Brain surface ependymoma with repeated episodes of intratumoral hemorrhage--case report.

A 70-year-old woman presented with a rare brain surface ependymoma with repeated intratumoral hemorrhage. She was admitted with progressive dementia. Two years earlier, a diagnosis of subcortical hematoma in the right frontal lobe had been made following a fall. On admission, magnetic resonance imaging showed a huge right frontal mass lesion with multiple hemorrhagic cysts. She underwent gross total resection. The tumor was located on the surface of the frontal lobe, and was sharply demarcated from the surrounding brain tissue with no attachment to the ventricular wall. The histological features were consistent with an ependymoma forming perivascular pseudorosettes. Immunohistochemistry showed positive staining for glial fibrillary acidic protein. Electron microscopy showed microvilli and zonula adherens. This case demonstrates the natural course of malignant progression of ectopic ependymomas. Ependymoma should be included in the differential diagnosis of tumors associated with repeated subcortical hematomas, even if located on the brain surface and distant from ventricles.