Pleomorphic Hyalinizing Angiectatic Tumor of Soft Parts: Ultrastructural Analysis of a Case with Original Features

Abstract

Pleomorphic hyalinizing angiectatic tumor, a rare neoplasm of uncertain lineage resembling malignant fibrous histiocytoma and schwannoma, was first described in 1996 by M. E. F. Smith et al. (Am Surg Pathol. 20:21-29). To date, less than 100 cases have been reported in the international literature. It occurs in subcutaneous and intramuscular soft tissues of extremities or trunk in adults without sex predilection. All lesions are composed of sheets and fascicles of spindled and pleomorphic cells associated with clusters of thick-walled ectatic vessels surrounded by a perivascular hyaline material and inflammatory cells such as mast cells. About one-half of these neoplasms express CD34. No patient has developed metastases but occasional local recurrences are possible. This tumor of uncertain lineage is suggested to be an aggressive locally growing low-grade sarcoma. Only 3 cases were previously studied by electron microscopy and appeared to consist of primitive fibroblastic cells. The authors report histological and ultrastructural characteristics of a new case of PHAT excised from the right buttock of a 66-year-old man with the presence of ganglion-like cells, a feature that has not been previously reported, and unusual central ischemic necrosis. The features of this case are suggestive of a fibroblastic origin.

Complex analysis of a recurrent pleomorphic hyalinizing angiectatic tumor of soft parts

“…The electron microscopic study revealed numerous cytoplasmic granular deposits consistent with hemosiderin, and masses of wavy filaments in the cytoplasm of lesional cells consistent with vimentin filaments (Fig. 3), consistent with previous observations [1,5,7].…”

Dermal Fibroma With a Distinctive Perivascular Cell Arrangement

“…These cells were abundant, although scattered throughout the tumor, and they were identified as mast cells, which was clearly highlighted in the Giemsa stain (Fig. Apart from neurofibroma, which is the most commonly mentioned in literature, [4][5][6] one can also mention dermatofibroma, 7,8 Gardner fibroma, 9 superficial acral fibromyxoma, 10,11 elastofibroma, 12 pleomorphic hyalinizing angiectatic tumor, [13][14][15] ossifying fibromyxoid tumor, 16 desmoplastic fibroblastoma, 17 cellular hemangiomas, 18 solitary fibrous tumor of oral mucosa, 19 and multinucleated cell angiohistiocytoma. It is well known how mast cells express CD117, which allows these cells to be highlighted in an immunohistochemical study.…”

New or unusual dermatopathology tumors: a review

“…PHAT was initially described in 1996 by Smith et al 10 and represents a rare low‐grade neoplasm with fibrous differentiation 11–13 . PHAT most commonly presents in adults as a slow‐growing mass involving the lower extremity and may mimic a hematoma clinically.…”