Internal carotid artery (ICA) pseudoaneurysm caused by skull base osteomyelitis is a rare complication of radiotherapy for nasopharyngeal carcinoma (NPC). Rupture of the pseudoaneurysm can occur with massive bleeding, which could be fatal. A 74-year-old man with NPC who had received chemoradiotherapy was detected as having an ICA pseudoaneurysm. He presented with a massive nosebleed of acute onset. Coil embolization of the ICA was performed, and he was saved without serious complications. It is important to keep in mind the possible development of an ICA pseudoaneurysm after radiotherapy for NPC.
