A Case of Internal Carotid Artery Aneurysm in the Parapharyngeal Space Treated by Endoscopic-Assisted Transoral Surgery

An extracranial internal carotid artery aneurysm is rarely found manifesting as a mass in the parapharyngeal space. We report a case of internal carotid artery aneurysm in the parapharyngeal space that was treated by endoscopic-assisted transoral surgery. A 74-year-old woman had undergone coil embolization for a left internal carotid artery aneurysm at another hospital 20 years earlier. She presented with the complaint of pharyngeal discomfort, and was referred to our hospital with suspected internal carotid artery aneurysm. A hard mass was palpable in the left soft palate, and CT and MRI examinations revealed two large internal carotid artery aneurysms in the left parapharyngeal space. Since no blood flow to the aneurysm was observed on angiography, we decided to remove only the interior aneurysm by endoscopic-assisted surgery with a Dingman mouth opener. The aneurysm was successfully removed, with no significant bleeding, as it was not adherent to the surrounding tissues. The patient could resume oral intake from the day after the surgery, and the preoperative symptoms promptly resolved. Most cases of extracranial internal carotid artery aneurysms are treated by endovascular therapy or surgery by the neurosurgeon and cardiovascular surgeon, while there are no reports in the literature, to the best of our knowledge, of cases treated by endoscopic-assisted transoral surgery. Since our case had undergone endovascular treatment and the aneurysm had organized, we could treat her by minimally invasive surgery. Endoscopic-assisted transoral surgery may be a useful treatment modality for selected cases of tumor or internal carotid artery aneurysms in the parapharyngeal space.