Neuropathology of superficial hemosiderosis

Abstract

Superficial siderosis is a radiological or pathological diagnosis of hemosiderin deposition in the brain and spinal cord that is caused by chronic subarachnoid hemorrhage. The classic triad of symptoms are bilateral sensorineural hearing loss, ataxia, and myelopathy, which typically leads to progressive and irreversible neurological dysfunction. The most common causes of the chronic subarachnoid hemorrhage that lead to superficial siderosis include CNS tumors, head and neck trauma, and arteriovenous malformations, although an occult source remains unidentified in some cases.

Neuropathology of superficial siderosis is characterized by deposition of hemosiderin into the subarachnoid space with resultant hemosiderin deposition mainly in astrocytes and microglia of the subpial layers, especially in infratentorial structures, cerebellum, brainstem and spinal cord. Olfactory bulbs and cranial nerves, especially VIII, are also vulnerable to hemosiderin deposition.