Asymptomatic Pyriform Sinus Tract Easily Mistaken for Thyroid Nodule

Abstract

A pyriform sinus tract/fistula is a rare clinical condition where remnants of the third or fourth pharyngeal pouches extend into the pyriform sinus, forming an internal tract. Common initial presentations of pyriform sinus tract/fistulas are cervical cystic masses in neonates or cervical infections in children but there have been a few reported cases of incidental detection of pyriform sinus tracts in adults. A 62-year-old man was referred from a local clinic for evaluation of a hypoechoic thyroid nodule with calcifications on ultrasonography (US). He had no symptoms of thyroid dysfunction or infection and was euthyroid on laboratory results. Neck US was re-performed in our institution and an air-containing nodule was observed in the posterior aspect of the left thyroid gland. Esophagography was performed to identify this lesion, revealing an obstructed sac structure communicating with the left pyriform sinus. The patient was diagnosed with a pyriform sinus and referred to an otolaryngologist.