Superior Cerebellar Artery Aneurysm in a Case of Moyamoya Disease: A Rare Entity.

Moyamoya disease is a rare condition characterized by progressive narrowing and occlusion of internal carotid artery and other major arteries of the brain with formation of multiple collaterals. The incidence of aneurysm in moyamoya disease is higher than normal population. Treating the simultaneous pathology of aneurysm and moyamoya disease in an individual is a rare entity. A 35-year-old male presented with headache, loss of consciousness, and generalized tonic-clonic seizure with subarachnoid hemorrhage. Digital Subtraction angiography showed moyamoya disease with left superior cerebellar artery aneurysm. Rupture of aneurysm was suspected to be the source of subarachnoid hemorrhage. Patient underwent clipping of the left superior cerebellar artery aneurysm with encephalo-duro-arterio-myo-synangiosis. Patient survived the procedures. All patients with subarachnoid hemorrhage in moyamoya disease should undergo angiogram and aneurysm should be looked for carefully. The site of aneurysm and the risk for damaging the collaterals should be kept in mind while planning the surgery in such cases.