A case of tentorial dural arteriovenous fistula presenting as acute subdural hemorrhage of the posterior fossa

Tentorial dural arteriovenous fistula (DAVF) usually manifests as parenchymal brain injury, such as intracranial hemorrhage or subarachnoid hemorrhage, and very rarely as single onset of acute subdural hemorrhage (ASDH). We describe a case of tentorial DAVF manifesting as ASDH in the posterior fossa with a favorable outcome after early direct surgery. A 29-year-old man suffered from sudden onset of severe headache and vomiting, and was transferred to our emergency department. Head computed tomography and magnetic resonance imaging showed ASDH in the right posterior fossa. Cerebral angiography showed tentorial DAVF with a shunting point in the right tentorial notch, with evidence of venous reflux and varicose vein formation. We attempted endovascular embolization, but guidance of the microcatheter to the shunting point was difficult. Therefore, we performed surgical venous transection, resulting in complete occlusion of the shunting point. Tentorial DAVF manifesting as ASDH, not associated with parenchymal brain damage, benefits from direct surgery, which allows simultaneous radical hematoma removal and venous transection.