Abstract
Two cases of arteriovenous malformation fed by small arteries and lying within the basal ganglia were presented.
Cerebral angiography revealed an abnormal vascular network like moyamoya disease. It also showed that the drainer had a particular orientation with an umbrella- or medusae-like pattern radiation toward the single draining vein like a venous angioma.
In one case, the malformation, which involved the putamen and the insula, total extirpation was carried out. In the other case, the malformation, which involved the area from the frontal base to the caudate nucleus, was treated only by feeder clipping.
The obscure locations of these lesions made them more difficult to resect than the usual arteriovenous malformation.
