A dural arteriovenous fistula of the anterior cranial fossa angiographically mimicking an anterior ethmoidal artery aneurysm.

Venous aneurysm or varix at the venous side of the fistula commonly exist in dural arteriovenous fistula (DAVF) of the anterior cranial fossa, which may be initially mistaken with aneurysm on computed tomography and magnetic resonance imaging, but always identified by angiography. We report a very unusual case of anterior cranial fossa DAVF angiographically mimicking an anterior ethmoidal artery aneurysm, which was ultimately corrected by surgery. A 41-year-old male presented with right frontal intraparenchymal hematoma with intraventricular extension. Angiography revealed a vascular lesion adjacent to the anterior fossa mimicking an anterior ethmoidal artery aneurysm, which was surgically proven to be a partially thrombosed venous varix of drainaging vein originated from the cribriform plate. A diagnosis of anterior cranial fossa DAVF was made, and venous varix was excised. Follow-up angiography after the operation revealed complete disappearance of the lesion. Our case illustrates a unique occasion that a proximal venous varix without obvious outflow angiographically in DAVF might be mistaken with an aneurysm.