[Superficial siderosis of the CNS. Case report and literature review].

Superficial siderosis of the central nervous system is caused by destructive deposition of haemosiderin in the leptomeninges and subpial layers of the brain and spinal cord. This deposition is the result of continuous or recurrent, often clinically silent, haemorrhage in the subarachnoid space, eventually without an evident bleeding source. Cerebellar ataxia, progressive bilateral sensorineural hearing loss, pyramidal tract signs, and dementia are the major clinical findings. The diagnosis is supported in vivo by the characteristic symptom constellation,xanthochromic cerebrospinal fluid,and typical MRI findings which show on the surface of the brainstem, cerebellum, cortex, and spinal cord. Early recognition of this rare entity may be of relevance for the further course and prognosis.