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OJHAS Vol. 10, Issue 1:
(Jan-Mar 2011) |
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Epithelioid
Cell Histiocytoma – An Unusual Variant of Dermatofibroma at an Uncommon
Site |
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Shulbha VS, Assistant Professor,
Department of Pathology,
Amita K Assistant Professor,
Department of Pathology,
Nischal KC, Assistant Professor, Department of
Dermatology,
Adichunchanagiri Institute of Medical Sciences,
B.G Nagar, Bellur, Mandya Dist, Karnataka, India. |
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Address for Correspondence |
Assistant
Professor,
Department of Pathology,
Adichunchanagiri Institute of Medical Sciences,
B.G Nagar, Bellur,
Mandya Dist, Karnataka, India.
E-mail:
drshulbha@rediffmail.com |
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Shulbha VS, Amita K, Nischal KC. Epithelioid
Cell Histiocytoma – An Unusual Variant of Dermatofibroma at an Uncommon
Site. Online J Health Allied Scs.
2011;10(1):16 |
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Submitted: Mar 2,
2011; Accepted: March 31, 2011; Published:
April 15, 2011 |
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| Abstract: |
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Epithelioid
cell histiocytoma (ECH) is a rare variant of cutaneous fibrous histiocytoma
involving primarily trunk and the extremities. It can delude the pathologist
in considering other benign non neoplastic and neoplastic lesions. Awareness
of this new entity can avert unnecessary treatment. We report a case
of epithelioid cell histiocytoma in a 40 yr old male who presented with
a painless nodular swelling over the dorsum of nose. The case is presented
here for its rarity and an uncommon site of involvement.
Key Words:
Epithelioid cell histiocytoma; Nose
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Epithelioid
cell histiocytoma (ECH) is a benign tumor of the dermis which can closely
resemble other benign and malignant tumors showing epithelioid features.1
ECH is an unusual and still poorly recognized variant of benign fibrous
histiocytoma. Epithelioid cell histiocytoma differs from most benign
fibrous histiocytomas in the following ways - the predominance of epithelioid
cells, relative lack of secondary elements (such as giant cells, foamy,
or hemosiderin-laden macrophages), relative sharp circumscription, prominent
vascularity, and centering in the papillary dermis in most cases.2
The lesion is characterised by its occurrence as a solitary elevated
nodule often with a vascular appearance. The histologic aspect resembles
the intradermal form of Spitz nevus. Most of the characteristic angulated
epitheloid cells that form the tumor are factor XIIIa positive and therefore
categorise the variant as fibrous histiocytoma.3 Here we
present a case of epithelioid cell histiocytoma in a 40 years old male
who presented with a painless nodular swelling over the dorsum of nose.
A
40 years old male presented with a painless nodular swelling over the dorsum
of nose slowly progressing to the present size for duration of 7 months.
No history of trauma or presence of such swellings elsewhere in the
body was elicited. Clinical examination revealed a pale, skin colored
nodule measuring 1x0.5 cm. External surface was smooth with no secondary
changes such as pigmentation or vascular markings noted. Clinical diagnosis
of a benign soft tissue tumor was put forth. The mass was excised
under local anaesthesia and sent for histopathological examination.
Gross revealed a skin covered mass measuring 1x0.5 cm. Cut surface was
solid and grey white. Microscopy showed a centrally located, circumscribed
tumor underlying an epidermal collarette. The tumor was composed of
epithelioid cells arranged in sheets and storiform pattern. (Fig 1).
Individual cells showed abundant eosinophilic cytoplasm with round vesicular
nuclei and prominent nucleoli. (Fig 2). Areas of myxoid change were
seen. Also seen were foamy macrophages, giant cells, hemosiderin laden
macrophages and inflammatory cell infiltrate.
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Fig 1: Photomicrograph
of Epithelioid Cell Histiocytoma (5X) |
Fig 2: Photomicrograph
of Epithelioid Cell Histiocytoma (40X) |
Epithelioid
cell histiocytoma (ECH)
is a rare and recently recognized variant of cutaneous fibrous histiocytoma
first described by Wilson et al.4 This tumor falls into the category of Dermatofibroma with architectural
and cellular/ stromal peculiarities.5
The age incidence of ECH is fourth decade with a female preponderance.1,,3
Clinically
the lesions are most commonly present over the trunk, upper and lower
extremities, followed by head and neck regions as circumscribed papules
measuring 1 x2 cm in greatest dimension.1
In our case study, location of the lesion at an uncommon site has been
emphasised upon. The most distinguishing feature of ECH is
the predominance of angulated epithelioid histiocytes with prominent
nucleoli which simulates amelanotic melanoma.2,6
However a sharp circumscription, central location, presence of giant
cells, foamy cells and hemosiderin laden macrophages helps to differentiate
ECH from malignant melanoma.2,7
In our case, special stains for melanin were negative.
Epithelioid
cell histiocytoma may clinically resemble many lesions including bacillary
angiomatosis, histiocytoma, dermatofibroma, pyogenic granulomas, blue
nevus, nodular malignant melanoma, metastatic melanoma and spitz nevus.
Histologically this form of histiocytoma could be mistaken for spitz
nevus, solitary reticulocytoma and atypical fibroxanthoma.3
The other differential diagnoses that can be considered are epithelioid
blue nevus, and cellular neurothekeoma.5,8 A spitz nevus shows epithelioid cells usually in singles against
a background of abundant dense, collagenous stroma.8
Relative lack of circumscription, a larger size and extension of the
lesion into the adjacent subcutaneous tissue differentiate a cellular
blue nevus from an ECH. Cellular neurothekeoma is a poorly circumscribed
reticular dermal lesion showing mitotic activity and cytologic atypia
which is unlikely to happen in ECH.8
ECH
are CD 163, CD v68, and vementin positive with focal nuclear immunoreactivity
for microophtalmia transcription factor and focal reactivity for Factor
XIIIa and S 100. Epithelioid cells are negative for CD3, CD10, CD 20,
CD -30, S 100 and keratin.(1) Thus S 100 positivity in case
of spitz nevus and cellular blue nevus helps to differentiate them from
ECH. ECH has to be widely excised to prevent recurrence.
ECH
is the new, rare variant of dermatofibroma that can ape benign non neoplastic
and neoplastic lesions both clinically and histopathologically .The
present case paramounts on placing this entity in the differential diagnosis
of epithelioid cell rich lesions. Awareness of this entity to both pathologist
and clinician can halt unnecessary treatment.
- Sarma DP, Repertinger
SK. Epithelioid Cell Histiocytoma: a Case Report and Brief Review
of the Literature, with an Emphasis on Differential Diagnosis. The Internet
Journal of Dermatology. 2009;7(2).
- Glusac EJ, McNiff
JM. Epithelioid cell histiocytoma: a simulant of vascular and melanocytic
neoplasms. Am J Dermatopathol. Feb 1999;21(1):1-7.
- Dezfoulian B, Nikkels
AF, Pierard-Franchimont C and Pierard GE. Epithelioid Cell histiocytoma:
A report of two cases. Dermatology 1995;190:349-350.
- Wilson Jones E,
CErio R, Smith NP. Epithelioid cell histiocytoma:A rare entity. Br J dermatol 1989;120:185 -195.
- Zelger BG, Zelger
B. Dermatofibroma. A clinico-pathologic classification scheme. Pathologe.
1998 Nov;19(6):412-419.
- Glusac EJ, Barr
RJ, Everett MA, Pitha J, Santa Cruz DJ. Epithelioid cell histiocytoma.
A report of 10 cases including a new cellular variant. Am J Surg Pathol.
Jun
1994;18(6):583-590.
- Zelger BG, Sidoroff
A, Zelger B. Combined dermatofibroma: co-existence of two or more variant
patterns in a single lesion. Histopathology. Jun 2000;36(6):529-539.
- Zelger B. Fibrohistiocytic
skin lesions. Verh Dtsch Ges Pathol. 1998;82:290-300.
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