Sonographic demonstration of a normal thyroid gland excludes ectopic thyroid in patients with thyroglossal duct cyst.

OBJECTIVE. Preoperative thyroid scintigraphy has been performed in patients with presumed thyroglossal duct cyst to document a normal thyroid and to exclude the possibility of an ectopic thyroid mimicking a thyroglossal duct cyst. Often, an ectopic thyroid is the patient's only functioning thyroid tissue, and its removal will result in hypothyroidism. The purpose of this study was to determine whether demonstration of a normal thyroid gland by sonography in children with thyroglossal duct cyst can exclude ectopic thyroid and thereby obviate routine preoperative thyroid scintigraphy. MATERIALS AND METHODS. We studied 30 patients with pathologically proved thyroglossal duct cysts who had neck sonograms, The sonograms were evaluated for the presence or absence of a normal thyroid gland, The medical records of these children were also reviewed. Three children had normal preoperative radionuclide thyroid scans. Ail the children were clinically euthyroid preoperatively, Follow-up was available in 15 of the 30 patients, and all of these patients were clinically euthyroid postoperatively. RESULTS. A sonographically normal thyroid gland was detected in ail patients. CONCLUSION. Preoperative sonographic identification of a normal thyroid gland in patients with thyroglossal duct cyst confirms a source of thyroid hormone separate from the thyroglossal duct cyst and thus excludes ectopic thyroid. Routine thyroid scintigraphy is not necessary.