Coexistence of multiple arteriovenous malformations and an anomalous aortic arch.

An unusual case of multiple congenital arteriovenous malformations (AVM) coexistent with an anomalous aortic arch is described. Our patient had been asymptomatic, with physical findings limited to a low grade systolic murmur, until the onset of acute subarachnoid hemorrhage. Arteriography was technically difficult and failed to demonstrate the origin of his hemorrhage or the configuration of his aortic arch. However, an AVM within the neck muscles was visualized. Magnetic resonance imaging of his chest revealed a right-sided, retroesophageal aortic arch with an anomalous pattern of branching. The intracranial AVM and the course of the great vessels was clearly revealed at autopsy. A possible embryologic mechanism underlying the origin and distribution of the arch vasculature is discussed.