Medullary venous malformation with an arterial component associated with a ruptured aneurysm--case report.

We report the rare of occurrence of a medullary venous malformation (MVM) with an arterial component associated with a saccular aneurysm on the opposite side. This 49-year-old male patient was admitted with headache and vomiting. He was diagnosed as having a subarachnoid hemorrhage on the basis of bloody cerebrospinal fluid. Angiography revealed a saccular aneurysm at the junction of the internal carotid and posterior communicating arteries on the left side. A MVM with an arterial component was also seen in the right basal frontal lobe. On the seventh hospital day, the aneurysm was clipped via a left frontotemporal craniotomy. The postoperative course was uneventful. There are many hypotheses concerning cerebral aneurysms; some are thought to derive from persistent primitive arteries in the early fetal period. On the other hand, MVM is thought to be intimately related to arteriovenous malformation, which is believed to develop from the premordial vascular plexus, also in early fetal life.