Fibrohistiocytic Tumors

Actin +/—, Desmin —/+, CD34 —/+, SlOO — Vimentin +, CD68 + (in multinucleated cells) 

Vimentin +, CD34 +, PDGF +, Actin —/+, Desmin FVIII CD31 SlOO Pan-Cytokeratin — 

Vimentin +, Estrogen receptors +, aP2 (P422) + Vimentin +, SlOO +, aP2 — 

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Dermatofibrosarcoma protuberans is a slow infiltrative growing fibrohistiocytic tumor mainly affecting adults between the 3" and 4 decade and appears in the deep dermis, composed of proliferating uniform small spindled cells arranged in a repetitive storiform pattern. 

Patterns of mesenchymal differentiation in cutaneous neoplasms are no less diverse than those encountered in deeper soft tissues. Fibroblastic or myofibroblastic, fibrohistiocytic, muscular, neural, epithelial, and vascular lesions may be seen as primary tumors in the dermis and subcutis. As is also true in deep soft tissues, the histologic evaluation of those neoplasms may fail to provide an unequivocal diagnosis. Hence immunophenotyping has proven to be valuable in this context. The diagnostic separation of various spindle-cell, polygonal-cell, epithelioid-cell, and small-cell lesions of the skin is assisted in many settings by immunohistochemical analysis. 

The concept that such tumors as atypical fibroxanthoma (AFX), malignant fibrous histiocytoma (MFH), and DFSP display fibrohistiocytic cellular featmes is more of a historical concept than a currently accepted tenet. Although... 

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