Gliosarcoma of the posterior fossa with features of a malignant fibrous histiocytoma.

A rare case of gliosarcoma occurring in the posterior fossa of a 62-year-old man is reported. Histologically, the tumor closely resembled that of a typical case of malignant fibrous histiocytoma (MFH). Such features have not been reported previously in gliosarcoma. The importance of using an immunoperoxidase preparation against the glial fibrillary acidic protein (GFAP) in diagnosing gliosarcoma is emphasized. Our case also lends support to the contention that MFH-like histologic features may occur in poorly differentiated neoplasms of diverse origins.