Aneurysms of the thoracic aorta are rare manifestations that have never been reported in association with a pulsatile cervical mass. A 55-year-old man presented with a 10-year history of a gradually increasing pulsatile mass in the left side of his neck. He had developed intermittent hoarseness for the previous 3 months. Imaging revealed a widened mediastinum, with an enlarged ascending aorta and thoracic aorta. It was diagnosed as an aneurysm of the thoracic aorta. An observation trial without surgical treatment was given in the patient, at a 10-month follow-up, the size of the mass had not changed significantly, but the symptom of hoarseness had abated.