medicina

Review
The Cyst of the Canal of Nuck: Anatomy, Diagnostic
and Treatment of a Very Rare Diagnosis—A Case Report
of an Adult Woman and Narrative Review of the Literature
Michael Kohlhauser 1, * , Julian Vinzent Pirsch 1 , Thorsten Maier 2 , Christian Viertler 3 and Roland Fegerl 1

1 Department of Surgery, State Hospital Weiz, Styrian Hospital Association (KAGes), 8160 Weiz, Austria
2 Radiological Center Weiz, Institute for CT and MRI Weiz OG, 8160 Weiz, Austria
3 Diagnostic and Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria
* Correspondence: michael.kohlhauser@stud.medunigraz.at; Tel.: +43-3172-22142265

Abstract: The cyst of the canal of Nuck is an extremely rare female hydrocele, usually occurring
in children, but also in adult women. It is caused by pathology of the canal of Nuck, which is the
female equivalent to the male processus vaginalis. Due to its rarity and the lack of awareness among
physicians, the cyst of the canal of Nuck is a seldom-encountered entity in clinical practice and is
commonly misdiagnosed. We report on a case of cyst of the canal of Nuck in a 42-year-old woman,
who presented with a painful swelling at her right groin. In addition, we conducted a review of the
current available literature. This review gives an overview of the anatomy, pathology, diagnostics, and
treatment of the cyst of the canal of Nuck. The aim of this review is not only to give a survey, but also
to raise awareness of the cyst of the canal of Nuck and serve as a reference for medical professionals.

Keywords: Nuck cyst; cyst of the canal of Nuck; hydrocele; hernia; canal of Nuck; rare diseases
Citation: Kohlhauser, M.; Pirsch, J.V.;
Maier, T.; Viertler, C.; Fegerl, R. The
Cyst of the Canal of Nuck: Anatomy,
Diagnostic and Treatment of a Very
Rare Diagnosis—A Case Report of an
1. Introduction
Adult Woman and Narrative Review A female hydrocele, namely cyst of the canal of Nuck, is an extremely rare entity that
of the Literature. Medicina 2022, 58, is not commonly encountered, especially in adults [1,2]. The origin of this disease is a
1353. https://doi.org/10.3390/ pathology during embryogenesis [3,4]. Clinically, a female hydrocele typically manifests as
medicina58101353 a swelling in the groin or genital region [5–22], which allows for a variety of differential
Academic Editors: Maria Sofia Cotelli
diagnoses. Due to its rarity, most health professionals are not aware of its existence
and Filippo Manelli and the cyst of the canal of Nuck is often misdiagnosed [7–9,12,23]. Precise diagnosis,
including a thorough clinical examination and adequate radiological imaging, is required
Received: 24 August 2022 to accurately determine its presence. We report a case of a 42-year-old woman with a
Accepted: 23 September 2022
cyst of the canal of Nuck who presented to our department. This case provides insight
Published: 27 September 2022
into the various diagnostic procedures used, describes the surgical approach, and gives
Publisher’s Note: MDPI stays neutral information about the histology. In addition, we conduct a review of the available literature
with regard to jurisdictional claims in to summarize the experiences of various physicians worldwide. This review provides basic
published maps and institutional affil- knowledge about the anatomy and pathogenesis. Secondly, we provide an overview of the
iations. prevalence of the cyst of the canal of Nuck. We present commonly used classifications and
describe the symptoms and key aspects of the diagnostics, which enable the distinction of
possible differential diagnosis of inguinal or genital swelling in females. Furthermore, we
examine the therapy and discuss different surgical approaches. This review should serve
Copyright: © 2022 by the authors.
as compendium to facilitate the identification of female hydroceles and their treatment.
Licensee MDPI, Basel, Switzerland.
This article is an open access article 2. Methodology
distributed under the terms and
Due to the extremely rare occurrence of the condition, we conducted a literature review
conditions of the Creative Commons
to understand the anatomical background, the diagnostics and treatment methods in order
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
to highlight best practice in medical care of this phenomenon. The following databases
4.0/).
were used to search for and identify the included literature: PubMed, Google Scholar, and

Medicina 2022, 58, 1353. https://doi.org/10.3390/medicina58101353 https://www.mdpi.com/journal/medicina

Medicina 2022, 58, 1353 2 of 13

MEDLINE. No date restriction was imposed on the search. The result of our review is
presented in narrative form in addition to our case report.

3. Case Report
A 42-year-old female patient was referred to the surgical outpatient department by her
general practitioner due to a small swelling on the right groin, with a suspected inguinal
hernia. The patient had observed this swelling two months before, and was suffering
dragging pain in the affected area. With the exception of a hysterectomy and a bilateral
salpingectomy by reason of multiple myoma uteri two years ago, there was neither a
history of abdominal or pelvic surgery nor trauma, and the patient was otherwise in good
health, without the appearance of nausea or vomiting. On physical examination, a non-
reducible deep-seated round tumor was detected and located in the right inguinal region
with a size of approximately 15 ⇥ 10 mm, with no pressure pain. The remaining abdominal
examination was inconspicuous, with soft abdominal wall conditions and regular peristaltic
sounds. There was no complaint of lower extremity weakness.
An ultrasound examination showed a hypoechoic cystic formation originated from the
round ligament of the uterus in the right inguinal region without vascular flow or peristalsis.
No changes in size or shape due to Valsalva maneuver could be determined. Magnetic
resonance imaging (MRI) was obtained to further define the extent and nature of the cyst.
The MRI revealed a 15 ⇥ 9 ⇥ 16 mm (transversal ⇥ sagittal ⇥ craniocaudal) well-defined,
cystic formation with a peripheral contrast-enhancement within the medial border of her
right inguinal ligament with no visible communication to the peritoneal cavity, compatible
with a hydrocele of the Nuck canal. An axial T2-weighted MRI image of this hydrocele is
displayed in Figure 1.

Figure 1. Axial T2-weighted MRI: cystic structure localized in the right inguinal canal, with no
communication to the peritoneal cavity.
Medicina 2022, 58, x FOR PEER REVIEW 3 of 13
Medicina 2022, 58, 1353 3 of 13

The patient was admitted to the ward for preparation for open surgery. Due to the
The patient
anatomical was admitted
conditions, an opentosurgical
the ward for preparation
procedure for open surgery.
was determined. Due to the
Pre-surgically, the
anatomical conditions,
cyst was detected by an open surgical procedure
ultrasonography, followedwas by determined.
a para-inguinal Pre-surgically, the cyst
incision over the
was detected
verified cystby ultrasonography,
formation. followed abysmall
Intrasurgically, a para-inguinal incision
cyst appeared, over thethe
between verified cyst
external
formation.
abdominal Intrasurgically,
oblique and thearight smallinguinal
cyst appeared,
ligament. between
The cystthe external
was abdominal
dissected from theoblique
round
and the right
ligament inguinal
(Figure ligament.
2), followed byThe cyst was
a ligation dissected
and fromexcision.
completely the round Theligament
internal(Figure
inguinal 2),
followed by a ligation and completely excision. The internal inguinal
ring defect was repaired without the use of a mesh, by suturing the tendon of the external ring defect was
repaired
abdominal without the to
oblique usethe
of ashelving
mesh, byedge
suturing
of thethe tendon ligament.
inguinal of the external abdominalthe
Post-surgery, oblique
cyst
to
wastheopened
shelving edge
with of the inguinal
a scalpel, wherebyligament.
a mucous,Post-surgery,
light-coloredthe cyst
fluid was
was opened with
discharged. Thea
scalpel, whereby
histological a mucous,
intervention light-colored
confirmed fluid was discharged.
the diagnosis of cyst of theThe histological
canal of Nuck.intervention
The image
confirmed the diagnosis
of the hematoxylin and of cyststaining
eosin of the canal of Nuck.
as well The image
as a brief of the hematoxylin
explanation is shown in and eosin
Figure 3.
staining as well as a brief explanation is shown in Figure 3. In our follow-up
In our follow-up 6 months after surgery, the patient was asymptomatic and satisfied with 6 months after
surgery, the patient was asymptomatic and satisfied with the treatment.
the treatment.

Figure 2. Intraoperative
Figure 2. picture of
Intraoperative picture of the
the cyst
cyst of
of the canal
canal of
of Nuck
Nuck after
after dissection
dissection from
from the
the round
round
ligament.
ligament.
Medicina 2022, 58, 1353
  4 of 13
   

 
Figure 3. Histology hematoxylin and eosin staining: cystic structure localized within fibromuscular
Figure 3. Histology hematoxylin and eosin staining: cystic structure localized within fibromuscular 
and adipose tissue demonstrating a flat to cuboidal mesothelial lining (left corner), consistent with 
and adipose tissue demonstrating a flat to cuboidal mesothelial lining (left corner), consistent with a
a hydrocele of the canal of Nuck. 
hydrocele of the canal of Nuck.

4. Review of Literature
4.1. Anatomical and Pathological Background
In 1691, Anton Nuck, a Dutch anatomist, was the first to describe the canal of Nuck [24].
The canal of Nuck is the female equivalent to the processus vaginalis in males, which usually
disappears within the first year of life. It consists of an evagination of peritoneum, which
is attached to the uterus by the round ligament, and proceeds through the inguinal ring
alongside the round ligament into the labia majora [3,11]. Usually, the superior part of this
outpouch obturates during or just before birth and disappears within the first year of life.
In rare cases, this obturation fails, resulting in a persistence of the canal of Nuck [3,4,24]
(Figure 4), which can cause the formation of a female hydrocele, namely the cyst of the
canal of Nuck [1,13]. This phenomenon in women was first reported by Coley in 1892 [25].
Similar to the male hydrocele, a female hydrocele probably arises due to an imbalance
of secretion from and absorption of fluid by the secretory membranes of the canal of
Nuck [3,26]. Although this imbalance is most frequently idiopathic, disturbed lymphatic
drainage caused by trauma, infection or inflammation are other possible reasons [11,16].

 
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Medicina 2022, 58, 1353
Medicina 2022, 58, x FOR PEER REVIEW
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Figure4.4.AAschematic
Figure schematicofofthe
thefemale
femaleanatomy
anatomyand
andthe
thepatent
patentcanal
canalofofNuck.
Nuck.

4.2.
4.2.Prevalence
Prevalence
According
Accordingtotothetheexisting
existing literature, only
literature, a few
only papers
a few papers have reported
have reportedthe the
prevalence of
prevalence
the cystcyst
of the of the canal
of the of Nuck
canal of Nuck in children. Paparella
in children. Paparella et et
al.al.
described
describeda aprevalence
prevalenceofof0.74%
0.74%
inin353
3531–14-year-old
1–14-year-oldfemale
femalepatients
patientswith
withinguinal
inguinalswellings
swellings[27].
[27].AAsimilar
similarfinding
findingwaswas
shown
shownbybyAkkoyun
Akkoyunetet al.,al.,
whowho reported a prevalence
reported a prevalence of 0.76% in ain
of 0.76% cohort of 0–16-year-old
a cohort of 0–16-year-
girls
old [23].
girls Huang et al. et
[23]. Huang found a prevalence
al. found of theofcyst
a prevalence theofcyst
theofcanal of Nuck
the canal in 1% in
of Nuck of 1%
girlsof
aged from 1 month up to 14 years [28]. No data about the prevalence in
girls aged from 1 month up to 14 years [28]. No data about the prevalence in adults areadults are available.
Therefore,
available.no valid statement
Therefore, no validabout the prevalence
statement in adult females
about the prevalence can
in adult be made
females canasbeofmade
yet.
as of yet.
4.3. Classification
4.3. The commonly used classification was developed by Counseller and Black, who
Classification
classified cysts of the canal of Nuck into three different types [29]. The most prevalent
The commonly used classification was developed by Counseller and Black, who
type forms a hydrocele along the round ligament without any communication with the
classified cysts of the canal of Nuck into three different types [29]. The most prevalent
peritoneal cavity. The second type communicates with the peritoneal cavity, and the third,
type forms a hydrocele along the round ligament without any communication with the
the “hour-glass” type, is constricted by the inguinal ring, whereby one part communicates
peritoneal cavity. The second type communicates with the peritoneal cavity, and the third,
with the peritoneal cavity, while the other part does not. The three different types of cyst of
the “hour-glass” type, is constricted by the inguinal ring, whereby one part communicates
the canal of Nuck are shown in Figure 5.
with the peritoneal cavity, while the other part does not. The three different types of cyst
of the canal of Nuck are shown in Figure 5.
A recent classification was published by Wang et al. in 2021 [30], who subdivided the
cyst of the canal of Nuck into four groups according to its anatomical position. Type A is
located subcutaneously over the inguinal canal, Type B resides inside the inguinal canal,
Type C is confined to the internal inguinal ring, and Type D extends from the internal
inguinal ring to the inguinal canal or subcutaneously.
Medicina 2022, 58, 1353 6 of 13

Figure 5. Schematic overview of the different types of cysts of the canal of Nuck as classified by
Counseller and Black.

A recent classification was published by Wang et al. in 2021 [30], who subdivided
the cyst of the canal of Nuck into four groups according to its anatomical position. Type
A is located subcutaneously over the inguinal canal, Type B resides inside the inguinal
canal, Type C is confined to the internal inguinal ring, and Type D extends from the internal
inguinal ring to the inguinal canal or subcutaneously.

4.4. Clinical Presentation and Diagnostic Methods

The clinical presentation of a cyst of the canal of Nuck shows an inguinal or genital,
painless or painful swelling, with no attending nausea or vomiting [5–22]. Some existing
reports identify that the mass can be reduced manually [8,17,19], and shows no increase
in volume when performing the Valsalva maneuver [14,19]. Several authors report an
increase in the volume of the swelling when the patient is standing [13,17], while others
do not [6]. In general, a differentiation from other entities that cause inguinal or genital
swelling based on symptoms and physiological examination is not possible. The most
important differential diagnosis of the cyst of the canal of Nuck is the inguinal hernia,
with which it is often initially mistaken [9,12,23]. The co-existence of an inguinal hernia
is reported in up to 40% of patients with a cyst of the canal of Nuck, making diagnosis
even more difficult [16–18]. Hydroceles that extend to the vulva may initially be mistaken
for Bartholin cysts. [6,7]. Other differential diagnoses for the cyst of the canal of Nuck
are lymphadenopathy, cold abscesses, endometriosis of the round ligaments, ganglion
cysts, varicosity of the round ligament and other vascular diseases, or neoplasms such as
lipomata or leiomyomata [3,10,17,20,21]. An overview of important differential diagnoses
of the cyst of the canal of Nuck is presented in Table 1.
Radiological imaging is of utmost importance in distinguishing from the differential
diagnoses presented above. For initial imaging of suspect inguinal or genital swellings,
sonography is the preferred investigative method. On ultrasound, the cyst of the canal
of Nuck appears as a thin-walled anechoic or hypoechoic formation with no changes on
Valsalva maneuver and lack of vascular flow on color Doppler [10,15,16,21]. In addition
to high-resolution sonography, cross-sectional imaging should be performed to obtain
detailed information about the cyst formation. The method of choice should be MRI, which
enables a more precise view of anatomical conditions with no radiation compared with
the computed tomography (CT). On MRI, the cyst of the canal of Nuck represents as a
thin-walled mass, which appears hypointense on T1-weighted sequences and hyperintense
on T2-weighted ones [1,16,21,22]. After contrast administration, no enhancing of the cystic
mass, which is considered a sign of benignity, can be observed within MRI [17,31,32]. Due
to its radiation, CT is only the second-line method, when accessing inguinal or genital
swellings, in particular when imaging children. On CT, the cyst of the canal of Nuck
Medicina 2022, 58, 1353 7 of 13

appears as a homogeneous fluid-filled unilocular sac extending along the course of the
round ligament [13,15,19]. As with MRI, no enhancement of the interior cyst can be
identified within CT-imaging after contrast administration [15,33].

Table 1. Comparison of the Cyst of the canal of Nuck and possible differential diagnosis.

Differential Diagnosis Symptoms Physical Examination Imaging

On ultrasound, an anechoic or
hypoechoic lesion without
changes in the Valsalva
maneuver and without
vascular flow can be detected.
On clinical examination, an Computed tomography (CT)
Cysts of the canal of Nuck inguinal or genital swelling is imaging shows the cyst of the
present as an inguinal or palpable. This mass shows no canal of Nuck as a
Cyst of the canal of Nuck genital, painless or painful increase in volume by homogeneous fluid-filled
swelling with no performing the Valsalva lesion along the round
gastrointestinal symptoms. maneuver, and may is ligament.
manually reducible. On magnetic resonance
imaging (MRI), it shows as a
thin-walled lesion, which
appears hypointense on
T1-weighted and hyperintense
on T2-weighted sequences.
Although it is rarely necessary,
imaging may be useful in
unclear situations. Ultrasound
is a highly sensitive method of
identifying hernias. While the
herniating fat appears
Inguinal hernias may be hyperechoic on ultrasound,
asymptomatic or symptomatic The gold standard for hernia the bowel may show
along with swelling, diagnostics is clinical peristalsis. Valsalva maneuver
discomfort, or pain in the examination, although is an important examination
groin. Activities that increase diagnosis is more difficult in during the sonography, to
Inguinal hernia [34–37] intra-abdominal pressure may women. A female inguinal increase the swelling and
increase these symptoms. hernia is confirmed if a bulge show characteristic movement
Sudden severe pain, nausea is palpable with the open of the herniating tissues.
and vomiting indicate hand over the groin during a When ultrasound is not
possible incarceration of Valsalva maneuver. sufficient, a dynamic MRI or
organs in the hernia sac. CT can be considered. On
MRI, hernias present as
pathological widening of the
anteroposterior inguinal canal
and/or protrusion of
gastro-enteric content within
the inguinal canal.
Medicina 2022, 58, 1353 8 of 13

Table 1. Cont.

Differential Diagnosis Symptoms Physical Examination Imaging

Inguinal lymph node size over On ultrasound, benign
1.5 cm should be suspected as lymphadenopathies emerge as
pathological. Pain and ovoid lesions with various
tenderness on a lymph node is borders, inconspicuous hilum,
a non-specific finding. and isoechoic internal
Lymphadenopathies resulting echogenicity, while neoplastic
from infections are usually disorders present as round
Localized inguinal
free moving. Acute lesions with a sharp border,
lymphadenopathy is typically
inflammation makes nodes no hilum and a hypoechoic
caused by infection, while
tauter with concomitant internal echogenicity.
Lymph-adenopathy [38,39] malignancy rarely presents
tenderness, while chronic Most benign
itself solely in the inguinal
inflammation leads to hard lymphadenopathies present as
lymph nodes.
nodes. Painless and ovoid lesions with a central
adamantine nodes, which are fatty hilum on CT and MRI.
fixed to the surrounding Round morphology in
tissues are usually caused by addition to changes in size,
metastatic cancer or signal intensity, and dynamic
granulomatous diseases. gadolinium contrast
Rubbery mobile nodes are enhancement are typical for
typical of lymphoma. malignant lesions.
On ultrasound, a Bartholin
During examination small cyst is a central hypoechoic to
asymptomatic cysts may be anechoic lesion, surrounded
observed as small masses, by a stronger reflective cystic
Bartholin cyst can be
while larger cysts and wall, which presents as
asymptomatic or
abscesses are associated with increased echo enhancement
symptomatic, associated with
Bartholin cysts [40–42] cellulitis, severe pain and on the posterior side.
painful swelling in not only
swelling. In addition, a On MRI, it shows as a small
the genital but also the
Bartholin gland abscess cystic mass with a high signal
inguinal region.
presents with erythema, intensity on T2-weighted
edema and sometimes sequences and also,
ruptured skin. depending on the mucoid
content, on T1-weighted ones.
On sonographic examination,
endometriosis of the round
ligament shows as an
inhomogeneous hypoechoic
On examination, the lesion with poorly defined
endometriosis of the round boundaries.
If endometriosis affects the ligament presents as groin On MRI scans, endometriosis
extra pelvic portion of the mass without fluctuation, of the round ligament, which
Endometriosis of the round round ligament it may present which is non-reducible and usually presents as a thin
ligament [43,44] as a painful, palpable groin possibly partially tender. hypointense structure,
mass with or without There are no changes through appears thickened, shortened
menstrual variation. straining, coughing or and irregular. While pure
adjustments in the patient’s fibrous lesions are
position. hypointense on T1- and T2-
weighted sequences,
hemorrhagic lesions are
hyperintense on T1-weighted
images.
Medicina 2022, 58, 1353 9 of 13

Table 1. Cont.

Differential Diagnosis Symptoms Physical Examination Imaging

Ganglion cysts present on
ultrasound as a hypoechoic
lesion without the ability to
identify the exact joint
connection.
On CT, ganglion cysts show
On clinical examination, lower attenuation than
Ganglion cysts of the hip joint
ganglion cysts show as tender, muscles, but higher ones than
are usually asymptomatic but
non-pulsatile masses, which fat. After contrast
may cause pain through
may limit the range of motion administration, a rim
compression of nerves and
Ganglion cysts [45,46] of the hip joint. Deeper cysts enhancement may be
vessels. They may present as
are more difficult to palpate observed.
swelling of the groin or
and usually a radiological MRI can show round or ovoid
genital region, when they
imaging is necessary to detect cystic masses with low signal
become larger.
them. intensities on T1- and high
ones on T2-weighted
sequences. Similar to CT, a
rim enhancement can be
observed on T1-weighted MRI
sequences, after contrast
administration.
On ultrasonography, lipomata
present as homogenous
hyperechogenic masses.
On palpation, lipomata are MRI is necessary for any
freely movable doughy deeper lipomas or lesion
Lipoma presents as a painless
subcutaneous masses. Deeper bigger than 5 cm. Lipomata
soft-tissue mass. Deeper ones
Lipomata [47] ones, namely intramuscular show as homogenous lesions,
may be larger and present as
lipomata move isointense to fat and may
asymmetrical.
simultaneously with muscle contain thin fibrous septae, on
contraction. MRI. CT is only the second
choice, when patients are
inept for MRI due to medical
reasons.
On ultrasound leiomyomata
present as well-defined, solid,
concentric, hypoechoic
masses. Due to its bad
On palpation a vulvar soft-tissue contrast, CT has a
Leiomyomata may arise in
leiomyoma shows as a minor role in diagnostics.
unusual regions such as the
partially mobile mass, which Vaginal Leiomyomata are
vulva. Clinically, these vulvar
Leiomyomata [48–50] is non-tender in most cases. In isotense to muscles on
leiomyomata usually present
certain superficial lesions, a T1-weighted MRI sequences
as painless swellings of the
peduncle is sometimes and enhance homogenously
genital region.
palpable. after contrast administration.
On T2-weighted sequences,
vulvar leiomyomata show a
low signal intensity similar to
that of smooth muscles.
Medicina 2022, 58, 1353 10 of 13

Table 1. Cont.

Differential Diagnosis Symptoms Physical Examination Imaging

The sonographical
characteristics of the round
ligament varicosities are
dilated veins that appear as
multiple echo free serpentine
tubes, some of which drain
into the inferior epigastric
artery, with no herniated
Varicosity of the round On physical examination, bowel or lymphadenopathy.
ligament is a further rare varicosity of the round Doppler sonography reveals
condition, which commonly ligament occurs as a soft groin hypervascularity with a
Varicosity of the round
occurs as painful or painless mass. Some authors describe venous flow pattern which
ligament [51–55]
inguinal swelling. In most an increase in size of the mass increases during
common cases, the occurrence in standing position and on Valsalva-maneuver. On both
is associated with pregnancy. Valsalva maneuver. MRI and CT, the varicosity of
the round ligament appears as
a well-defined serpentine
structure extending along the
inguinal course of the round
ligament of the uterus. In the
case of thrombosis, the MRI
will show a high T1 and a low
T2 signal.

4.5. Treatment
Due to the extreme rarity of cysts of Nuck’s canal, no standard therapeutic procedure
as yet exists. Although conservative therapy options such as aspiration or sclerotherapy of
female hydroceles are reported in the literature, hydrocelectomy is recommended, with or
without ligation of the cyst, as treatment of choice [6,7,10,15,19,21,22,56]. Due to anatomical
conditions or pathologies such as necrosis of the round ligament, a radical excision of
it may be necessary, in addition to hydrocelectomy [9,17,22]. Several authors suggest
repairing intraoperative defects by using a polyurethane mesh [5,22,32]. In addition to
hydrocelectomy, an aesthetic correction of the vulva may be required as part of the surgery,
if the hydrocele has extended to the labia majora [6,7].
Recent therapeutic approaches consider laparoscopic intervention for the treatment
of female hydroceles [8,30,57,58]. In particular, the transabdominal preperitoneal (TAPP)
and the totally extra-peritoneal (TEP) techniques are considered as popular laparoscopic
methods, which can also be used in the treatment of cyst of the canal of Nuck [8,12,30,58].
Laparoscopy can not only be used as a treatment option, but also as an additional diagnostic
method to determine the hydrocele and anatomical conditions. Compared with TEP,
TAPP has a better diagnostic potential, due to the improved imaging of the abdominal
cavity, its anatomical variations and the hydrocele itself [8,12,30,58]. However, sometimes
difficult anatomical conditions may prevent a laparoscopic repair, requiring conversion to
traditional open anterior surgery [59]. Furthermore, laparoscopic intervention requires a
mesh prosthesis to repair the defect within the abdominal wall [8,30,58]. Therefore, the
surgical intervention of a cyst of the Nuck’s canal must be well considered and adapted in
advance of to the anatomical conditions, as well as the skill of the surgeon.

5. Discussion
A hydrocele in young females is a very uncommon disease, and it occurs even more
rarely in adult women. Due to its infrequency, many health professionals are not even
aware of its existence. Therefore, it is of utmost importance to raise awareness of clinicians,
including surgeons and radiologists on the presence of the canal of Nuck as well as the
possibility of a female hydrocele.
Medicina 2022, 58, 1353 11 of 13

The primary symptom of the cyst of the canal of Nuck is a painless or painful swelling
in the groin or the labia majora [1,2,7,8,10,11,22]. Initially, in many of the reported cases in
the literature, they were wrongly suspected of being an inguinal hernia [9,12,23], which
is the most common differential diagnosis of the cyst of the canal of Nuck. Through well-
targeted physical examination, followed by high-resolution sonography, a differentiation
of a cyst of the canal of Nuck from other entities can easily be performed. With MRI,
the anatomical condition can be clarified and the diagnosis of cyst of the canal of Nuck
determined. Therefore, in our opinion, an MRI investigation for suspect inguinal or genital
swelling should be mandatory.
The treatment of choice is surgical excision of the cyst. Based on our literature research,
only a few reports about surgical approaches are available. However, due to the rarity
of a Nuck’s canal cyst, there is no defined standard method of intervention to date. In
our opinion, the surgical approach should be adapted, based on the type of cyst of the
canal of Nuck, the anatomical conditions, and the experience of the responsible surgeon.
Although laparoscopic approaches have advantages such as reduced blood loss, less wound
drainage, and a better aesthetic outcome, they are associated with higher risk for peri- and
postoperative complications such as enterotomy, bowel injury, postoperative bleeding and
ileus [60]. Thus, it is of utmost importance to consider the risk-benefit ratio before surgery.
Due to the variation of the hydrocele with no connection to the peritoneal cavity, it was
decided to perform an open ligation and hydrocelectomy in the present case, followed by
repair of the inguinal defect without the use of mesh.
In the available literature, only a few reports of cysts of the canal of Nuck have
been published since its discovery [5–22]. However, in recent years, the number of pub-
lished cases regarding this topic has increased significantly. One possible reason is the
improvement in imaging methods, which enables a better overview of this anomaly and its
anatomical features.
In conclusion, the cyst of the canal of Nuck in adult women is an extremely rare disease.
If one is aware of its existence, it can be easily diagnosed using modern diagnostic methods
and treated by adequate surgical approaches. A cyst of the canal of Nuck should always be
considered as a possible cause in suspect inguinal and genital swellings in females.

6. Conclusions
Due to the rare clinical occurrence and the lack of literature, a diagnosis of a cyst of
the canal of Nuck is often difficult to make, not only for inexperienced surgeons, but also
for medical experts. Thus, interdisciplinary collaboration in healthcare between various
different fields, such as radiology and surgery, is necessary to prevent misdiagnosis as well
as resultant errors in treatment. A focused physical examination followed by high-resolution
sonography enables the diagnosis of a cyst of the canal of Nuck. To plan an adequate
surgical intervention, cross-sectional imaging, preferably MRI, allowing clarification of
the anatomical conditions is of utmost importance. Our review provides insight into the
anatomical background, diagnostics, and surgical intervention of a cyst of the canal of Nuck.
This article may serve as the foundation for raising awareness about the possibility of female
hydroceles and provide guidelines for diagnostic and surgical methods.

Author Contributions: Project administration, conceptualization and methodology, M.K.; Diagnosis

and surgical care, J.V.P. and M.K.; Analysis and provision of MRI images, T.M.; Histological evaluation
and provision of histological imaging, C.V.; Literature research, M.K.; Visualization of the schematic
images, M.K., Writing—original draft preparation, M.K.; Writing—review and editing, J.V.P., C.V., T.M.
and R.F.; Supervision, R.F. All authors have read and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Informed Consent Statement: Informed consent was obtained from the patient who is reported about
in this case report. Written informed consent was obtained from the patient to publish this paper.
Data Availability Statement: For data requests, please contact the corresponding author.
Medicina 2022, 58, 1353 12 of 13

Conflicts of Interest: The authors declare no conflict of interest.

References
1. Prodromidou, A.; Paspala, A.; Schizas, D.; Spartalis, E.; Nastos, C.; Machairas, N. Cyst of the canal of Nuck in adult females: A
case report and systematic review. Biomed. Rep. 2020, 12, 333–338. [CrossRef] [PubMed]
2. Fikatas, P.; Megas, I.F.; Mantouvalou, K.; Alkatout, I.; Chopra, S.S.; Biebl, M.; Pratschke, J.; Raakow, J. Hydroceles of the canal of
nuck in adults—Diagnostic, treatment and results of a rare condition in females. J. Clin. Med. 2020, 9, 4026. [CrossRef] [PubMed]
3. Nasser, H.; King, M.; Rosenberg, H.K.; Rosen, A.; Wilck, E.; Simpson, W.L. Anatomy and pathology of the canal of Nuck. Clin.
Imaging 2018, 51, 83–92. [CrossRef] [PubMed]
4. Holley, A. Pathologies of the canal of Nuck. Sonography 2018, 5, 29–35. [CrossRef]
5. Okoshi, K.; Mizumoto, M.; Kinoshita, K. Endometriosis-associated hydrocele of the canal of Nuck with immunohistochemical
confirmation: A case report. J. Med. Case Rep. 2017, 11, 354. [CrossRef] [PubMed]
6. Ferreira, A.F.; Marques, J.P.; Falcão, F. Hydrocele of the canal of Nuck presenting as a sausage-shaped mass. BMJ Case Rep. 2017,
2017, bcr-2017-221024. [CrossRef]
7. Pandey, A.; Jain, S.; Verma, A.; Jain, M.; Srivastava, A.; Shukla, R.C. Hydrocele of the canal of Nuck-Rare differential for vulval
swelling. Indian J. Radiol. Imaging 2014, 24, 175–177. [CrossRef]
8. Matsumoto, T.; Hara, T.; Hirashita, T.; Kubo, N.; Hiroshige, S.; Orita, H. Laparoscopic diagnosis and treatment of a hydrocele of
the canal of Nuck extending in the retroperitoneal space: A case report. Int. J. Surg. Case Rep. 2014, 5, 861–864. [CrossRef]
9. Uzun, I.; İnan, C.; Varol, F.; Erzincan, S.; Sütcü, H.; Sayin, C. Hemorrhagic cyst of the canal of Nuck after vaginal delivery
presenting as a painful inguinal mass in the early postpartum period. Eur. J. Obstet. Gynecol. Reprod. Biol. 2017, 213, 147–148.
[CrossRef]
10. Walter, H.; Stickel, M.D.; Martin Manner, M. Female hydrocele of canal of nuck. J. Ultrasound Med. 2010, 107, 38–39.
11. Zawaideh, J.P.; Trambaiolo Antonelli, C.; Massarotti, C.; Remorgida, V.; Derchi, L.E. Cyst of Nuck: A Disregarded Pathology. J.
Minim. Invasive Gynecol. 2018, 25, 376–377. [CrossRef] [PubMed]
12. Bunting, D.; Szczebiot, L.; Cota, A. Laparoscopic hernia repair-When is a hernia not a hernia? J. Soc. Laparoendosc. Surg. 2013, 17,
654–656. [CrossRef] [PubMed]
13. Kim, K.S.; Choi, J.H.; Kim, H.M.; Kim, K.P.; Kwon, Y.J.; Hwang, J.H.; Lee, S.Y. Hydrocele of the canal of nuck in a female adult.
Arch. Plast. Surg. 2016, 43, 476–478. [CrossRef] [PubMed]
14. Bagley, J.E.; Davis, M.B. Cyst of canal of nuck. J. Diagn. Med. Sonogr. 2015, 31, 111–114. [CrossRef]
15. Patnam, V.; Narayanan, R.; Kudva, A. A cautionary approach to adult female groin swelling: Hydrocoele of the canal of Nuck
with a review of the literature. BMJ Case Rep. 2016, 2016, bcr2015212547. [CrossRef]
16. Ozel, A.; Kirdar, O.; Halefoglu, A.M.; Erturk, S.M.; Karpat, Z.; Lo Russo, G.; Maldur, V.; Cantisani, V. Cysts of the canal of Nuck:
Ultrasound and magnetic resonance imaging findings. J. Ultrasound 2009, 12, 125–127. [CrossRef] [PubMed]
17. Caviezel, A.; Montet, X.; Schwartz, J.; Egger, J.F.; Iselin, C.E. Female hydrocele: The cyst of nuck. Urol. Int. 2009, 82, 242–245.
[CrossRef]
18. Ryan, J.D.; Joyce, M.R.; Pierce, C.; Brannigan, A.; O’Connell, P.R. Haematoma in a hydrocele of the canal of Nuck mimicking a
Richter’s hernia. Hernia 2009, 13, 643–645. [CrossRef]
19. Sethi, V.; Patel, H. Hydrocele in the canal of nuck—CT appearance of a developmental groin anomaly. J. Radiol. Case Rep. 2016, 10,
29–33. [CrossRef]
20. Hwang, B.; Bultitude, J.; Diab, J.; Bean, A. Cyst and endometriosis of the canal of Nuck: Rare differentials for a female groin mass.
J. Surg. Case Rep. 2022, 2022, rjab626. [CrossRef]
21. Jagdale, R.; Agrawal, S.; Chhabra, S.; Jewan, S.Y. Hydrocele of the canal of Nuck: Value of radiological diagnosis. J. Radiol. Case
Rep. 2012, 6, 18–22. [CrossRef] [PubMed]
22. Kono, R.; Terasaki, H.; Murakami, N.; Tanaka, M.; Takeda, J.; Abe, T. Hydrocele of the canal of Nuck: A case report with magnetic
resonance hydrography findings. Surg. Case Rep. 2015, 1, 86. [CrossRef] [PubMed]
23. Akkoyun, I.; Kucukosmanoglu, I.; Yalinkilinc, E. Cyst of the canal of Nuck in pediatric patients. N. Am. J. Med. Sci. 2013, 5,
353–356. [CrossRef] [PubMed]
24. Nuck, A. Adenographia curiosa et uteri foeminei anatome nova. Am. J. Obstet. Gynecol. 1975, 123, 66. [CrossRef]
25. Coley, W.B., II. Hydrocele in the Female: With a Report of Fourteen Cases. Ann. Surg. 1892, 16, 42–59. [CrossRef]
26. Dagur, G.; Gandhi, J.; Suh, Y.; Weissbart, S.; Sheynkin, Y.R.; Smith, N.L.; Joshi, G.; Khan, S.A. Classifying Hydroceles of the
Pelvis and Groin: An Overview of Etiology, Secondary Complications, Evaluation, and Management. Curr. Urol. 2017, 10, 1–14.
[CrossRef]
27. Papparella, A.; Vaccaro, S.; Accardo, M.; DE Rosa, L.; Ronchi, A.; Noviello, C. Nuck cyst: A rare cause of inguinal swelling in
infancy. Minerva Pediatr. 2021, 73, 180–183. [CrossRef]
28. Huang, C.S.; Luo, C.C.; Chao, H.C.; Chu, S.M.; Yu, Y.J.; Yen, J.B. The presentation of asymptomatic palpable movable mass in
female inguinal hernia. Eur. J. Pediatr. 2003, 162, 493–495. [CrossRef]
29. Counseller, V.S.; Black, B.M. Hydrocele of the canal of Nuck. Report of seventeen cases. Ann. Surg. 1941, 113, 625–630. [CrossRef]
30. Wang, L.; Maejima, T.; Fukahori, S.; Shun, K.; Yoshikawa, D.; Kono, T. Laparoscopic surgical treatment for hydrocele of canal of
Nuck: A case report and literature review. Surg. Case Rep. 2021, 7, 121. [CrossRef]
Medicina 2022, 58, 1353 13 of 13

31. Manenti, G.; D’Amato, D.; Ranalli, T.; Marsico, S.; Castellani, F.; Salimei, F.; Floris, R. Cyst of canal of Nuck in a young woman
affected by kniest syndrome: Ultrasound and MRI features. Radiol. Case Rep. 2019, 14, 217–220. [CrossRef] [PubMed]
32. Topal, U.; Sarıtaş, A.G.; Ülkü, A.; Akçam, A.T.; Doran, F. Cyst of the canal of Nuck mimicking inguinal hernia. Int. J. Surg. Case
Rep. 2018, 52, 117–119. [CrossRef]
33. Scott, M.; Helmy, A.H. Rare encounter: Hydrocoele of canal of Nuck in a Scottish rural hospital during the COVID-19 pandemic.
BMJ Case Rep. 2020, 13, 13–16. [CrossRef] [PubMed]
34. Jamadar, D.A.; Jacobson, J.A.; Morag, Y.; Girish, G.; Ebrahim, F.; Gest, T.; Franz, M. Sonography of inguinal region hernias. Am. J.
Roentgenol. 2006, 187, 185–190. [CrossRef] [PubMed]
35. Shakil, A.; Aparicio, K.; Barta, E.; Munez, K. Inguinal Hernias: Diagnosis and Management. Am. Fam. Physician 2020, 102, 487–492.
[PubMed]
36. Van den Berg, J. Inguinal Hernias: MRI and Ultrasound. Semin. Ultrasound CT MRI 2002, 23, 156–173. [CrossRef]
37. Simons, M.P.; Smietanski, M.; Bonjer, H.J.; Bittner, R.; Miserez, M.; Aufenacker, T.J.; Fitzgibbons, R.J.; Chowbey, P.K.; Tran, H.M.;
Sani, R.; et al. International guidelines for groin hernia management. Hernia 2018, 22, 1–165. [CrossRef]
38. Mohseni, S.; Shojaiefard, A.; Khorgami, Z.; Alinejad, S.; Ghorbani, A.; Ghafouri, A. Peripheral lymphadenopathy: Approach and
diagnostic tools. Iran. J. Med. Sci. 2014, 39, 158–170.
39. Torabi, M.; Aquino, S.L.; Harisinghani, M.G. Current Concepts in Lymph Node Imaging Continuing Education. J. Nucl. Med.
2004, 45, 1509–1518.
40. Eppel, W.; Worda, C. Ultrasound Imaging of Bartholin’ s Cysts. Gynecol. Obstet. Investig. 2000, 49, 179–182. [CrossRef]
41. López, C.; Balogun, M.; Ganesan, R.; Olliff, J.F. MRI of vaginal conditions. Clin. Radiol. 2005, 60, 648–662. [CrossRef] [PubMed]
42. Lee, M.Y.; Dalpiaz, A.; Schwamb, R.; Miao, Y.; Waltzer, W.; Khan, A. Clinical pathology of Bartholin’s glands: A review of the
literature. Curr. Urol. 2014, 8, 22–25. [CrossRef] [PubMed]
43. Licheri, S.; Pisano, G.; Erdas, E.; Ledda, S.; Casu, B.; Cherchi, M.V.; Pomata, M.; Daniele, G.M. Endometriosis of the round
ligament: Description of a clinical case and review of the literature. Hernia 2005, 9, 294–297. [CrossRef] [PubMed]
44. Gui, B.; Valentini, A.L.; Ninivaggi, V.; Marino, M.; Iacobucci, M.; Bonomo, L. Deep pelvic endometriosis: Don’t forget round
ligaments. Review of anatomy, clinical characteristics, and MR imaging features. Abdom. Imaging 2014, 39, 622–632. [CrossRef]
45. Yukata, K.; Nakai, S.; Goto, T.; Ikeda, Y.; Shimaoka, Y.; Yamanaka, I.; Sairyo, K.; Hamawaki, J.I.J. Cystic lesion around the hip joint.
World J. Orthop. 2015, 6, 688–704. [CrossRef]
46. Angelini, A.; Zanotti, G.; Berizzi, A.; Staffa, G.; Piccinini, E.; Ruggieri, P. Synovial cysts of the hip. Acta Biomed. 2017, 88, 483–490.
[CrossRef]
47. Johnson, C.N.; Ha, A.S.; Chen, E.; Davidson, D. Lipomatous soft-tissue tumors. J. Am. Acad. Orthop. Surg. 2018, 26, 779–788.
[CrossRef]
48. Fasih, N.; Prasad Shanbhogue, A.K.; Macdonald, D.B.; Fraser-Hill, M.A.; Papadatos, D.; Kielar, A.Z.; Doherty, G.P.; Walsh,
C.; McInnes, M.; Atri, M. Leiomyomas beyond the uterus: Unusual locations, rare manifestations. Radiographics 2008, 2, 1931.
[CrossRef]
49. Sun, C.; Zou, J.; Wang, Q.; Wang, Q.; Han, L.; Batchu, N.; Ulain, Q.; Du, J.; Lv, S.; Song, Q.; et al. Review of the pathophysiology,
diagnosis, and therapy of vulvar leiomyoma, a rare gynecological tumor. J. Int. Med. Res. 2018, 46, 663–674. [CrossRef]
50. Wozniak, A.; Wozniak, S. Ultrasonography of uterine leiomyomas. Menopause Rev. 2017, 16, 113–117. [CrossRef]
51. Mine, Y.; Eguchi, S.; Enjouji, A.; Fukuda, M.; Yamaguchi, J.; Inoue, Y.; Fujita, F.; Tsukamoto, O.; Masuzaki, H. Round ligament
varicosities diagnosed as inguinal hernia during pregnancy: A case report and series from two regional hospitals in Japan. Int. J.
Surg. Case Rep. 2017, 36, 122–125. [CrossRef] [PubMed]
52. Naik, S.S.; Balasubramanian, P. Round ligament varices mimicking inguinal hernia during pregnancy. Radiol. Case Rep. 2019, 14,
1036–1038. [CrossRef] [PubMed]
53. Ryu, K.H.; Yoon, J.H. Ultrasonographic diagnosis of round ligament varicosities mimicking inguinal hernia: Report of two cases
with literature review. Ultrasonography 2014, 33, 216–221. [CrossRef] [PubMed]
54. Tokue, H.; Aoki, J.; Tsushima, Y.; Endo, K. Characteristic of computed tomography and magnetic resonance imaging finding of
thrombosed varices of the round ligament of the uterus: A case report. J. Comput. Assist. Tomogr. 2008, 32, 559–561. [CrossRef]
55. Ng, C.; Wong, G.T. Round ligament varicosity thrombosis presenting as an irreducible inguinal mass in a postpartum woman. J.
Clin. Imaging Sci. 2019, 9, 28. [CrossRef]
56. Cornacchia, C.; Dessalvi, S.; Boccardo, F. Surgical treatment of cyst of the canal of nuck and prevention of lymphatic complications:
A single-center experience. Lymphology 2019, 52, 143–148. [CrossRef]
57. Qureshi, N.J.; Lakshman, K. Laparoscopic excision of cyst of canal of Nuck. J. Minim. Access Surg. 2014, 10, 87–89. [CrossRef]
58. Shahid, F.; El Ansari, W.; Ben-Gashir, M.; Abdelaal, A. Laparoscopic hydrocelectomy of the canal of Nuck in adult female: Case
report and literature review. Int. J. Surg. Case Rep. 2020, 66, 338–341. [CrossRef]
59. Wang, L.; Maejima, T.; Fukahori, S.; Shun, K.; Yoshikawa, D.; Kono, T. Laparoscopic assisted hydrocelectomy of the canal of Nuck:
A case report. Surg. Case Rep. 2021, 7. [CrossRef]
60. Eker, H.H.; Hansson, B.M.E.; Buunen, M.; Janssen, I.M.C.; Pierik, R.E.G.J.M.; Hop, W.C.; Bonjer, H.J.; Jeekel, J.; Lange, J.F.
Laparoscopic vs Open Incisional Hernia Repair. JAMA Surg. 2013, 148, 259. [CrossRef]