Spontaneous direct carotid-cavernous sinus fistula secondary to a persistent primitive trigeminal artery treated by trans-venous coil embolisation.

A healthy 51-year-old female presented with a spontaneous direct carotid-cavernous sinus fistula associated with a persistent primitive trigeminal artery. She had no history of connective tissue or cerebrovascular disorders or significant head trauma. This is a rare lesion with only 18 previously reported cases. It had similar clinical presentation and imaging appearance to a high-flow direct carotid-cavernous fistula and was uncovered after successful trans-venous coil embolisation of the fistula. It therefore needs to be considered in cases of direct carotid-cavernous fistula without history of trauma. Knowledge of types of persistent primitive trigeminal artery is also important for their critical treatment implications.