Cognard Type Ⅴ Torcular Dural Arteriovenous Fistula: A Rare Entity.

Tentorial dural arteriovenous fistulas (DAVFs) are a dangerous subtype of fistula. Lawton et al classified this type of fistula into 6 categories based on specific operative strategies. Clinical manifestations of 6 types of tentorial DAVFs vary to some extent. Cognard type V DAVFs in the tentorial region are usually petrosal/superior petrosal sinus DAVFs. DAVFs with perimedullary venous drainage around the torcular herophili are rare. The veins of the posterior fossa are intricate and variable. There are anatomic communications between the perimedullary vein and cerebellar vein or veins of the brainstem. Almost all of the Cognard type V DAVFs are found in the posterior fossa. Here, we present a Cognard type V DAVF with a fistula located around the torcular herophili.