A 53-year-old man presented with acute onset of severe headache, and possible witnessed seizure. Imaging confirmed intraventricular hemorrhage primarily focused within the fourth ventricle with diffuse subarachnoid hemorrhage within the posterior fossa and along the tentorium (Figure 1A). No severe neurologic deficits were observed initially. His cerebral angiogram revealed a high flow dural arterial venous fistulous malformation of the tentorium supplied by the bilateral external carotid and left vertebral arteries into a large venous varix within the fourth ventricle at the site of the hemorrhage (Figure 1B, C). Deep venous drainage is observed into the Galenic and Straight Sinus of the posterior fossa. Successful trans-arterial embolization with liquid embolics (N-butyl cyanoacrylate, NBCA) of the bilateral external and left vertebral posterior meningeal artery feeders was successful at reducing >90% of these high-pressure indirect shunts (Figure 1D), with a small residual shunts from the distal occipital arteries that were subsequently targeted for cure with Gamma Knife Radiosurgery.
