicular lesions vs., 1:209, 211 Contractural arachnodactyly, congenital, 1:238
painful or enlarged sternoclavicular joint vs., Contractures
111:2,3 Dupuytren contracture, 111:170
sclerosing dysplasias vs., 11:68, 71 soft tissue, II I: 170-171
solid periostitis vs., 1:117,120 Copper deficiency
solitary sclerotic bone lesion vs., 11:21,25 infantile, long bone metaphyseal fraying vs.,
Cleidocranial dysplasia 1:32
abnormal radiocarpal angle vs., 1:234 long bone growth plate widened physis vs.,
dwarfism with short ribs vs., 111:188 1:109
nonarticular clavicular lesions vs., 1:209,211 Cornelia de Lange syndrome
symphysis pubis widening vs., 1:327, 329 forearm deformity vs., 1:229
Clubfoot (talipes equinovarus), congenital foot radial dysplasia/aplasia vs., 1:226
deformity vs., 111:138, 140 Coronoid process fracture, medial elbow pain
Clubhand related to, 111:23, 25
radial, forearm deformity vs., 1:229 Cortical tunneling, 11:92-93
ulnar Cortical/endosteal thickening, long bones, diffuse,
forearm deformity vs., 1:229 1:90-93
radial dysplasia/aplasia vs., 1:226, 227 Coumadin (warfarin) complications, irregular or
Coarctation of aorta, thoracic stippled long bone epiphysis vs., 1:12-13, 15
inferior rib notching vs., 1:308-309 Coxa magna deformity, 1:338-339
superior rib notching vs., 1:310 differential diagnosis, 1:338-339
Collagen vascular disorders, protrusio acetabuli vs., hip labral tear related to, 1:341, 343
1:335 Coxa valga, hip labral tear related to, 1:341, 343
Collateral ligament Craniometaphyseal dysplasia (Pyle dysplasia), long
XI
INDEX
>< bone undertubulation vs., 1:97 Denervation hypertrophy, enlarged muscle vs.,
QJ
"'C Cruciate ligament 11:173,174
c: anterior, reconstruction of, cyclops lesion Dermatofibrosarcoma protuberans, subcutaneous
associated with, intraarticular mass vs., mass vs., 11:170
1:202,204 Dermatomyositis
mucoid degeneration, knee fluid collections vs., intermuscular edema vs., 11:181, 182
1:356,358-359 linear and curvilinear calcification vs., 11:117,
Crystalline arthropathy 119
effusions, shoulder fluid collections vs., 1:222 mimic, heterotopic ossification vs., III:163
groin/hip pain related to, 11I:48 nodular calcification vs., 11:110, 113
hip pain in elderly patients related to, 111:68 periarticular calcification vs., 1:187, 189
knee soft tissue lesions with f1uid/fluid levels vs.,
anterior knee pain related to, 111:80 11:154,156
medial knee pain related to, 11I:86 thigh pain related to, 111:61,63
protrusio acetabuli vs., 1:334 Dermoid cyst, skull, target lesions of bone vs., 11:41
shoulder instability related to, 11I:9, 11 Desmoplastic fibroma
Cubital tunnel syndrome, elbow/wrist nerve long bone central diaphyseal non-aggressive
entrapment vs., 11I:28, 30 lesion vs., 1:69
Cubitus valgus, congenital, elbow deformities vs., long bone central metaphyseal non-aggressive
111:16 lesion vs., 1:35, 36
Cuboid fracture, lateral ankle pain related to, Developmental dysplasia, hip. See Hip,
111:114, 116 developmental dysplasia.
Cushing disease Diabetes mellitus, musculoskeletal complications.
avascular necrosis related to, 11I:161 See also Diabetic foot complications.
childhood platyspondyly vs., 1:285, 287 arthritis mutilans vs., 1:162
generalized osteoporosis vs., 11:83, 86 arthritis with osteopenia vs., 1:138, 139
hypertrophic callus formation vs., 11:74 enlarged muscle vs., 11:172, 174
muscle atrophy vs., 11:176-177 generalized osteoporosis vs., 11:84
Cyanotic heart disease, congenital, generalized intermuscular edema vs., 11:181, 183
increased bone density in child vs., 11:64 muscle atrophy vs., 11:176, ] 78
Cyclops lesion, ACL reconstruction, intraarticular neuropathic osteoarthropathy vs., 1:164
mass vs., 1:202,204 Diabetic foot complications, 111:142-143
Cystic angiomatosis acroosteolysis vs., 1:247
adult polyostotic lesions vs., 11:2-3, 6 ball of foot pain related to, 111:127, 129
flat bones with focally expanded or bubbly Charcot neuropathy in, 111:142, 143
lesion vs., 1:3, 5 arthritis with osteopenia vs., 1:138, 139
solitary rib lesion vs., 1:313 atrophic joint destruction vs., 1:158, 160
Cystic fibrosis, hypertrophic, periostitis of multiple differential diagnosis, 111:142-143
bones in children vs., 1:131 pes planovalgus (flatfoot) vs., 111:132-133, 134
Cystic lymphangioma (mimic), enlarged peripheral Diaphyseal lesions, long bones
nerves vs., 11:187, 189 aggressive
Cystic masses, 11:160-165 adult, 1:73
Cysticercosis, linear and curvilinear calcification child, 1:74-77
vs., 11:117,121 with endosteal thickening, 1:78-79
Cysts, arthritis with large subchondral cysts vs., cen tral, non-aggressive, 1:66-69
1:155,156 cortically based
lytic, 1:84-89
sclerotic, 1:80-83
D Diffuse idiopathic skeletal hyperostosis (DISH)
Dactylitis, 1:266-267 ankylosis vs., 1:176-177,178
Deep venous thrombosis discal mineralization vs., 1:270, 272
calcified chronic, linear and curvilinear enthesopathy vs., 11:96, 98
calcification vs., 11:117, 120 linear and curvilinear calcification vs., 11:119
calf pain related to, 111:93,96 linear ossification along anterior spine vs., 1:280
intermuscular edema vs., 11:180, 182 mimic
Deltoid ligament sprain, medial ankle pain related arthritis with normal bone density vs., 1:135,
to, 111:109, 113 136
XII
INDEX
arthritis with productive changes vs., 1:]43, with short extremities, 111:186-187
144 with short ribs, 1II:188-189
bilateral symmetric sacroiliitis vs., 1:3]6, 318 Dyggve-Melchior-Clausen syndrome, symphysis
spinal osteophytes vs., 1:298 pubis widening vs., 1:327
pseudoarthrosis vs., 11:94, 95 Dyschondrosteosis
soft tissue ossification vs., 11:106, 108 abnormal radiocarpal angle vs., 1:235,237
symphysis pubis with productive changes/ dwarfism with short extremities vs., 111:186
fusion vs., 1:324 forearm deformity vs., 1:229
tendon and ligament ossification vs., 11:100 radial dysplasia/aplasia vs., 1:226
Digits. See Fingers and toes. Dysplasia epiphysealis hemimelica. See Trevor
Dilantin therapy, rickets and osteomalacia related Fairbank disease.
to, 1Il:166-167, 169 Dystrophic calcification. See Calcification,
Discal mineralization, 1:270-273 dystrophic.
Discectomy, anterior cervical, with fusion, squaring
of vertebra vs., 1:290
Discogenic endplate changes, increased marrow fat E
vs., 11:136, 138 Eagle-Barrett (prune belly syndrome)
Discogenic sclerosis, vertebral body sclerosis vs., symphysis pubis widening vs., 1:327
1:292,293 with stylohyoid ligament ossification, tendon
Discs, intervertebral. See Intervertebral disc. and ligament ossification vs., 11:100, 101
DISH. See Diffuse idiopathic skeletal hyperostosis Eccrine hidradenoma
(DISH). cystic masses vs., 11:161, 165
Dislocations subcutaneous mass vs., 11:167, 171
arthroplasty components. See Arthroplasty Echinococcal cyst/disease
components, loosening and dislocation. lesions originating in vertebral body vs., 1:301,
carpal bones 305
radial-sided wrist pain related to, 111:43, linear and curvilinear calcification vs., 11:117,
46-47 121
ulnar-sided pain wrist related to, 1II:37, 40 Edema
hip, avascular necrosis related to, 111:156, 158 bone marrow. See Bone marrow edema.
patella, transient, anterior knee pain related to, intermuscular, 11:180-183
111:80,82 subchondral edematous-like signal, 11:130-131
shoulder Effusions
painful or enlarged sternoclavicular joint vs., arthritis-related, shoulder fluid collections vs.,
111:2 1:222,223
rotator cuff symptoms vs., 111:4-5, 6 joint
widened joint space related to, 1:170, 173 mimic, anechoic mass vs., 11:194, 195
Disuse osteoporosis. See Osteoporosis, disuse. unspecified, widened joint space related to,
Down syndrome (trisomy 21) 1:171,173
abnormal radiocarpal angle vs., 1:234-235 pericardial, malignant, soft tissue uptake on
anemia with musculoskeletal manifestations vs., bone scan vs., 11:202
111:153 pleural, malignant, soft tissue uptake on bone
bullet shaped vertebra/anterior vertebral body scan vs., 11:202
beaking vs., 1:282 Ehlers-Danlos syndrome
delayed bone age vs., 11:104 arachnodactyly vs., 1:238
mimic, dwarfism with horizontal acetabular pes planovalgus (flatfoot) vs., 111:133
roof vs., 111:191 shoulder instability related to, 1II:9
Dracunculiasis, linear and curvilinear calcification symphysis pubis widening vs., 1:327
vs., 11:117 ulnar deviation of MCr joints vs., 1:264
Drug therapy, high dose, complications, long bone widened joint space related to, 1:171
metaphyseal bands and lines vs., 1:27 Elastofibroma, soft tissue lesions with
Dupuytren contracture, soft tissue contractures predominately low T1 & T2 signal vs., 11:151,
related to, 111:170 152
Dwarfism. See also Thanatophoric dwarf. Elbow
childhood platyspondyly vs., 1:285,287 deformities in children and young adults,
with horizontal acetabular roof, 111:190-]91 111:16-17
with major spine involvement, 111:184-185 nerve entrapment, 111:28-31
XIII
INDEX
>< olecranon bursitis, 1l1:26-27 Epicondylar avulsion, medial, pediatric, medial
Q.I
"'C pain elbow pain related to, 111:22-23,24
C lateral,III:18-21 Epicondylitis
medial, 1l1:22-25 lateral elbow pain related to, 111:18,19
Ellis-van Creveld syndrome (chondroectodermal medial elbow pain related to, 111:22,23
dysplasia) Epidermal inclusion cyst
abnormal radiocarpal angle vs., 1:235, 237 phalangeal cystic/lytic lesions vs., 1:253, 256
dwarfism with horizontal acetabular roof vs., soft tissue mass of finger vs., 1:243
111:191 subcutaneous mass vs., 1l:167
dwarfism with short extremities vs., 1l1:186, 187 Epidermal nevus syndrome, focal gigantism/
dwarfism with short ribs vs., 111:188 macrodactyly related to, 111:181
Embolic disease, during infancy, unilateral short Epidermolysis, long bone overtubulation vs., I: 103
limb related to, 1l1:173, 175 Epidural space
Enchondroma abscess, painful scoliosis vs., 111:144, 145
adult polyostotic lesions vs., 11:5 hematoma, painful scoliosis vs., 111:144, 145
benign osseous lesions with aggressive Epiphyseal dysplasia. See also Spondyloepiphyseal
appearance vs., II:54 dysplasia.
long bone central diaphyseal non-aggressive long bone epiphyseal overgrowth/ballooning
lesion vs., 1:66, 67 vs., 1:16, 17
long bone central metaphyseal non-aggressive multiple
lesion vs., 1:34, 35 abnormal radiocarpal angle vs., 1:234, 236
matrix-containing bone lesions vs., 11:44, 45 dwarfism with short extremities vs., II1:186
phalangeal cystic/lytic lesions vs., 1:252, 253 irregular or stippled long bone epiphysis vs.,
phalanx, long bone metaphyseal bubbly lesion 1:13
vs., 1:45, 47 Epiphysis, long bones
sclerotic bone lesion with central lucency vs., epiphyseal/apophyseal/subchondral lytic lesion,
11:32,35 1:22-25
solitary geographic lytic lesions vs., 11:14, 15 fracture, pediatric, long bone epiphyseal
solitary rib lesion vs., 1:312,314 overgrowth/ballooning vs., 1:16, 17
solitary sclerotic bone lesion vs., 11:20, 22 irregular or stippled, 1:12-15
target lesions of bone vs., 11:40-41,43 overgrowth/balloon ing, I:16-17
Endplate changes, discogenic, increased marrow fat sclerosis/ivory, 1:18-21
vs., 1l:136, 138 slipped capital femoral epiphysis. See Slipped
Engelmann-Camurati disease capital femoral epiphysis.
generalized increased bone density vs. Epithelioid sarcoma, soft tissue target lesions vs.,
adult, 11:61 11:158
child, 11:65, 67 Epitrochlearis, anconeus, medial elbow pain related
long bone diffuse cortical endosteal thickening to, 111:23,25
vs., 1:90-91, 93 Erdheim-Chester disease
long bone undertubulation vs., 1:97, 100-101 bone within bone appearance vs., 1l:77, 79
sclerosing dysplasias vs., 11:69, 72 generalized increased bone density vs., adult,
solid periostitis vs., 1:117, 121 11:61,63
Enlarged, painful sternoclavicular joint, 111:2-3 mimic, sclerosing dysplasias vs., 11:69, 73
Enlarged muscle, 1l:172-175 Erosive arthritis, 1:146-151. See also Osteoarthritis,
Enlarged peripheral nerves, 11:186-189 erosive.
Enostosis (bone island) Erythroblastosis fetalis
long bone central metaphyseal non-aggressive anemia with musculoskeletal manifestations vs.,
lesion vs., 1:34, 35 111:153
long bone eccentric metaphyseal non-aggressive generalized increased bone density in child vs.,
lesion vs., 1:48, 49 11:65
multiple sclerotic bone lesion vs., 11:26 long bone metaphyseal bands and lines vs., 1:27
polyostotic lesions vs., 1l:2, 3 Estrogen deficiency, generalized osteoporosis vs.,
sclerosing dysplasias vs., 11:68, 69 11:83
solitary sclerotic bone lesion vs., 11:20, 21 Ewing sarcoma
vertebral body sclerosis vs., 1:292, 294 aggressive periostitis vs., 1:112, 114
Enthesopathy, 11:96-99 childhood platyspondyly vs., 1:284, 286
degenerative, 11:96, 97 flat bones with permeative lesions vs., 1:6, 8
differential diagnosis, 1l:96-99
XIV
INDEX
lesions originating in vertebral body vs., 1:301, Feet. See Foot.
305 Femoral acetabular impingement
long bone central metaphyseal aggressive lesion arthritis with preserved cartilage space vs., 1:167,
vs., 1:41,43 169
long bone diaphyseal aggressive lesion vs. in teenagers, III:149, 150
adult, 1:70, 72 Femoral epiphysis, slipped capital. See Slipped
child, 1:74, 76 capital femoral epiphysis.
with endosteal thickening, 1:78, 79 Femoral head, elliptical morphology, hip labral tear
long bone diffuse cortical endosteal thickening related to, 1:340, 342
vs., 1:91, 93 Femoral neck
long bone epiphyseal sclerosis/ivory vs., 1:18- fractures
19,21 avascular necrosis related to, 111:156, 158
metastatic malunion, hip labral tear related to, 1:341,
adult polyostotic lesions vs., 11:2-3, 5 343
bone cancer vs., 11:57 lateral bump, hip labral tear related to, 1:340,
childhood polyostotic lesions vs., 1l:8-9, 11 341
nonarticular clavicular lesions vs., 1:209, 211 Femur
painful scoliosis vs., 11I:145, 146 distal, enlargement of intercondylar notch,
solitary rib lesion vs., 1:313, 315 1:346-347
solitary sclerotic bone lesion vs., 11:21, 24 proximal
supra-acetabular iliac destruction vs., 1:330 bone marrow edema syndromes, 11:126-129
tarsal cystic/lytic lesions vs., 1:391 focal deficiency, unilateral short limb related
vertebral body sclerosis vs., 1:293, 297 to, J!I:173, 177
Exercise, excessive, delayed bone age vs., 1l:105 reduced anteversion, hip labral tear related to,
Exostosis. See Multiple hereditary exostosis. 1:341,345
Extensor digitorum brevis, avulsion, lateral ankle trauma, coxa magna deformity vs., 1:338, 339
pain related to, 111:115, 117 Fetal alcohol syndrome, short metacarpal/
Extensor tendon mechanism injury, lateral elbow metatarsal bones vs., 1:260-261
pain related to, 111:19 Fibroblastic sarcoma, acral myxoinflammatory, soft
Extramedullary hematopoiesis, soft tissue lesions tissue mass of finger vs., 1:241
with predominately low Tl & T2 signal vs., Fibrodysplasia ossificans progressiva
11:151 heterotopic ossification vs., 1lI:163, 165
paravertebral ossification and calcification vs.,
1:277,279
F soft tissue contractures related to, 1Il:171
Fabella, stress fracture, painful knee replacement soft tissue ossification vs., 11:107, 109
related to, 111:99 Fibrolipomatous hamartoma, enlarged peripheral
Fabry disease (vertebral bodies), generalized nerves vs., 1l:187, 189
osteoporosis vs., 11:83 Fibroma
Facet joint, septic, painful scoliosis vs., 111:145, 147 chondromyxoid
False negative scans and photopenic lesions, flat bones with focally expanded or bubbly
11:196-197 lesion vs., 1:3, 5
Familial Mediterranean fever, arthritis with long bone eccentric metaphyseal non-
osteopenia vs., 1:139 aggressive lesion vs., 1:49, 51
Fanconi anemia long bone metaphyseal bubbly lesion vs.,
anemia with musculoskeletal manifestations vs., 1:45,47
111:153 matrix-containing bone lesions vs., 11:49
forearm deformity vs., 1:228 solitary geographic lytic lesions vs., 11:15, 19
radial dysplasia/aplasia vs., 1:226 desmoplastic
short metacarpal/metatarsal bones vs., 1:261, long bone central diaphyseal non-aggressive
263 lesion vs., 1:69
Fat cells. See Adipocytes. long bone central metaphyseal non-
Fat necrosis aggressive lesion vs., 1:35, 36
bone lesions with bright T1 signal vs., 11:146- juvenile aponeurotic, bizarre horizontal
147, 148 periosteal reaction vs., I:123, 124
subcutaneous mass vs., 11:166, 168 tendon sheath
Fatty deposition, focal, increased marrow fat vs., soft tissue lesions with predominately low T1
11:136, 138 & T2 signal vs., [[:151, 152
xv
INDEX
soft tissue mass of finger vs., 1:240, 243 advanced bone age vs., II:102, 103
tenosynovitis/tenosynovial fluid vs., 11:184 childhood polyostotic lesions vs., II:8, 10
Fibromatosis generalized increased bone density in child
bizarre horizontal periosteal reaction vs., 1:123, vs., 11:65, 67
124 protrusio acetabuli vs., 1:335,337
desmoid-type, soft tissue lesions with pseudoarthrosis vs., 11:94
predominately low Tl & T2 signal vs., skull, multiple sclerotic bone lesion vs., 11:26-
II:151,152 27, 29
plantar skull base, solitary sclerotic bone lesion vs.,
ball of foot pain related to, Ill:127 II:21,25
soft tissue lesions with predominately low Tl solitary geographic lytic lesions vs., 11:14, 17
& T2 signal vs., 11:152 solitary rib lesion vs., 1:312, 313
Fibromatosis colli supra-acetabular iliac destruction vs., 1:331,333
enlarged muscle vs., II:173, 175 tibial bowing vs., 1:352, 354
nonarticular clavicular lesions vs., 1:209 tibial metadiaphyseal cortically based lesion vs.,
soft tissue contractures related to, III:170, 171 1:94
Fibroosseous pseudotumor of digits, swelling and unilateral short limb related to, 11I:172-173,175
periostitis of digit (dactylitis) vs., 1:266, 267 vertebral body sclerosis vs., 1:292, 296
Fibrosarcoma Fibrous hamartoma of infancy, subcutaneous mass
aggressive periostitis vs., 1:113, 115 vs., 11:167
flat bones with permeative lesions vs., 1:11 Fibrous histiocytoma
long bone diaphyseal aggressive lesion vs., 1:71, angiomatoid
73 soft tissue lesions with fluid/fluid levels vs.,
metastatic, bone cancer vs., 11:57, 58 II:154
myxofibrosarcoma subcutaneous mass vs., II:l71
acral myxoinflammatory fibroblastic, soft of bone, malignant. See Malignant fibrous
tissue mass of finger vs., 1:241 histiocytoma.
subcutaneous mass vs., II:171 Fibroxanthoma
sequestration vs., 11:36, 38 Achilles tendon thickening/enlargement vs.,
soft tissue lesions with fluid/fluid levels vs., 1:374,375
1l:154 benign osseous lesions with aggressive
supra-acetabular iliac destruction vs., 1:333 appearance vs., II:54
Fibrosis childhood polyostotic lesions vs., 11:8
post-operative, anterior knee pain related to, healing, multiple sclerotic bone lesion vs., 11:27,
Ill:81 29
vertebral body sclerosis vs., 1:297 long bone diaphyseal lesions vs.
Fibrous dysplasia central, non-aggressive, 1:67,68
benign osseous lesions with aggressive cortically based
appearance vs., II:54 lytic, 1:84, 85
genu valgum (knock knees) vs., 1:371 sclerotic, 1:81, 83
lesions originating in vertebral body vs., 1:301, long bone metaphyseal lesions vs.
304 bubbly, 1:44, 45
long bone diaphyseal lesions vs. cortically based, 1:57, 59
aggressive adult, 1:71, 73 eccentric, non-aggressive, 1:48, 49
central, non-aggressive, 1:66, 68 matrix-containing bone lesions vs., II:47
cortically based mimic, olecranon bursitis vs., 11I:27
lytic, 1:84,86-87 sclerotic bone lesion with central lucency vs.,
sclerotic, 1:81 11:32,33
long bone metaphyseal lesions vs. soft tissue mass of foot vs., 1:383,387
central, non-aggressive, 1:35, 37 solitary geographic lytic lesions vs., II:14, 16
cortically based, 1:57,59 solitary sclerotic bone lesion vs., II:20, 22
long bone undertubulation vs., 1:96, 98 thin bone, long bone central metaphyseal non-
matrix-containing bone lesions vs., 11:44, 46 aggressive lesion vs., 1:35, 38
pelvis, flat bones with focally expanded or Fibular fracture, lateral ankle pain related to,
bubbly lesion vs., 1:2,4 III:114,117
phalangeal cystic/lytic lesions vs., 1:253 Filariasis, linear and curvilinear calcification vs.,
polyostotic 11:117
adult polyostotic lesions vs., II:2, 4 Fingers and toes
xvi
INDEX
acroosteolysis, 1:246-249 11:136,138
acroosteosclerosis, 1:250-251 Focal gigantism/macrodactyly, 111:180-183
arachnodactyly, 1:238-239 Fong disease. See Nail patella syndrome (Fong).
congenital contractural, 1:238 Foot. See also Ankle; Calcaneus; Fingers and toes;
dactylitis, 1:266-267 Talus; Tarsal entries.
fibroosseous pseudotumor of digits, swelling Achilles tendon. See Achilles tendon.
and periostitis of digit (dactylitis) vs., 1:266, ball of foot pain, 111:126-131
267 bound, cavus foot deformity vs., 11I:137
focal gigantism/macrodactyly, 111:180-183 calcaneal erosions, posterior tubercle, 1:376-379
interphalangeal-predominant arthritis, 1:194- cavus foot deformity, 11I:136-137
197 congenital deformity, 111:138-141
metacarpophalangeal-predom inan t arthri tis, diabetic complications. See Diabetic foot
1:192-193 complications.
phalangeal cystic/lytic lesions, 1:252-257 flatfoot. See Pes planovalgus (flatfoot).
sesamoiditis, 1:258-259 heel pain, 11I:120-125
short metacarpal/metatarsal, 1:260-263 nerve entrapment syndromes, lower extremity
short rib polydactyly, childhood platyspondyly nerve entrapment vs., 111:65
vs., 1:285 rocker bottom (congenital vertical talus)
sickle cell dactylitis, periostitis of multiple bones congenital foot deformity vs., 111:139,141
in children vs., 1:131, 133 pes planovalgus (flatfoot) vs., 11I:133,135
soft tissue mass in, 1:240-245 soft tissue mass, 1:382-387
swelling and periostitis of digit (dactylitis), Forearm deformity, 1:228-231
1:266-267 Foreign body
ulnar deviation of metacarpophalangeal joints, acroosteosclerosis vs., 1:251
1:264-265 ball of foot pain related to, 11I:127,130
Fish (biconcave) or H-shaped vertebra, 1:288-289 heel pain related to, 11I:121, 123
Flat bones metallic, intraarticular low signal material vs.,
focally expanded or bubbly lesion, 1:2-5 11:190, 191
permeative lesion, 1:6-11 overlying metallic, photopenic lesions and false
Flatfoot. See Pes planovalgus (flatfoot). negative scans vs., 11:196
Flexor mechanism injury, medial elbow pain soft tissue lesions with predominately low Tl &
related to, 11I:22,24 T2 signal vs., 11:150, 151-152
Flow voids, soft tissue lesions with predominately soft tissue mass of finger vs., 1:240, 242
low Tl & T2 signal vs., 11:150 subcutaneous mass vs., 11:167,168
Fluid collections Fracture healing
knee, 1:356-361 aggressive periostitis vs., 1:113, 114
shoulder, 1:222-225 complications, elbow deformities vs., 111:16
Fluoride complications. See also Fluorosis. solid periostitis vs., 1:116, 117
generalized increased bone density vs. solitary rib lesion vs., 1:312, 313
adult, 11:60,62 target lesions of bone vs., 11:40
child, 11:65 vertebral body sclerosis vs., 1:292
linear and curvilinear calcification vs., 11:121 Fractures
long bone diffuse cortical endosteal thickening ankle, medial ankle pain related to, 11I:108,
vs., 1:91 lll-112
long bone metaphyseal bands and lines vs., 1:27 avulsion
solid periostitis vs., 1:117 anterior arch C1, ossification/calcification
symphysis pubis with productive changes/ anterior to C1 vs., 1:274
fusion vs., 1:324 early, nodular calcification vs., 11:110,113
tendon and ligament ossification vs., 11:101 intraarticular, calcified intraarticular body/
Fluorosis bodies vs., 1:180, 182
ankylosis vs., 1:177 OSSification/calCification anterior to C1 vs.,
enthesopathy vs., 11:97 1:274,275
periostitis of multiple bones/acropachy vs., pelvic (mimic), enthesopathy vs., 11:97,99
1:127 calcaneal. See Calcaneus, fractures.
spinal osteophytes vs., 1:298 calf pain related to, 11I:93-94
tendon and ligament ossification vs., 11:100 callus formation. See Callus formation.
vertebral body sclerosis vs., 1:293 capitellar, lateral elbow pain related to, 11I:21
Focal fatty deposition, increased marrow fat vs.,
XVII
INDEX
clavicle, nonarticular clavicular lesions vs., hip pain in elderly patients related to, 111:69
1:208, 209-210 thigh pain related to, 1II:61
compression fracture, acute, vertebral body tibial bowing vs., 1:352, 353
sclerosis vs., 1:292, 294 wrist clicking/clunking/instability related to,
condylar 11I:33
lateral elbow pain related to, III:18, 20 metaphyseal
medial elbow pain related to, III:23, 25 in child abuse, long bone metaphyseal
coronoid process, medial elbow pain related to, fraying vs., 1:32, 33
1Il:23, 25 long bone metaphyseal cupping vs., 1:30
cuboid, lateral ankle pain related to, 1Il:116 metatarsal, lateral ankle pain related to, 1Il:114,
delayed union of, hypertrophic callus formation 115
vs., 11:74 motion of, hypertrophic callus formation vs.,
entrapped soft tissue in, widened joint space 11:74-75
related to, 1:170 navicular
epiphyseal, long bones, pediatric, long bone anterior ankle pain/impingement related to,
epiphyseal overgrowth/ballooning vs., 1:16, III:105, 107
17 avascular necrosis related to, 1II:157
epiphyseal marrow signal, abnormal, vs., 11:132 medial ankle pain related to, 1II:111-112
femoral neck nonunion of
avascular necrosis related to, Ill: 156, 158 hypertrophic callus formation vs., 11:74,75
malunion, hip labral tear related to, 1:341, pseudoarthrosis vs., 11:94
343 olecranon, medial elbow pain related to, III:22,
fibula, lateral ankle pain related to, 111:114 24
fragments osteochondral, subchondral edematous-like
impaction, calcified intraarticular body/ signal vs., 11:130
bodies vs., 1:180, 181 patellar, anterior knee pain related to, III:80, 83
mimic, soft tissue ossification vs., 11:106, 108 pelvis, groin/hip pain related to, 1II:48
retained, widened joint space related to, peri prosthetic
1:170,172 hip pain related to, III:75, 79
glenoid, shoulder instability related to, IIl:9, 11 knee pain related to, IIl:99, 103
growth plate premature physeal closure vs., physeal
1:106 advanced bone age vs., 11:103
hip genu varum (bow leg deformity), l:372
groin/hip pain related to, 11I:48,49-50 long bone growth plate widened physis vs.,
lateral hip pain related to, III:54, 56 1:108, 109
pain in elderly patients related to, 11I:68, pediatric
69-70 long bone metaphyseal fraying vs., 1:32,
humeral head, shoulder instability related to, 33
111:8,10 unilateral short limb related to, Ill: 172,
humeral neck, surgical, glenohumeral 173
malalignment vs., 1:216, 217 radial head/neck, lateral elbow pain related to,
hyperextension (teardrop), ossification/ 111:18,19-20
calcification anterior to C1 vs., 1:274, 275 scaphoid, avascular necrosis related to, 1Il:156,
in burns, hypertrophic callus formation vs., 158
11:74 sesamoiditis vs., 1:258, 259
infection of, hypertrophic callus formation vs., shoulder, rotator cuff symptoms vs., IIl:5, 6
11:74,75 stress reaction, thigh pain related to, 111:60,62
insufficiency. See Insufficiency fractures. subcapital, Garden IV (mimic), benign osseous
knee, medial knee pain related to, 1Il:86 lesions with aggressive appearance vs., II:55
lower extremity talar
calf pain related to, 1Il:92 anterior ankle pain/impingement related to,
thigh pain related to, TII:60, 61 1Il:105, 107
malunion lateral process, lateral ankle pain related to,
abnormal radiocarpal angle vs., 1:234, 235 IIl:115, 119
calf pain related to, 1lI:93 Tillaux, lateral ankle pain related to, 111:115,118
cavus foot deformity vs., IlI:136 vertebral body, asymmetric, painful scoliosis vs.,
forearm deformity vs., 1:228, 229 Ill: 144
XVIII
INDEX
wrist supra-acetabular iliac destruction vs., 1:331 ::s
radial-sided pain related to, 111:42,43 Generalized increased bone density, adult, 11:60-63 Q..
1'0
ulnar-sided pain related to, 111:36,39 Genu valgum (knock knees), [:370-371 X
Freiberg infarction, ball of foot pain related to, Giant cell tumor
111:127, 130 aggressive, long bone central metaphyseal
Friedrich disease, nonarticular clavicular lesions lesion vs., aggressive, 1:41, 43
vs., 1:209 benign osseous lesions with aggressive
Frostbite appearance vs., 11:51, 53
acroosteolysis vs., 1:246, 248 bone lesions with fluid/fluid levels vs., 11:144,
acroosteosclerosis vs., 1:250, 251 145
irregular or stippled long bone epiphysis vs., flat bones with focally expanded or bubbly
1:13 lesion vs., 1:2, 3
Fungal infections lesions crossing disc space vs., 1:268
arthritis related to lesions originating in vertebral body vs., 1:301,
atrophic joint destruction vs., 1:159, 161 304
monoarthritis vs., 1:199, 201 long bone epiphyseal/apophyseal/subchondral
low virulence, arthritis with preserved cartilage lytic lesion vs., [:22, 23
space vs., 1:167 long bone metaphyseal lesions vs.
soft tissue lesions with predominately low T1 & T2 bubbly, 1:44, 46
signal vs., 11:151 central
aggressive, 1:41,43
non-aggressive, 1:35, 38
G eccentric
Gadolinium, concentrated, soft tissue lesions with aggressive, 1:52, 54
predominately low 1'1 & T2 signal vs., 11:151 non-aggressive, 1:48, 50
Ganglion cyst mimic, inferior rib notching vs., 1:309
anechoic mass vs., 11:194 patellar lytic lesions vs., [:348-349, 350-351
cystic masses vs., 11:160, 161 phalangeal cystic/lytic lesions vs., 1:252, 255
intraosseous soft tissue ossification vs., 11:107
carpal cystic/lytic lesions vs., 1:232 solitary geographic lytic lesions vs., 11:14, 16
tarsal cystic/lytic lesions vs., 1:390 solitary rib lesion vs., 1:313,315
knee fluid collections vs., 1:357,360 supra-acetabular iliac destruction vs., 1:331,333
radial-sided wrist pain related to, 111:42,45 tarsal cystic/lytic lesions vs., 1:391
shoulder fluid collections vs., 1:223, 225 tendon sheath
soft tissue lesions with fluid/fluid levels vs., arthritis with large subchondral cysts vs.,
II: 155 1:157
soft tissue mass of foot vs., 1:382, 385 long bone epiphyseal/apophyseal!
su bperiostea I subchondral lytic lesion vs., 1:23,25
bizarre horizontal periosteal reaction vs., mimic, arthritis with large subchondral cysts
[:123,125 vs., 1:155
long bone surface (juxtacortical) lesion vs., monoarthritis vs., 1:199,201
1:61,64 phalangeal cystic/lytic lesions vs., 1:252-253,
wrist clicking/clunking/instability related to, 256
111:33,35 soft tissue lesions with predominately low T1
Gastrocnemius & T2 signal vs., 11:150, 152
strain, knee fluid collections vs., 1:356, 359 soft tissue mass of finger vs., 1:240, 241
variant, extraarticular popliteal mass vs., 1:363 soft tissue mass of foot vs., 1:382, 386
Gaucher disease tenosynovitis/tenosynovial fluid vs., 11:184,
abnormal epiphyseal marrow signal vs., 11:133, 185
135 Giantism, localized (mimic), arachnodactyly vs.,
avascular necrosis related to, III:161 1:238,239
bone within bone appearance vs., 11:79 Gigantism, focal, 111:180-183
fish (biconcave) or H-shaped vertebra, 1:288 differential diagnosis, 111:180-183
generalized increased bone density vs., adult, long bone growth plate widened physis vs.,
11:60,62 1:109
generalized osteoporosis vs., 11:83, 86 GLAD (glenoid labrum articular disruption),
long bone undertubulation vs., 1:96,98 anteroinferior labral/capsule injury vs., [[[:12,
13
XIX
INDEX
>< Glenohumeral ligament solitary geographic lytic lesions vs., 11:15, 19
QJ
"'C humeral avulsion of (HAGL), anteroinferior subcutaneous mass vs., 11:167
c: labral/capsule injury vs., JJJ:12, 13 tarsal cystic/lytic lesions vs., 1:390, 391
tear, shoulder instability related to, 111:8-9, 10 widened joint space related to, 1:171, ] 74
Glenohumeral malalignment, 1:216-217 wrist pain related to
Glenoid cavity radial-sided, 1ll:42
fracture, shoulder instability related to, 111:9, 11 ulnar-sided, 1II:36, 38
malformation, shoulder instability related to, Gouty tophus, soft tissue mass of foot vs., 1:382,
111:9, 11 385
Glenoid labrum articular disruption (GLAD), Granulation tissue, soft tissue mass of finger vs.,
anteroinferior labral/capsule injury vs., 11I:12, 1:242
13 Granuloma, injection, nodular calcification vs.,
Glomus tumor 1J:11O, 112
phalangeal cystic/lytic lesions vs., 1:253, 256 Granuloma annulare, soft tissue mass of foot vs.,
soft tissue mass of finger vs., 1:240, 243 1:383
soft tissue mass of foot vs., 1:383, 387 Graves disease, orbit, enlarged muscle vs., 1J:173
subcutaneous mass vs., 11:167, 169 Groin/hip pain, 11I:48-53
Gonadotropin tumor, ectopic, advanced bone age Growth arrest lines, long bone metaphyseal bands
vs., 11:102 and lines vs., 1:26, 27
Gout Growth deformities, radiation-induced
ankle, medial ankle pain related to, 111:108, 111 advanced bone age vs., 11:102, 103
arthritis mutilans vs., 1:163 bullet shaped vertebra/anterior vertebral body
arthritis with large subchondral cysts vs., 1:154, beaking vs., 1:282, 283
156 elbow deformities vs., 111:]6
arthritis with normal bone density vs., 1:134, growth plate premature physeal closure vs.,
136 1:106, 107
arthritis with preserved cartilage space vs., 1:166, unilateral short limb related to, 111:173, ] 76
]69 Growth plate
arthritis with productive changes vs., 1:142, 143 premature physeal closure, 1:106-107
ball of foot pain related to, JJJ:126, ]29 widened physis, 1:108-111
calcaneal erosions, posterior tubercle vs., 1:377, Guillain-Barre syndrome, muscle atrophy vs.,
379 11:177
carpal cystic/lytic lesions vs., 1:232, 233
chondrocalcinosis vs., 1:184, 185
distal femur intercondylar notch enlargement H
vs., 1:346,347 HAGL (humeral avulsion of glenohumeral
erosive arthritis vs., 1:146, 148 ligament), anteroinferior labral/capsule injury
groin/hip pain related to, 11[:48 vs., 111:13
intraarticular low signal material vs., II:] 90, 192 Haglund syndrome
intraarticular mass vs., 1:203, 204 Achilles tendon thickening/enlargement vs.,
knee, anterior knee pain related to, 111:80 1:374,375
long bone epiphyseal/apophyseal/subchondral calcaneal erosions, posterior tubercle vs., 1:377,
lytic lesion vs., 1:22, 25 378
mixed erosive/productive arthritis vs., 1:152, 153 enthesopathy vs., 11:96, 98
monoarthritis vs., 1:198,200 heel pain related to, 111:121, 123
nodular calcification vs., [1:110, 113 retrocalcaneal bursitis vs., 1:380
olecranon bursitis vs., 111:26,27 Hajdu-Cheney acroosteolysis syndrome, 1:247
patellar lytic lesions vs., 1:348, 350 Hallux valgus deformity, ball of foot pain related
periarticular calcification vs., 1:186, 188 to, 111:126, 128
phalangeal cystic/lytic lesions vs., 1:252, 254 Hamartoma
retrocalcaneal bursitis vs., [:380 fibrolipomatous, enlarged peripheral nerves vs.,
sacroiliitis vs. 11:187, 189
bilateral asymmetric, 1:320 of infancy, fibrous, subcutaneous mass vs.,
unilateral, 1:322 11:167
soft tissue lesions with predominately low T1 & Hamate fracture, ulnar-sided pain wrist related to,
T2 signal vs., 11:150, 152 111:37,40
soft tissue mass of finger vs., 1:240, 242 Hardware. See a/so Arthroplasty components.
xx
INDEX
complications spine, benign osseous lesions with aggressive
thigh pain related to, IJI:61, 63 appearance vs., 11:54
wrist clicking/clunking/instability related to, synovial
111:33, 35 distal femur intercondylar notch
reactive changes, long bone cortically based, enlargement VS., 1:346, 347
lytic diaphyseal lesion vs., 1:85,89 intraarticular mass VS., 1:203, 205
removed, sequestration vs., 11:36, 39 soft tissue lesions with f1uid/fluid levels vs.,
Hardware failure 11:155
ankle, medial ankle pain related to, 1II:108, 112 Hemangiopericytoma
hip adult polyostotic lesions vs., 11:3
groin/hip pain related to, 111:49, 52 bone lesions with bright Tl signal vs., 11:147
lateral hip pain related to, 111:54, 57 nodular calcification VS., 11:111, 114
pain in elderly patients related to, m:69, 72 osseous
painful hip replacement related to, m:75, benign osseous lesions with aggressive
78-79 appearance vs., 11:55
knee supra-acetabular iliac destruction VS., 1:331
medial knee pain related to, 111:86,89 Hemarthrosis
painful knee related to, 111:99 shoulder fluid collections vs., 1:222-223
Heart disease, congenital, repaired, inferior rib soft tissue lesions with f1uid/fluid levels vs.,
notching vs., 1:308 11:154, 156
Heavy metal poisoning widened joint space related to, 1:170,172
bone within bone appearance vs., 11:77 Hematoma
long bone metaphyseal bands and lines vs., anechoic mass vs., 11:194, 195
1:26,28 calf pain related to, 1II:92, 95
Heel pad atrophy, heel pain related to, 11I:121 chronic, soft tissue lesions with predominately
Heel pain, 111:120-125. See also Calcaneus. low Tl & T2 signal vs., 11:150
Helmut sclerosis, vertebral body sclerosis vs., 1:293 cystic masses vs., 11:161, 164
Hemangioendothelioma, osseous enlarged muscle VS., 11:172,173
adult polyostotic lesions vs., 11:3, 6 epidural space, painful scoliosis vs., 111:144, 145
tarsal cystic/lytic lesions vs., 1:391 hip pain in elderly patients related to, 111:69, 72
Hemangioma knee fluid collections vs., 1:356, 358
cavernous, soft tissue lesions with lateral hip pain related to, 111:55, 57
predominately low T1 & T2 signal vs., nodular calcification VS., 11:111
11:151 shoulder fluid collections vs., 1:223, 224
in traosseous soft tissue lesions with f1uid/fluid levels vs.,
increased marrow fat vs., 11:136, 138 11:154,155
lesions originating in vertebral body vs., soft tissue mass of finger vs., 1:240
1:300,301 soft tissue ossification VS., 11:106
mimic, sequestration vs., 11:37,39 subacute, bone lesions with bright Tl signal vs.,
vertebral body sclerosis vs., 1:292, 294 11:146,148
skull (mimic), bizarre horizontal periosteal subcutaneous mass vs., 11:166, 168
reaction vs., 1:123, 125 thigh pain related to, 111:60, 62
soft tissue Hematopoiesis, extramedullary, soft tissue lesions
bone lesions with bright T1 signal vs., 11:146, with predominately low T1 & T2 signal vs.,
148 11:151
cystic masses vs., 11:161, 164 Hematopoietic stimulation, bone marrow
enlarged muscle vs., 11:175 hyperplasia vs., 11:140-141, 143
extraarticular popliteal mass vs., 1:363, 365 Hemihypertrophy, 111:178-179
focal gigan tism/macrodactyly related to, Hemochromatosis
111:180, 182 arthritis with large subchondral cysts vs., 1:155,
linear and curvilinear calcification VS., 11:116, 157
118 arthritis with normal bone density VS., 1:137
nodular calcification vs., 11:111,114 arthritis with productive changes VS., 1:142
periarticular calcification vs., 1:187, 189 carpal cystic/lytic lesions VS., 1:232
soft tissue mass of finger vs., 1:241,245 discal mineralization vs., 1:271
soft tissue mass of foot vs., 1:382, 386 linear ossification along anterior spine vs., 1:280
soft tissue neoplasms with calcification vs., metacarpophalangeal-predominant arthritis vs,/
11:122, 124 1:192, 193
XXI
INDEX
mixed erosive/productive arthritis vs., 1:152, 153 arthritis
primary, generalized osteoporosis vs., 11:83 lateral hip pain related to, 1Il:54, 56
Hemophilia, musculoskeletal complications pain in elderly patients related to, 111:68,
advanced bone age vs., 11:102, 103 70-71
arthritis with large subchondral cysts vs., 1:155, coxa magna deformity, 1:338-339
157 developmental dysplasia
arthritis with osteopenia vs., 1:141 avascular necrosis related to, 111:157,159
atrophic joint destruction vs., 1:158, 161 coxa magna deformity vs., 1:338
distal femur intercondylar notch enlargement in teenagers, 111:149,150
vs., 1:346, 347 lateral hip pain related to, 1II:55, 57
early, arthritis with preserved cartilage space vs., overcorrection osteotomy for, hip labral tear
1:166, 168 related to, ]:341, 345
elbow deformities vs., 111:16,17 unilateral short limb related to, 111:172,175
erosive arthritis vs., 1:150 widened joint space related to, 1:171,
flat bones with focally expanded or bubbly 173-174
lesion vs., 1:3, 5 dislocation, avascular necrosis related to,
focal gigantism/macrodactyly related to, 1Il:181, 111:156,158
183 fractures
in teenagers, 1Il:149, 150 groin/hip pain related to, 11I:48,49-50
long bone diaphyseal lesions vs. lateral hip pain related to, 11I:54,56
aggressive pain in elderly patients related to, 1II:68,
adult, 1:71 69-70
child,I:75 groin/hip pain, 11I:48-53
cortically based, lytic, 1:85, 89 ~b~l~aLSa~b~l~a~h~.
long bone epiphyseal overgrowth/ballooning lateral pain, 11I:54-57
vs., 1:16 malformation, groin/hip pain related to, 11I:49,
long bone growth plate premature physeal 53
closure vs., 1:106 osteoarthritis
long bone overtubulation vs., 1:102-103, 104 lateral hip pain related to, 111:56
monoarthritis vs., ]:199, 201 pain in elderly patients related to, 111:68,70
regional osteoporosis vs., 11:89 rapidly destructive
unilateral short limb related to, 111:172,176 atrophic joint destruction vs., 1:159, 161
Hemophilic arthropathy, intraarticular low signal bone marrow edema syndromes vs.,
material vs., 11:191, 193 11:127, 129
Hemophilic pseudotumor pain in
anechoic mass vs., 11:194 groin/hip pain, 1II:48-53
benign osseous lesions with aggressive in elderly patients, 111:68-73
appearance vs., 11:55 lateral pain, 111:54-57
bizarre horizontal periosteal reaction vs., 1:122, with hip replacement, 1II:74-79
124 pathology (referred pain), medial knee pain
heel pain related to, 111:121,125 related to, 11I:87
solitary geographic lytic lesions vs., 11:15,19 protrusio acetabuli, 1:334-337
supra-acetabular iliac destruction vs., 1:331 differential diagnosis, 1:334-337
tarsal cystic/lytic lesions vs., ]:391, 393 secondary, hip labral tear related to, 1:341,
Hemorrhage, subperiosteal, bone within bone 344
appearance vs., 11:76 septic, coxa magna deformity vs., 1:338, 339
Heparin therapy, generalized osteoporosis vs., 11:83 snapping hip, 11I:58-59
Hepatoma, metastatic, bone cancer vs., 11:57,58 tendon impingement, snapping hip related to,
Heterotopic ossification. See Ossification, 111:58-59
heterotopic. trauma, coxa magna deformity vs., 1:338,339
Hibernoma, bone lesions with bright T1 signal vs., HIV-related arthritis
11:147, 149 arthritis with osteopenia vs., 1:139
Hidradenoma, eccrine erosive arthritis vs., 1:150
cystic masses vs., 11:161, 165 interphalangeal-predominant arthritis vs., 1:195,
subcutaneous mass vs., 11:167,171 196
Hip. See also Arthroplasty components; Hardware swelling and periostitis of digit (dactylitis) vs.,
failure. 1:266,267
XXII
INDEX
Hodgkin disease, solitary sclerotic bone lesion vs., Hyperextension (teardrop) fracture, ossification/
11:25 calcification anterior to C1 vs., 1:274, 275
Hoffa disease, anterior knee pain related to, 1ll:81 Hypermobility syndrome, congenital,
Holt-Oram syndrome anteroinferior labral/capsule injury vs., 111:12
forearm deformity vs., 1:228 Hyperparathyroidism
nonarticular clavicular lesions vs., 1:209 acroosteolysis vs., 1:246, 247
radial dysplasia/aplasia vs., 1:226, 227 arthritis mutilans vs., 1:163
Homocystinuria cortical tunneling vs., 11:92,93
arachnodactyly related to, 1:238,239 discal mineralization vs., 1:271, 273
childhood platyspondyly related to, 1:285, 287 distal clavicular resorption vs., 1:212, 213
fish (biconcave) or H-shaped vertebra related to, fish (biconcave) or H-shaped vertebra vs., 1:288
1:288 generalized osteoporosis vs., 11:82-83, 85-86
generalized osteoporosis related to, 11:83, 87 linear ossification along anterior spine vs., 1:280,
phalanges, long bone overtubulation related to, 28]
1:103, 105 long bone diaphyseal lesion vs., cortically based,
Humeral avulsion of glenohumeral ligament lytic, 1:85, 89
(HAGL), anteroinferior labral/capsule injury medial metaphyseal erosion of proximal
vs., 111:]2, 13 humerus vs., 1:214, 215
Humeral head mimic
fracture, shoulder instability related to, 1Il:8, 10 erosive arthritis vs., 1:147, 149
retroversion, shoulder instability related to, 1Il:9 inferior rib notching vs., 1:308,309
rotation (mimic), glenohumeral malalignment interphalangeal-predominant arthritis vs.,
vs., 1:216, 217 1:194,196
Humeral neck fracture, surgical, glenohumeral multiple sclerotic bone lesion vs., 11:27, 30
malalignment vs., 1:216,217 superior rib notching vs., 1:310
Humerus symphysis pubis widening vs., 1:326
instability, glenohumeral malalignment related protrusio acetabuli vs., 1:335
to, 1:216, 217 superscan vs., 11:204
normal variant ("upper humeral notch"), supra-acetabular iliac destruction vs., 1:331, 333
medial metaphyseal erosion of proximal symphysis pubis with productive changes/
humerus vs., 1:214 fusion vs., 1:324,325
proximal, medial metaphysis erosion, 1:214-215 treated, multiple sclerotic bone lesion vs., 11:27,
Hunter syndrome, dwarfism with major spine 30
involvement vs., 111:184 with brown tumor
Hurler syndrome acroosteosclerosis vs., 1:251
bullet shaped vertebra/anterior vertebral body adult polyostotic lesions vs., 11:2,5
beaking vs., 1:282, 283 benign osseous lesions with aggressive
dwarfism with major spine involvement vs., appearance vs., 11:50, 52
111:]84, 185 bone lesions with fluid/fluid levels vs., Il:144,
Hydatid cyst, cystic masses vs., 11:16] 145
Hydroxyapatite deposition disease carpal cystic/lytic lesions vs., 1:232
ossification/calcification anterior to Cl vs., childhood polyostotic lesions vs., 11:12
1:274-275 flat bones with focally expanded or bubbly
rotator cuff symptoms vs., 11I:5 lesion vs., 1:3, 5
Hyperalimentation. See Total parenteral nutrition. flat bones with permeative lesions vs., 1:7, ]0
Hypercalcemia healing, multiple sclerotic bone lesion vs.,
idiopathic, long bone metaphyseal bands and 11:27,28
lines vs., 1:27 hyperossified (mimic), sclerosing dysplasias
linear and curvilinear calcification vs., 11:117, vs., 11:69, 71-72
120 lesions originating in posterior vertebral
of infancy, idiopathic, generalized increased elements vs., 1:306, 307
bone density in child vs., 11:65 long bone diaphyseal lesions vs.
Hyperemia aggressive, adult, 1:70-71, 72
focal gigantism/macrodactyly related to, 1ll:181, central, non-aggressive, 1:67, 69
183 long bone metaphyseal lesions vs.
hemihypertrophy related to, 111:178 central, non-aggressive, 1:34, 36
long bone metaphyseal bands and lines vs., 1:26 non-aggressive, 1:49,51
patellar lytic lesions vs., 1:348, 350
XXIII
INDEX
phalangeal cystic/lytic lesions vs., 1:252, 255 Hypophosphatemic rickets (X-linked), [II: 167
with renal osteodystrophy. See Renal Hypopituitarism, increased marrow fat vs., 11:137
osteodystrophy, with hyperparathyroidism. Hypoplastic/aplastic pedicle, lesions originating in
Hyperphosphatasia (juvenile Paget), generalized posterior vertebral elements vs., 1:306
increased bone density in child vs., 11:65 Hypospadias, symphysis pubis widening vs., 1:327
Hyperthyroidism, generalized osteoporosis vs., Hypothalamic mass, advanced bone age vs., 11:102
11:83 Hypothyroidism
Hypertrophic callus formation, II:74-75 anemia with musculoskeletal manifestations vs.,
Hypertrophic osteoarthropathy. See 111:153
Osteoarthropathy, hypertrophic. child (mimic), dwarfism with major spine
Hypervitaminosis A involvement vs., 111:184
long bone metaphyseal cupping vs., 1:30 congenital, bullet shaped vertebra/anterior
nonarticular clavicular lesions vs., 1:209 vertebral body beaking vs., 1:282
periostitis of multiple bones in children vs., irregular or stippled long bone epiphysis vs.,
1:130-131,132 1:12, 14
periostitis of multiple bones/acropachy vs., long bone growth plate widened physis vs.,
1:127 [:109, 111
Hypervitaminosis D regional osteoporosis vs., 11:89
bone within bone appearance vs., 1T:76 short metacarpal/metatarsal bones vs., 1:260,
nodular calcification vs., II: III 262
periostitis of multiple bones/acropachy vs., treated, long bone metaphyseal bands and lines
1:127 vs., 1:27
Hypochondroplasia
dwarfism with major spine involvement vs.,
111:184 I
dwarfism with short extremities vs., 11I:186 Iatrogenic
short metacarpal/metatarsal bones vs., [:261 growth plate premature physeal closure vs.,
Hypogonadism 1:106, 107
delayed bone age vs., 11:104 shoulder fluid collections vs., 1:223
generalized osteoporosis vs., 11:83 tenosynovitis/tenosynovial fluid vs., 11:184, 185
Hypoparathyroidism. See also Ichthyosis syndrome, arachnodactyly vs., 1:239
Pseudo h ypopa ra th yroidism. Iliac destruction, supra-acetabular, 1:330-333
enthesopathy vs., 11:97 Iliacus muscle syndrome, lower extremity nerve
generalized increased bone density vs. entrapment vs., 111:64, 66
adult, 11:60-61,63 Iliopsoas muscle/tendon
child, 11:65 abscess, painful scoliosis vs., 11I:144, 146
long bone metaphyseal bands and lines vs., 1:27 bursitis, painful hip replacement related to,
short metacarpal/metatarsal bones vs., [:260, 111:75, 79
262 tendon impingement, snapping hip related to,
spinal osteophytes vs., 1:298 111:58,59
tendon and ligament ossification vs., 11:100 Iliotibial band, snapping hip related to, 111:58, 59
Hypophosphatasia Iliotibial bursitis, knee fluid collections vs., 1:357,
childhood platyspondyly vs., 1:285, 287 360
cortical tunneling vs., 11:93 Immobilization
enthesopathy vs., 11:97,99 bone within bone appearance vs., 11:76, 78
long bone growth plate widened physis vs., muscle atrophy vs., 11:176, 177
1:109, 111 osteoporosis due to
long bone metaphyseal bands and lines vs., 1:27 cortical tunneling vs., 11:92
long bone metaphyseal cupping vs., [:30,31 generalized, 11:84
long bone metaphyseal fraying vs., 1:32, 33 regional, 11:88, 89-90
long bone overtubulation vs., I: 103, 105 prolonged, long bone metaphyseal cupping vs.,
long bone undertubulation vs., 1:97, 101 1:30
mimic, rickets and osteomalacia vs., 11I:167, 169 soft tissue contractures related to, 111:170
protrusio acetabuli vs., 1:335, 337 with polio, long bone metaphyseal cupping vs.,
symphysis pubis widening vs., 1:327, 329 1:30
tendon and ligament ossification vs., 11:100 Imperforate anus, symphysis pubis widening vs.,
tibial bowing vs., 1:353 1:327,329
xxiv
INDEX
Infantile cortical hyperostosis. See Caffey disease. with Charcot neuropathy, neuropathic
Infection osteoarthropathy vs., 1:164, 165
ankle, medial ankle pain related to, 111:108-109, Insufficiency fractures
112 appendicular, long bone cortically based
anterior knee pain related to, 111:81 metaphyseal lesion vs., 1:56, 57
calcified or fungal, soft tissue lesions with benign osseous lesions with aggressive
predominately low T1 & T2 signal vs., appearance vs., 11:50-51, 53
11:151 bone marrow edema syndromes vs., 11:126, 127
calf pain related to, IlI:93, 96-97 calcaneal
congenital, long bone metaphyseal bands and diabetic foot complications vs., 111:143
lines vs., 1:27, 29 heel pain related to, 111:120, 121-122
fungal. See Fungal infections. calf pain related to, 111:94
groin/hip pain related to, 1lI:49, 52 fibula, lateral ankle pain related to, 111:114, 117
heterotopic ossification vs., 111:162 medial knee pain related to, 111:86, 89
hip pain in elderly patients related to, 111:69 solitary sclerotic bone lesion vs., 11:20,21
neurologic, heterotopic ossification vs., [11:162- subchondral edematous-like signal vs., 11:130,
163 131
sesamoiditis vs., 1:258,259 tarsal and metatarsal bones, diabetic foot
shoulder fluid collections related to, 1:223 complications vs., 111:143
tenosynovitis/tenosynovial fluid vs., 11:184, 185 Insult prior to skeletal maturity, unilateral short
with low virulence organisms, arthritis with limb related to, 11l:173, 176
preserved cartilage space vs., 1:167 Intercalated segment instability
wrist pain related to dorsal, 111:32, 34
radial-sided, 111:43, 47 volar, 11I:32, 34
ulnar-sided, 111:37,41 Intercondylar notch
Infectious bursitis, olecranon bursitis vs., 1I!:26 cyst, knee fluid collections vs., 1:356-357
Inflammatory arthritis. See Ankylosing spondylitis; enlargement, distal femur, 1:346-347
Chronic reactive arthritis; Juvenile idiopathic Intermuscular edema, 1I:180-183
arthritis; Psoriatic arthritis; Rheumatoid Interosseous nerve syndrome
arthritis. elbow/wrist nerve entrapment vs., 111:31
Inflammatory bowel disease arthritis posterior, elbow/wrist nerve entrapment vs.,
arthritis with osteopenia vs., 1:139, 141 1I!:29
arthritis with productive changes vs., 1:145 Interphalangeal-predominant arthritis, 1:194-197
calcaneal erosions, posterior tubercle vs., 1:376, Intervertebral disc. See also Vertebrae and vertebral
378 body.
erosive arthritis vs., 1:150 calcification, bone lesions with bright Tl signal
heel pain related to, IlI:121, 124 vs., 11:147
in teenagers, 111:148, 151 disc disease, spinal osteophytes vs., 1:298, 299
linear ossification along anterior spine vs., 1:280, discal mineralization, 1:270-273
28] discectomy, anterior cervical, with fusion,
mixed erosive/productive arthritis vs., 1:153 squaring of vertebra vs., 1:290
regional osteoporosis vs., 11:89 discography (mimic), discal mineralization vs.,
sacroiliitis vs. 1:270,272
bilateral asymmetric, [:320, 321 fusion (congenital), discal mineralization vs.,
bilateral symmetric, 1:316-317, 318-319 1:270,272
squaring of one or more vertebra vs., 1:290,292 fusion (surgical)
Injection discal mineralization vs., 1:270,271-272
intramuscular, intermuscular edema vs., 11:180 lesions crossing disc space vs., 1:268
medication, soft tissue lesions with fluid/fluid paravertebral ossification and calcification
levels vs., 11:154, 156 vs., 1:276
soft tissue uptake on bone scan vs., 11:199 lesions crossing disc space, 1:268-269
Injection granuloma, nodular calcification vs., paravertebral ossification and calcification,
11:110, 112 1:276-279
Insensitivity/indifference to pain, congenital Intestinal malabsorption, rickets and osteomalacia
acroosteolysis vs., 1:247 related to, 1lI:1 66, 168
arthritis mutilans vs., 1:]62, ]63 Intraarticular air/gas
in teenagers, 11I:151 intraarticular low signal material vs., 11:191, 193
xxv
INDEX
>< mimic, meniscal size alteration vs., 1:367 Juvenile idiopathic arthritis
~
"'C Intraarticular body/bodies, calcified, 1:180-183 advanced bone age vs., 11:102
C Intraarticular chondroma. See Chondroma, ankylosis VS., 1:176,178
intraarticular. arthritis mutilans VS., 1:163
Intraarticular fluid arthritis with large subchondral cysts vs., 1:155,
glenohumeral malalignment related to, 1:217 157
glenohumeral malalignment vs., 1:216 arthritis with osteopenia vs., 1:138, 140
Intraarticular low signal material, all sequences, calcaneal erosions, posterior tubercle vs., 1:377
11:190-193 delayed bone age vs., U:105
Intraarticular mass, 1:202-205 diagnostic clues, 111:148, 149
differential diagnosis, 1:202-205 discal mineralization vs., 1:271,273
glenohumeral malalignment related to, 1:216, distal femur intercondylar notch enlargement
217 vs., 1:346, 347
Intraarticular neoplasm, shoulder instability early, arthritis with preserved cartilage space VS.,
related to, 111:9 1:166, 168
Intracondylar notch cyst, knee fluid collections vs., effusions, shoulder fluid collections vs., 1:222,
1:356-357,360 223
Intraosseous ganglion cyst elbow deformities vs., 111:16,17
carpal cystic/lytic lesions vs., 1:232 epiphyseal marrow signal vs., abnormal, 11:132,
tarsal cystic/lytic lesions vs., 1:390 134
Intraosseous hemangioma. See Hemangioma, erosive arthritis vs., 1:147,149
in traosseous. focal gigantism/macrodactyly related to, 111:180,
Intraosseous lipoma. See Lipoma, intraosseous. 181
Intraosseous neoplasms generalized osteoporosis vs., 11:82, 85
anterior knee pain related to, 111:85 linear ossification along anterior spine vs., 1:280,
calf pain related to, 1II:93, 97 281
groin/hip pain related to, 11I:49, 53 long bone diffuse cortical endosteal thickening
knee, anterior knee pain related to, 1Il:81 vs., 1:90
lateral hip pain related to, 11I:55, 57 long bone epiphyseal overgrowth/ballooning
medial ankle pain related to, 1II:109, 113 vs., 1:16
medial knee pain related to, 1II:87, 91 long bone growth plate premature physeal
rotator cuff symptoms vs., Ill:7 closure vs., 1:106, 107
thigh pain related to, [11:61 long bone irregular or stippled epiphysis vs.,
Intrapelvic mass, hip pain in elderly patients 1:12,14
related to, 111:69,73 long bone metaphyseal bands and lines VS.,
Intraspinal tumors, painful scoliosis vs., Ill:145, 1:26-27
147 long bone overtubulation VS., 1:102,104
Iodinated contrast, complications, intermuscular metacarpophalangeal-predominant arthritis vs.,
edema vs., 11:181, 183 1:192,193
Iron deficiency anemia, IIJ:152, 153 periostitis of multiple bones in children VS.,
1:130, 132
protrusio acetabuli vs., 1:334, 336
J radial-sided wrist pain related to, 111:42
Jaccoud arthropathy regional osteoporosis vs., 11:89, 91
mimic, metacarpophalangeal-predominant retrocalcaneal bursitis vs., 1:380,381
arthritis vs., I:] 92 sacroiliitis vs., bilateral asymmetric, 1:320
ulnar deviation of MCr joints vs., 1:264 short metacarpal/metatarsal bones vs., 1:260,
Jogger's foot/heel, lower extremity nerve 262
entrapment vs., 111:65 soft tissue contractures related to, III:171
Joint destruction, atrophic, 1:]58-]6] solid periostitis vs., 1:116, 119
Joint effusion squaring of one or more vertebra vs., 1:290, 292
mimic, anechoic mass vs., 11:194, 195 swelling and periostitis of digit (dactylitis) vs.,
unspecified, widened joint space related to, 1:266,267
1:171,173 tarsal cystic/lytic lesions vs., 1:392
Joint space, widened, 1:170-175 ulnar deviation of MCr joints vs., 1:264
Juvenile aponeurotic fibroma, bizarre horizontal unilateral short limb related to, 1I1:172, 175
periosteal reaction vs., 1:123, 124 wrist pain related to
XXVI
INDEX
radial-sided, 11I:42, 45 lateral hip pain related to, 111:56
ulnar-sided, 111:36 lateral hip pain vs., 111:54
juvenile rheumatoid arthritis. See juvenile snapping hip related to, 111:58
idiopathic arthritis. shoulder instability related to, 111:8,9-10
juxtacortical chondroma. See Chondroma, Labroligamentous periosteal sleeve avulsion,
periosteal. anterior, anteroinferior labral/capsule injury
vs., 111:12, 13
Labrum
K anterosuperior, variations/pathology, 1:218-221
Kaposi sarcoma, subcutaneous mass vs., 11:167 labral/capsule injury, anteroinferior, 111:12-13
Kidney. See Renal entries. pseudo-SLAP lesion, anterosuperior labral
Kiloh Nevin syndrome, elbow/wrist nerve variations/pathology vs., 1:219
entrapment vs., 11I:29 SLAP lesions
Klinefelter syndrome, forearm deformity vs., 1:229 type I-IV, 1:218-219, 220
Klippel-Trenaunay-Weber syndrome type V-X, 1:219, 220
focal gigantism/macrodactyly related to, 111:181 sublabral foramen
hemihypertrophy related to, 111:178, 179 anterosuperior labral variations/pathology
soft tissue mass of finger vs., 1:241,245 vs., 1:218
Knee. See also Arthroplasty components; Hardware with superior sublabral recess (sulcus),
failure; Meniscus. anterosuperior labral variations/
arthritis pathology vs., 1:219, 221
anterior knee pain related to, 11I:80, 82 superior sublabral recess (sulcus), anterosuperior
calf pain related to, 111:92 labral variations/pathology vs., 1:218,219
genu valgum (knock knees) vs., 1:370 Langerhans cell histiocytosis
medial knee pain related to, 111:86 benign osseous lesions with aggressive
fluid collections, 1:356-361 appearance vs., 11:50, 52
genu valgum (knock knees), 1:370-371 childhood platyspondyly vs., 1:284, 285
genu varum (bow leg deformity), 1:372-373 childhood polyostotic lesions vs., 11:8, 10
intercondylar notch enlargement, distal femur, flat bones with focally expanded or bubbly
1:346-347 lesion vs., 1:3
lipoma arborescens flat bones with permeative lesions vs., 1:6, 9
anterior knee pain related to, 111:81,85 lesions originating in vertebral body vs., 1:301,
bone lesions with bright Tl signal vs., 11:147, 304
149 long bone diaphyseal lesions vs.
intraarticular mass vs., 1:203, 205 aggressive, child, 1:74, 76
widened joint space related to, 1:171, 175 central, non-aggressive, 1:66, 68
pain cortically based, lytic, 1:85, 89
anterior, III:80-85 long bone epiphyseal/apophyseal/subchondral
medial, III:86-91 lytic lesion vs., 1:23, 24
painful knee replacement, 111:98-103 long bone metaphyseal lesions vs.
patellar lytic lesions, 1:348-351 central
synovitis, knee fluid collections vs., 1:356, 358 aggressive, 1:41, 43
Kniest dysplasia non-aggressive, 1:35, 37
childhood platyspondyly vs., 1:285 cortically based, 1:57, 59
dwarfism with major spine involvement vs., eccentric
111:184 aggressive, 1:52-53, 54
dwarfism with short extremities vs., 111:186, 187 non-aggressive, 1:49, 51
patellar lytic lesions vs., 1:349,351
phalangeal cystic/lytic lesions vs., 1:253, 257
L sclerotic bone lesion with central lucency vs.,
Labral cyst 11:33,35
cystic masses vs., II:160, 162 sequestration vs., 11:36,38
shoulder fluid collections vs., 1:222,224 solitary geographic lytic lesions vs., II:14, 17
Labral tear solitary rib lesion vs., 1:313,315
hip symphysis pubis widening vs., 1:327, 329
etiology, 1:340--345 vertebral body sclerosis vs., 1:292, 295
groin/hip pain related to, 111:48, 51 Larsen syndrome, abnormal radiocarpal angle vs.,
1:235,237
INDEX
Lead poisoning polyostotic lesions vs.
anemia with musculoskeletal manifestations vs., adult, 1I:2-3, 6
111:152,154 childhood, [[:8, 11
delayed bone age vs., 11:104, 105 superscan vs., [[:204, 205
Legg-Calve-Perthes disease Ligament injury
abnormal epiphyseal marrow signal vs., 11:132, tendon/ligament microtrauma, with
134 calcification, enthesopathy vs., 11:96, 98
avascular necrosis related to, 1ll:159 widened joint space related to, 1:170, 171
coxa magna deformity vs., 1:338,339 Ligamentum teres tear, snapping hip related to,
hip labral tear related to, [:341, 343 111:58
in teenagers, 111:151 Limbus vertebra (mimic), lesions originating in
long bone epiphyseal sclerosis/ivory vs., [:19, 21 vertebral body vs., 1:300, 303
long bone growth plate widened physis vs., Linea aspera hypertrophy (mimic), bone within
1:108-109,110 bone appearance vs., 1I:77, 79
long bone irregular or stippled epiphysis vs., Linear and curvilinear calcification, 11:116-121
1:12, 14 Linear ossification along anterior spine, 1:280-281
unilateral short limb related to, H!:l72, 174 Lipodystrophy, subcutaneous mass vs., 11:167
widened joint space related to, [:171,175 Lipohemarthrosis, soft tissue lesions with fluid/
Leiomyoma fluid levels vs., 1I:154, 156
deep, soft tissue ossification vs., [[:106 Lipoma
subcutaneous mass vs., II: 170 atypical, subcutaneous mass vs., 11:167
Leiomyosarcoma, soft tissue lesions with fluid/fluid in traosseous
levels vs., 11:154 increased marrow fat vs., 11:136, 138
LEOPARD syndrome, abnormal radiocarpal angle long bone central metaphyseal lesion vs.,
vs., 1:235 non-aggressive, 1:35, 37
Leprosy matrix-containing bone lesions vs., 11:48
acroosteolysis vs., 1:247, 249 solitary geographic lytic lesions vs., 1I:l5, 18
arthritis mutilans vs., 1:163 solitary sclerotic bone lesion vs., 11:23
linear and curvilinear calcification vs., 11:117, target lesions of bone vs., 11:40, 41
121 tarsal cystic/lytic lesions vs., 1:390, 392
periarticular calcification vs., 1:187, 191 parosteal
soft tissue contractures related to, [[[:170 bizarre horizontal periosteal reaction vs.,
Leriche syndrome, thigh pain related to, [[[:61 1:122, 124
Leri-Weill dyschondrosteosis. See long bone surface (juxtacortical) lesion vs.,
Dyschondrosteosis. 1:61,65
Lesch-Nyhan syndrome, acroosteolysis vs., 1:247 soft tissue neoplasms with calcification vs.,
Leukemia 11:123, 125
aggressive periostitis vs., 1:113 soft tissue
bone marrow edema syndromes vs., 1I:127 bone lesions with bright T1 signal vs., 11:146,
bone marrow hyperplasia vs., 11:141, 143 147
bone within bone appearance vs., 1I:76 soft tissue mass of finger vs., 1:241
childhood platyspondyly vs., 1:284, 286 soft tissue mass of foot vs., 1:382, 385
flat bones with permeative lesions vs., 1:7, 10 subcutaneous mass vs., 11:166, 168
long bone central metaphyseal lesion vs., soft tissue ossification vs., II:I07
aggressive, 1:41,43 spindle cell, subcutaneous mass vs., 11:170
long bone diaphyseal lesion vs., aggressive, Lipoma arborescens, knee
child, 1:74, 76 anterior knee pain related to, 111:81,85
long bone metaphyseal bands and lines vs., bone lesions with bright Tl signal vs., 11:147
1:26,29 intraarticular mass vs., 1:203,205
medial metaphyseal erosion of proximal widened joint space related to, !:l71, 175
humerus vs., 1:214,215 Lipomatosis
metastatic, bone cancer vs., 11:57 mimic, hemihypertrophy related to, 11I:l78
mimic, generalized increased bone density in nerve
child vs., 11:64 bone lesions with bright Tl signal vs., 11:147,
nonarticular clavicular lesions vs., 1:209, 211 149
periostitis of multiple bones/acropachy vs., enlarged peripheral nerves vs., II: 187, 189
1:127 Lipomatous tumor, atypical, bone lesions with
bright Tl signal vs., 11:146, 147
INDEX
Liposarcoma central
atypical, subcutaneous mass vs., 11:167 aggressive, 1:40-43
enlarged muscle vs., 11:175 non-aggressive, 1:34-39
myxoid, bone lesions with bright Tl signal vs., cortically based, 1:56-59
11:146, 148 eccentric
soft tissue lesions vs. aggressive, 1:52-55
bone lesions with bright Tl signal vs., 11:146, non-aggressive, 1:48-51
148 Long thoracic nerve syndrome, nerve entrapment
soft tissue neoplasms with calcification, of shoulder vs., 111:14
11:123, 124 Loose bodies
with fluid/fluid levels, 11:154 anterior ankle pain/impingement related to,
soft tissue ossification vs., 11:107, 109 11I:105, 107
Liposclerosing myxofibrous tumor calcified intraarticular body/bodies vs., 1:180,
increased marrow fat vs., 11:137, 139 18]
long bone central metaphyseal non-aggressive hip, snapping hip related to, TII:58, 59
lesion vs., 1:38 intraarticular low signal material vs., Il:190, 192
long bone eccentric metaphyseal non-aggressive intraarticular mass vs., 1:202, 203
lesion vs., 1:49, 51 mimic, sclerotic bone lesion with central
matrix-containing bone lesions vs., 11:48 lucency vs., 11:32-33, 35
solitary sclerotic bone lesion vs., 11:21, 25 nodular calcification vs., 11:110, 112
target lesions of bone vs., 11:40, 42 soft tissue ossification vs., 11:106
Lisfranc ligament disruption, traumatic, pes Lower extremities. See a/50 Ankle; Foot; Hip; Knee.
planovalgus (flatfoot) vs., 11I:133, 135 calf pain, 111:92-97
Little Leaguer's elbow, medial elbow pain related dwarfism with short extremities, 111:186-187
to, 111:23 extraarticular popliteal mass, 1:362-365
Liver disease, chronic, rickets and osteomalacia intercondylar notch enlargement, distal femur,
related to, 111:166, 168 1:346-347
Long bones nerve entrapment, 111:64-67
diffuse cortical/endosteal thickening, 1:90-93 thigh pain, 111:60-63
growth plate tibial bowing, 1:352-355
premature physeal closure, 1:106-107 Lunate injuries, avascular necrosis related to,
widened physis, 1:108-111 111:156, 158
overtubulation, 1:102-105 Lung carcinoma, metastatic
surface (juxtacortical) lesion, 1:60-65 bone cancer vs., 11:56, 57-58
tibial metadiaphyseal cortically based lesion, multiple sclerotic bone lesion vs., 11:28
1:94-95 Lunotriquetral instability
undertubulation, 1:96-101 ulnar-sided pain wrist related to, 111:36,39
Long bones, diaphyseal lesions wrist clicking/clunking/instability related to,
aggressive 11I:32, 34
adult, 1:73 Lupus erythematosus, systemic. See Systemic lupus
child, 1:74-77 erythematosus.
with endosteal thickening, 1:78-79 Lymph node (mimic), extraarticular popliteal mass
central, non-aggressive, 1:66-69 vs., 1:363
cortically based Lymphangioma
lytic, 1:84-89 cystic (mimic), enlarged peripheral nerves vs.,
sclerotic, 1:80-83 11:187, 189
Long bones, epiphyseal cystic masses vs., 11:161, 164
epiphyseal/apophyseal/subchondral lytic lesion, focal gigantism/macrodactyly related to, 111:180
1:22-25 mimic, hemihypertrophy related to, 111:178,179
irregular or stippled, 1:12-15 Lymphatic malformations, soft tissue lesions with
overgrowth/ballooning, 1:16-17 fluid/fluid levels vs., 11:154, 156
sclerosis/ivory, I:18-21 Lymphocele, anechoic mass vs., 11:194
Long bones, metaphyseal Lymphoma
bands and lines, 1:26-29 aggressive periostitis vs., 1:113, 115
cupping, 1:30-31 bone marrow edema syndromes vs., 11:127
fraying, 1:32-33 enlarged muscle vs., 11:174
Long bones, metaphyseal lesions flat bones with permeative lesions vs., 1:6-7, 10
bubbly, 1:44-47 . lesions crossing disc space vs., 1:268,269
XXIX
INDEX
>< lesions originating in vertebral body vs., 1:300- polyostotic lesions vs.
QJ
"'0 301,303 adult, 11:7
= long bone diaphyseal aggressive lesions vs.
adult, 1:70, 72
childhood, 11:12
short metacarpal/metatarsal bones vs., 1:261,
child, 1:74-75, 76 263
with endosteal thickening, 1:78, 79 tibial bowing vs., 1:353
long bone eccentric metaphyseal aggressive unilateral short limb related to, 111:173,177
lesion vs., 1:53, 55 Malabsorption, intestinal, rickets and osteomalacia
long bone epiphyseal/apophyseal/subchondral related to, 111:166,168
lytic lesion vs., 1:23,24 Malignant fibrous histiocytoma
metastatic adult, 1:71, 73
bone cancer vs., 11:56-57, 58 aggressive periostitis vs., 1:112, 114
multiple sclerotic bone lesion vs., 11:30 child, 1:75, 77
multifocal enlarged muscle vs., 1l:175
adult polyostotic lesions vs., 11:2-3, 6 flat bones with permeative lesions vs., 1:6, 9
childhood polyostotic lesions vs., 11:9, 11 long bone central metaphyseal aggressive lesion
nonarticular clavicular lesions vs., 1:209,211 vs., 1:40-41, 42
patellar lytic lesions vs., 1:349 long bone eccentric metaphyseal aggressive
sequestration vs., 11:36, 38 lesion vs., 1:53, 55
solitary sclerotic bone lesion vs., 11:25 matrix-containing bone lesions vs., 11:45, 48
subcutaneous mass vs., 11:169 sequestration vs., 11:36,38
superscan vs., 11:204 soft tissue lesions with fluid/fluid levels vs.,
supra-acetabular iliac destruction vs., 1:331, 333 11:154
vertebral body sclerosis vs., 1:292, 295 soft tissue mass of finger vs., 1:241
Lytic lesions, solitary geographic, 11:14-19 soft tissue neoplasms with calcification vs.,
11:123, 124
subcutaneous mass vs., 11:167, 169
M Malnutrition
Macrodactyly, 111:180-183 generalized osteoporosis vs., II :82, 84
Macrodystrophia lipomatosa long bone metaphyseal bands and lines vs., 1:26
enlarged peripheral nerves vs., 11:187, 189 Marfan syndrome
focal gigantism/macrodactyly related to, abnormal radiocarpal angle vs., 1:234, 236
111:180-181,182 arachnodactyly vs., 1:238
soft tissue mass of foot vs., 1:383,387 pes planovalgus (flatfoot) vs., 111:133, 135
Madelung deformity phalanges, long bone overtubulation vs., 1:103,
abnormal radiocarpal angle vs., 1:234, 235 104
forearm deformity vs., 1:228,230 shoulder instability related to, Ill:9
wrist clicking/clunking/instability related to, superior rib notching vs., 1:310
111:33 symphysis pubis widening vs., 1:327
wrist pain related to widened joint space related to, 1:171, 175
radial-sided, 111:43 Mastocytosis
ulnar-sided, 111:37, 41, 47 generalized increased bone density vs., adult,
Maffucci syndrome IJ:61,63
abnormal radiocarpal angle vs., 1:234 generalized osteoporosis vs., 11:83, 87
focal gigantism/macrodactyly related to, 111:181, multiple sclerotic bone lesion vs., 11:31
183 solitary sclerotic bone lesion vs., 11:21,25
forearm deformity vs., 1:228,231 superscan vs., 11:204, 205
long bone central metaphyseal non-aggressive vertebral body sclerosis vs., 1:293, 297
lesion vs., 1:39 Matrix-containing bone lesions, 11:44-49
long bone growth plate premature physeal Medial collateral ligament. See Collateral ligament,
closure vs., 1:106, 107 medial.
long bone metaphyseal bubbly lesion vs., 1:47 Median neuropathy, medial elbow pain related to,
long bone undertubulation vs., 1:97, 101 111:23,25
matrix-containing bone lesions vs., 11:44 Mediterranean fever, familial, arthritis with
nodular calcification vs., 11:114 osteopenia vs., 1:139
periarticular calcification vs., 1:187, 191 Medulloblastoma, metastatic
phalangeal cystic/lytic lesions vs., 1:253,257 bone cancer vs., 11:57, 58
xxx
INDEX
multiple sclerotic bone lesion vs., 11:29 flounce (mimic), meniscal size alteration vs.,
Melanoma 1:367,369
metastatic, bone cancer vs., 11:57, 58 fragments, intraarticular mass vs., 1:202-203,
soft tissue lesions with predominately low Tl & 204
T2 signal vs., 1l:151 intraarticular air (mimic), meniscal size
soft tissue target lesions vs., 11:158 alteration VS., 1:367, 369
subcutaneous mass vs., 11:167, 169 ligament merging with lateral meniscus
Melorheostosis (mimic), meniscal size alteration vs., 1:367,
acroosteosclerosis vs., 1:251 369
childhood polyostotic lesions vs., 1l:12 small anterior root, medial meniscus (mimic),
generalized increased bone density in child vs., meniscal size alteration VS., 1:367
11:65 Menkes kinky-hair syndrome. See Copper
long bone cortically based sclerotic diaphyseal deficiency.
lesion vs., 1:81, 83 Meralgia paresthetica
long bone diffuse cortical endosteal thickening lateral hip pain related to, 11J:55
vs., 1:90,92 lower extremity nerve entrapment vs., 111:64
mimic, solid periostitis vs., 1:117, 120 Mesenchymal chondrosarcoma, soft tissue
multiple sclerotic bone lesion vs., 11:27, 29 neoplasms with calcification vs., 11:l25
nodular calcification vs., 11:111 Mesomelic dysplasia
sclerosing dysplasias vs., 11:68, 70 abnormal radiocarpal angle vs., 1:237
vertebral body sclerosis vs., 1:297 dwarfism with short extremities vs., 111:186
Meningocele, cavus foot deformity related to, forearm deformity VS., 1:229
111:137 Metacarpal/metatarsal, short, 1:260-263
Meningococcemia Metacarpophalangeal joints, ulnar deviation,
acroosteolysis vs., 1:247 1:264-265
long bone growth plate premature physeal M etacarpophalangeal-predom ina n t a rth ri tis,
closure vs., 1:107 1:192-193
mimic, long bone epiphyseal overgrowth/ Metadiaphyseal cortically based lesion, tibial,
ballooning VS., 1:17 1:94-95
unilateral short limb related to, 11l:173, 175 Metaphyseal bar, congenital foot deformity vs.,
Meningomyelocele, muscle atrophy vs., 11:177, 179 1ll:139, 141
Meniscal cyst Metaphyseal chondrodysplasia
anterior knee pain related to, 11I:80, 82 long bone metaphyseal fraying vs., 1:32
cystic masses VS., 11:160, 162 mimic, rickets and osteomalacia vs., 111:167
intrameniscal, meniscal size alteration vs., 1:367, tibial bowing vs., 1:353
369 Metaphyseal dysplasia
knee fluid collections vs., 1:356, 358 long bone growth plate widened physis vs.,
medial knee pain related to, 1l1:86, 88 1:109
Meniscalossicle long bone metaphyseal cupping vs., 1:30,31
calcified intraarticular body/bodies vs., 1:181, Metaphyseal erosion, medial, of proximal
183 humerus, 1:214-215
meniscal size alteration vs., 1:367, 369 Metaphyseal fracture
Meniscal tears child abuse, long bone metaphyseal fraying vs.,
anterior knee pain related to, 111:80, 82 1:32,33
bucket handle long bone metaphyseal cupping vs., 1:30
meniscal size alteration vs., 1:367,368 Metaphyseal lesions, long bones
with flipped fragment (mimic) bubbly, 1:44-47
alteration of meniscaJ size vs., 1:366 central
meniscal size alteration vs., 1:368 aggressive, 1:40-43
medial knee pain related to, 111:86,88 non-aggressive, 1:34-39
Meniscus cortically based, 1:56-59
alteration of size, 1:366-369 eccentric
degeneration, alteration of meniscal size vs., aggressive, 1:52-55
1:367 non-aggressive, 1:48-51
discoid, alteration of meniscal size vs., 1:366 Metaphysis, long bones
extrusion (mimic), alteration of meniscal size bands and lines, 1:26-29
vs., 1:367 cupping, 1:30-31
XXXI
INDEX
fraying, 1:32-33 long bone metaphyseal bubbly lesion vs.,
Metastatic calcification. See Calcification, 1:44,46
metastatic. transitional cell carcinoma, bone cancer vs.,
Metastatic disease 11:57
adjacent to arthroplasty, arthroplasty with Iytic/ treated, solid periostitis vs., 1:1l7, 120
cystic lesions vs., 1:206,207 uterine carcinoma, bone cancer vs., 11:57
aggressive periostitis vs., I:112-113, 114 Metatarsal bones
blastic, vertebral body sclerosis vs., 1:292, 294 fractures
bone, 11:56-59 insufficiency, diabetic foot complications vs.,
bone marrow. See Bone marrow metastases. 11I:143
carcinoid, multiple sclerotic bone lesion vs., lateral ankle pain related to, 111:114,115
11:31 short, 1:260-263
childhood platyspondyly vs., 1:284 Metatarsus adductus, congenital foot deformity vs.,
diffuse, superscan vs., 11:204 111:138
Ewing's sarcoma. See Ewing sarcoma, metastatic. Metatropic dwarf, childhood platyspondyly vs.,
hemorrhagic, soft tissue lesions with 1:285
predominately low T1 & T2 signal vs., Methotrexate complications, periostitis of multiple
11:151 bones in children vs., 1:131
lesions crossing disc space vs., 1:269 Midcarpal instability, palmar, 111:32
lesions originating in vertebral body vs., 1:300, Milwaukee shoulder (hydroxyapatite deposition
302 disease), rotator cuff symptoms vs., 111:5
long bone metaphyseal bands and lines vs., 1:27 Mixed connective tissue disease
lung carcinoma arthritis with osteopenia vs., 1:139
bone cancer vs., 11:56,57-58 nodular calcification vs., 11:110-111
multiple sclerotic bone lesion vs., 11:27,28 ulnar deviation of MCr joints vs., 1:264
lymphoma Monoarthritis, 1:198-201
bone cancer vs., 11:56-57,58 Morquio syndrome
multiple sclerotic bone lesion vs., 11:30 abnormal radiocarpal angle vs., 1:237
medulloblastoma bullet shaped vertebra/anterior vertebral body
bone cancer vs., 11:57, 58 beaking vs., 1:282, 283
multiple sclerotic bone lesion vs., 11:29 dwarfism with major spine involvement vs.,
nonarticular clavicular lesions vs., 1:208, 210 111:184, 185
osteolytic, symphysis pubis widening vs., 1:326, Morton neuroma
328 ball of foot pain related to, 111:126, 128
osteosarcoma enlarged peripheral nerves vs., 11:187, 188
bone cancer vs., 11:57, 58 lower extremity nerve entrapment vs., 111:64,66
childhood polyostotic lesions vs., 11:12 soft tissue mass of foot vs., 1:382, 385
multiple sclerotic bone lesion vs., 11:29 Mucoid cysts, soft tissue mass of finger vs., 1:240
soft tissue ossification vs., 1I:107, 109 Mucolipidosis II and III, dwarfism with short ribs
renal cell carcinoma vs., 111:188
flat bones with focally expanded or bubbly Mucopolysaccharidoses
lesion vs., 1:2, 4 abnormal radiocarpal angle vs., 1:237
long bone metaphyseal bubbly lesion vs., childhood platyspondyly vs., 1:284, 286
1:44,46 dwarfism with short ribs vs., 111:188, 189
sclerotic long bone growth plate widened physis vs.,
mimic, sclerosing dysplasia vs., 11:68, 70 1:109,111
multiple sclerotic bone lesion vs., 1I:26 long bone undertubulation vs., 1:96,98
soft tissue target lesions vs., 11:158 nonarticular clavicular lesions vs., 1:209,211
solitary rib lesion vs., 1:312,314 painful or enlarged sternoclavicular joint vs.,
subcutaneous, soft tissue mass of finger vs., 111:2
1:241,245 short metacarpal/metatarsal bones vs., 1:261,
subcutaneous mass vs., 11:167, 170 262
thigh pain related to, 111:60,63 Multicentric reticulohistiocytosis. See
thyroid Reticu loh istiocytosis, 111 ul ticen tric.
bone cancer vs., 11:56, 58 Multiple epiphyseal dysplasia
flat bones with focally expanded or bubbly abnormal radiocarpal angle vs., 1:234, 236
lesion vs., 1:2, 4 dwarfism with short extremities vs., 111:186
XXXII
INDEX
irregular or stippled long bone epiphysis vs., enlarged muscle vs., 11:173
1:13 long bone overtubulation vs., 1:103
Multiple hereditary exostosis muscle atrophy vs., 11:177, 179
abnormal radiocarpal angle vs., [:234, 236 Mycobacterium marinum, swelling and periostitis
forearm deformity vs., 1:228, 230 of digit (dactylitis) vs., 1:266
long bone undertubulation vs., 1:96, 97 Mycosis fungoides, subcutaneous mass vs., 11:171
mimic, superior rib notching vs., 1:311 Myelofibrosis
polyostotic lesions vs. abnormal epiphyseal marrow signal vs., 11:133,
adult, 11:5 135
childhood, 11:8, 11 anemia with musculoskeletal manifestations vs.,
short metacarpal/metatarsal bones vs., 1:261, 111:152-153, 154-155
Multiple myeloma generalized increased bone density vs., adult,
fish (biconcave) or H-shaped vertebra, 1:288, 289 11:60, 62
flat bones with permeative lesions vs., 1:7, 10 superscan vs., Il:204
generalized osteoporosis vs., 11:82, 84 vertebral body sclerosis vs., 1:293, 296
lesions crossing disc space vs., 1:268 Myeloma, plasma cell, vertebral body sclerosis vs.,
lesions originating in vertebral body vs., 1:300, 1:293
303 Myocardial infarction, soft tissue uptake on bone
long bone central metaphyseal aggressive lesion scan vs., 11:200
vs., 1:40, 42 Myonecrosis
long bone diaphyseal aggressive adult lesion vs., calcific
1:70,72 calf pain related to, 111:92,95
nonarticular clavicular lesions vs., 1:208 mimic, heterotopic ossification vs., 111:163
osteopenia vs., IT:80, 81 nodular calcification vs., 11:111, 115
photopenic lesions and false negative scans vs., enlarged muscle vs., 11:172, 174
11:196,197 soft tissue uptake on bone scan vs., 11:199
polyostotic lesions vs., 11:2, 4 Myositis, infectious, intermuscular edema vs.,
solitary rib lesion vs., 1:312,314 II:181
subcutaneous mass vs., 11:167 Myositis ossificans
supra-acetabular iliac destruction vs., 1:330, 332 early, nodular calcification vs., 11:110, 112
tarsal cystic/lytic lesions vs., 1:391, 395 late, soft tissue ossification vs., II:106, 108
Muscle mimic
accessory, soft tissue mass of foot vs., 1:383, 387 long bone surface (juxtacortical) lesion vs.,
atony, widened joint space related to, 1:170, 171 1:60,62
atrophy, 11:176-179 soft tissue neoplasms containing calcification
enlargr"j,II:172-175 vs., II:122, 123
soren< jS, delayed onset, thigh pain related to, periarticular calcification vs., 1:186, 188
11I:62 soft tissue lesions with fluid/fluid levels vs.,
Muscle hypertrophy, 11:172-175 11:155
compensatory hypertrophy vs., 11:172, 173 Myxofibrosarcoma
differential diagnosis, II:172-175 acral myxoinflammatory fibroblastic, soft tissue
exercised-induced,II:172 mass of finger vs., 1:241
Muscle injury subcutaneous mass vs., 11:171
calf pain related to, 111:92 Myxofibrous tumor, liposclerosing. See
lower extremity, thigh pain related to, 11I:60, 62 Liposclerosing myxofibrous tumor.
mimic, anechoic mass vs., 11:194, 195 Myxoid liposarcoma, bone lesions with bright T1
muscle atrophy vs., 11:176, 179 signal vs., 11:146, 148
shoulder fluid collections vs., 1:223, 225 Myxoma
Muscle strain anechoic mass vs., 11:194, 195
calf pain related to, 111:92,94 mimic, cystic masses vs., 11:161, 165
hip
groin/hip pain related to, 111:48,51
lateral hip pain related to, 111:54,56 N
pain in elderly patients related to, 111:69,71 Nail patella syndrome (Fong)
Muscular dystrophy forearm deformity vs., 1:229,231
cavus foot deformity related to, 111:137 irregular or stippled long bone epiphysis vs.,
1:13,15
XXXIII
INDEX
)( mimic, dwarfism with horizontal acetabular Neurofibroma, cellular, soft tissue target lesions vs.,
Q.I
"C roof vs., 1lJ:191 Tl:158
c:: radial dysplasia/aplasia vs., 1:227 Neurofibromatosis
Navicular fractures enlarged peripheral nerves vs., 11:186, 187
anterior ankle pain/impingement related to, hemihypertrophy related to, 111:178-179
111:105, 107 inferior rib notching vs., 1:308, 309
avascular necrosis related to, 1Il:157 long bone central diaphyseal non-aggressive
medial ankle pain related to, 11I:111-112 lesion vs., 1:67
Necrotizing fasciitis, intermuscular edema vs., long bone overtubulation vs., 1:102, 104
11:181,183 muscle atrophy vs., 11:176, 179
Neonatal spine, normal, bone within bone pseudoarthrosis vs., 11:94, 95
appearance vs., 11:76, 77 subcutaneous mass vs., 11:167, 169
Neoplasms. See also specific type. superior rib notching vs., 1:310, 311
Achilles tendon thickening/enlargement vs., tibial bowing vs., 1:352-353, 354
1:374 unilateral short limb related to, 111:173, 176
anaplastic and aggressive, photopenic lesions with high thoracic scoliosis, painful scoliosis
and false negative scans vs., 11:196,197 vs., 111:145, 147
bone. See Bone neoplasms. Neurogenic claudication
intraarticular, shoulder instability related to, calf pain related to, 111:92
111:9 thigh pain related to, 111:60
intramuscular, enlarged muscle vs., 11:173 Neurogenic sarcoma, enlarged peripheral nerves
intraosseous. See Intraosseous neoplasms. vs., 11:189
intraspinal tumors, painful scoliosis vs., 111:145, Neurologic infection, heterotopic ossification vs.,
147 11I:162-163
malignant Neurologic injury, glenohumeral malalignment vs.,
necrotic, cystic masses vs., 11:161, 164 1:216
soft tissue lesions with fluid!f1uid levels vs., Neuroma, Morton. See Morton neuroma.
11:154, 156 Neuroma, traumatic
metastatic. See Metastatic disease. enlarged peripheral nerves vs., 11:187, 188
mixed fluid contents, soft tissue lesions with heel pain related to, 111:121
fluid!f1uid levels vs., 11:155 Neuropathic arthropathy
recurrence, subcutaneous mass vs., 11:167, 170 non-diabetic, arthritis with normal bone density
sesamoiditis vs., 1:258 vs., 1:135, 137
ulnar deviation of MCr joints vs., 1:265 osteoarthropathy, 1:164-165
with calcification, soft tissue uptake on bone Neuropathic Charcot joint. See Charcot joint,
scan vs., 11:199,201 neuropathic.
Nephrogenic systemic fibrosis Neuropathic disease, long bone metaphyseal
intermuscular edema vs., 11:181 fraying vs., 1:32
soft tissue con tractures related to, III: 170 Neuropathy
Nerve entrapment. See also Carpal tunnel muscle atrophy vs., 11:176
syndrome; Tarsal tunnel syndrome; Ulnar suprascapular, rotator cuff symptoms vs., 111:4,6
tunnel syndrome. "tall man" insensate, neuropathic
calf pain related to, 111:93 osteoarthropathy vs., 1:164, 165
elbow and wrist, 111:28-31 Niemann Pick disease, long bone undertubulation
groin/hip pain related to, 111:49 vs., 1:96
lower extremity, 111:64-67 Nodular calcification of soft tissue, 11:110-115
thigh pain related to, 111:61 Nodular synovitis
shoulder, 1Il:14-15 intraarticular low signal material vs., 11:191, 193
Nerve injury, unspecified, widened joint space intraarticular mass vs., 1:203, 204
related to, 1:171,174 Non-neoplastic structure
Nerve sheath tumors, soft tissue neoplasms with mixed fluid contents, soft tissue lesions with
calcification vs., 11:123, 125 fluid!f1uid levels vs., 11:154-155
Neuroblastoma soft tissue lesions with fluid/fluid levels vs.,
metastatic, bone cancer vs., 11:57,58 11:157
mimic, generalized increased bone density in Noonan syndrome
child vs., 11:64, 66 dwarfism with major spine involvement vs.,
soft tissue uptake on bone scan vs., 11:198-199, 111:184,185
203
XXXIV
INDEX
short metacarpal/metatarsal bones vs., 1:260 OPLL. See Ossification of posterior longitudinal ::s
Normal variant tendon. Q.
~
acroosteosclerosis vs., 1:250 Orbital pseudotumor, enlarged muscle vs., 11:173, ><
child (mimic), irregular or stippled long bone 175
epiphysis vs., 1:12, 13 Os trigonum syndrome, medial ankle pain related
humerus ("upper humeral notch"), medial to, 11I:109, ]]2
metaphyseal erosion of proximal humerus Osgood-Schlatter disease, anterior knee pain
vs., 1:214 related to, III:81, 85
inferior rib notching vs., 1:308 Osseous angiosarcoma. See Angiosarcoma, osseous.
long bone metaphyseal bands and lines vs., Osseous lesions, benign, with aggressive
1:26,28 appearance, 11:50-55
short metacarpal/metatarsal bones vs., 1:260 Osseous neoplasms. See Bone neoplasms.
squaring of one or more vertebra vs., 1:290, 292 Ossification
tenosynovitis/tenosynovial fluid vs., 11:184 acetabular rim, hip labral tear related to, 1:341,
344
heterotopic, 111:162-165
o differential diagnosis, III:] 62-] 65
Obturator tunnel syndrome, lower extremity nerve painful hip replacement related to, 11I:75, 78
entrapment vs., 111:65,67 soft tissue mass of finger vs., 1:240-241, 244
Occupational acroosteolysis, 1:247 soft tissue ossification vs., 11:106, 107-108
Ochronosis soft tissue uptake on bone scan vs., 11:202
ankylosis vs., 1:177 linear ossification along anterior spine, 1:280-
arthritis with osteopenia vs., 1:139, 14] 281
discal mineralization vs., 1:271, 273 ossification/calcification anterior to Cl, 1:274-
erosive arthritis vs., 1:147,151 275
generalized osteoporosis vs., 11:83, 86 paravertebral ossification and calcification,
linear ossification along anterior spine vs., 1:280, 1:276-279
281 posterior longitudinal tendon. See Ossification
pseudoarthrosis vs., 11:94 of posterior longitudinal tendon.
spinal osteophytes vs., 1:298, 299 post-traumatic, tendon and ligament
symphysis pubis with productive changes/ ossification vs., 1]:100, 10]
fusion vs., 1:324, 325 soft tissue, 11:106-109
Olecranon bursitis, 11I:26-27 differential diagnosis, 11:106-109
Olecranon fracture, medial elbow pain related to, soft tissue uptake on bone scan vs., 11:203
1ll:22, 24 tendon and ligament, 11:100-101
Oilier disease Ossification of posterior longitudinal tendon
abnormal radiocarpal angle vs., 1:234, 236 linear and curvilinear calcification vs., TI:120
focal gigantism/macrodactyly related to, 1ll:181, mimic
182-183 ankylosis vs., ]:177
forearm deformity vs., 1:228, 231 arthritis with normal bone density vs., 1:135,
long bone growth plate premature physeal 136
closure vs., 1:106, 107 arthritis with productive changes vs., 1:143
long bone metaphyseal lesions vs. soft tissue ossification vs., 11:106
bubbly, 1:47 tendon and ligament ossification vs., 11:100, 101
central, non-aggressive, 1:39 Ossified lesions, dense, soft tissue lesions with
long bone undertubulation vs., 1:97, ] 00 predominately low T1 & T2 signal vs., 11:150
matrix-containing bone lesions vs., 11:44, 49 Osteitis condensans, clavicle
phalangeal cystic/lytic lesions vs., [:253,257 nonarticular clavicular lesions vs., ]:209, 211
polyostotic lesions vs. painful or enlarged sternoclavicular joint vs.,
adult,II:7 111:2,3
childhood, 11:12 sclerosing dysplasias vs., 11:68, 71
short metacarpal/metatarsal bones vs., 1:261, solid periostitis vs., 1:117,120
262 solitary sclerotic bone lesion vs., 11:21, 25
tibial bowing vs., 1:353 Osteitis condensans ilii (mimic)
unilateral short limb related to, III:] 73,177 sacroiliitis vs., bilateral symmetric, 1:316, 318
Oncogenic osteomalacia, rickets and osteomalacia sclerosing dysplasias vs., 11:68, 70
vs., 111:166, 168 Osteitis pubis
groin/hip pain related to, 111:49,53
xxxv
INDEX
mimic, sclerosing dysplasias vs., 11:68, 71 fusion vs., 1:324
symphysis pubis widening vs., 1:326, 327 tarsal cystic/lytic lesions vs., 1:390
symphysis pubis with productive changes/ wrist pain related to
fusion vs., 1:324, 325 radial-sided, 111:42, 44
Osteoarth ritis ulnar-sided, 111:36, 38
ankle, medial ankle pain related to, 111:108, 111 Osteoarthropathy
arthritis with large subchondral cysts vs., 1:154, extra thoracic hypertrophic, periostitis of
155 multiple bones/acropachy vs., 1:126, 128
arthritis with normal bone density vs., 1:134, hypertrophic
135 bizarre horizontal periosteal reaction vs.,
arthritis with productive changes vs., 1:142, 143 1:122, 123
ball of foot pain related to, 111:126, 127 long bone diffuse cortical endosteal
carpal cystic/lytic lesions vs., 1:232 thickening vs., 1:90, 92
chondrocalcinosis vs., 1:184 mimic, generalized increased bone density
early, arthritis with preserved cartilage space vs., vs., adult, 11:60, 63
1:166, 167 periostitis of multiple bones in children VS.,
effusions, shoulder fluid collections vs., 1:222, 1:131
223 solid periostitis vs., 1:116, 118
epiphyseal marrow signal vs., abnormal, 11:132, hypertrophic pulmonary, periostitis of multiple
134 bones/acropachy vs., 1:126, 127
erosive neuropathic, 1:164-165
arthritis with normal bone density vs., 1:134, Osteoblastoma
135 benign osseous lesions with aggressive
erosive arthritis vs., I: 146, 148 appearance vs., 11:55
interphalangeal-predominant arthritis vs., bone lesions with fluid/fluid levels vs., 11:144
1:194,196 flat bones with focally expanded or bubbly
mixed erosive/productive arthritis vs., 1:152 lesion vs., 1:3
groin/hip pain related to, 111:48,50 lesions originating in posterior vertebral
hip elements vs., 1:306, 307
lateral hip pain related to, 111:56 long bone central metaphyseal lesion vs., non-
pain in elderly patients related to, 111:68, 70 aggressive, 1:39
rapidly destructive matrix-containing bone lesions vs., 11:49
atrophic joint destruction vs., I: 1 59, 161 painful scoliosis vs., 11I:145,147
bone marrow edema syndromes vs., paravertebral ossification and calcification vs.,
11:127, 129 1:277,279
hip labral tear related to, 1:340, 341 patellar lytic lesions vs., 1:349
interphalangeal-predominant arthritis vs., 1:194, sclerotic bone lesion with central lucency vs.,
195 11:33, 35
knee Osteochondral fracture, subchondral edematous-
anterior knee pain related to, 11I:80 like signal vs., 11:130
hip pain in elderly patients related to, 111:69 Osteochondral lesion
medial knee pain related to, 11I:86, 88 talar
long bone epiphyseal/apophyseal/subchondral anterior ankle pain/impingement related to,
lytic lesion vs., 1:22 111:105, 107
mimic, sacroiliitis vs. lateral ankle pain related to, 111:114-115,117
bilateral asymmetric, 1:320, 321 medial ankle pain related to, 111:108, 110
bilateral symmetric, 1:316, 318 tarsal cystic/lytic lesions vs., 1:393
unilateral, 1:322 Osteochondri~is dissecans, medial knee pain
painful or enlarged sternoclavicular joint vs., related to, 111:87, 90
III :2 Osteochondroma
phalangeal cystic/lytic lesions vs., 1:252,254 bursitis surrounding, knee fluid collections vs.,
post-traumatic, monoarthritis vs., 1:198,200 1:357,360
protrusio acetabuli vs., 1:334, 335 hip, snapping hip related to, 111:59
rotator cuff symptoms vs., 111:5, 7 lesions originating in vertebral body vs., 1:301,
sesamoiditis vs., 1:258 305
subchondral cyst, patellar lytic lesions vs., 1:348, long bone cortically based metaphyseal lesion
349 vs., 1:57, 58
symphysis pubis with productive changes/ matrix-containing bone lesions vs., 11:44, 46
XXXVI
INDEX
mimic, long bone surface (juxtacortical) lesion vs., long bone cortically based diaphyseal lesions
1:60,63 vs.
paravertebral ossification and calcification vs., lytic, 1:84, 86
1:277,278 sclerotic, 1:80-81, 82
polyostotic lesions vs. long bone cortically based metaphyseal
adult, 11:5 lesions vs., 1:56-57,58
childhood, 11:8, 11 matrix-containing bone lesions vs., 11:47
solitary rib lesion vs., 1:312-313, 314 mimic, sequestration vs., 11:36,37
Osteochondromatosis painful scoliosis vs., 111:144, 146
genu valgum (knock knees) vs., 1:371 periosteal, long bone surface (juxtacortical)
synovial. See Synovial osteochondromatosis. lesion vs., 1:61
Osteochondromatous proliferation, bizarre, long bone sclerotic bone lesion with central lucency vs.,
surface (juxtacortical) lesion vs., 1:61,64 11:32,33
Osteodystrophy. See Renal osteodystrophy. solid periostitis vs., 1:116, 119
Osteofibrous dysplasia solitary sclerotic bone lesion vs., 11:20,22
long bone cortically based metaphyseal lesion vs., target lesions of bone vs., JT:40, 4]
1:57,59 solitary sclerotic bone lesion vs., 11:20, 22
long bone diaphyseal cortically based lytic lesion Osteomalacia. See also Rickets and osteomalacia.
vs., 1:85,88 axial
solitary geographic lytic lesions vs., [1:15, 19 atypical, rickets and osteomalacia vs., 111:167
tibial bowing vs., 1:353, 355 vertebral body sclerosis vs., 1:293
tibial metadiaphyseal cortically based lesion vs., fish (biconcave) or H-shaped vertebra, 1:288
1:94,95 hypophosphatemic, linear ossification along
Osteogenesis imperfecta anterior spine vs., 1:280
childhood platyspondyly vs., 1:284, 286 oncogenic, rickets and osteomalacia vs., 111:166,
fish (biconcave) or H-shaped vertebra, 1:288 ]68
forearm deformity vs., 1:228, 23] protrusio acetabuli vs., 1:335
generalized osteoporosis vs., 11:83,87 Osteomyelitis
genu varum (bow leg deformity), 1:372,373 adult
hypertrophic callus formation vs., 11:74, 75 benign osseous lesions with aggressive
long bone growth plate widened physis vs., 1:109, appearance vs., 11:50,51
111 long bone central metaphyseal aggressive
long bone overtubulation vs., 1:103, 104-105 lesion vs., 1:40, 42
long bone undertubulation vs., 1:97, 100 long bone epiphyseal/apophyseal/
protrusio acetabuli vs., 1:335 subchondral lytic lesion vs., 1:23,25
pseudoarthrosis vs., 11:94, 95 polyostotic lesions vs., Ir:6
superior rib notching vs., 1:3]0 supra-acetabular iliac destruction vs., 1:330,
tibial bowing vs., [:353, 355 332
Osteogenesis imperfecta tarda, periostitis of multiple ankle, medial ankle pain related to, IrI:108
bones/acropachy vs., 1:127, 129 ball of foot pain related to, 111:126-127, 129
Osteoid osteoma. See Osteoma, osteoid. benign osseous lesions with aggressive
Osteolysis appearance vs., 11:50
metastatic, symphysis pubis widening vs., 1:326, bone marrow edema syndromes vs., 11:]27, 129
328 calcaneal erosions, posterior tubercle vs., 1:377,
post-traumatic, distal clavicular resorption vs., 379
1:212,213 chronic
Osteoma acroosteosclerosis vs., 1:250, 25]
long bone cortically based sclerotic diaphyseal long bone central diaphyseal non-aggressive
lesion vs., 1:81,83 lesion vs., 1:67, 68
long bone surface (juxtacortical) lesion vs., 1:61, 65 long bone central metaphyseal non-
mimic, sclerosing dysplasias vs., 11:68, 71 aggressive lesion vs., 1:34, 36
multiple sclerotic bone lesion vs., 11:27, 30 long bone cortically based sclerotic
osteoid diaphyseal lesion vs., 1:81,83
hip, in teenagers, 11I:149 long bone eccentric metaphyseal non-
in teenagers, 1II:151 aggressive lesion vs., 1:49, 51
lesions originating in posterior vertebral long bone undertubulation vs., 1:96-97, 99
elements vs., 1:306, 307 sclerotic bone lesion with central lucency vs.,
11:32,34
XXXVII
INDEX
>< sequestration vs., 11:36,37 photopenic lesions and false negative scans vs.,
ClJ
"'C solid periostitis vs., 1:116, 118 11:196
c::: target lesions of bone vs., Il:40, 42 retrocalcaneal bursitis vs., 1:380, 381
vertebral body sclerosis vs., 1:292, 295 septic joint vs., Il:130, 131
chronic recurrent multifocal solitary geographic lytic lesions vs., [[:14, 17
benign osseous lesions with aggressive solitary rib lesion vs., 1:312,314
appearance vs., 11:55 subchondral edematous-like signal vs., [[:130,
childhood polyostotic lesions vs., 11:12 131
long bone central metaphyseal aggressive tarsal cystic/lytic lesions vs., 1:390, 392-393
lesion vs., 1:41 thigh pain related to, 111:61,63
long bone diffuse cortical endosteal vertebral, granulomatous, paravertebral
thickening vs., 1:90,92 ossification and calcification vs., 1:277, 279
solid periostitis vs., 1:117, 121 vertebral body
diabetic foot complications vs., m:142, 143 lesions crossing disc space vs., 1:268
digital swelling and periostitis (dactylitis) vs., lesions originating in vertebral body vs.,
1:266,267 1:300
epiphyseal marrow signal vs., abnormal, 11:132, painful scoliosis vs., 111:144, 145
134 pyogenic, paravertebral ossification and
flat bones with permeative lesions vs., 1:6, 8 calcification vs., 1:276, 277
forearm deformity vs., 1:228, 230 with involucrum, bone within bone appearance
genu valgum (knock knees) vs., 1:371 vs., 11:76, 78
genu varum (bow leg deformity), 1:373, 375 Osteonecrosis
groin/hip pain related to, m:49 ankle, medial ankle pain related to, IIl:109, 113
heel pain related to, 111:120, 122 bisphosphonate-related, sequestration vs., 11:37,
hip pain in elderly patients related to, 111:69,73 39
irregular or stippled long bone epiphysis vs., capitellar, lateral elbow pain related to, 111:18,20
1:12, 15 epiphyseal marrow signal vs., abnormal, 11:132,
long bone diaphyseal lesions vs. 134
aggressive hip
adult, 1:70, 71 bone marrow edema syndromes vs., 11:126,
with endosteal thickening, 1:78 128
cortically based, lytic, 1:84, 86 groin/hip pain related to, 111:48,51
long bone eccentric metaphyseal lesion vs., pain in elderly patients related to, 111:69,72
aggressive, 1:52, 54 snapping hip related to, 111:58
long bone growth plate premature physeal knee, medial knee pain related to, m:87, 90
closure vs., 1:106 lesions originating in vertebral body vs., 1:300,
long bone growth plate widened physis vs., 303
1:108, 110 long bone epiphyseal sclerosis/ivory vs., 1:18, 19
multifocal, periostitis of multiple bones in long bone irregular or stippled epiphysis vs.,
children vs., 1:130, 132 1:12, 14
patellar lytic lesions vs., 1:349, 351 marrow fat increase vs., 11:137, 139
pediatric mimic
benign osseous lesions with aggressive arthritis with preserved cartilage space vs.,
appearance vs., 11:50, 52 1:167, 169
childhood polyostotic lesions vs., Jl:8, 10 with secondary osteoarthritis, arthritis with
generalized increased bone density vs., productive changes vs., 1:143, 145
[[:64-65, 67 photopenic lesions and false negative scans vs.,
long bone central metaphyseal aggressive 11:196, 197
lesion vs., 1:40,42 rad iation-i nd uced
long bone diaphyseal aggressive lesion vs., avascular necrosis related to, 111:157,159
1:74,75 benign osseous lesions with aggressive
long bone epiphyseal/apophyseal/ appearance vs., 11:51,53
subchondral lytic lesion vs., 1:22-23, 24 elbow deformities vs., 111:16
long bone metaphyseal fraying vs., 1:32,33 flat bones with permeative lesions vs., 1:7, 11
unilateral short limb related to, 11[:172, 174 heel pain related to, [11:121, 125
periostitis vs., aggressive, 1:113, 114-115 long bone central diaphyseal non-aggressive
phalangeal cystic/lytic lesions vs., 1:252, 255 lesion vs., 1:67, 69
INDEX
mimic, generalized increased bone density osteopenia vs., 1l:80
vs., 11:60,62 regional, 1]:88-91
nonarticular clavicular lesions vs., 1:208, 210 regional migratory, regional osteoporosis vs.,
superior rib notching vs., 1:310, 311 11:89,91
supra-acetabular iliac destruction vs., 1:330 senile
symphysis pubis widening vs., 1:326 fish (biconcave) or H-shaped vertebra, 1:288
rotator cuff symptoms vs., 111:5,6 generalized osteoporosis vs., 1l:82, 83
sesamoiditis vs., 1:258, 259 transient
short metacarpal/metatarsal bones vs., 1:260, hip, regional osteoporosis vs., 1l:89, 91
261 mimic, arthritis with osteopenia vs., 1:139,
tarsal cystic/lytic lesions vs., 1:390 141
thigh pain related to, 1Il:61, 63 Osteosarcoma
wrist conventional
clicking/clunking/instability related to, aggressive periostitis vs., I:112, 113
I1I:33, 35 extraarticular popliteal mass vs., 1:362, 364
radial-sided wrist pain related to, 111:43,47 flat bones with permeative lesions vs., 1:6, 8
ulnar-sided wrist pain related to, 1Il:37, 41 long bone central metaphyseal aggressive
Osteopathia striata lesion vs., 1:40, 42
long bone metaphyseal bands and lines vs., 1:27 long bone diaphyseal aggressive lesion vs.,
sclerosing dysplasias vs., II:69 1:71,73
Osteopenia, 11:80-81 long bone eccentric metaphyseal aggressive
with arthritis, 1:138-141 lesion vs., 1:52, 53-54
Osteopetrosis long bone epiphyseal sclerosis/ivory vs., 1:19,
anemia with musculoskeletal manifestations vs., 21
1II:153, 155 matrix-containing bone lesions vs., 11:45,47
bone within bone appearance vs., 11:76,77-78 solitary geographic lytic lesions vs., 11:15
generalized increased bone density vs. solitary sclerotic bone lesion vs., 11:20,23
adult, 11:61,63 extraskeletal
child, 11:65,67 soft tissue neoplasms with calcification vs.,
long bone epiphyseal sclerosis/ivory vs., 1:19, 21 11:123, 125
long bone metaphyseal bands and lines vs., 1:27 soft tissue ossification vs., 11:107,109
long bone undertubulation vs., 1:97, 100 high grade surface, long bone surface
sclerosing dysplasias vs., 11:69,72 (juxtacortical) lesion vs., [:61, 64
superscan vs., 11:204,205 lesions originating in vertebral body vs., ]:301,
vertebral body sclerosis vs., 1:293, 296 305
Osteophytes long bone diaphyseal aggressive lesion in child
spinal, 1:298-299 vs., 1:74, 76
talar beak vs., 1:388, 389 metastatic
Osteopoikilosis bone cancer vs., 11:57,58
acroosteosclerosis vs., 1:250 childhood polyostotic lesions vs., 11:12
long bone epiphyseal sclerosis/ivory vs., 1:19, 21 multiple sclerotic bone lesion vs., 11:29
multiple sclerotic bone lesion vs., 1l:27, 29 soft tissue ossification vs., 11:107, 109
sclerosing dysplasias vs., 11:68-69, 71 mimic, bizarre horizontal periosteal reaction vs.,
Osteoporosis 1:123, 124
disuse paravertebral ossification and calcification vs.,
benign osseous lesions with aggressive 1:277, 279
appearance vs., II:53 parosteal
cortical tunneling vs., 11:92 extraarticular popliteal mass vs., 1:362, 364
long bone metaphyseal bands and lines vs., long bone surface (juxtacortical) lesion vs.,
1:26,28 1:60,61-62
regional osteoporosis vs., 11:88,89-90 matrix-containing bone lesions vs., 1l:45, 48
generalized, I1:82-87 mimic, tibial metadiaphyseal cortically based
idiopathic juvenile lesion vs., 1:94, 95
childhood platyspondyly vs., 1:285 soft tissue ossification vs., 11:107, 109
generalized osteoporosis vs., 11:83,87 solitary sclerotic bone lesion vs., 1l:21, 24
increased marrow fat vs., 11:136, 137 patellar lytic lesions vs., 1:349
long bone metaphyseal bands and lines vs., 1:27 periosteal
XXXIX
INDEX
long bone surface (juxtacortical) lesion vs., generalized increased bone density vs., [[:60, 62
[:60-61,63 heel pain related to, [[1:121
matrix-containing bone lesions vs., 1I:45, 48 lesions originating in vertebral body vs., 1:300,
mimic 302
aggressive periostitis vs., 1:113, 115 long bone central metaphyseal non-aggressive
tibial metadiaphyseal cortically based lesion vs., 1:34,36
lesion vs., [:94, 95 long bone diaphyseal lesions vs.
soft tissue neoplasms with calcification vs., central, non-aggressive, [:66, 67
[[:125 cortically based
solitary sclerotic bone lesion vs., 1[:21,24 lytic, [:84, 86
soft tissue uptake on bone scan vs., [[:199, 203 sclerotic, 1:8]
solitary rib lesion vs., 1:313, 315 long bone diffuse cortical endosteal thickening
supra-acetabular iliac destruction vs., 1:331, 333 vs., 1:90, 91
surface, soft tissue neoplasms with calcification mimic, long bone undert.ubulation vs., 1:96, 98
vs., [[:125 multiple sclerotic bone lesion vs., 11:26, 28
telangiectatic nonarticular clavicular lesions vs., 1:208, 210
bone lesions with fluid/fluid levels vs., polyostotic lesions vs., [[:4
[1:144-145 protrusio acetabuli vs., 1:334, 336
long bone eccentric metaphyseal lesion vs. sclerotic bone lesion with central lucency vs.,
aggressive, 1:53, 55 [1:32,34
non-aggressive, 1:49 solitary geographic lytic lesions vs., 11:15, 18
solitary geographic lytic lesions vs., [1:15, 18 solitary sclerotic bone lesion vs., 11:21, 23
tarsal cystic/lytic lesions vs., 1:391 squaring of one or more vertebra vs., 1:290, 29]
vertebral body sclerosis vs., 1:293, 297 supra-acetabular iliac destruction vs., 1:330, 332
Osteosclerosis, intramedullary tarsal cystic/lytic lesions vs., 1:391, 395
long bone diffuse cortical endosteal thickening tibial bowing vs., [:352, 353
vs., 1:91, 93 vertebral body sclerosis vs., 1:292, 295
sclerosing dysplasias vs., 1l:69, 73 Paget sarcoma, flat bones with permeative lesions
Osteosclerotic dysplasia, generalized increased vs., 1:7,1]
bone density in child vs., 11:65 Pain, congenital insensitivity/indifference
Otopalatodigital syndrome, dwarfism with short acroosteolysis vs., 1:247
ribs vs., 1[[:188 arthritis mutilans vs., 1:162, 163
Otto disease in teenagers, [[1:151
hip labral tear related to, 1:341, 344 with Charcot neuropathy, neuropathic
protrusio acetabuli vs., 1:335, 337 osteoarthropathy vs., 1:164, 165
Overtubulation, long bones, 1:102-105 Paint gun injury, soft tissue mass of finger vs., 1:242
Oxalosis Pancoast tumor, solitary rib lesion vs., [:312, 314
bone within bone appearance vs., [[:77 Pancreatitis, chronic, rickets and osteomalacia
nonarticular clavicular lesions vs., 1:209 related to, 111:166
primary, long bone metaphyseal bands and lines Para neoplastic syndrome
vs., 1:27 chondrocalcinosis vs., [:185
periarticular calcification vs., 1:190
Paraplegia
p complications, superior rib notching vs., [:3]]
Pach yde rm operiostosis discal mineralization vs., 1:271
long bone diffuse cortical endosteal thickening linear ossification along anterior spine vs., 1:280
vs., 1:91 paravertebral ossification and calcification vs.,
periostitis of multiple bones/acropachy vs., 1:276,278
[:127, 129 with Charcot neuropathy, neuropathic
solid periostitis vs., 1:117,12] osteoarthropathy vs., 1:164, 165
Paget disease Parasites, nodular calcification vs., 11:111
benign osseous lesions with aggressive Paraspinal abnormalities
appearance vs., [1:54 linear ossification along anterior spine, 1:280-
bone within bone appearance vs., [[:76, 78 281
degeneration to osteosarcoma, matrix- ossification/calcification anterior to Cl, 1:274-
containing bone lesions vs., [[:49 275
fish (biconcave) or H-shaped vertebra, 1:288, 289 paravertebral ossification and calcification,
forearm deformity vs., 1:229, 231 1:276-279
xl
INDEX
Paraspinal muscle injury, painful scoliosis vs., multiple bones/acropachy, adult, 1:126-129
111:]45 physiologic
Paravertebral ossification and calcification, 1:276- lower extremity, solid periostitis vs., 1:] 17,
279 121
Parsonage-Turner syndrome periostitis of multiple bones in children vs.,
late, soft tissue contractures related to, J1I:170 1:130, 131
nerve entrapment of shoulder vs., 111:14, 15 solid, 1:116-121
Patella Peripheral nerve injury, muscle atrophy vs., 11:176,
bursitis (anterior), knee fluid collections vs., 178
1:356,358 Peripheral nerve sheath tumor
dorsal defect (mimic), patellar lytic lesions vs., benign
1:349, 351 enlarged peripheral nerves vs., 11:187, 188
fracture, anterior knee pain related to, 1II:80, 83 extraarticular popliteal mass vs., 1:362, 364
lytic lesions, 1:348-351 solitary geographic lytic lesions vs., 11:15, 19
subluxation, anterior knee pain related to, malignant
111:80, 83 enlarged peripheral nerves vs., 11:188-189
transient dislocation, anterior knee pain related extraarticular popliteal mass vs., 1:363,364
to, 111:80, 82 soft tissue lesions with fluid!f1uid levels vs.,
Patella alta, anterior knee pain related to, III:80, 83 11:155, 157
Patella baja, anterior knee pain related to, 11I:80, 83 soft tissue target lesions vs., 11:158, 159
Patellar tendon tears/tendinosis, anterior knee pain Peripheral nerves, enlarged, 11:186-189
related to, Ill:80-81, 84 Peroneal nerve
Patellofemoral syndrome, anterior knee pain entrapment, superficial, lower extremity nerve
related to, 111:80,81-82 entrapment vs., I11:65, 67
Pedicle. See Vertebral pedicle. injury, painful knee replacement related to,
Pelvic injury, symphysis pubis widening vs., 1:326, 11]:99
327-328 Peroneal tendon
Pelvicaliceal system, dilated, soft tissue uptake on subluxation, lateral ankle pain related to,
bone scan vs., 11:200 Ill:1l5, 118
Pelvis tendinosis/tear/tenosynovitis, lateral ankle pain
fibrous dysplasia, flat bones with focally related to, Ill: 114, 117
expanded or bubbly lesion vs., 1:2, 4 Peroneal tunnel syndrome, lower extremity nerve
groin/hip pain, 11I:48-53 entrapment vs., 1\I:64, 65
intrapelvic mass, hip pain in elderly patients Peroneus quartus muscle disorder, lateral ankle
related to, 111:69, 73 pain related to, 111:115
sacroiliitis Pertechnetate, gastric secretion of, soft tissue
bilateral asymmetric, 1:320-321 uptake on bone scan vs., 11:200
bilateral symmetric, 1:316-319 Perthes lesion, anteroinferior labral/capsule injury
unilateral, 1:322-323 vs., Ill: 12, 13
supra-acetabular iliac destruction, 1:330-333 Pes anserine bursitis
symphysis pubis medial, knee fluid collections vs., 1:356, 358-
widening, 1:326-329 359
with productive changes/fusion, 1:324-325 medial knee pain related to, 1l1:86, 89
Periarticular calcification, I:186-] 9] Pes cavus (mimic), congenital foot deformity vs.,
Pericardial effusion, malignant, soft tissue uptake 1Il:139, 141
on bone scan vs., 11:202 Pes planovalgus (flatfoot), 1Il:132-135
Perilunate instability, wrist c1icking/c1unking/ differential diagnosis, III: 132-135
instability related to, 111:32, 34 flexible
Periosteal reaction congenital foot deformity vs., 1l1:138, 139
bizarre horizontal, 1:122-]25 pes planovalgus (flatfoot) vs., 1II: 132, 133-
of newborn, physiologic (mimic), generalized 134
increased bone density vs., 11:64, 65 Pes planus (mimic), pes planovalgus (flatfoot) vs.,
Periostitis 1Il:132, 133
aggressive, 1:112-115 Phalangeal cystic/lytic lesions, 1:252-257
digits (dactylitis), 1:266-267 Phalanges. See Fingers and toes.
florid reactive, long bone surface (juxtacortical) Phenobarbital therapy, rickets and osteomalacia
lesion vs., 1:61, 64 related to, 1Il:166-167
multiple bones, child, 1:130-133 Phlebolith, nodular calcification vs., 11:110, 1]]
xli
INDEX
Photopenic lesions and false negative scans, Plantar fibromatosis
11:196-197 ball of foot pain related to, 111:127, 131
Physeal bar, elbow deformities vs., 111:16 soft tissue lesions with predominately low T1 &
Physeal fractures T2 signal vs., 11:152
advanced bone age vs., 11:103 Plantar plate
genu varum (bow leg deformity), 1:372 rupture, ball of foot pain related to, 111:127,
long bone growth plate widened physis vs., 130-131
1:108,109 tear, sesamoiditis vs., 1:258, 259
pediatric Plasma cell myeloma, vertebral body sclerosis vs.,
long bone metaphyseal fraying vs., 1:32, 33 1:293,296
unilateral short limb related to, 111:172, 173 Plasmacytoma
Physiologic periosteal reaction of newborn, flat bones with focally expanded or bubbly
generalized increased bone density in child vs., lesion vs., 1:2, 3
11:64,65 flat bones with permeative lesions vs., [:11
Pigmen ted villonodular synovi tis lesions originating in vertebral body vs., 1:301,
arthritis with large subchondral cysts vs., 1:155, 304
156 long bone central metaphyseal lesion vs.
arthritis with normal bone density vs., 1:135, aggressive, 1:41, 43
137 non-aggressive, 1:35, 37
arthritis with preserved cartilage space vs., 1:167 long bone diaphyseal aggressive lesion vs., 1:72
carpal cystic/lytic lesions vs., 1:232,233 solitary geographic lytic lesions vs., 11:14, 16
distal femur intercondylar notch enlargement supra-acetabular iliac destruction vs., 1:330, 332
vs., 1:346,347 Platyspondyly, childhood, congenital and
erosive arthritis vs., 1:146, 148 acquired, 1:284-287
extraarticular popliteal mass vs., 1:362, 364 Pleural effusion, malignant, soft tissue uptake on
in teenagers, 111:149, 150 bone scan vs., 11:202
intraarticular low signal material vs., 11:191, 193 Plica syndrome, medial
intraarticular mass vs., 1:202, 204 anterior knee pain related to, 111:81,84
knee pain related to medial knee pain related to, 1lI:87, 90
anterior, 111:81,84 POEMS syndrome
medial, 111:87,91 generalized increased bone density vs., adult,
long bone epiphyseal/apophyseal/subchondral 11:61,63
lytic lesion vs., 1:22, 24 multiple sclerotic bone lesion vs., 11:27, 31
monoarthritis vs., 1:199, 200 sclerosing dysplasias vs., [1:72
patellar lytic lesions vs., 1:349 sclerotic bone lesion with central lucency vs.,
soft tissue lesions with predominately low T1 & IT:33, 35
T2 signal vs., 11:150, 152 Poland syndrome, short metacarpal/metatarsal
soft tissue mass of foot vs., 1:382, 386 bones vs., 1:261
solitary geographic lytic lesions vs., 11:15 Polio
tarsal cystic/lytic lesions vs., 1:390, 392 cavus foot deformity vs., 111:136, 137
ulnar deviation of Mep joints vs., 1:264 discalmineralization vs., 1:271
widened joint space related to, 1:170, 173 long bone overtubulation vs., 1:102, 103
within bursa, knee fluid collections vs., 1:357, mimic, congenital foot deformity vs., 1lI:139,
361 141
Pilomatrixoma/pilomatrix carcinoma, muscle atrophy vs., II: 177, 179
subcutaneous mass vs., 11:167, 171 superior rib notching vs., 1:310
Piriformis syndrome, lower extremity nerve unilateral short limb related to, 111:173, 177
entrapment vs., 111:65,67 with prolonged immobilization, long bone
Plantar fascia rupture, heel pain related to, 111:120, metaphyseal cupping vs., 1:30
123 Polycythemia vera
Plantar fasciitis anemia with musculoskeletal manifestations vs.,
calcaneal erosions, posterior tubercle vs., 1:377, !I1:153
enthesopathy vs., 11:96, 98 Polymyalgia rheumatica, rotator cuff symptoms
heel pain related to, 111:120, 121 vs., /lI:5
soft tissue mass of foot vs., 1:382, 384 Polymyositis
Plantar fibroma, soft tissue mass of foot vs., 1:382, intermuscular edema vs., 11:181, 182
385
xlii
INDEX
periarticular calcification vs., 1:187, 189 Progeria
soft tissue lesions with fluid/fluid levels vs., dwarfism with major spine involvement vs.,
II: 154, 156 111:]84
thigh pain related to, 111:61,63 muscle atrophy vs., 11:177
Polyneuropathy, organomegaly, endocrinopathy, M superior rib notching vs., 1:310
proteins, skin changes. See POEMS syndrome. Progressive osseous heteroplasia, heterotopic
Polyostotic aggressive bone tumor, periostitis of ossification vs., 111:163
multiple bones in children vs., 1:130, 132 Progressive systemic sclerosis
Polyostotic lesions acroosteolysis vs., 1:246, 247
adult, 11:2-7 acroosteosclerosis vs., 1:250
child, 11:8-13 arthritis with osteopenia vs., 1:138-139, 140
Polyvinyl-chloride exposure, acroosteolysis vs., chondrocalcinosis vs., 1:184, 185
1:247,249 distal clavicular resorption vs., 1:212
Popliteal artery aneurysm erosive arthritis vs., 1:147, 151
extraarticular popliteal mass vs., 1:363, 365 linear and curvilinear calcification vs., II:117,
knee fluid collections vs., 1:357, 361 119
Popliteal cyst mimic, heterotopic ossification vs., 1lI:163
calf pain related to, 111:92,94 nodular calcification vs., 11:110, 112
cystic masses vs., 11:160, 162 ossification/calcification anterior to Cl vs.,
extraarticuJar popliteal mass vs., 1:362, 363 1:274,275
knee fluid collections vs., 1:356,357 paravertebral ossification and calcification vs.,
ruptured 1:277,278
extraarticular popliteal mass vs., 1:362, 363 periarticular calcification vs., 1:186, 189
intermuscular edema vs., 11:180, 18] soft tissue mass of finger vs., 1:240, 243-244
knee fluid collections vs., 1:356,357 Pronator syndrome, elbow/wrist nerve entrapment
synovitis, extraarticular popliteal mass vs., vs., !lI:28, 30-31
1:362,364 Prostaglandin complications
Popliteal entrapment syndrome, lower extremity long bone diffuse cortical endosteal thickening
nerve entrapment vs., 111:65 vs., 1:90,92
Popliteal mass, extraarticular, 1:362-365 mimic, generalized increased bone density in
Popliteus myotendinous injury, knee fluid child vs., II:64, 66
collections vs., 1:356, 359-360 periostitis of multiple bones in children vs.,
Posterior longitudinal tendon ossification. See 1:131,133
Ossification of posterior longitudinal tendon. Prostate carcinoma, metastatic, bone cancer vs.,
Post-operative changes 11:56,58
Achilles tendon thickening/enlargement vs., Proteus syndrome, focal gigantism/macrodactyly
1:374,375 related to, Ill: 181
clavicle, distal clavicular resorption vs., 1:212 Protrusio acetabuli, 1:334-337
fibrosis, anterior knee pain related to, 11I:81 differential diagnosis, 1:334-337
forearm deformity vs., 1:228, 230 secondary, hip labral tear related to, 1:341,344
heterotopic ossification vs., 111:162, 165 Proximal femur bone marrow edema syndromes,
inferior rib notching vs., 1:308, 309 11:126-129
intercondylar notch enlargement, distal femur, Prune belly syndrome (Eagle-Barrett syndrome)
1:346 symphysis pubis widening vs., 1:327
meniscal size alteration vs., 1:366, 368 with stylohyoid ligament ossification, tendon
muscle atrophy vs., 11:176,177 and ligament ossification vs., 11:100, 101
photopenic lesions and false negative scans vs., Pseudoachondroplasia
11:196 bullet shaped vertebra/anterior vertebral body
soft tissue lesions with predominately low T1 & beaking vs., 1:282, 283
T2 signal vs., 11:150, 151 childhood platyspondyly vs., 1:284, 286
soft tissue ossification vs., 11:107 dwarfism with short extremities vs., 111:186
superior rib notching vs., 1:311 irregular or stippled long bone epiphysis vs.,
Post-traumatic. See Trauma. 1:13
Pregnancy, symphysis pubis widening vs., 1:326 muscle atrophy vs., 11:177
Primitive neuroectodermal tumor, soft tissue Pseudoarthrosis, 11:94-95
lesions with fluid/fluid levels vs., 11:154 congenital
nonarticular clavicular lesions vs., 1:209
xliii
INDEX
tibial, unilateral short limb related to, 111:173, sacroiliitis vs.
176 bilateral asymmetric, 1:320
tibial bowing vs., 1:353, 355 bilateral symmetric, 1:317, 319
tibial fracture in, 11:95 unilateral, 1:322, 323
differential diagnosis, 11:94-95 "sausage digit," swelling and periostitis of digit
lesions crossing disc space vs., 1:268, 269 (dactylitis) vs., 1:266
Pseudo h ypopa rath yroi d ism solid periostitis vs., 1:116, 118
linear and curvilinear calcification vs., 11:121 squaring of one or more vertebra vs., 1:290
long bone metaphyseal bands and lines vs., 1:27 symphysis pubis with productive changes/
nodular calcification vs., 11:111, 115 fusion vs., 1:324
periarticular calcification vs., 1:187, 191 ulnar deviation of Mep joints vs., 1:264, 265
rickets and osteomalacia vs., III:167, 169 Pubalgia, groin/hip pain related to, 111:49
sequestration VS., 11:37, 39 Pulmonary blood flow, decreased, inferior rib
short metacarpal/metatarsal bones vs., 1:261, notching vs., 1:308
263 Pulmonary osteoarthropathy, hypertrophic,
target lesions of bone VS., 11:41,43 periostitis of multiple bones/acropachy vs.,
Pseudo- pseudo hypopara th yroid ism 1:126, 127
rickets and osteomalacia vs., III:167, 169 Pycnodysostosis
short metacarpal/metatarsal bones vs., 1:261, acroosteolysis vs., 1:247,249
263 generalized increased bone density vs.
Pseudo-SLAP lesion, anterosuperior labral adult, 11:61
variations/pathology vs., 1:219 child, 11:65, 67
Pseudotumor long bone epiphyseal sclerosis/ivory vs., 1:19
fibroosseous of digits, swelling and periostitis of long bone undertubulation vs., 1:97, 101
digit (dactylitis) VS., 1:266, 267 sclerosing dysplasias vs., 11:69, 73
hemophilia-related symphysis pubis widening vs., 1:327
supra-acetabular iliac destruction vs., 1:331 Pyle dysplasia, long bone undertubulation vs., 1:97
tarsal cystic/lytic lesions vs., 1:391, 393 Pyomyositis, enlarged muscle vs., 11:172, 174
orbital, enlarged muscle vs., 11:173, 175 Pyrophosphate arthropathy
Psoriatic arthritis arthritis with large subchondral cysts vs., 1:154,
acroosteolysis vs., 1:246-247,248 155-156
acroosteosclerosis vs., 1:250 arthritis with normal bone density vs., 1:135,
ankylosis vs., 1:176, 177 136
arthritis mutilans vs., 1:162 arthritis with productive changes vs., 1:142, 144
arthritis with normal bone density vs., 1:134- carpal cystic/lytic lesions vs., 1:232
135,136 chondrocalcinosis vs., 1:]84
arthritis with preserved cartilage space vs., 1:168 discal mineralization vs., 1:270, 273
arthritis with productive changes vs., 1:143, 144 early, arthritis with preserved cartilage space vs.,
ball of foot pain related to, III:127, 131 1:166, 168
calcaneal erosions, posterior tubercle vs., 1:376, erosive arthritis vs., 1:146-]47, 149
378 knee, anterior knee pain related to, IIl:80, 82
effusions, shoulder fluid collections vs., 1:222, linear ossification along anterior spine vs., 1:280
223 long bone epiphyseal/apophyseal/subchondral
enthesopathy vs., 11:97, 99 lytic lesion vs., 1:22, 24
erosive arthritis vs., 1:146, 148 medial knee pain related to, 111:89
groin/hip pain related to, 11[:48, 50 metacarpophalangeal-predominant arthritis vs.,
heel pain related to, III:121, 124 1:]92, 193
in teenagers, 111:148, 150 mimic, periarticular calcification vs., 1:186, 188
interphalangeal-predominant arthritis vs., I:194, mixed erosive/productive arthritis VS., 1:152
195 nodular calcification vs., [1:110, ] 11
linear ossification along anterior spine vs., 1:280 soft tissue mass of finger vs., 1:241
mixed erosive/productive arthritis vs., 1:152, 153 solitary geographic lytic lesions vs., 11:]5,18
painful or enlarged sternoclavicular joint vs., subchondral cyst, patellar lytic lesions vs., 1:348,
111:2 349
paravertebral ossification and calcification vs., tarsal cystic/lytic lesions vs., 1:390
1:276 wrist pain related to
periostitis of multiple bones/acropachy vs., radial-sided, 111:42,45
1:127, 128 ulnar-sided, 111:36,38
xliv
INDEX
Reactive arthritis, chronic. See Chronic reactive
Q arthritis.
Quadriceps tendon tear
Reactive sclerosis, pedicle, lesions originating in
anterior knee pain related to, 111:81,84
posterior vertebral elements vs., 1:307
painful knee replacement related to, 111:99
Reflex sympathetic dystrophy. See Complex
Quadrilateral space syndrome, nerve entrapment
regional pain syndrome.
of shoulder vs., 111:14,15
Reiter disease. See Chronic reactive arthritis.
Renal cell carcinoma, metastatic
R bone cancer vs., 11:56, 58
flat bones with focally expanded or bubbly
Radial aplasia/hypoplasia/dysplasia, 1:226-227
lesion vs., 1:2, 4
differential diagnosis, 1:226-227 long bone metaphyseal bubbly lesion vs., 1:44,
elbow deformities vs., 111:16,17
46
Radial clubhand, forearm deformity vs., 1:229 Renal disease, chronic, anemia related to, 111:152,
Radial entrapment neuropathy, elbow/wrist nerve
153
entrapment vs., 111:28-29,31
Renal failure
Radial head
rickets and osteomalacia related to, 111:166,
dislocation
167-168
elbow deformities vs., TII:16, 17
soft tissue uptake on bone scan vs., II: 198
lateral elbow pain related to, 111:18,20
Renal osteodystrophy
head/neck fracture, lateral elbow pain related to,
delayed bone age vs., 11:104
111:18,19-20
distal clavicular resorption vs., 1:212, 213
subluxation (nursemaid elbow), lateral elbow
genu valgum (knock knees) vs., 1:370
pain related to, 111:19
healed/healing
Radial neuropathy, lateral elbow pain related to,
bone within bone appearance vs., 11:76, 78
llJ:19,21
generalized increased bone density vs.
Radial tunnel syndrome, elbow/wrist nerve
adult, 1I:60, 61
entrapment vs., 111:29
child, 11:64,65
Radial-sided wrist pain, 111:42-47
with brown tumor, multiple sclerotic bone
Radiation effects
lesion vs., 11:28
adipocyte increase, increased marrow fat vs
11:136-137, 139 ., long bone diffuse cortical endosteal thickening
vs., 1:90, 92
childhood platyspondyly vs., 1:284, 286
long bone epiphyseal sclerosis/ivory vs., 1:18, 20
growth deformities. See Growth deformities
long bone growth plate widened physis vs.,
radiation-induced. '
1:108,110
long bone metaphyseal bands and lines vs., 1:26
medial metaphyseal erosion of proximal
long bone metaphyseal cupping vs., 1:30
humerus vs., 1:214, 215
long bone metaphyseal fraying vs., 1:32
mimic
long bone overtubulation related to, 1:103, 105
periostitis of multiple bones in children vs.,
osteonecrosis. See Osteonecrosis, radiation-
1:131, 133
induced.
sacroiliitis vs.
photopenic lesions and false negative scans vs.,
bilateral asymmetric, 1:320, 321
11:196, 197
bilateral symmetric, 1:317, 319
sarcoma. See Sarcoma, radiation-induced.
neostosis
soft tissue abnormalities, intermuscular edema
bizarre horizontal periosteal reaction vs.,
vs., lJ:181, 183
1:122, 123
Radiculopathy, C8-Tl (mimic), medial elbow pain
multiple sclerotic bone lesion vs., 11:27,30
related to, 111:23
periostitis of multiple bones/acropachy vs.,
Radiocarpal angle, abnormal, 1:234-237
1:126-127, 128
Radiographic technique (mimic), osteopenia vs.
solid periostitis vs., 1:116, 119
11:80 '
vertebral body sclerosis vs., 1:292, 295
Radioulnar joint instability, distal, wrist clicking/
with brown tumor
clunklllg/instability related to, 111:33
flat bones with permeative lesions vs., 1:7, 10
Radioulnar synostosis
healing, multiple sclerotic bone lesion vs.,
forearm deformity vs., 1:228
11:28
radial dysplasia/aplasia vs., 1:227
hyperossifled (mimic), sclerosing dysplasias
Raynaud disease, acroosteolysis vs., 1:249
vs., 11:69
INDEX
><
QJ
lesions originating in vertebral body vs., or retro-Achilles tendon bursitis, heel pain
"'C 1:301 related to, III: 120
s::: polyostotic lesions vs. Rhabdomyolysis, enlarged muscle vs., [1:172, 174
adult, 11:2, 5 Rhabdomyosarcoma
childhood,II:12 embryonal, soft tissue ossification vs., II: 107
solitary geographic lytic lesions vs., 11:15, 18 soft tissue, enlarged muscle vs., 1I:175
with hyperparathyroidism Rheumatoid arthritis. See also Juvenile idiopathic
chondrocalcinosis vs., 1:184, 185 arthritis; Still disease, adult.
cortical tunneling vs., 11:92, 93 acroosteosclerosis vs., 1:250
fish (biconcave) or H-shaped vertebra, 1:288 ankle, medial ankle pain related to, 111:108,111
generalized osteoporosis vs., 11:82, 84 ankylosis vs., 1:177, 179
linear and curvilinear calcification vs., 11:116, arthritis mutilans vs., 1:162
118 arthritis with large subchondral cysts vs., [:154,
linear ossification along anterior spine vs., 156
1:280 arthritis with osteopenia vs., 1:138, 139
long bone metaphyseal cupping vs., 1:30 atrophic joint destruction vs., 1:158, 159-160
nodular calcification vs., 11:110, 113 ball of foot pain related to, 111:127, 130
osteopenia vs., 11:80, 81 calcaneal erosions, posterior tubercle vs., [:376,
periarticular calcification vs., I:186, 189 377
protrusio acetabuli vs., 1:335, 337 carpal cystic/lytic lesions vs., 1:232, 233
superscan vs., 11:204, 205 cortical tunneling vs., 11:92
tibial bowing vs., 1:352, 354 distal clavicular resorption vs., 1:212,213
Renal stones, groin/hip pain related to, III:49 distal femur intercondylar notch enlargement
Repetitive trauma, chronic vs., 1:347
arthritis with large subchondral cysts vs., 1:155, early
156 arthritis with preserved cartilage space vs.,
carpal cystic/lytic lesions vs., 1:232,233 1:166, 167
chondrocalcinosis vs., 1:184, 185 symphysis pubis widening vs., 1:326
long bone growth plate widened physis vs., effusions, shoulder fluid collections vs., 1:222,
1:108, 109 223
long bone metaphyseal fraying vs., 1:32 enthesopathy vs., 11:97
symphysis pubis widening vs., 1:326 erosive arthritis vs., I:146, 147
tenosynovitis/tenosynovial fluid vs., II:184, 185 generalized osteoporosis vs., 1I:82, 85
Reticuloh istiocytosis groin/hip pain related to, 11I:48
acroosteolysis vs., 1:249 heel pain related to, 1Il:121, 124
multicentric hip
acroosteolysis vs., 1:247, 249 pain in elderly patients related to, 111:68,71
arthritis with normal bone density vs., 1:135, protrusio acetabuli vs., 1:334, 336
137 knee, medial knee pain related to, 111:86,88
erosive arthritis vs., 1:15] medial metaphyseal erosion of proximal
interphalangeal-predominant arthritis vs., humerus vs., 1:214
1:195,197 metacarpophalangeal-predominant arthritis vs.,
ulnar deviation of Mer joints vs., 1:265 1:192
Retinoid complications olecranon bursitis vs., 111:26,27
linear ossification along anterior spine vs., [:280, pes planovalgus (flatfoot) vs., 111:133
281 regional osteoporosis vs., 11:88-89, 90
periostitis of multiple bones in children vs., retrocalcaneal bursitis vs., 1:380, 38]
1:131 robust
periostitis of multiple bones/acropachy vs., arthritis with large subchondral cysts vs.,
1:127 1:155, 157
spinal osteophytes vs., 1:298, 299 arthritis with normal bone density vs., [:135,
spondyloarthropathy (mimic), arthritis with 137
productive changes vs., 1:143 erosive arthritis vs., 1:151
Retrocalcaneal bursitis, 1:380-381 metacarpophalangeal-predomi nant arthritis
Achilles tendon thickening/enlargement vs., vs., 1:192, 193
1:374 phalangeal cystic/lytic lesions vs., 1:253,257
differential diagnosis, 1:380-381 rotator cuff symptoms vs., 1I1:5, 7
xlvi
INDEX
sacroi Iiitis vs. Rocker bottom foot (congenital vertical talus)
bilateral asymmetric, 1:320 congenital foot deformity vs., IlI:139, 141
bilateral symmetric, 1:317 pes planovalgus (flatfoot) vs., I1I:133, 135
unilateral, 1:322 Rotator cuff atrophy, glenohumeral malalignment
symphysis pubis with productive changes/ vs., 1:216
fusion vs., 1:325 Rotator cuff symptoms, 111:4-7
tarsal cystic/lytic lesions vs., 1:390, 392 Rotator cuff tendinosis/tear
ulnar deviation of MCP joints vs., 1:264 chronic
wheelchair, superior rib notching vs., 1:310,311 distal clavicular resorption vs., 1:212
widened joint space related to, 1:170, 172 medial metaphyseal erosion of proximal
wrist pain related to humerus vs., 1:214
radial-sided, 111:42,44 glenohumeral malalignment vs., 1:216
ulnar-sided, 111:36,37 rotator cuff symptoms vs., 1Il:4, 5-6
Rheumatoid nodule shoulder instability related to, III:8, 9
mimic, olecranon bursitis vs., 111:26
nodular calcification vs., 11:111, 113
soft tissue mass of finger vs., 1:240, 243 s
soft tissue mass of foot vs., 1:383 Sacrococcygeal teratoma, bone lesions with fluid/
Rhomboid fossa (mimic), nonarticular clavicular fluid levels vs., 11:144, 145
lesions vs., 1:208,210 Sacroiliac dysfunction, lateral hip pain related to,
Rib notching 11[:55, 57
inferior, 1:308-309 Sacroi Iiitis
superior, 1:310-311 bilateral asymmetric, 1:320-321
Ribbing disease bilateral symmetric, [:316-319
generalized increased bone density in child vs., Saphenous nerve syndrome
11:65 lower extremity nerve entrapment vs., [1[:64-65
long bone diffuse cortical endosteal thickening medial knee pain related to, 111:87
vs., 1:91 SAPHO. See Synovitis, acne, palmoplantar
sclerosing dysplasias vs., 11:69 pustulosis, hyperostosis, and osteitis (SAPHO).
Ribs Sarcoid, sclerosing dysplasias vs., 11:73
dwarfism with short ribs, 111:188-189 Sarcoidosis
fractures, multiple healing (mimic), multiple acroosteosclerosis vs., 1:250
sclerotic bone lesion vs., 11:26, 28 carpal cystic/lytic lesions vs., [:232
solitary lesion, 1:312-315 heel pain related to, 111:121
Rickets and osteomalacia, 111:166-169 long bone central metaphyseal lesion vs., non-
atypical axial osteomalacia, 111:167 aggressive, [:39
cortical tunneling vs., 11:92,93 multiple sclerotic bone lesion vs., 11:31
delayed bone age vs., 11:105 nodular calcification vs., 1l:l11
genu valgum (knock knees) vs., 1:371 phalangeal cystic/lytic lesions vs., 1:253, 256
healing, long bone undertubulation vs., 1:97, polyostotic lesions vs.
100 adult, II:7
hypophosphatemic rickets (X-linked), I1I:167 childhood,II:12
irregular or stippled long bone epiphysis vs., solitary sclerotic bone lesion vs., n:21, 25
1:12, 14 swelling and periostitis of digit (dactylitis) vs.,
long bone growth plate widened physis vs., 1:266
1:108, 110 tarsal cystic/lytic lesions vs., 1:391
long bone metaphyseal bands and lines vs., Sarcoma
1:26,28 acral myxoinflammatory fibroblastic, soft tissue
long bone metaphyseal cupping vs., 1:30, 31 mass of finger vs., 1:241
long bone metaphyseal fraying vs., 1:32, 33 chondrosarcoma. See Chondrosarcoma.
oncogenic osteomalacia related to, 111:166, 168 epithelioid, soft tissue target lesions vs., 11:158
osteopenia vs., II:80, 81 Ewing. See Ewing sarcoma.
protrusio acetabuli vs., 1:335 fibrosarcoma. See Fibrosarcoma.
rickets of prematurity, 111:166 Kaposi, subcutaneous mass vs., [1:167
tibial bowing vs., 1:352, 354 leiomyosarcoma, soft tissue lesions with fluid/
vitamin D dependent, [II:167, 169 fluid levels vs., [1:154
vitamin D resistant, enthesopathy vs., 11:97, 99 lesions crossing disc space vs., 1:268, 269
x/vii
INDEX
liposarcoma. See Liposarcoma. multiple sclerotic bone lesion vs., 11:26
myxofibrosarcoma sclerosing dysplasias vs., 11:68, 70
acral myxoinflammatory fibroblastic, soft Scoliosis
tissue mass of finger vs., 1:241 high thoracic, with neurofibromatosis, painful
subcutaneous mass vs., 11:171 scoliosis vs., 111:145,147
neurogenic, enlarged peripheral nerves vs., painful, 111:144-147
11:189 Scurvy
osseous angiosarcoma. See Angiosarcoma, generalized osteoporosis vs., 11:83,87
osseous. healing, long bone undertubulation vs., 1:97,
osteosarcoma. See Osteosarcoma. 101
Paget, flat bones with permeative lesions vs., 1:7, long bone growth plate widened physis vs.,
11 1:109,111
radiation-induced long bone metaphyseal bands and lines vs.,
flat bones with permeative lesions vs., 1:7, 11 1:27,29
long bone diaphyseal aggressive lesion vs. long bone metaphyseal cupping vs., 1:30, 31
adult, 1:71, 73 mimic, generalized increased bone density in
child,I:75 child vs., 11:64, 66
long bone eccentric metaphyseal aggressive periostitis of multiple bones in children vs.,
lesion vs., 1:53 1:131,133
matrix-containing bone lesions vs., 11:49 solid periostitis vs., 1:117, 121
rhabdomyosarcoma Sebaceous cyst
embryonal, soft tissue ossification vs., 11:107 cystic masses vs., 11:160
soft tissue, enlarged muscle vs., 11:175 subcutaneous mass vs., 11:166, 167
soft tissue Semimembranous tendon bursitis
dystrophic calcification in, periarticular extraarticular popliteal mass vs., 1:363, 364
calcification vs., 1:187, 190 knee fluid collections vs., 1:357,361
mimic, cystic masses vs., 11:161, 165 Septic joint
synovial. See Synovial sarcoma. ankle, medial ankle pain related to, 11I:108-109
Saturday night palsy, nerve entrapment of shoulder ankylosis vs., 1:177, 179
vs., Ill: 14 arthritis with osteopenia vs., 1:138, 140
"Sausage digit," swelling and periostitis of digit atrophic joint destruction vs., 1:158, 160
(dactylitis) vs., 1:266, 267 ball of foot pain related to, 111:126-127, 129
Scaphoid fractures, avascular necrosis related to, bone marrow edema syndromes vs., 11:127, 129
111:156, 158 distal clavicular resorption vs., 1:212
Scapholunate ligament tear distal femur intercondylar notch enlargement
radial-sided wrist pain related to, 11I:42-43, 46 vs., 1:346
wrist clicking/clunking/instability related to, early, arthritis with preserved cartilage space vs.,
11I:32, 34 1:166, 168
Schmorl node epiphyseal marrow signal vs., abnormal, 11:132
mimic, lesions originating in vertebral body vs., erosive arthritis vs., 1:147,149,151
1:300,302 facet, painful scoliosis vs., 111:145, 147
vertebral body sclerosis vs., 1:292, 293 fungal, with tuberculosis, arthritis with
Schwannoma, conventional, soft tissue target osteopenia vs., 1:139
lesions vs., 11:158-159 groin/hip pain related to, 111:49,52
Sciatic neuropathy, lower extremity nerve hip
entrapment vs., 11I:64, 66 coxa magna deformity vs., 1:338, 339
Sciatica pain in elderly patients related to, 111:69,73
calf pain related to, 11I:92 in teenagers, 11I:148-149, 150
groin/hip pain related to, 111:49 knee, medial knee pain related to, 11I:87, 90
hip pain in elderly patients related to, 11I:69 long bone epiphyseal overgrowth/ballooning
lateral hip pain related to, 111:55 vs., 1:16, 17
thigh pain related to, 11I:60 long bone growth plate premature physeal
Sclerosing dysplasias, 11:68-73 closure vs., 1:106
Sclerotic bone lesion monoarthritis vs., 1:198, 199
multiple, 11:26-31 osteomyelitis vs., 11:130, 131
solitary, 11:20-25 painful hip replacement related to, 111:74,77
with central lucency, 11:32-35 painful knee replacement related to, 111:98
Sclerotic metastases
INDEX
painful or enlarged sternoclavicular joint vs., fish (biconcave) or H-shaped vertebra, 1:288, 289
III :2, 3 generalized increased bone density vs.
protrusio acetabuli vs., 1:335, 337 adult, 11:60,62
regional osteoporosis vs., 11:89,91 child, 11:64, 66
rotator cuff symptoms vs., 111:5,7 generalized osteoporosis vs., II:82, 85
sacroiliitis vs., unilateral, 1:322, 323 "hand-foot," swelling and periostitis of digit
shoulder fluid collections vs., 1:223 (dactylitis) vs., 1:266, 267
subchondral edematous-like signal vs., 11:130, long bone diaphyseal lesions vs.
131 aggressive, child, 1:7S, 77
symphysis pubis widening vs., 1:326, 328 central, non-aggressive, 1:67, 69
symphysis pubis with productive changes/ long bone diffuse cortical endosteal thickening
fusion vs., 1:324 vs., 1:90, 92
thigh pain related to, 11I:61 long bone metaphyseal cupping vs., 1:30
ulnar deviation of Mep joints vs., 1:264 long bone undertubulation vs., 1:96,99
widened joint space related to, 1:170, 172 protrusio acetabuli vs., 1:335
Sequestra, pinhole, target lesions of bone vs., 11:40, solid periostitis vs., 1:1]6-117,120
42 spleen, soft tissue uptake on bone scan vs.,
Sequestration, 11:36-39 11:198,200
Seroma, anechoic mass vs., 11:194 Silastic implant
Sesamoiditis, 1:258-259 arthropathy, arthritis with preserved cartilage
ball of foot pain related to, 111:127, 130 space vs., 1:167, 169
differential diagnosis, 1:258-259 intraarticular low signal material vs., 11:190, 192
Sever disease Sinding Larsen Johansson disease, anterior knee
heel pain related to, 111:121, 124 pain related to, 11I:81,85
retrocalcaneal bursitis vs., 1:380, 381 Sinus tarsus syndrome, lateral ankle pain related
Sex hormones, excessive, advanced bone age and, to, 111:115, 118
11:102 Skeletal disorders, inherited, distal femur
Short limb, unilateral, 111:172-177 intercondylar notch enlargement vs., 1:346
Short metacarpal/metatarsal bones, 1:260-263 Skin and subcutaneous lesions, soft tissue mass of
Short rib polydactyly foot vs., 1:383, 387
childhood platyspondyly vs., 1:285 Skull hemangioma (mimic), bizarre horizontal
dwarfism with short ribs vs., 111:188 periosteal reaction vs., 1:123, 125
Shoulder girdle and upper arm. See also Clavicle; SLAP lesions
Humerus; Labrum. type I-IV, 1:218-219, 220
anteroinferior labral/capsule injury, 11I:12-13 type V-X, 1:219,220
arthroplasty impingement, medial metaphyseal Slipped capital femoral epiphysis
erosion of proximal humerus vs., 1:214 avascular necrosis related to, 111:]57, 159
fluid collections about the shoulder, 1:222-225 coxa magna deformity vs., 1:338
fracture, rotator cuff symptoms vs., 111:5,6 growth plate widened physis vs., 1:108, 110
glenohumeral malalignment, 1:216-217 hip labral tear related to, 1:341, 343
intraarticular fluid, glenohumeral malalignment unilateral short limb related to, 111:172, 174
vs., 1:216,217 Smoking, complications, bone marrow hyperplasia
nerve entrapment, 111:14-15 vs., 11:140, 141
painful or enlarged sternoclavicular joint, Snapping hip, 111:58-59
111:2-3 Soft tissue
rotator cuff symptoms, 111:4-7 abnormalities, radiation-induced, intermuscular
shoulder instability, 1II:8-]] edema vs., 11:181, 183
subluxation/dislocation, rotator cuff symptoms abscess. See Abscess, soft tissue.
vs., 111:4-5,6 contractures, III:170-171
unilateral short limb, 111:172-177 hematoma. See Hematoma.
Sickle cell anemia, musculoskeletal complications impingement, painful knee replacement related
anemia with musculoskeletal manifestations vs., to, 111:99
111:152,154 implants, soft tissue ossification vs., 11:107
avascular necrosis related to, 111:157, 159 lesions
bone marrow hyperplasia vs., 11:140, 142 with fluid/fluid levels, 11:154-157
dactylitis, periostitis of multiple bones in with predominately low T] & T2 signal,
children vs., 1:131, 133 11:150-153
xlix
INDEX
)( mass erosion (mimic) long bone epiphyseal/ Intervertebral disc; Vertebrae and vertebral
QJ
"'0 apophyseal/subchondral lytic lesion vs., body.
c: 1:23,25 congenital and acquired childhood
mass invasion (mimic), long bone cortically platyspondyly, 1:284-287
based lytic diaphyseal lesion vs., 1:85, 88 dwarfism with major spine involvement,
neoplasms. See Soft tissue neoplasms. 111:184-185
nodular calcification, 11:110-115 injury, heterotopic ossification vs., 11I:162, 165
ossification, 11:106-109 linear ossification along anterior spine, 1:280-
soft tissue uptake on bone scan vs., 11:203 281
overlying, loss or absence (mimic), regional neonatal, normal, bone within bone appearance
osteoporosis vs., II:88, 90 vs., 11:76, 77
target lesions, 11:158-159 ossification/calcification anterior to C1, 1:274-
uptake on bone scan, 11:198-203 275
Soft tissue neoplasms osteophytes, 1:298-299
adjacent to bone, bizarre horizontal periosteal painful scoliosis, 111:144-147
reaction vs., 1:123, 125 paralysis, spinal osteophytes vs., 1:298
anterior knee pain related to, 111:85 paravertebral ossification and calcification,
calcification in, 11:122-125 1:276-279
calf pain related to, 1II:93, 97 with Charcot neuropathy, neuropathic
excavation (mimic), long bone cortically based osteoarthropathy vs., 1:164, 165
metaphyseal lesion vs., 1:57, 59 Spondyloarthropathy
fingers, 1:240-245 arthritis with large subchondral cysts vs., 1:155
foot, 1:382-387 arthritis with preserved cartilage space vs., 1:166
groin/hip pain related to, 111:49,53 retinoid (mimic), arthritis with productive
hemangioma. See Hemangioma, soft tissue. changes vs., 1:143
hip pain in elderly patients related to, 1II:69, 73 seronegative
intermuscular edema vs., 11:181, 183 mimic, spinal osteophytes vs., 1:298,299
knee, anterior knee pain related to, 1II:81 retrocalcaneal bursitis vs., 1:380, 381
lateral elbow pain related to, Ill: 19 Spondyloepi physeal dysplasia
lateral hip pain related to, 1lI:55, 57 childhood platyspondyly vs., 1:284-285, 287
lipoma, bone lesions with bright T1 signal vs., dwarfism with major spine involvement vs.,
11:146, 147 111:184, 185
locally invasive, tarsal cystic/lytic lesions vs., genu valgum (knock knees) vs., 1:371
1:391 genu varum (bow leg deformity), 1:372
medial ankle pain related to, 11I:109, 113 irregular or stippled long bone epiphysis vs.,
medial knee pain related to, 11I:87, 91 1:13,15
periarticular calcification vs., 1:190 muscle atrophy vs., 11:177
soft tissue mass of foot vs., 1:383, 387 symphysis pubis widening vs., 1:327,329
thigh pain related to, 1lI:61, 63 Spondylosis
wrist pain related to degenerative, discal mineralization vs., 1:270,
radial-sided, 111:43,47 271
ulnar-sided, 111:37,41 lesions originating in posterior vertebral
Soleus, accessory (mimic), Achilles tendon elements vs., 1:306
thickening/enlargement vs., 1:374 Spondylosis deformans, spinal osteophytes vs.,
Solitary geographic lytic lesions, 11:14-19 1:298
Solitary sclerotic bone lesion, 11:20-25 Sports anemia, bone marrow hyperplasia vs.,
Spherocytosis, bone marrow hyperplasia vs., 11:141 11:140, 142
"Spina ventosa," swelling and periostitis of digit Squamous cell carcinoma
(dactylitis) vs., 1:266 metastatic, bone cancer vs., 11:57
Spinal cord injury subcutaneous mass vs., II: 170
cavus foot deformity related to, 111:137 Statins, complications of, thigh pain related to,
hypertrophic callus formation vs., 11:74 11I:61
muscle atrophy vs., 11:176 Stem cell stimulation, abnormal epiphyseal
Spinal fatigue syndrome, painful scoliosis vs., marrow signal vs., 11:133
111:144-145 Sternoclavicular hyperostosis/SAPHO
Spindle cell lipoma, subcutaneous mass vs., 11:170, linear ossification along anterior spine vs., 1:280
171 painful or enlarged sternoclavicular joint vs.,
Spine. See also Ankylosing spondylitis; 111:2,3
INDEX
spinal osteophytes vs., 1:298 with Eagle-Barrett syndrome, tendon and
Sternoclavicular joint, painful or enlarged, 111:2-3 ligament ossification vs., 11:100, 101
Steroid therapy Subacromial bursitis
avascular necrosis related to, 11I:156,157 rotator cuff symptoms vs., 111:4, 6
calcified intraarticular body/bodies vs., 1:181 shoulder fluid collections vs., 1:222,224
fish (biconcave) or H-shaped vertebra related to, Subacromial spur, enthesopathy vs., 11:96,98
1:288,289 Subcapital fracture, Garden IV, benign osseous
generalized osteoporosis related to, 11:82, 84 lesions with aggressive appearance vs., 11:54
hypertrophic callus formation related to, II: 74 Subchondral cyst
increase of fat cells due to, increased marrow fat large, with arthritis, 1:154-157
vs., 11:136-137, 138 long bone epiphyseal/apophyseal/subchondral
muscle atrophy due to, I1:176 lytic lesion vs., 1:22
Still disease, adult metaphyseal extension, long bone eccentric
ankylosis vs., 1:177, 179 non-aggressive metaphyseal lesion vs., 1:49,
arthritis with osteopenia vs., 1:139, 141 50
erosive arthritis vs., 1:147, 151 osteoarthritis, patellar lytic lesions vs., 1:348,
interphalangeal-predominant arthritis vs., 1:195, 349
197 pre-operative, arthroplasty with lytic/cystic
Stress fractures lesions vs., 1:206, 207
adult pyrophosphate arthropathy, patellar lytic
long bone cortically based metaphyseal lesions vs., 1:348, 349
lesion vs., 1:56, 58 solitary geographic lytic lesions vs., 11:14, 15
long bone cortically based sclerotic supra-acetabular iliac destruction vs., 1:330, 33]
diaphyseal lesion vs., 1:80, 81 tarsal cystic/lytic lesions vs., 1:390
long bone eccentric metaphyseal lesion vs., Subchondral edematous-like signal, 11:130-131
non-aggressive, 1:48, 50 Subclavian artery obstruction, inferior rib notching
mimic, symphysis pubis with productive vs., 1:308
changes/fusion vs., 1:325 Subcutaneous mass, 11:166-171
sclerotic bone lesion with central lucency vs., Subia bra I foramen
11:32,34 anterosuperior labral variations/pathology vs.,
ball of foot pain related to, 111:126, 128 1:2]8
benign osseous lesions with aggressive wi th superior sublabral recess (sulcus),
appearance vs., 11:50-51, 53 anterosuperior labral variations/pathology
bisphosphonate-related, long bone diaphyseal vs., 1:219, 221
lesion vs., cortically based, sclerotic, 1:81,83 Sublabral recess, superior (sulcus)
bone marrow edema syndromes vs., 11:126, 128 anterosuperior labral variations/pathology vs.,
calcaneal, heel pain related to, 111:120, 122 1:218,219
fabella, painful knee replacement related to, with sublabral foramen, anterosuperior labral
111:99 variations/pathology vs., 1:219,221
malunion, symphysis pubis widening vs., 1:326, Subluxation
328 patella, anterior knee pain related to, 111:80, 83
pediatric, long bone cortically based sclerotic peroneal tendon, lateral ankle pain related to,
diaphyseal lesion vs., 1:80, 82 11I:115, 118
solid periostitis vs., 1:116, 119 radial head (nursemaid elbow), lateral elbow
solitary sclerotic bone lesion vs., I1:20, 2] pain related to, 1II:19
talus, anterior ankle pain/impingement related shoulder girdle, rotator cuff symptoms vs.,
to, 111:104, 106 111:4-5,6
tibia, anterior ankle pain/impingement related widened joint space related to, I:] 70, 173
to, 111:104, 106 Subperiosteal hemorrhage, bone within bone
Stress reaction appearance vs., 1I:76
bone marrow edema syndromes vs., 11:126, 128 Subperiosteal resorption (mimic), periostitis of
sesamoiditis vs., 1:258, 259 multiple bones/acropachy vs., 1:126, 128
Sturge-Weber disease, hemihypertrophy related to, Superior labral anteroposterior lesions (SLAP)
111:178 types 1-1\1,1:218-219, 220
Stylohyoid ligament ossification types V-X, 1:219, 220
mimic, ossification/calcification anterior to C1 Superscan, 11:204-205
vs., 1:274, 275 Suprascapular nerve entrapment, nerve
Ii
INDEX
entrapment of shoulder vs., 1II:14, 15 monoarthritis vs., 1:199, 200
Suprascapular neuropathy, rotator cuff symptoms nodular calcification vs., [[:111, 113
vs., 111:4,6 shoulder fluid collections vs., [:223, 225
Sural nerve syndrome, lower extremity nerve soft tissue ossification vs., 11:106, 108
entrapment vs., ([[:65, 67 soft tissue uptake on bone scan vs., 11:198
Surgical resection tenosynovitis/tenosynovial fluid vs., 11:184, 185
growth plate premature physeal closure vs., widened joint space related to, 1:17l, 174
1:106, 107 within bursa, knee fluid collections vs., 1:357,
photopenic lesions and false negative scans vs., 361
11:196 Synovial process, proximal tibio-fibular joint, knee
Symphysis pubis fluid collections vs., 1:357, 361
widening, 1:326-329 Synovial sarcoma
with productive changes/fusion, 1:324-325 cystic, soft tissue lesions with fluid/fluid levels
Syndesmosis sprain vs., 11:155, 157
anterior ankle pain/impingement related to, extraarticular popliteal mass vs., 1:362, 364
([[:104, 106 linear and curvilinear calcification vs., 11:120
intermuscular edema vs., 11:180, 182 nodular calcification vs., II: 111, 1] 4
lateral ankle pain related to, ([[:115, 119 periarticular calcification vs., [:187, 190
Syndesmotic impingement, lateral ankle pain soft tissue neoplasms with calcification vs.,
related to, 11I:115, 119 11:122, 123
Synovial chondromatosis, soft tissue mass of finger Synovitis. See also Tenosynovitis.
vs., 1:241 intraarticular low signal material vs., 11:190, 192
Synovial chondrosarcoma knee, knee fluid collections vs., [:356, 358
calcified intraarticular body/bodies vs., 1:181 nodular
intraarticular mass vs., 1:203 intraarticular low signal material vs., 11:191,
Synovial cyst 193
anechoic mass vs., 11:194 intraarticular mass vs., 1:203,204
cystic masses vs., 11:]60,162 pigmented villonodular. See Pigmented
shoulder fluid collections vs., 1:223,225 villonodular synovitis.
soft tissue lesions with fluid/fluid levels vs., popliteal cyst, extraarticular popliteal mass vs.,
11:155 1:362,364
Synovial fringe, lateral elbow pain related to, 111:19, silicone-induced, tarsal cystic/lytic lesions vs.,
21 [:391,395
Synovial hemangioma viral (toxic)
distal femur intercondylar notch enlargement monoarthritis vs., 1:]99,20]
vs., 1:346, 347 widened joint space related to, [:170, 173
intraarticular mass vs., 1:203, 205 Synovitis, acne, palmoplantar pustulosis,
soft tissue lesions with fluid/fluid levels vs., hyperostosis, and osteitis (SAPHO)
11:] 55 arthritis with productive changes vs., [:143, 145
Synovial osteochondromatosis mixed erosive/productive arthritis vs., 1:152
anterior knee pain related to, 11I:81, 84 nonarticular clavicular lesions vs., [:208-209
arthritis with normal bone density vs., 1:134, sternoclavicular hyperostosis in
136 linear ossification along anterior spine vs.,
arthritis with preserved cartilage space vs., 1:167 [:280
calcified intraarticular body/bodies vs., 1:180, painful or enlarged sternoclavicular joint vs.,
182 111:2,3
distal femur intercondylar notch enlargement spinal osteophytes vs., [:298
vs., 1:346, 347 Syphilis
erosive arthritis vs., 1:146, 148 congenital, long bone diaphyseal lesion vs.,
extraarticular, periarticular calcification vs., aggressive, child, 1:75
[:187, 191 medial metaphyseal erosion of proximal
extraarticular popliteal mass vs., [:363, 364 humerus vs., [:215
hip, snapping hip related to, 11[:58,59 secondary
in teenagers, 111:151 solid periostitis vs., [:117
intraarticular low signal material vs., 11:190, 192 supra-acetabular iliac destruction vs., 1:331
intraarticular mass vs., 1:202, 203-204 swelling and periostitis of digit (dactylitis)
medial knee pain related to, 111:87, 91 vs., 1:266
tertiary
Iii
INDEX
sclerotic bone lesion with central lucency vs., avascular necrosis
11:33 anterior ankle pain/impingement related to,
sequestration vs., 11:37 111:104-105, 107
supra-acetabular iliac destruction vs., 1:331 post-traumatic, III: IS 7
tibial bowing vs., 1:353, 355 congenital vertical (rocker bottom foot)
with Charcot neuropathy, neuropathic congenital foot deformity vs., 111:139, 141
osteoarthropathy vs., 1:165 pes planovalgus (flatfoot) vs., 111:133, 135
Syringomyelia, with Charcot joint fractures
atrophic joint destruction vs., 1:158, 160 anterior ankle pain/impingement related to,
neuropathic osteoarthropathy vs., 1:164 111:105, 107
Systemic diseases lateral process, lateral ankle pain related to,
anemia with musculoskeletal manifestations, 111:115,119
111:152-155 osteochondral lesion
arthritis in teenagers, 111:148-151 anterior ankle pain/impingement related to,
avascular necrosis, III:156-161 111:105, 107
dwarfism. See Dwarfism. lateral ankle pain related to, 11I:114-115, 117
focal gigantism/macrodactyly, 11I:180-183 medial ankle pain related to, I11:108, 110
hemihypertrophy, 1ll:178-179 stress fracture, anterior ankle pain/impingement
heterotopic ossification, 111:162-165 related to, 111:104, 106
rickets and osteomalacia, 111:166-169 subtalar arthritis, lateral ankle pain related to,
short limb, unilateral, 111:172-177 111:114,117
soft tissue contractures, 111:170-171 talar beak, 1:388-389
Systemic fibrosis, nephrogenic Target lesions
intermuscular edema vs., 11:181 of bone, 11:40-43
soft tissue contractu res related to, III:170 of soft tissue, I1:158-159
Systemic lupus erythematosus Tarsal bones
arthritis with osteopenia vs., 1:138, 140 cystic/lytic lesions, 1:390-395
arthritis with preserved cartilage space vs., 1:167, insufficiency fracture, diabetic foot
169 complications vs., 111:143
avascular necrosis related to, 1II:159 Tarsal coalition
effusions, shoulder fluid collections vs., 1:222, ankylosis vs., 1:177,179
223 ball of foot pain related to, 111:127, 131
erosive arthritis vs., 1:147, ISO congenital foot deformity vs., II1:138-139, 140
linear and curvilinear calcification vs., II:121 heel pain related to, 111:121, 125
mimic lateral ankle pain related to, 1I1:115, 118
heterotopic ossification vs., 111:163 medial ankle pain related to, 1II:109, 112
metacarpophalangeal-predominant arthritis pes planovalgus (flatfoot) vs., 1Il:133, 135
vs., 1:192, 193 talar beak vs., 1:388, 389
nodular calcification vs., 11:111, 115 Tarsal tunnel syndrome
periarticular calcification vs., 1:187, 190 anterior, lower extremity nerve entrapment vs.,
superior rib notching vs., 1:310 111:65,67
ulnar deviation of MCr joints vs., 1:264, 265 enlarged peripheral nerves vs., II:186, 187
Systemic sclerosis, progressive. See Progressive heel pain related to, 11I:120-121, 123
systemic sclerosis. lower extremity nerve entrapment vs., 1Il:65,
66-67
medial ankle pain related to, 11I:109, 113
T Teenagers, arthritis in, 111:148-151. See also Juvenile
Talar ridge idiopathic arthritis.
hypertrophied, talar beak vs., 1:388, 389 Telangiectatic osteosarcoma. See Osteosarcoma,
talar beak vs., 1:388 telangiectatic.
Talipes equinovarus (club foot), congenital foot Tendinitis, calcific
deformity vs., 111:138, 140 nodular calcification vs., 11:110, 112
"Tall man" insensate neuropathy, neuropathic periarticular calcification vs., 1:186, 187
osteoarthropathy vs., 1:164, 165 Tendon and ligament ossification, 11:100-101
Talofibular ligament tear, anterior, lateral ankle Tendon injury
pain related to, 111:114, 115 calf pain related to, III:92, 95
Talus hip
groin/hip pain related to, 1Il:48, 51
liii
INDEX
>< lateral hip pain related to, IIl:54, 56 Thanatophoric dwarf
~
"'C pain in elderly patients related to, 11I:68, 71 childhood platyspondyly vs., 1:285,287
c: lower extremity, thigh pain related to, III:60, 62 dwarfism with horizontal acetabular roof vs.,
medial ankle pain related to, IlI:108, 109 1II:190, 191
muscle atrophy vs., 11:176,178 dwarfism with major spine involvement vs.,
sesamoiditis vs., 1:258 11I:184, 185
soft tissue mass of foot vs., 1:382, 384 dwarfism with short extremities vs., 1II:186, 187
tenosynovitis/tenosynovial fluid vs., I1:184 dwarfism with short ribs vs., 111:188, 189
tug lesion Thermal injuries. See Burns; Frostbite.
long bone diaphyseal cortically based lytic Thigh pain, 11l:60-63
lesion vs., 1:85, 88 Thoracic nerve syndrome, long, nerve entrapment
mimic, long bone surface (juxtacortical) of shoulder vs., 111:14
lesion vs., 1:61, 64 Thoracic outlet syndrome, nerve entrapment of
wrist clicking/clunking/instability related to, shoulder vs., III:14
III:33, 35 Thorotrast exposure, bone within bone appearance
wrist pain related to vs., 11:77
radial-sided, 111:42,45 Thrombocytopenia-absent radius syndrome,
ulnar-sided, 111:36,39 forearm deformity vs., 1:228
Tendon sheath. See Fibrobroma, tendon sheath; Thrombophlebitis, thigh pain related to, 1II:61
Giant cell tumor, tendon sheath. Thrombosis, deep venous
Tendon tear calcified chronic, linear and curvilinear
intermuscular edema vs., 11:180, 182 calcification vs., I1:117, 120
shoulder fluid collections vs., 1:222, 224 calf pain related to, 111:93,96
Tendon/ligament microtrauma, with calcification, intermuscular edema vs., 1l:180, 182
enthesopathy vs., 11:96, 98 Thyroid acropachy
Tenosynovial chondromatosis, soft tissue mass of long bone diffuse cortical endosteal thickening
finger vs., 1:241, 245 vs., 1:91
Tenosynovitis periostitis of multiple bones/acropachy vs.,
bicipital, shoulder fluid collections vs., 1:222 1:127,129
infectious, soft tissue mass of finger vs., 1:240, solid periostitis vs., I:] 17,121
242 Thyroid neoplasm, metastatic
medial ankle pain related to, 1II:108, 110 bone cancer vs., 1l:56, 58
mimic, anechoic mass vs., 11:194, 195 flat bones with focally expanded or bubbly
peroneal, lateral ankle pain related to, 11I:114, lesion vs., 1:2, 4
117 long bone metaphyseal bubbly lesion vs., 1:44,
soft tissue lesions with fluid/fluid levels vs., 46
II:155 Thyrotoxicosis, cortical tunneling vs., 1l:92
Tenosynovitis/tenosynovial fluid, II: 184-185 Tibia
Teratoma, sacrococcygeal, bone lesions with fluid/ bowing of, 1:352-355
fluid levels vs., 1l:144, 145 congenital pseudarthrosis, unilateral short limb
Testicular/scrotal/adnexal pa thology related to, IlI:173, 176
groin/hip pain related to, 1ll:49 stress fracture, anterior ankle pain/impingement
hip pain in elderly patients related to, III:69, 73 related to, Ill:104, 106
Thalassemia Tibialmetadiaphyseal cortically based lesion, long
anemia with musculoskeletal manifestations vs., bones, 1:94-95
111:153, 155 Tibial stress syndrome/adductor insertion
bone marrow hyperplasia vs., 11:140, 142 avulsion syndrome, cortically based, sclerotic
delayed bone age vs., 11:105 diaphyseal lesion vs., 1:80, 82
generalized osteoporosis vs., I1:83, 86 Tibialis anterior tendon
inferior rib notching vs., 1:308 tear, anterior ankle pain/impingement related
long bone undertubulation vs., 1:96, 99 to, IIJ:104, 106
mimic, bizarre horizontal periosteal reaction vs., tendinosis, anterior ankle pain/impingement
1:123, 125 related to, Ill: 104, 106
Thalassemia major, fish (biconcave) or H-shaped Tibialis posterior tendon tear, pes planovalgus
vertebra vs., 1:288 (flatfoot) vs., Ill:132, 134
Thalidomide embryopathy, forearm deformity vs., Tibio-fibular joint, proximal synovial process, knee
1:229 fluid collections vs., 1:357, 361
liv
INDEX
Tillaux fracture, lateral ankle pain related to, genu valgum (knock knees) vs., 1:371
1lI:115, 118 intraarticular mass vs., 1:203, 205
Toe(s). See Fingers and toes. irregular or stippled long bone epiphysis vs.,
Tophus [:13,15
gouty, soft tissue mass of foot vs., 1:382, 385 nodular calcification vs., II:111, 115
mimic, olecranon bursitis vs., 111:26,27 Triangular fibrocartilage tear
Total parenteral nutrition ulnar-sided wrist pain related to, 111:36,38
long bone growth plate widened physis vs., wrist clicking/clunking/instability related to,
[:109,111 11I:32,33
prolonged, long bone metaphyseal bands and Triceps tendon rupture
lines vs., 1:26 medial elbow pain related to, III:23, 25
Transitional cell carcinoma, metastatic, bone olecranon bursitis vs., 11I:26,27
cancer vs., 1I:57 Triquetral fracture, ulnar-sided wrist pain related
Trauma to, 11I:36-37,40
acute Trisomy 13-15
ball of foot pain related to, 111:126,128 forearm deformity vs., 1:229
lesions originating in posterior vertebral radial dysplasia/aplasia vs., 1:226
elements vs., 1:306, 307 Trisomy 18
medial knee pain related to, 11I:86,89 forearm deformity vs., 1:229
ankle (talus and navicular), avascular necrosis radial dysplasia/aplasia vs., 1:226, 227
related to, 1lI:157 ulnar deviation of Mer joints vs., 1:265
childhood platyspondyly vs., 1:284 Trisomy 21. See Down syndrome (trisomy 21).
chondrolysis after Tuberculosis
atrophic joint destruction vs., [:159, 161 and fungal septic joint
monoarthritis vs., 1:199, 201 arthritis with osteopenia vs., 1:139
clavicular, distal clavicular resorption vs., 1:212, erosive arthritis vs., 1:147, 151
213 arthritis associated with, atrophic joint
enlarged peripheral nerves vs., 11:186-187, 188 destruction vs., 1:159, 161
femur, coxa magna deformity vs., 1:338, 339 bone within bone appearance vs., 11:77
fingers and toes, short metacarpal/metatarsal discal mineralization vs., 1:271, 273
bones vs., [:260, 261 long bone central diaphyseal non-aggressive
heterotopic ossification vs., 11I:162, 163-165 lesion vs., 1:67, 69
hip, coxa magna deformity vs., 1:338, 339 long bone central metaphyseal non-aggressive
insult prior to skeletal maturity, unilateral short lesion vs., 1:39
limb related to, 111:173,176 low virulence, arthritis with preserved cartilage
intermuscular edema vs., 1I:180, 181 space vs., 1:167
long bone metaphyseal bands and lines vs., monoarthritis vs., 1:199,201
1:26,28 polyostotic lesions vs., II:7
olecranon bursitis vs., 11I:26 "spina ventosa," swelling and periostitis of digit
osteoarthritis related to, monoarthritis vs., (dactylitis) vs., 1:266
1:198,200 widened joint space related to, 1:171,174-175
painful or enlarged sternoclavicular joint vs., Tuberous sclerosis
111:2 acroosteosclerosis vs., 1:250, 251
pelvic, symphysis pubis widening vs., 1:326, generalized increased bone density in child vs.,
327-328 11:65
protrusio acetabuli vs., 1:334, 336 hemihypertrophy related to, 1lI:178
repetitive, tenosynovitis/tenosynovial fluid vs., periostitis of multiple bones/acropachy vs.,
1I:184, 185 1:127, 129
soft tissue contractures related to, 1lI:171 phalangeal cystic/lytic lesions vs., [:253
tendon and ligament ossification vs., 11:100,101 vertebral body sclerosis vs., 1:293
wrist, avascular necrosis related to, IlI:156, 158 Tug lesion
Traumatic neuroma, enlarged peripheral nerves vs., long bone diaphyseal lesion vs., cortically based,
11:187,188 lytic, 1:85, 88
Trevor Fairbank disease mimic, long bone surface (juxtacortical) lesion
calcified intraarticular body/bodies vs., 1:181, vs., 1:61,64
183 Tumoral calcinosis
childhood polyostotic lesions vs., 11:12 idiopathic, periarticular calcification vs., 1:187,
191
Iv
INDEX
><
QJ
nodular calcification vs., 11:111, 115 long bone metaphyseal bubbly lesion vs., 1:45,
"'C painful or enlarged sternoclavicular joint vs., 47
r:: 111:2 long bone undertubulation vs., 1:96, 98
paravertebral ossification and calcification vs., patellar lytic lesions vs., 1:349, 351
1:276-277,278 phalangeal cystic/lytic lesions vs., 1:253, 256
periarticular calcification vs., 1:187, 191 solitary geographic lytic lesions vs., 11:14, 16
soft tissue lesions with fluid/fluid levels vs., tarsal cystic/lytic lesions vs., \:394
11:154, 156 Unilateral short limb, 11I:172-177
soft tissue mass of finger vs., 1:240, 244 Upper extremities. See Elbow; Fingers and toes;
soft tissue mass of foot vs., 1:383 Forearm deformity; Shoulder girdle and upper
Tunnel syndromes. See Carpal tunnel syndrome; arm.
Tarsal tunnel syndrome; Ulnar tunnel Urethral duplication, symphysis pubis widening
syndrome. vs., 1:327
Turner syndrome Urine contamination (mimic), soft tissue uptake on
abnormal radiocarpal angle vs., 1:234, 236 bone scan vs., 11:199-200
mimic Uterine carcinoma, metastatic, bone cancer vs.,
genu varum (bow leg deformity), 1:372, 373 11:57
long bone epiphyseal overgrowth/ballooning Uterine fibroid, nodular calcification vs., 11:111,
vs., 1:16, 17 114
tibial bowing vs., 1:353, 355
short metacarpal/metatarsal bones vs., 1:260, 262
v
Van Buchem disease, generalized increased bone
u density in child vs., 11:65
Ulcer/ulceration Varicose veins, subcutaneous mass vs., 11:166, 168
ball of foot pain related to, IlI:126, 129 Vascular abnormalities
in diabetic foot complications, III:142 calf pain related to, m:92-93
Ulnar abutment ulnar-sided wrist pain related to, 111:37, 41
arthritis with productive changes vs., 1:142-143, Vascular channel, sequestration vs., 11:37
144 Vascular compromise, photopenic lesions and false
carpal cystic/lytic lesions vs., [:232, 233 negative scans vs., 11:196
ulnocarpal, ulnar-sided wrist pain related to, Vascular insufficiency. See Venous insufficiency.
111:36,39 Vascular malformations. See also Arteriovenous
Ulnar aplasia/hypoplasia, elbow deformities vs., malformations.
111:16,17 mimic, hemihypertrophy related to, 111:178, 179
Ulnar clubhand soft tissue lesions with fluid/fluid levels vs.,
forearm deformity vs., 1:229 11:154, 156
radial dysplasia/aplasia vs., 1:226, 227 subcutaneous mass vs., 11:169
Ulnar deviation of metacarpophalangeal joints, Vascular tumors
1:264-265 long bone central diaphyseal non-aggressive
Ulnar neuropathy, medial elbow pain related to, lesion vs., 1:67
111:23,25 long bone central metaphyseal non-aggressive
Ulnar styloid fracture, ulnar-sided wrist pain lesion vs., 1:39
related to, 11I:37, 40 osseous, phalangeal cystic/lytic lesions vs.,
Ulnar tunnel syndrome 1:253,257
elbow/wrist nerve entrapment vs., III:29, 31 patellar lytic lesions vs., 1:349
enlarged peripheral nerves vs., 11:186, 187 polyostotic lesions vs., 11:3
Ulnar-sided wrist pain, 11I:36-41 Vasculitis, acroosteolysis vs., 1:247,248
Undertubulation, long bones, 1:96-101 VATER association
Unicameral bone cyst forearm deformity vs., 1:229, 231
bone lesions with fluid/fluid levels vs., 11:144, radial dysplasia/aplasia vs., 1:227
145 short metacarpal/metatarsal bones vs., 1:261,
flat bones with focally expanded or bubbly 263
lesion vs., 1:3, 4 Venous distension (mimic), shoulder fluid
long bone central diaphyseal non-aggressive collections vs., 1:223
lesion vs., 1:66-67, 68 Venous insufficiency
long bone central metaphyseal non-aggressive calf pain related to, III:93, 96
lesion vs., 1:35,37
Ivi
INDEX
intermuscular edema vs., 11:180 Vertical talus, congenital. See Talus, congenital
periostitis of multiple bones/acropachy vs., vertical (rocker bottom foot).
1:126, 128 Vitamin A complications. See also
Venous stasis Hypervitaminosis A.
long bone diffuse cortical endosteal thickening generalized increased bone density in child vs.,
vs., 1:90, 91 11:64,66
solid periostitis vs., 1:116, 117 growth plate premature physeal closure vs.,
Vertebrae and vertebral body. See also Intervertebral 1:106
disc. solid periostitis vs., 1:117,120
asymmetric fracture, painful scoliosis vs., 111:144 Vitamin 0 complications. See also
augmentation (mimic), vertebral body sclerosis Hypervitaminosis D.
vs., 1:292, 294 bone within bone appearance vs., 11:76
block vertebra (congenital fusion), squaring of generalized increased bone density in child vs.,
one or more vertebra vs., 1:290, 291 11:64
bullet shaped vertebra/anterior vertebral body long bone metaphyseal bands and lines vs., 1:27
beaking, 1:282-283 nodular calcification vs., 11:111
cervical vertebrae solid periostitis vs., 1:117
ossification/calcification anterior to Cl, Vitamin 0 deficiency, rickets and osteomalacia
1:274-275 related to, 111:166, 168
radiculopathy, rotator cuff symptoms vs., Vitamin D dependent rickets, 111:167, 169
111:4 Vitamin deficiency anemia, 111:152, 153
congenital and acquired childhood Von Hippel-Landau disease, hemihypertrophy
platyspondyly, 1:284-287 related to, 111:178
discogenic end plate changes, increased marrow
fat vs., 11:136, 138
discogenic sclerosis, vertebral body sclerosis vs., w
1:292,293 Warfarin (coumadin) complications, irregular or
Fabry disease (vertebral bodies), generalized stippled long bone epiphysis vs., 1:12-13, 15
osteoporosis vs., II :83 Wartenberg syndrome, elbow/wrist nerve
fish (biconcave) or H-shaped vertebra, 1:288-289 entrapment vs., 111:29
fusion, posterior, squaring of one or more Weightlessness, increased marrow fat vs., 11:137
vertebra vs., 1:290 Werdnig-Hoffmann disease, muscle atrophy vs.,
lesions originating in posterior vertebral 11:177
elements, 1:306-307 Wilson disease
lesions originating in vertebral body, 1:300-305 arthritis with osteopenia vs., 1:139
limbus vertebra (mimic), lesions originating in arthritis with productive changes vs., 1:143, 145
vertebral body vs., 1:300, 303 Wire/cerclage fixation, olecranon bursitis vs., 111:26
osteomyelitis Wrist
granulomatous, paravertebral ossification clicking/clun king/instabil ity, 1I1:32-35
and calcification vs., 1:277, 279 nerve entrapment, 111:28-31
lesions crossing disc space vs., 1:268 post-traumatic, avascular necrosis related to,
lesions originating in vertebral body vs., 111:156, 158
1:300 radial-sided pain, 1Il:42-47
painful scoliosis vs., III: 144,145 ulnar-sided pain, 111:36-41
pyogenic, paravertebral ossification and
calcification vs., 1:276, 277
paravertebral ossification and calcification, x
1:276-279 Xanthoma. See Fibroxanthoma.
spinal osteophytes, 1:298-299
squaring of one or more vertebra, 1:290-291
vertebral body sclerosis, 1:292-297
Vertebral pedicle
hypoplastic/aplastic, lesions originating in
posterior vertebral elements vs., 1:306
reactive sclerosis, lesions originating in posterior
vertebral elements vs., 1:306, 307
Vertebroplasty cement (mimic), discal
mineralization vs., 1:270, 272
Ivii

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S.J.Manaster, MO, PhO, FACR

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Printed in Canada by Friesens, Altona, Manitoba, Canada

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Library of Congress Cataloging-ill-Publication Data

Our EXPERTddx series is designed to help radiologists reach reliable-indeed, expert-conclusions.

B.j. Manaster, MD, PhD, FACR

Medical Text Editing

Art Direction and Design

Elbow and Forearm

Proximal Humerus, Erosion Medial Metaphysis 1-214 Vertebral Shape

Spinal Osteophytes 1-298 Foot and Ankle

Ribs Soft Tissue Mass in the Foot 1-382

Metastases to Bone II-56

Hypertrophic Callus Formation 11-74 Cystic Masses 11-160

Bone within Bone Appearance 11-76 Subcutaneous Mass 11-166

Osteopen ia 11-80 Enlarged Muscle 11-172

Osteoporosis, Generalized 11-82 Muscle Atrophy 11-176

Regional Osteoporosis 11-88 Intermuscular Edema 11-]80

Pseudoarthrosis 11-94 Enlarged Peripheral Nerves 11-]86

Bone Age, Delayed 11-104

Radiograph/eT, Soft Tissue

Abnormal Epiphyseal Marrow Signal 11-132 Rotator Cuff Symptoms 11I-4

Increased Marrow Fat 11-136 Shoulder Instability 11I-8

Marrow Hyperplasia 11-140 Anteroinferior Labral/Capsule Injury 11I-12

MR, Soft Tissue Elbow and Forearm

Avascular Necrosis 11I-156

Lateral Hip Pain III-54 Rickets & Osteomalacia 11I-166

Hip Pain, Elderly Patient 11I-68 Focal Gigantism/Macrodactyly 11I-180

Dwarfism with Short Extremities 11I-186

Dwarfism with Short Ribs 11I-188

Painful Knee Replacement 11I-98

Ankle and Foot

Pain in the Ball of the Foot 11I-126

Congenital Foot Deformity 11I-138

ro DIFFERENTIAL DIAGNOSIS • Plasmacytoma

lesion in flat bone in patient in 30-60 year may be bubbly

Giant Cell Tumor (GCT) Plasmacytoma

AP radiograph shows a hugely expanded lytic lesion

Aneurysmal Bone Cyst (ABC) Chondrosarcoma, Conventional

Unicameral Bone Cyst (UBC) Unicameral Bone Cyst (UBC)

(Leh) AP radiograph shows

(Left) AP radiograph shows

o Adults: Generally solitary bone lesion 3

Metastases, Bone Marrow Metastases, Bone Marrow

AP radiograph shows a diffuse permeative Iylic lesion

Ewing Sarcoma Ewing Sarcoma

Osteosarcoma, Conventional Osteosarcoma, Conventional

however, tha t the lesion

(Left) AP radiograph shows a

Langerhans Cell Histiocytosis (LCH) Langerhans Cell Histiocytosis (LCH)

Multiple Myeloma (MM) Multiple Myeloma (MM)

Angiosarcoma, Osseous Radiation Osteonecrosis

Radiation-Induced Sarcoma Pagel Sarcoma

o Hypoplastic nose, eye malformations, o a.k.a., Fong disease, osteo-onychodysplasia

o Non-rhizomelic type: Conradi o Radial head hypoplasia, subluxation r

dominant constant finding than nail & patella OJ

Normal Variant in Child (Mimic) Normal Variant in Child (Mimic)