Primary intracerebral malignant fibrous histiocytoma: immunohistochemical findings and etiopathogenetic considerations.

We report a case of malignant fibrous histiocytoma (MFH) arising as a second malignancy in a 13-year-old girl with a previous primitive neuroectodermal tumor of the cerebellum (medulloblastoma). The earlier tumor had been resected and treated with chemotherapy. Because of the age of the patient, no radiation therapy was used. The second neoplasm (an MFH), which presented almost 12 years later, was located within the left frontal region and had discrete meningeal attachment. Histologically, it showed the characteristic storiform pattern and pleomorphism of an MFH and displayed characteristic immunohistochemical reactivity. Careful clinical and radiologic investigation failed to reveal any other neoplasm in the body. This case is unique in that the MFH occurred in a young child after an earlier primary primitive neuroectodermal tumor, although at a distant site, and, importantly, without prior radiation therapy. In this report, we briefly review the literature with an emphasis on immunohistochemistry and histogenesis, raising the possibility that the MFH was induced by chemotherapy.