We have experienced 11 cases of cerebral arteriovenous malformation (AVM) associated with an aneurysm or an arterio-venous varix(AVV). Five of the patients were male and six were female, and the mean age was 42. Eight cases were supratentorial, and three were infratentorial. Initial symptoms were bleeding in seven cases, seizure in one, and involuntary movement in one. Among the seven cases with bleeding as the initial symptom, bleeding occured from the aneurysm in three cases, and from the AVM in two cases; in two cases the source of bleeding was undetermined. A two-stage operation was performed in five cases of initial bleeding lesions. Surgical results were excellent in all but one case, in which neither the AVM nor the aneurysm was accessible. The etiology of these combinations of lesions could be explained by the hemodynamic theory. In high flow AVMs, the probability of formation of an aneurysm or the risk of rupture of the aneurysm should be considered during the follow-up period. And in such cases, to prevent rupture of the aneurysm, radical surgery of the AVM should be considered, taking into account the risk of postoperative neurological deficits.
