A 59-year-old man was admitted to the hospital due to leg edema. He had multiple sclerosis-like episodes of transient diplopia at the age of 36 years and spastic paraplegia at the age of 38. After admission he showed various fluctuating neuropsychological symptoms (disorientation, hallucination, apraxia, aphasia) and cranial nerve palsy. Magnetic resonance imaging revealed abnormal signal intensity in the right thalamus and deep white matter. The patient was diagnosed as having malignant lymphoma and treated with steroid therapy and chemotherapy. Although partial improvement of clinical findings was observed, recurrent cerebral hemorrhage followed. Autopsy findings revealed perivascular infiltration of T cells in the brain, spinal cord and other general organs.