Ruptured Anterior Wall Aneurysm of the Internal Carotid Artery with Only Vascular Stenosis on Initial Angiography: A Case Report

Summary: Diagnosis and treatment of anterior wall aneurysm of the internal carotid artery (IC) is dif-ficult. We hereby report a case of ruptured anterior wall aneurysm of the IC. A 71-year-old woman was transferred to our hospital with sudden headache and altered consciousness. Computed tomography (CT) brain and CT angiography demonstrated subarachnoid hemorrhage and only vascular stenosis in the C1 portion of the right IC. Angiography showed similar vascular findings. Elective surgery was planned as the origin of subarachnoid hemorrhage (SAH) was unclear. Repeat angiography revealed an outpouching from the anterior wall of the IC. The aneurysm was successfully treated by trapping of the C1 portion of the IC with a high-flow bypass. She recovered without any neurological deficit in 3 months. There is a possibility that initial angiography of the anterior wall aneurysm showed only vascular stenosis, which changed form in a short period. Magnetic resonance imaging (MRI) is useful for confirming intramural hematoma, and serial angiographic follow-up examinations are important.