Cancer of the external auditory canal is rare among head and neck cancers. Although the treatment of first choice is surgical resection, chemoradiotherapy is frequently selected for patients with advanced disease. Recently, proton therapy has been adopted for the treatment of cancers in the head and neck region, including in the external auditory canal, as it was shown to be almost as effective as radiotherapy, but with fewer adverse effects. Pseudoaneurysms have been reported as a fatal complication of radiation therapy or proton therapy for the nasopharynx and nasal cancer. Herein, we report the case of a 75-year-old male patient with cancer of the external auditory canal, who presented with recurrent episodes of bleeding due to ruptured pseudoaneurysms of the external carotid artery system, necessitating vascular interventional radiology and superficial temporal artery ligation several times after proton therapy. In patients receiving proton therapy, the possibility of complications such as necrosis, infection, and bleeding due to pseudoaneurysm formation and rupture should be borne in mind.
