[Two cases of superficial siderosis of the central nervous system. Findings of the cerebrospinal fluid, magnetic resonance imaging and positron emission tomography].

Two cases (case 1, a 45-year-old man; case 2, a 68-year-old man) of superficial siderosis of the central nervous system are presented. Main neurological symptoms were anosmia, sensorineural deafness, dysarthria, ataxia, and pyramidal tract signs. Lumbar puncture revealed bloody cerebrospinal fluid (CSF) in both cases. In case 1, the CSF became watery clear after administration of hemostatic medicines. T2-weighted magnetic resonance images showed cerebellar atrophy and marginal hypointensity of the brainstem, cerebellum, and the entire spinal cord. T2-weighted images of the cranial nerves showed hypointensity of the VIII nerves which were clinically impaired as compared with normointensity of the VII nerves which presented no clinical symptom. These findings may reflect difference in the degree of hemosiderin depostion between the VII and VIII nerves. While case 1 had a borderline score of WAIS-R (IQ79), case 2 showed overt dementia (performance IQ65). Positron emission tomography showed that cerebral blood flow and cerebral oxygen metabolism were reduced in the basal temporal lobes in both cases.