Carotid-cavernous fistula caused by rupture of persistent primitive trigeminal artery trunk aneurysm--case report.

A 60-year-old female presented with a carotid-cavernous fistula (CCF) manifesting as left abducens nerve palsy. Left internal carotid digital subtraction angiography showed a persistent primitive trigeminal artery (PPTA) near the CCF. Super-selective angiography showed direct shunt flow between the PPTA trunk aneurysm and the left cavernous sinus. The aneurysm was successfully occluded with detachable coils. The CCF disappeared and the PPTA was preserved. The abducens nerve paralysis had disappeared 6 months later. CCF caused by a PPTA trunk aneurysm is extremely rare. We speculate that the PPTA trunk aneurysm formed and then ruptured due to hemodynamic stress caused by hypoplasia of the basilar artery.