Endovascular treatment for a ruptured aneurysm in the posterior inferior cerebellar artery feeding a torcular dural arteriovenous fistula: Case report

Background: Dural arteriovenous fistulas (DAVF) complicate intracranial hemorrhages that are secondary to cortical venous reflux (CVR). Clinicians usually pay attention to CVR but not to other uncommon etiologies in hemorrhagic cases. Here, we report the rare case of a ruptured pial feeder aneurysm arising from the posterior inferior cerebellar artery (PICA) that was successfully treated with endovascular surgery. Case description: An 81-year-old man was transferred to the emergency department of our hospital because of sudden onset of vertigo and vomiting. Head computed tomography showed a hyperdense area of up to 2.6 cm in the cerebellar vermis, intraventricular hemorrhage in the fourth ventricle, and subarachnoid hemorrhage in the cerebellopontine cistern. Digital subtraction angiography (DSA) showed a torcular DAVF. CVR was observed in the bilateral cerebellar veins (Borden type 3, Cognard type 4). DSA revealed a small aneurysm in the vermian branch of the left PICA feeding the DAVF. Because the aneurysm was arising from the vermian branch itself, we decided to occlude it with 12.5% N-butyl-2-cyanoacrylate. The vermian branch harboring the aneurysm was successfully obliterated. Rebleeding did not occur postoperatively. Conclusions: The CVR is a common etiology of intracranial hemorrhage caused by DAVF. However, clinicians should be aware that the pial feeder may also contribute to hemorrhagic complications. Our case illustrates the significance of the existence of the pial feeder in hemorrhagic DAVF and the potential contribution of an aneurysm arising from the pial feeder to the etiology. Care should be taken not to overlook the pial feeder on radiologic imaging, and appropriate surgical management should be performed to prevent rupture.