GASTROENTEROLOGY 2013;145:726–729 Question: A 70-year-old woman presented with a painless and nonprogressive left neck mass for 2 months. It was palpated incidentally, and there was no associated dysphagia or hoarseness. Physical examination revealed the left-sided, lower midline neck mass, 2 2 cm in size. It was mobile, elastic, and well-margined. The examination of the head and neck including nasopharynx, oral cavity, hypopharynx, and larynxwas unremarkable. All of the routine blood chemistry tests, including thyroid function tests were normal. The head and neck ultrasonography revealed a 2.2 1.7-cm isoechoic nodule (FigureA, arrow) in the posterior aspect of the left thyroid lobe with internal hyperechoic foci (FigureA, arrowheads), hypoechoic rim and dirty shadowing. Fine-needle aspiration revealed benign squamous cells (Figure B). There was no thyroid tissue present. What is your diagnosis? Look on page 913 for the answer and see the GASTROENTEROLOGY web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.