Gliosarcoma arising from an anaplastic ependymoma: a case report of a rare entity.

We report the first case of a gliosarcoma arising from an anaplastic ependymoma and the second case of gliosarcoma arising from any type of ependymal neoplasm. The patient was a 48-year-old woman with a solid and cystic, peripherally enhancing, 7-cm right frontal mass lesion. Histologically, the lesion displayed characteristics of anaplastic ependymoma (grade III, World Health Organization scale). The tumor recurred despite multiple cycles of postoperative radiation and chemotherapy. After the fourth recurrence, the tumor displayed a biphasic pattern of differentiation. The first pattern was similar to the original anaplastic ependymoma, whereas there was a second new sarcomatous pattern resembling fibrosarcoma that was admixed with and overrunning the ependymal component. The spectrum of gliosarcoma is therefore expanded to include not only astrocytic and oligodendroglial components but ependymal components as well.