Unusual spontaneous dural cavernous sinus fistula between right external carotid artery and left cavernous sinus--a case report

A 64 year-old female had left exophthalmos which resulted from a spontaneous dural cavernous sinus fistula between the right external carotid artery and left cavernous sinus. The left cavernous sinus was fed directly from internal maxillary branches of right external carotid artery with the sparing of right cavernous sinus and intracavernous sinus. Symptoms and signs of dural cavernous sinus fistula developed slowly in the left eye only. Although this kind of spontaneou dural cavernous sinus fistula is very rare. The possibility of arterial feeding from contralateral carotid artery should not be ignored in any patient that is suffered from dural cavernous sinus fistula while angiographic study is performed.