Ruptured Aneurysm of the Accessory Middle Cerebral Artery Associated with Moyamoya Disease – A Case Report

The accessory middle cerebral artery can provide collateral blood supply in moyamoyadisease. We report a case of unilateral moyamoya disease which demonstrates the anatomyof the right accessory middle cerebral artery and a ruptured peripheral aneurysm on theartery. Our patient was a 56-year-old woman who initially suffered from headache andlethargy. Right caudate nucleus hemorrhage with intraventricular extension and spontaneoussubarachnoid hemorrhage were found on brain computed tomography. A ruptured peripheralaccessory middle cerebral artery aneurysm associated with unilateral moyamoya disease wasdiagnosed on cerebral angiography. Surgical intervention to excise the peripheral accessorymiddle cerebral artery aneurysm assisted by frameless navigation guidance to reduce the riskof damage to collateral vessels was done successfully. Histopathology of excised tissueshowed thi s anoma ly wa s a ps eudoaneurysm. The management of an aneurysm inmoyamoya di s e a s e should be modi f i ed ba s ed on i t s loc a t ion and col l a t e r a l ve s s e l s .Prevention of aneurysm bleeding and preservation of collateral vessels during craniotomyare the critical when managing hemorrhagic moyamoya disease. This case suggests that surgical intervention for ruptured intracranial aneurysms is safe with the use of frameless navigation guidance to minimize collateral vessel injuries.