Dural Arteriovenous Fistula of the Superior Petrosal Sinus Associated with a Rapidly Growing Huge Varix: Case Report

We report a 61-year-old Japanease man with a superior petrosal sinus dural arteriovenous fistula (AVF) with a rapidly growing varix presenting as intracranial hemorrhage. He complained of headache and cerebellar ataxia. A computed tomography (CT) study revealed a huge high-density mass in the left cerebellar hemisphere. The mass had not been detected on a CT scan obtained elsewhere a month earlier. Magnetic resonance imaging revealed a huge flow void in the left cerebellopontine angle, and angiography showed a dural AVF located adjacent to the left superior petrosal sinus. It was supplied by the external carotid arteries and drained via the vein of Galen and a huge varix. After preoperative NBCA embolization of the feeding vessels, he underwent direct surgical ligation of the draining vein. However, as the size of the varix did not decrease and he developed brainstem symptoms, we excised the thrombosed varix. Ours is very rare case of superior petrosal sinus dural AVF resulting in consciousness disturbance due to brainstem compression by a huge varix. We postulate that the development of an intrathrombotic vascular channel and repeated recanalization may have been important factors in the rapid growth of the huge varix.