Pial Arteriovenous Fistula Occurring Secondary to Chronic Cerebral Venous Sinus Thrombosis

An arteriovenous fistula (AVF) involving pial circulation is a rare pathology. It comprises of a single or multiple arteries draining into the venous channels without a nidus as in AV malformations. These lesions make 1.6% of all intracranial vascular abnormalities. Unlike dural AVFs, 80% of pial AVFs are supratentorial and typically lie adjacent to the ventricular ependyma or just beneath the brain surface. This report describes the occurrence of pial AVF, predominantly in the region of prepontine cistern, secondary to chronic cerebral vein thrombosis. Pial AVFs are rare lesions however they do exist and one should be wary with adequate knowledge of imaging findings and clinical picture to make the diagnosis in time. Diagnosis at the earliest is of utmost importance to save the patient from the devastating complications which are part of the natural course of the disease.