The authors report two rare cases of arteriovenous malformation (AVM) associated with moyamoya disease. An AVM, supplied by transdural communicating arteries, was located in the right occipital lobe in one patient who presented with ischemia. The second AVM, which was supplied by basal moyamoya vessels, was located in the posterior part of the left frontal lobe in a patient who developed intracerebral hemorrhage that occupied the left basal ganglion.
A review of the literature revealed a total of 12 AVMs in 11 patients with moyamoya disease including our cases. All AVMs were cerebral and two were supplied by normal cerebral arteries, whereas six AVMs were supplied by basal moyamoya vessels at the base of the brain and four AVMs were supplied by external carotid arteries through the transdural communicating arteries. Every AVM drained into deep or cortical cerebral veins. These findings suggest that the hyperangiogenic character of moyamoya disease occasionally induces the development of acquired arteriovenous shunts that mimic AVM.