Pure amnesia caused by bilateral temporal lobe astrocytoma--case report.

A 32-year-old male presented with progressive pure amnesia caused by astrocytoma invading the bilateral medial temporal lobes. Methionine positron emission tomography demonstrated the extent of tumor invasion well. His memory impairment was partially improved by treatment for the astrocytoma. Lesion of the bilateral hippocampus causes memory impairment, but pure memory loss without other associated neurological sign or deterioration of consciousness is rare in a case of cerebral neoplasm.