Resolution of migraine-like headache by coil embolization of a primitive trigeminal artery aneurysm.

Objective We report a rare case of migraine-like headache associated with an unruptured primitive trigeminal artery (PTA) aneurysm with a coincident finding of anterior cerebral artery (ACA) fenestration. We discuss the possible mechanism of the headache and review the relevant literature. Case Presentation A 59-year-old woman was admitted with the chief complaint of episodes of pulsatile headache recurring over 3 months. The headaches were moderate to severe in intensity, located on the right side, sometimes triggered and aggravated by strenuous activity, and progressively accompanied by nausea. Headache episodes occurred three to six times per month and typically lasted for several hours each. Radiological examinations demonstrated the presence of a large right-side PTA aneurysm 23x18x17mm in size, which was associated with an ACA fenestration. She was successfully treated with endovascular embolization, and postoperatively, her headaches were completely resolved. At follow-up 12 months after surgery, the patient reported complete resolution of her headache. Discussion Both primitive trigeminal artery aneurysm and fenestration of the cerebrovascular system are rare developmental anomalies. The PTA courses alongside and is in anatomical proximity to the trigeminal nerve. Therefore, PTA aneurysms are more likely to cause symptoms, due to compression of the trigeminal nerve. The trigeminovascular system has been implicated in the genesis of migraine headaches. We propose the high-velocity pulsatile flow through the aneurysm across the surface of the trigeminal nerve as the etiology of the migraine-like headaches. Endovascular embolization might be a preferred procedure for dealing with patients in this setting.