Dural Arteriovenous Fistula of the Vein of Trolard Mimicking a Cavernous Sinus Fistula.

BACKGROUND: Arteriovenous fistulas (AVFs) involving the cavernous sinus usually become clinically apparent due to eye symptoms. Although rare, the same symptoms can be associated with AVFs located remote from the cavernous sinus when the shunt drains into its tributaries. We report the unusual case of a dural AVF in which such communication was not immediately obvious from the diagnostic angiogram. CASE DESCRIPTION: A 61-year-old male presented with increasing lid swelling, proptosis, and redness of the right eye for 1 month. Digital subtraction angiography showed no evidence of a cavernous sinus fistula but revealed a dural AVF between the right middle meningeal artery and the vein of Trolard. The fistula had a minor drainage through a small superficial middle cerebral vein toward the middle cranial fossa. Late venous-phase images eventually revealed faint opacification of the right cavernous sinus and superior ophthalmic vein. Endovascular treatment was performed by transarterial embolization with complete occlusion of the AVF obtained after 2 sessions. CONCLUSIONS: Dural AVFs involving cortical veins may cause atypical symptoms suggesting a cavernous sinus fistula due to remote venous drainage. Understanding venous anatomy helps to correlate vascular pathology and clinical symptoms and thus allows efficient and safe treatment.