Superficial siderosis of the central nervous system

Superficial siderosis of the central nervous system (CNS) is a rare entity characterized by the deposition of hemosiderin in the leptomeninges. In most cases it is caused by chronic and recurrent bleeding into the subarachnoid space as a subclinical form and for long periods of time. The cases described in the literature are associated with tumors, aneurysms, arteriovenous malformations, changes in post-surgical, traumatic cervical and brachial plexus injuries. However, the cause of bleeding is unclear in 40-50% of cases. This report describes the case of a 38-year-old man with a history of trauma with a complete lesion of the left brachial plexus. The patient presented progressively worsening gait imbalance, bilateral deafness, tinnitus and memory loss over two years. Neurological examination disclosed bilateral hearing loss, left upper limb plegia with atrophy of muscle mass, spastic paraparesis with pyramidal signs and gait ataxia. The analytical/genetic study was consistent with hereditary hemochromatosis. In addition to typical findings of siderosis, MR disclosed pseudomeningocele while CT angiography and angiography revealed an aneurysm of the internal carotid artery. Although rare, we should be aware of superficial siderosis especially in imaging studies in patients with deafness or ataxia and in those with lesions of the brachial plexus. The imaging signals are subtle and can easily go unrecognized. The radiological investigation must be extensive to find the primary cause.