[Superficial siderosis of the central nervous system: report of two new cases]

Superficial siderosis of the central nervous system (CNS) is a rare disease characterized by deafness, ataxia and pyramidal dysfunction. It is due to hemosiderin deposition in the subpial membranes of the brain, spinal cord and cranial nerves. Most cases are secondary to chronic or recurrent bleeding into the subarachnoid space. Diagnosis is permitted by magnetic resonance imaging (MRI).

We report two patients with a chronic, slowly progressive cerebellar ataxia and hearing loss. MRI showed T2 hypointense signals in the brain, cerebellum and spinal cord diagnostic of superficial siderosis of the CNS. Xanthochromia was present in one patient. Evoked potentials showed retrochoclear hearing loss. Extensive vascular studies were negative for bleeding sources. One patient, treated with oral anticoagulants, benefited from reduction of the International Normalized Ratio.

Due to its rarity, clinical suspicion is essential for diagnosis of superficial siderosis of the CNS.