Fistula of the posterior communicating artery and cavernous sinus.

A 24-year-old man was admitted with conjunctival hyperemia of the left eye and progressive chemosis and proptosis 1 month after a head injury. An angiogram showed an arterial-cavernous sinus fistula of the posterior communicating artery, which was treated with minicoils. The atypical configuration, transvenous embolization, and unusual nature of the communication suggested that communication developed through a newly generated vessel in granulation tissue.