Acquired mural (dural) arteriovenous shunts of the vein of Galen. Report of 4 cases.

4 patients with acquired arteriovenous shunts located in the wall of an ectatic vein of Galen (VG) are reported. They represent so-called VG dural arterio-venous malformations (DAVM). These shunts involve the vasa vasorum normally present in the VG wall. Physiopathology, clinical signs and age groups are usually the same as those encountered in other DAVMs; conversely they are totally different from the other mural shunts of the VG, detected in the pediatric population (true VG arteriovenous malformations), and leading to different clinical symptoms. Venous approach in these VG DAVMs is almost always contraindicated unless secondary occlusion of VG afferent has spontaneously excluded the pouch from the cerebral venous circulation.