Long-Term Ultrasound Follow-Up of Incidentally Detected Thyroglossal Duct Cysts in Adults.

BACKGROUND AND PURPOSE: There has been no previous study that used ultrasonography for longitudinal changes of thyroglossal duct cysts, to our knowledge. We assessed the prevalence and interval changes in incidentally detected thyroglossal duct cysts in adults. MATERIALS AND METHODS: From January 2010 to December 2016, we identified 796 ultrasonography radiologic reports from 513 subjects that contained the words thyroglossal or TGDC among 54,369 participants. Of 513 subjects, 172 (M/F = 103:69, mean age, 53 11 years) who underwent 2 sonography studies were enrolled. Two reviewers determined ultrasonography features, including maximal diameter, location, internal echogenicity, wall thickness, and the presence of posterior enhancement, internal septa, and solid components. RESULTS: The mean follow-up time of total 172 lesions was 2.01 +/- 1.13 years. Thyroglossal duct cysts ranged from 2 to 32 mm (mean, 8.77 +/- 3.83 mm) on the initial ultrasonography examination. On follow-up ultrasonography studies, 14 lesions (8.2%) increased by >2 mm, while most thyroglossal duct cysts (133 lesions, 77.3%) remained stable in size. During the follow-up period, 31 lesions (18.0%) showed interval changes in ultrasonography features. There was no significant relationship between the presence of ultrasonography feature changes and size changes (P = .12). CONCLUSIONS: On ultrasonography, 0.9% of adults had incidental thyroglossal duct cysts. Most did not increase in size with time despite changes in various ultrasonography features. Therefore, we recommend performing an observation at long intervals of 2-3 years for asymptomatic thyroglossal duct cysts, and we suggest that fine-needle aspiration can be suspended unless suspicious findings of malignancy are detected.