BackgroundArteriovenous malformations (AVMs) with vascular abnormalities, including aneurysms, have been reported frequently. However, the coexistence of AVM and unilateral moyamoya disease is rare. We report herein an AVM patient who presented with acute ischemic stroke with unilateral moyamoya disease and occlusion of the feeding artery.Case ReportA-41-year old man was admitted with sudden dysarthria and facial palsy. Brain computed tomography and magnetic resonance imaging revealed an acute infarction adjacent to a large AVM in the right frontal lobe. Cerebral angiography revealed occlusions of the proximal right middle cerebral and proximal anterior cerebral arteries, which were the main feeders of the AVM. Innumerable telangiectatic moyamoya-type vessels between branches of the anterior cerebral artery and dilated lenticulostriate arteries on the occluded middle cerebral artery were detected. However, a nidus of the AVM was still opacified through the distal right callosomarginal artery, which was supplied by the remaining anterior cerebral artery and leptomeningeal collaterals from the posterior cerebral artery.ConclusionsWhile AVM accompanied by unilateral moyamoya disease is rare, our case suggests an association between these two dissimilar vascular diseases.