Pial arteriovenous fistula with giant varices: report of two cases with good surgical outcome.

Pial arteriovenous fistulas (pAVF) are rare vascular lesions consisting of one or more arterial connections to a single venous channel without any intervening nidus of vessels or capillaries. Case 1: A 65-year-old woman with a complaint of headache and left hand paresthesia was referred to us. Magnetic resonance imaging showed a large saccular lesion with signal void in the posterior part of the right sylvian fissure and catheter angiography showed a giant venous aneurysm fed by one branch of the middle cerebral artery (MCA) and draining into the vein of Trolard. Case 2: A 12-year-old boy was transferred to our hospital with a history of sudden loss of consciousness and hemiplegia. Brain computed tomography revealed a massive hemorrhagic mass in the right hemisphere and cerebral angiography showed a pAVF with a large aneurysmal varix, which was fed by multiple branches of the right MCA and draining into the superior sagittal sinus. Both patients underwent craniotomy and after ligation of vascular connections, aneurysmal varices were removed completely. Surgical resection can be a safe method for treatment of pAVFs, particularly in those with large varices.