A Case of Rebleeding and Peripheral Neoaneurysm in the Choroidal Artery Resolved by Additional Cerebral Revascularization in Adult Hemorrhagic Moyamoya Disease with Subsequent Revascularization

The authors encountered an interesting phenomenon in an adult hemorrhagic patient with moyamoya disease. A peripheral aneurysm in the distal branch of the right lateral posterior choroidal artery was resolved by additional cerebral revascularization surgery. This case illustrated that cerebral revascularization surgery with large craniotomy was more effective than it was with small craniotomy for preventing rebleeding events.A 38-year-old woman was admitted to our hospital with disturbed consciousness, left hemiparesis, and total aphasia. She had a history of hemorrhagic moyamoya disease and had undergone cerebral revascularization surgeries in both hemispheres to prevent rebleeding. These surgeries included superficial temporal artery/middle cerebral artery [STA-MCA] double bypass with large craniotomy in the left hemisphere 5 years previously and STA-MCA single bypass with small craniotomy 2 years previously on the opposite side.Computed tomography (CT) demonstrated that right intracerebral hemorrhage and intraventricular hemorrhage had occurred as a rebleeding event. Seven months after the rebleeding event, angiography showed a new peripheral aneurysm of the distal branch of the right lateral posterior choroidal artery and development of abnormal collateral flow from the posterior cerebral artery (PCA). We performed an additional cerebral revascularization surgery (occipital artery [OA]-MCA bypass + encephalo-myosynangiosis in the occipital lobe and encephalo-duro-periosteal-synangiosis in the frontal lobe) in the right hemisphere. By three months after surgery, the peripheral aneurysm had disappeared.This case suggests that cerebral revascularization surgery with STA-MCA single bypass and small craniotomy is insufficient to prevent rebleeding and that cerebral revascularization surgery with STA-MCA double bypass and a larger craniotomy is necessary to prevent rebleeding in adult hemorrhagic moyamoya patients.