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Cytodiagnosis in dermatology
Baby Shana, Betsy Ambooken, N. Asokan
Department of Dermatology, Government Medical College, Thrissur, Kerala, India.

*Corresponding author: Cytodiagnosis – a simple, rapid, cheap, and often reliable method of diagnosis in fresh tissues
Baby Shana, – was introduced by Dudgeon and Patrick, in 1927, though George Papanicolaou is considered
Senior Resident, Department of as the father of exfoliative cytology. Various methods of cytodiagnosis include Tzanck smear,
Dermatology and Venereology,
imprint smear, tissue smear, exudate smear, skin scraping smear, and aspiration cytology.
Govt Medical College Thrissur,
Kerala India.
TZANCK SMEAR
shanaxyz@gmail.com
Tzanck test or Tzanck smear was first introduced in 1947 by Arnault Tzanck.
Received : 19 July 19
Accepted : 23 July 19 Preparation
Published : 02 December 19
Samples are taken from a fresh vesicle. The vesicle is unroofed and the floor is gently scraped.
DOI Material thus obtained is smeared onto a microscopic slide, allowed to air dry, and stained with
10.25259/JSSTD_40_2019
Giemsa or Leishman stain. Other stains used are hematoxylin and eosin, Wright, Papanicolaou,
Quick Response Code: methylene blue, and toluidine blue.
Table 1 shows the Tzanck smear findings in various dermatoses.[1]

Tzanck smear in pemphigus group of disorders

Tzanck smear is a very useful test for the diagnosis of pemphigus vulgaris, particularly in the
early stages of oral pemphigus. A typical Tzanck cell is a large round epithelial cell or keratinocyte
with a large nucleus, hazy or absent nucleoli, perinuclear halo, and peripheral condensation of
basophilic cytoplasm (“mourning edged” cells).
There may be features of cell adherence such as “Sertoli rosette cells” and “Streptocytes” which
are relatively less characteristic cytodiagnostic signs in pemphigus vulgaris. “Sertoli rosette” is
aggregates of cells with a keratinocyte at the center surrounded by a ring of leukocytes. There may
be adherent chains of leukocytes formed by filamentous, glue-like substances called “Streptocytes.”

Tzanck smear in infections

Herpes simplex, varicella and herpes zoster[2-4]

A fresh vesicle <3 days old must be chosen as older lesions may get crusted or secondarily infected
and the characteristic cytological features may not be there. Characteristic feature is the presence
of typical multinucleated giant cells. The cells are swollen (“ballooning cell or pregnant cell”)
and large, 60–80 µ in diameter. Nuclei exhibit molding so that they can fit together in a jigsaw
puzzle-like fashion within the cell. The nuclei show great variation in size and shape. Intranuclear

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 Shana, et al.: Cytodiagnosis in dermatology

Table 1: Tzanck smear findings in various dermatoses.

Disease Tzanck smear findings
Immunobullous
Pemphigus vulgaris Numerous larger acantholytic cells (Tzanck cells) and few eosinophils [Figure 1]
Pemphigus vegetans Acantholytic cells and many inflammatory cells – especially eosinophils
Pemphigus foliaceous Smaller, cuboidal, and less numerous acantholytic cells
Bullous pemphigoid Eosinophils and few lymphocytes and neutrophils
Cutaneous infections
Herpes infections Multinucleated epithelial giant cells [Figure 2]
Staphylococcal scalded skin syndrome Dyskeratotic acantholytic cells, absent or few inflammatory cells, absent cocci
Bullous impetigo Dyskeratotic acantholytic cells, neutrophils, and Gram‑positive cocci in clusters
Candidiasis Yeast cells with pseudohyphae
Genodermatoses
Hailey–Hailey disease Plenty of acantholytic cells
Darier’s disease Corps ronds, grains, and few acantholytic cells
Spongiotic dermatitis
Allergic contact dermatitis Tadpole cells [Figure 3], lymphocyte predominance[1]
Irritant contact dermatitis Tadpole cells, neutrophil predominance[1]

inclusion bodies surrounded by a clear halo are characteristic

of herpetic infection but are often difficult to find. Varicella
in adult patients and paucilesional or atypical forms of
herpes zoster, i.e.,  cases where lesions are non-dermatomal
in distribution but generalized (so-called herpes zoster
varicellosus), is often misdiagnosed as bacterial folliculitis.
Tzanck smear may help in these instances.

Bullous impetigo, staphylococcal scalded skin syndrome

(SSSS), and toxic epidermal necrolysis (TEN)

SSSS and TEN have some clinical similarities. Tzanck

smear taken from a fresh bulla shows abundance of
dyskeratotic keratinocytes without inflammatory cells in
SSSS, whereas in TEN necrotic keratinocytes, fibroblasts
and inflammatory cells are seen.[3,5] Cytodiagnosis should Figure  1: Acantholytic cells in pemphigus showing large nucleus,
be confirmed either by a frozen section taken from the perinuclear halo, and peripheral condensation of cytoplasm.
bulla roof or by a biopsy.

Vaccinia, orf, Milker’s nodules, and variola[2,3]

Smears show a variable number of acantholytic or detached

squamous keratinocytes. These keratinocytes may contain
eosinophilic cytoplasmic inclusion bodies called a “Guarnieri
bodies,” frequently surrounded by a clear halo. In orf and
Milker’s nodules, there will be a background of inflammatory
cells and necrotic squamous keratinocytes.

Pustular or bullous superficial fungal infections[2,3]

Candida and dermatophytes (especially geophilic or

zoophilic strains) can present with pustules or bullae.
Although KOH preparation is quite helpful in diagnosis,
the presence of hyphae or pseudohyphae can also be easily Figure  2: Multinucleated giant cells with secondary acantholytic
identified in Giemsa stained smears. cells in varicella.

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 Shana, et al.: Cytodiagnosis in dermatology

Tzanck smear in genodermatosis flagellum. In older lesions, cytological testing is of limited

diagnostic use as protozoa are rarely seen.
i. Hailey–Hailey disease: Cytodiagnosis is helpful in
differentiating Hailey–Hailey disease from intertrigo, Donovanosis
flexural psoriasis, or eczema, which are close simulators
of this genodermatosis. Tzanck smear shows numerous Tissue smear is more sensitive than biopsy. It may show
acantholytic cells. Greenblatt/Pund cells which are large macrophage/epithelioid
ii. Darier’s disease: Cytology reveals “corps ronds” and
“grains.” “Corps ronds” are isolated round keratinocytes
with an eosinophilic cytoplasm, which is retracted from the
nucleus and denser peripherally. Grains are small, hyaline,
eosinophilic ovoid bodies resembling pomegranate seeds.

Tzanck smear in vesicular and pustular dermatosis in neonates

Smears from pustules in transient neonatal pustulosis and

infantile acropustulosis show predominance of neutrophils,
whereas eosinophils are predominantly seen in erythema
toxicum neonatorum and eosinophilic pustulosis.

TISSUE SMEAR
For cytodiagnosis, lesion should be incised with a sharp, Figure 3: Tadpole cells with few neutrophils in irritant dermatitis.
pointed scalpel. The incision should be superficial to avoid
bleeding. A  sample of tissue is then obtained with either a
blunt scalpel or a small curette and the tissue obtained is
pressed between two slides, air dried, and stained.
Table 2 shows the tissue smear findings in various dermatoses.

Leishmaniasis

In Leishmaniasis, the cytological smear is obtained by gentle

scarification along with the margins of the lesion. It shows
the presence of numerous protozoa (Leishman-Donovan
bodies) within histiocytes known as Wright’s cells [Figure 4].
Intracellular Leishmaniae are seen as bee-swarm-like
formations.[6] They can also be extracellular. In oil immersion,
Leishmaniae appear as small blue ovoid, ellipsoid, or pyriform
bodies with a deeply basophilic cytoplasm, a trophonucleus, Figure  4: Leishman stained smear of cutaneous leishmaniasis
a paranucleus or kinetoplast, and a minute endocytoplasmic demonstrating numerous LD bodies.

Table 2: Tissue smear findings in various dermatoses.

Disease Tissue smear findings
Cutaneous infections
Leishmaniasis Leishman‑Donovan bodies, Wright’s cells
Donovanosis Greenblatt and Pund cells, Donovan bodies
Molluscum contagiosum Henderson‑Patterson bodies
Cutaneous tumors
Basal cell epithelioma Clusters of basaloid cells
Squamous cell epithelioma Isolated atypical squamous cells
Paget’s disease of breast Paget’s cells
Erythroplasia of Queyrat Poikilokaryosis (variation in size, shape, and staining of nuclei), naked and clumped nuclei
Bullous mastocytosis Mast cells with metachromatic granules
Langerhans cell histiocytosis Atypical Langerhans cells

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 Shana, et al.: Cytodiagnosis in dermatology

cell containing cystic spaces, with nuclei pushed to one the cytological findings are quite suggestive, we should always
side and darkly staining inclusions called Donovan bodies. perform a histological examination and immunophenotyping
Donovan bodies are blue-black bipolar condensations with a to confirm diagnosis.
safety pin appearance.
FINE-NEEDLE ASPIRATION CYTOLOGY[8]
Basal cell carcinoma [2,3,7]

Fine-needle aspiration cytology (FNAC) is a useful

Cytology reveals clusters of basaloid cells with some of them cytodiagnostic method in differentiating benign tumors
showing retention of peripheral palisading, as in the histology. from malignant and also in various cutaneous infections.
Basaloid cells are similar to normal basal keratinocytes in Epidermal inclusion cyst [Figure 5], trichilemmal cyst, basal
appearance but are larger and more deeply basophilic. They cell carcinoma (BCC), SCC, melanoma, sebaceous carcinoma,
are uniform in size, elongated and the nucleus is central oval, Merkel cell tumor, pilomatricoma, granular cell tumor,
intensely basophilic and occupies four-fifths of the cells. Kaposi sarcoma, and various skin adnexal tumors are some
of the lesions that can be diagnosed on FNAC. Subcutaneous
Squamous cell carcinoma[2,3] nodules due to metastases from various solid organ
malignancies such as cervix, lung, breast, prostate, ovary, liver,
Cytology is helpful in the nodular, soft, or ulcerated non- kidney, and gallbladder can be diagnosed using FNAC.
keratotic varieties of squamous cell carcinoma (SCC), but
not in keratotic or verrucous lesions. The two characteristic In pilomatricoma, cytological examination of smear may show
cytodiagnostic features of SCC are the absence of ghost cells, basaloid cells, and numerous acute inflammatory
cluster formation by cells and pleomorphism. At higher cells. In BCC, there will be predominance of basaloid cells
magnification, abnormal nuclear changes (hypertrophic, which are seen cytologically as cohesive cellular fragments
hyperchromatic, or multilobated nuclei and abnormal with sharp borders and peripheral palisading. FNAC of
mitoses) and bizarre changes in cytoplasm staining foreign body granulomas shows multinucleated giant cells,
(basophilic in some, eosinophilic in others) are seen. acute inflammation, and demonstrable foreign bodies. FNAC
of lipoma shows adipose tissue. The fat cells are with a single
large vacuole in the cytoplasm with nuclei pushed to the
Paget’s disease[3]
periphery. FNAC from gouty tophi reveals needle shaped
Paget’s cells appear larger than keratinocytes and are seen as crystals of monosodium urate [Figure 6] and negatively
round to oval cells with weakly eosinophilic or amphophilic, birefringent crystals under polarised light [Figure 7].
vacuolated cytoplasm, and a hypertrophic nucleolated Another important application of FNAC in dermatology
nucleus. They occur singly or in small clusters and stains is in the diagnosis of many infective conditions presenting
with special stains for epithelial mucin such as mucicarmine, as cutaneous nodules such as parasitic infections like
Alcian blue, and periodic acid–Schiff stain. cysticercosis, fungal infections such as aspergillosis,
erythema nodosum leprosum, lepromatous leprosy, and
Erythroplasia of Queyrat[3] molluscum contagiosum.
Smear shows spindle-shaped, polyhedral, and round cells
with pleomorphic nuclei, which is practically diagnostic.

Bullous mastocytosis[3]

Cytodiagnosis of mastocytoma is especially useful in pediatric

cases, in which performing a biopsy under local anesthesia
may be very difficult. Tzanck smear from bullous lesions is
stained with 1% methylene blue for 1 min, which shows plenty
of mast cells, which are identified by their irregular shape and
metachromatic staining of granules as purple.

Langerhans cell histiocytosis[3]

Smear shows multinucleate atypical Langerhans cells

which are 12–15  mm sized with pale, weakly eosinophilic
or amphophilic, granular cytoplasm and large lobulated, Figure 5: Papanicolaou stained smear showing keratin debris with
convoluted, reniform, or centrally grooved nuclei. Although multinucleated giant cells in epidermal cyst.

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 Shana, et al.: Cytodiagnosis in dermatology

CONCLUSION
Cytodiagnosis can be a valuable aid in the diagnosis of
various infectious and non-infectious dermatoses. The
architectural patterns of disease are studied in standard
histological sections, whereas the exact cell types involved
in the disease process are analyzed in cytodiagnostic smears.
Hence, it may be said that histology examines the “house,”
while cytology examines the “bricks” which forms the house.
It is particularly useful when rapid diagnosis is important as
in SSSS, TEN, or disseminated herpes when the lesions are at
sites where biopsy may be difficult, such as eyelids.

Acknowledgment

The authors would like to thank Subi C T, Lab Technician –

Figure 6: Needle-shaped monosodium urate crystals in gouty tophi.
Grade 1, Department of Dermatology, Government Medical
College, Thrissur.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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How to cite this article: Shana B, Ambooken B, Asokan N. Cytodiagnosis
margins of a resected tumor for the presence of malignant
in dermatology. J Skin Sex Transm Dis 2019;1(2):112-6.
cells.

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