Preoperative sonography in presumed thyroglossal duct cysts.

OBJECTIVE To determine the utility of ultrasonography as a sole diagnostic study in the preoperative preparation of patients with presumed thyroglossal duct cysts. DESIGN Retrospective chart review. SETTINGS Children's Memorial Hospital, Chicago, Ill. PATIENTS Forty-five pediatric patients with midline masses. MAIN OUTCOME MEASURE Accuracy in the determination of a normally positioned thyroid gland excluding the presence of a solitary ectopic thyroid gland. RESULTS A retrospective chart review was performed at our institution for the period February 1990 to January 1996. A total of 45 patients with midline masses were identified, 39 of whom had undergone preoperative ultrasonography as their sole diagnostic imaging study. In all 39 patients, both a cyst and a normal thyroid gland were identified. All 39 patients underwent the standard Sistrunk procedure. Thirty-seven patients had pathologically confirmed thyroglossal duct cysts. The remaining 2 had dermoid cysts. There were no cases of postoperative hypothyroidism. CONCLUSIONS The incidence of ectopic thyroid in the diagnosis of thyroglossal duct cysts has been reported to be as high as 1% to 2%. In our surgical and clinical experience, the actual incidence of solitary ectopic thyroid tissue is substantially lower. Nevertheless, to prevent the inadvertent removal of the only functioning thyroid tissue, with resultant postoperative hypothyroidism and possible medicolegal consequences, we advocate the routine preoperative identification of normal thyroid gland. We recommend ultrasound as an accurate, cost-effective, noninvasive imaging modality in the preoperative evaluation of all patients with neck masses suspicious for thyroglossal duct cyst. Also, it does not require sedation.