Pharyngoesophageal diverticulum resembling a thyroid nodule on ultrasound.

BACKGROUND Ultrasound is routinely used in evaluating thyroid nodules and performing fine-needle aspiration cytology (FNAC). Occasionally, nonthyroidal lesions can mimic thyroid nodules on imaging and get wrongly aspirated. METHODS A 63-year-old woman was reported to have an incidental left thyroid "nodule" on neck ultrasound scan. It was isoechoic with a surrounding hypoechoic rim and contained tiny foci of echogenicity. Similar findings were noted in a second surgeon-performed ultrasound scan. RESULTS An ultrasound-guided FNAC showed abundant squamous cells, bacteria, and vegetable cells with no evidence of thyroid cells or colloid. The suspicion of a pharyngoesophageal diverticulum was confirmed on barium swallow. She remained asymptomatic with no increase in size at 6 months follow-up. CONCLUSION A pharyngoesophageal diverticulum can be mistaken for a posteriorly placed "thyroid nodule" on ultrasound scan if the subtle differentiating signs are missed. An awareness of this condition is important to avoid unnecessary needle biopsies.