Indirect cavernous sinus arterio-venous fistula

Case contributed by Chris O'Donnell
Diagnosis certain


Episcleral venous dilatation involving the left orbit with asymmetrical left proptosis. No history of trauma.

Patient Data

Age: 45
Gender: Male

Proptosis of the left globe associated with asymmetrical enlargement of the left superior ophthalmic vein and distended veins adjacent to the lateral wall of the left cavernous sinus and overlying the left temporal lobe adjacent to the greater wind of sphenoid including the inferior anastomotic vein of Labbé.  Note signal within these veins on the TOF MRA indicating arterialization of flow indicative of an A-V fistula with origin form a small branch of the cavernous internal carotid artery (arrow).

Case Discussion

These findings are typical of a so-called indirect (A-V) fistula between the cavernous internal carotid artery and veins within and lateral to the cavernous sinus producing raised retro-orbital pressures due to arterialization of the orbital veins (causing the globe to be proptosed).  Confirmation of the diagnosis requires catheter angiography with a view to embolization.

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