Extra-axial subarachnoid ependymoma of the cerebral convexity.

A 29-year-old man had two episodes of seizures in 9 months. Following the first seizure he developed hemiparesis, which gradually progressed. Investigations revealed a large cerebral convexity mass lesion simulating a meningioma. During operation, a reddish-brown and well-defined tumor located in the subarachnoid space was encountered. Histopathological examination revealed a typical ependymoma. Extra-axial cerebral convexity ependymomas are extremely rare. The case is reported and a brief review of six similar cases reported in the literature is undertaken.