Intraorbital Arteriovenous Fistula Mimicking an Anterior Cranial Fossa Dural Arteriovenous Fistula

Introduction: Intraorbital arteriovenous fistulas (AVFs) that lie purely within the orbit is quite rare and sometimes it can be misdiagnosed as an anterior cranial fossa dural AVF. The optimal treatment of intraorbital AVFs is still a matter of debate because of the small number of reported cases.

Case Presentation: A 72-year-old female patient presented a 4-month history of progressive proptosis of left eye in association with upper lid swelling and conjunctival chemosis. MRI and CT demonstrated 2 cm vascular mass-like lesion in upper superomedial aspect of globe, engorged draining left superior ophthalmic vein (SOV). Digital subtraction angiography showed an AVF, which was fed from ophthalmic artery and superior temporal artery branches and draining to SOV and it mimicked an anterior cranial fossa dural AVF. However, angiographic XperCT scan showed that the lesion located at intraorbital space and she experienced a stabbing injury near the left orbit. Finally, intraorbital AVF was diagnosed and the lesion was symptomatic, open surgical excision was planned. After anterior orbitotomy, a thickened serpiginous thrombosed SOV was found, which was resected completely after ligation of the proximal feeding artery. Postoperative course was uneventful with good clinical outcome. CT angiography scan obtained at the time of discharge demonstrated no evidence of residual AVF.

Conclusion: Posttraumatic intraorbital AVF in association with varicose SOV, as reported here, was rare disease and mimicked an anterior cranial fossa dural AVF. In such cases, direct surgical exposure of the SOV followed by excision may accomplish complete closure of the fistula without significant risk for iatrogenic injury.