Abstract
A 51-year-old man presented with a nonpulsatile anterior neck mass which suggested a thyroglossal duct cyst. at CT a small cystic mass was revealed. the mass contained a well-defined, crescent-shaped, low-density area with homogeneous contrast enhancement. on MR T2-weighted spin-echo and gradient-echo images the mass was as hyperintense as the neck vessels. Angiography and operation confirmed an aneurysm of the left superior thyroid artery with a mural thrombus