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

K, Amita

KC, Nischal

VS, Shulbha

English

Shulbha VS

Amita K

Nischal KC

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Epithelioid Cell Histiocytoma – An Unusual Variant of Dermatofibroma at an Uncommon Site

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Case Report:
Epithelioid Cell Histiocytoma – An Unusual Variant of Dermatofibroma at an Uncommon Site
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.
Address For Correspondence:
Dr. Shulbha V Sejekan,
Assistant Professor,
Department of Pathology,
Adichunchanagiri Institute of Medical Sciences,
B.G Nagar, Bellur,
Mandya Dist, Karnataka, India. 
E-mail: drshulbha@rediffmail.com
Citation:  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
URL: http://www.ojhas.org/issue37/2011-1-16.htm
Open Access Archives: http://cogprints.org/view/subjects/OJHAS.html and http://openmed.nic.in/view/subjects/ojhas.html
Submitted: Mar 2, 2011; Accepted: March 31, 2011; Published: April 15, 2011
Abstract:
Epithelioid  cell  histiocytoma  (ECH)  is  a  rare  variant  of  cu-
taneous 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 in-
volvement.
Key Words: Epithelioid cell histiocytoma; Nose
Introduction:
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 epi-
thelioid 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 vas-
cular  appearance.  The  histologic  aspect  resembles  the  in-
tradermal form of Spitz nevus. Most of the characteristic angu-
lated epitheloid cells that form the tumor are factor XIIIa posit-
ive  and  therefore  categorise  the  variant  as  fibrous  histiocyt-
oma.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.
Case Report:
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.
Fig 1: Photomicrograph of Epithelioid Cell Histiocytoma (5X)
Fig 2: Photomicrograph of Epithelioid Cell Histiocytoma (40X)
1
This work is licensed under a
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No Derivative Works 2.5 India License
Online Journal of Health and Allied Sciences
Peer Reviewed, Open Access, Free Online Journal
Published Quarterly :  Mangalore, South India : ISSN 0972-5997
Volume 10, Issue 1; Jan-Mar 2011
Discussion:
Epithelioid cell histiocytoma (ECH) is a rare and recently re-
cognized  variant  of  cutaneous  fibrous  histiocytoma  first  de-
scribed by Wilson et al.4 This tumor falls into the category of 
Dermatofibroma with architectural and cellular/ stromal peculi-
arities.5  The age incidence of ECH is fourth decade with a fe-
male 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 un-
common site has been emphasised upon. The most distinguish-
ing feature of ECH is the predominance of angulated epithe-
lioid  histiocytes  with  prominent  nucleoli  which  simulates 
amelanotic  melanoma.2,6  However  a  sharp  circumscription, 
central location, presence of giant cells, foamy cells and hemos-
iderin laden macrophages helps to differentiate ECH from ma-
lignant  melanoma.2,7  In  our  case,  special  stains  for  melanin 
were negative.
Epithelioid cell histiocytoma may clinically resemble many le-
sions  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  fibrox-
anthoma.3 The  other  differential  diagnoses  that  can  be  con-
sidered  are  epithelioid  blue  nevus,  and  cellular  neur-
othekeoma.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 ex-
tension of the lesion into the adjacent subcutaneous tissue dif-
ferentiate a cellular blue nevus from an ECH. Cellular neur-
othekeoma  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.
Conclusion:
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. 
References:
1. Sarma DP, Repertinger SK. Epithelioid Cell Histio-
cytoma: a Case Report and Brief Review of the Lit-
erature, with an Emphasis on Differential Diagnosis. 
The Internet Journal of Dermatology. 2009;7(2).
2. Glusac  EJ,  McNiff  JM.  Epithelioid  cell  histiocyt-
oma: a simulant  of  vascular and melanocytic  neo-
plasms. Am J Dermatopathol. Feb 1999;21(1):1-7.
3. Dezfoulian B,  Nikkels  AF,  Pierard-Franchimont  C 
and Pierard GE. Epithelioid Cell histiocytoma: A re-
port of two cases. Dermatology 1995;190:349-350.
4. Wilson Jones E, CErio R, Smith NP. Epithelioid cell 
histiocytoma:A  rare  entity.  Br  J  dermatol 
1989;120:185 -195.
5. Zelger  BG, Zelger  B.  Dermatofibroma.  A clinico-
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6. Glusac EJ, Barr RJ, Everett MA, Pitha J, Santa Cruz 
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8. Zelger B. Fibrohistiocytic skin lesions. Verh Dtsch 
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2


A clinicopathologic classification scheme. Pathologe.

Combined dermatofibroma: co-existence of two or more variant patterns in a single lesion. Histopathology.

Epithelioid Cell Histiocytoma: a Case Report and Brief Review of the Literature, with an Emphasis on Differential Diagnosis. The Internet Journal of Dermatology.

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Epithelioid cell histiocytoma: a simulant of vascular and melanocytic neoplasms.

Epithelioid cell histiocytoma:A rare entity.

Epithelioid cell histiocytoma. A report of 10 cases including a new cellular variant. Am J Surg Pathol.

Fibrohistiocytic skin lesions. Verh Dtsch Ges Pathol.

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Epithelioid Cell Histiocytoma – An Unusual Variant of Dermatofibroma at an Uncommon Site

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