Persistent embryonic veins in the arteriovenous malformation of the telencephalon.

The arterial components of the telencephalic arteriovenous malformations arise from the anterior cerebral and middle cerebral arteries. The complexity of the development process in this region obscures the fundamental segmental pattern. There are three regions where the primitive pial vessels cross at right angles. They are: a) over the convexity of the cerebral hemispheres, b) in the Sylvian territory, c) in the region of the basal ganglia. The malformations over the surface drain into the superior sagittal sinus. The Sylvian and deep telencephalic malformations drain primarily into the tentorial sinus, and this is often replaced by a medial drainage into the internal cerebral vein through the tributaries of the basal vein.