Giant Aneurysm in the V1 Segment of Vertebral Artery: A Case Report and Literature Review.

Aneurysms in the V1 segment of the extracranial vertebral artery are extremely rare. Furthermore, half of the cases are giant aneurysms larger than 25 mm. This study reports a case of unruptured giant V1 aneurysm of the right vertebral artery that was successfully treated with endovascular coil embolization. An 85-year-old woman experienced dizziness sporadically. Magnetic resonance imaging demonstrated a mass in the right subclavian region. Radiological examinations showed an aneurysm originating from the V1 segment of the right vertebral artery. The aneurysm was successfully embolized with platinum coils, with preserved patency of the vertebral artery. Although aneurysms in the V1 portion of the vertebral artery are extremely rare, there is a possibility of thrombosis or rupture. Endovascular treatment such as coil embolization may be effective for a V1 vertebral artery aneurysm.