Soft tissue
Fibrohistiocytic tumors
Epithelioid fibrous histiocytoma

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 13 September 2016, last major update August 2012

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PubMed Search: Epithelioid fibrous histiocytoma

Cite this page: Epithelioid fibrous histiocytoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuefhepithelioid.html. Accessed December 10th, 2016.
Definition / General
  • Variant with 50% or more of tumor cells having epithelioid morphology
Epidemiology
Pathophysiology
Clinical Features
  • Uncommon, usually presents as small (0.5 to 2 cm), solitary, very rarely multiple, skin colored elevated nodules
  • Usually seen on trunk and extremities, rarely in head and neck regions
Case Reports
Treatment
Micro Description
  • Often exophytic with epidermal collarette
  • Circumscribed with uniform, medium to large angulated epithelioid cells (50%+ of tumor cells) that are often perivascular
  • Many binucleated cells are often seen
  • May be cellular (Am J Surg Pathol 1994;18:583)
  • Periphery shows typical features of dermatofibroma
  • Minimal inflammation, no prominent giant cells
Micro Images

Images hosted on PathOut servers:

Histiocyte-like cells with abundant cytoplasm, no / rare spindle cells

Epithelioid cells in hyalinized stroma



60 year old man with scalp lesion



Left to right: above case is Vimentin+, Factor XIIIa+, CD68-, keratin-, Melan A-



Images hosted on other servers:

Epithelioid cells with vesicular nuclei

Negative Stains
Differential Diagnosis
  • Epithelioid sarcoma: deep seated, granuloma-type clusters with necrosis, more atypia, keratin+, CD163-
  • Granuloma: epithelioid histiocytes in well formed clusters, surrounded by lymphocytes
  • Histiocytic sarcoma: marked atypia and mitotic activity
  • Melanoma: tight clustering of atypical cells, S100+, HMB45+
  • Rosai-Dorfman disease: multiple skin lesions and adenopathy, histiocytes are S100+ and pleomorphic with emperipolesis, also prominent B cells and plasma cells
  • Solitary epithelioid histiocytoma: dense eosinophilic and glassy cytoplasm, often with spiked cytoplasmic extensions, variable nuclear grooves and multinucleated cells, frequent lymphocytes and neutrophils, CD68+, CD163+ (Am J Surg Pathol 2006;30:521)
  • Spitz nevus: nevoid type clusters in periphery with spindle cell component, S100+