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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

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● Variant with 50% or more of tumor cells having epithelioid morphology

 

Epidemiology

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● Mean/median age 40-42 years (Br J Dermatol 1989;120:185), no gender preference

 

Pathophysiology

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● May arise from dermal microvascular unit (J Cutan Pathol 2003;30:415)

 

Clinical

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● Uncommon, usually presents as small (1 cm or less), solitary, elevated nodule in extremities

 

Case reports

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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

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● Excision, only rarely recurs (Histopathology 1994;24:123)

 

Micro description

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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

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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

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Factor XIIIa, vimentin

 

Negative stains

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Keratin, S100, myogenic markers, CD68, CD163

 

Differential diagnosis

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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

 

 

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