Thyroglossal duct cysts: sonographic appearances in adults.

BACKGROUND AND PURPOSE Previous reports have suggested that thyroglossal duct cysts (TDCs) appear on sonograms as well-defined cystic masses with thin walls and posterior enhancement. In our experience, however, TDCs have a variable sonographic appearance. We report our findings in 40 patients with TDCs and document the variability of sonographic patterns. METHODS All patients in whom the diagnosis of TDC was made clinically (by at least two head and neck surgeons) and sonography detected a cystic mass related to the hyoid bone were included in this study. Sonograms of 40 patients with TDCs were reviewed. The features evaluated were the location, internal echogenicity, posterior enhancement, presence of septa, solid component, and fistulous tract. The echo pattern was not compared with the biopsy results. RESULTS Four patterns of TDCs were identified: anechoic (28%), homogeneously hypoechoic with internal debris (18%), pseudosolid (28%), and heterogeneous (28%). The majority showed posterior enhancement (88%), were midline (63%), and infrahyoid in location (83%). Only half of all TDCs showed a typical thin wall. CONCLUSION On sonograms, TDCs in adults are not simple cysts, as previously suggested, but have a complex pattern ranging from a typical anechoic to a pseudosolid appearance.