Intraosseous Dural Arteriovenous Fistula Causing Contralateral Intracerebral Hemorrhage

Dural arteriovenous fistulas (dAVFs) represent 10%–15% of all intracranial vascular malformations.1 Cranial dAVFs occur near the transverse, sigmoid, and cavernous sinuses, and patients usually present with symptoms of pulsatile tinnitus and/or headaches.2 The Borden classification system is used to characterize dAVFs according to their venous drainage pattern.3 Borden type II and III dAVFs are associated with intracerebral hemorrhage (ICH) presentations and higher annual risks of rebleeding and mortality.4 Intraosseous dAVFs are a rare variant where arterial blood supply fistulizes with diploic veins and drains into the cerebral venous system.5 Case reports of intraosseous dAVFs have shown presentations with ICHs6 and marked cortical venous drainage.5 To date, however, intraosseous dAVFs have not been reported in association with contralateral hemorrhagic events. A 70-year-old female with a previous history of hemicolectomy for an adenocarcinoma, chronic renal failure, and hyperthyroidism was brought to the hospital after being found in her home with decreased level of consciousness. On the left external carotid artery angiogram, an early-filling vein was noted along the posterolateral aspect of the left orbit that was supplied by the left middle meningeal artery (MMA) (Figure 2A–B).