Idiopathic superficial siderosis of the central nervous system.

SS is a rare central nervous system disease caused by the deposition of hemosiderin in the brain and spinal cord, which results in the progression of neurological deficits. The cause of this hemorrhage is often subarachnoid haemorrhage, intracranial surgery, carcinoma, arteriovenous malformation, nerve root avulsion, and dural abnormality. The condition progresses slowly and, by the time diagnosis is confirmed, the damage is often irreversible. In our cases, brain MRI clarified the definitive diagnosis, but we could not find the source of bleeding. SS should be considered in cases with ataxia and hearing loss, even if no source of bleeding is found.