[Angiomatoid malignant fibrous histiocytoma]

By clinical, pathologic and immunohistochemical study on aniomatoid malignant fibrous histiocytoma, which is a relatively uncommon soft tissue tumor described by Enzinger in 1979, and often misdiagnosed, we are reporting 32 cases of this lesion. The distinctive histopathology were: (1) Cystic change filled with hemorrhagic fluid or blood, (2) surrounded by nests of fibroblastlike and histocyte-like cells and (3) intermingled with chronic inflammatory cells, (4) often surrounded by a fibrous pseudocapsule. Immunohistochemical staining done in 4 cases showed all to be positive in lysozyme, three positive in Mac 387 and CD 68. These results support their histiocytic origin. Follow-up information was available in 25 of 32 cases. All the 25 patients were alive, 4 with recurrence (16%), 1 with metastasis (4%). These results concur with the opinion that intrinsically, this is a low grade tumor.