Tentorial schwannoma in a 64-year-old female: case report.

A 64-year-old woman presented with the history of transient global amnesia. Magnetic resonance imaging with contrast medium showed a lobulated heterogeneously enhanced cystic lesion attached to the superior surface of the right tentorium, indenting the right temporal lobe laterally and midbrain medially. A small part of the lesion was located under the right tentorium and did not involve the right trigeminal nerve. The lesion was subtotally resected via the subtemporal approach and did not affect the trochlear and trigeminal nerves. Histological examination showed that the lesion was schwannoma. Intracranial schwannomas usually arise from the cranial nerves. The present case of tentorial schwannoma not associated with the cranial nerves is extremely rare. Schwannoma should be included in the differential diagnosis of tumors arising from the tentorium.