Home Chapter Home Jobs Conferences Fellowships Books
Skin / Soft Tissue Tumors
Epithelioid fibrous histiocytoma
Author: Nat Pernick, M.D., PathologyOutlines.com, Inc.
Reviewer: David Lucas, M.D., University of Michigan Health Systems (January 2009)
Revised: 11 June 2009, last major update June 2009
Definition
=========================================================================
● Variant with 50% or more of tumor cells having epithelioid morphology
Epidemiology
=========================================================================
● Mean/median age 40-42 years (Br J Dermatol 1989;120:185), no gender preference
Pathophysiology
=========================================================================
● May arise from dermal microvascular unit (J Cutan Pathol 2003;30:415)
Clinical
=========================================================================
● Uncommon, usually presents as small (1 cm or less), solitary, elevated nodule in extremities
Case reports
=========================================================================
● 20 year old man with multiple lesions (Am J Dermatopathol 2008;30:373)
● 60 year old man with scalp lesion (Case of the Week #116)
● Underlying a damaged artery (J Dermatol 2005;32:721)
Treatment and prognosis
=========================================================================
● Excision, only rarely recurs (Histopathology 1994;24:123)
Micro description
=========================================================================
● Circumscribed with uniform, medium to large angulated epithelioid cells (50%+ of tumor cells) that are often perivascular
● Overlying epidermal effacement
● May be cellular (AJSP 1994;18:583)
● Minimal inflammation, no prominent giant cells
Micro images
=========================================================================
Histiocyte-like cells with abundant Epithelioid cells Large epithelioid cells
cytoplasm, no / rare spindle cells in hyalinized stroma
60 year old man with scalp lesion
Vimentin+ Factor XIIIa+ CD68 negative Keratin negative
Melan A negative
Other images: epithelioid cells with vesicular nuclei
Positive stains
=========================================================================
● Factor XIIIa, vimentin
Negative stains
=========================================================================
● Keratin, S100, myogenic markers, CD68, CD163
Differential diagnosis
=========================================================================
● Epithelioid sarcoma - deep seated, granuloma-type clusters with necrosis, more atypia, keratin+, CD163-
● Granulomas - 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+ (AJSP 2006;30:521)
End of Skin / Soft Tissue Tumors > Epithelioid fibrous histiocytoma
This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must also be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.
All information on this website is protected by Copyright, (c) 2001-2009, PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions.