Spontaneous carotid-cavernous fistula supplied by the contralateral meningohypophyseal trunk: case report and literature review.

Carotid-cavernous sinus fistulas (CCF) are abnormal communications between the carotid artery and the cavernous sinus. Most spontaneous CCFs are low-flow fistulas, supplied by branches of the omolateral internal carotid artery or the external carotid artery. A 64-year-old man, with increasing diplopia, mild exophthalmos on the left side, blurred left vision and omolateral red eye, was admitted to our institution. The patient underwent a bilateral cerebral angiography that showed a left CCF fed by meningo-hypophyseal branches of the right internal carotid artery and draining from the cavernous sinus into a parahippocampal vein. A transarterial embolization of the carotid-cavernous fistula was performed, with complete obliteration of the fistula. Although anecdotal reports exist, there is a scarcity of well-documented cases of exclusively contralateral flow in the carotid-cavernous fistula. Most of the reported cases referred to contralateral flow into the carotid-cavernous fistula by the external carotid artery branches. To the best of our knowledge, there are no previous cases of a spontaneous CCF supplied by contralateral meningo-hypophyseal branches. A discussion of treatment options and a literature review are also performed.