Superficial siderosis of the central nervous system secondary to a thalamic hamartoma.

A patient with radiologically evident superficial siderosis of the central nervous system secondary to a thalamic hamartoma is reported. Cerebral hamartomas are rare, benign congenital lesions which when vascular can cause repeated subarachnoid haemorrhages, which results in deposition of iron (haemosiderin) in the leptomeninges and in the subpial layers of the brain and spinal cord. Progressive sensorineural deafness and cerebellar ataxia, which are typical clinical manifestations of superficial siderosis, may then appear. The importance of prompt diagnosis and treatment is highlighted.