Superficial Siderosis of the Central Nervous System. A More Frequent Disease than Previously Assumed?

Superficial siderosis of the central nervous system (CNS) involves deposits of haemosiderin on surfaces due to chronic haemorrhage in the subarachnoid space. The origin of this can be idiopathic or arise from an identifiable Source of bleeding, e.g., a vascular malformation. About 200 cases have so far been reported in the literature and are characterised by a progresssive dementia syndrome, ataxia and deafness. We report on 3 patients whom we diagnosed in our clinic during an 18-month period. in two of the three patients haemosiderin deposits in the brain stem and cerebellum were not recognised in several previous magnetic resonance imaging studies (MRI). In one case there was superficial siderosis Without any signs of a source of the bleeding, in the other two patients a bleeding source was identified. On the basis of the present cases, the question is posed as to whether superficial siderosis of the central nervous system is not appreciably more frequent than previously assumed simply because it is not taken into differential diagnostic considerations.