Two pediatric cases with occlusions of the ipsilateral internal carotid and posterior cerebral arteries associated with moyamoya vessels: "unilateral" moyamoya disease.

Two pediatric cases of unilateral Moyamoya disease are reported. The clinical symptoms and the findings of electroencephalography, angiography, and positron emission tomography in these cases were quite the same as those in the cases with bilateral involvement, which is typical of this disease. In both cases angiography demonstrated unilateral occlusion not only of the internal carotid artery but also of the posterior cerebral artery together with so-called Moyamoya vessels on the same side. Although infectious diseases were mentioned in the patients' histories, no obvious basic diseases related to the cerebrovascular occlusion were detected. We consider that these cases with unilateral involvement suggest the presence of unilateral Moyamoya disease without progression onto the opposite side.