Pedunculated hemangiopericytoma‐like tumor: peculiar fibroepithelial polyp or fibrous histiocytoma variant

Abstract

Pathologists are continually challenged with the difficult task of discriminating between innocuous disease processes and potentially malignant entities. Apropos of this concern, we present a series of three cutaneous polypoid lesions that simulated fibroepithelial polyp, yet upon close scrutiny yielded histologic features of solitary fibrous tumor (SFT) or hemangiopericytoma. These pedunculated lesions showed a storiform pattern of spindled cells with interspersed gaping vascular channels reminiscent of SFT or hemangiopericytoma. Interestingly, the immunohistochemical staining profile of these lesions was negative for CD34 and positive for bcl-2 and factor XIIIa. These findings were discordant with SFT and suggest a relationship with fibrous histiocytoma. We propose that this entity represents a hitherto described variant of fibrous histiocytoma known as pedunculated hemangiopericytoma-like fibrous histiocytoma.

Hemangiopericytoma-Like Dermatofibroma With Mast Cells

“…8 The few studies on dermatofibromas with a hemangiopericytoma-like pattern identified numerous blood vessels, many of which had a ramified ''staghorn-like'' appearance. [10][11][12] The immunophenotype of dermatofibroma is well defined, with positivity for factor XIIIa and CD68 and negativity for CD34, although cases with focal CD34 positivity have been reported. 8 An interesting finding in the present case was the elevated presence of mast cells revealed by tryptase immunostaining, which has only been described in epithelioid cell histiocytoma with hemangiopericytoma-like features.…”