Primary cerebral lymphoma manifested by dementia.

Primary cerebral lymphoma (PCL) accounts for less than 1% of intracranial neoplasms. In immunocompromised patients, multicentric lymphoma of the brain is typically manifested by focal neurologic deficits. In the immunocompetent individual, PCL involves leptomeninges and presents meningeal signs. Leptomeningeal lymphoma manifested by dementia has not been previously reported and should be included in the differential diagnosis of patients with Alzheimer's disease.