Pure dural arteriovenous fistulas are still not properly understood, and pose problems wich are far from being resolved. Among these, dural fistulas with cortical venous drainage represent a very special entity since they alone are expressed clinically by a neurological brain syndrome. Diagnosis is difficult and mistakes can be made as it is only by means of hyperselective arteriography of the branches of the external carotid that an accurate diagnosis can be made. However, their diagnosis assumes considerable importance since surgical or radiological treatment of hese fistulas brings about complete disappearance of clinical symptoms.