Brain stem arteriovenous malformation with large venous varix.

The case of a patient with arteriovenous malformation (AVM) with a venous varix that occurred at the medulla oblongata is reported. The AVM bled twice in a short period. The AVM was fed by the small ramus, possibly the anterior spinal artery, originating from the right distal vertebral artery and draining into a large venous varix and then into the venous systems surrounding the brain stem. The obstruction of the feeding artery was performed, and the varix subsequently disappeared. The remaining abnormal vasculature was then treated with stereotactic radiosurgery. The treatment of an AVM at the medulla oblongata is still challenging, but the appropriate combination of modalities will improve the patient outcome.