We describe two rare cases of spontaneous closure of cerebral dural arteriovenous fistulas (DAVFs) with a small nidus and draining directly in a single cortical vein with several ectasias. Eighteen previously published cases of spontaneous closure of cerebral DAVF comprised more benign fistula types. In literature, several explanations for DAVF occlusion have been proposed. We hypothesize that, in addition to the known causes, the specific contrast medium used during the diagnostic selective angiography might have played a role in the thrombosis and subsequent fistula closure.