A Case of Multiple Thyroglossal Duct Cysts: Usefulness of Intraoperative Ultrasound for Cysts Hidden Within the Lingual Muscle

Abstract

We present the case of a boy with multiple thyroglossal duct cysts (TDCs). At 1 year of age, a mass was noted in the midline of the neck. Computed tomography revealed a cyst caudal to the hyoid bone, leading to the diagnosis of a solitary TDC. At 2 years of age, ultrasonography showed three small, low-echoic lesions above the hyoid bone, and magnetic resonance imaging revealed two cysts adjacent to the caudal aspect of the hyoid bone. Surgery was performed at 2 years and 2 months of age. After detaching the hyoid bone, the primary cyst attached to the hyoid bone and one small cyst were confirmed; however, one cyst remained along the usual fistula detachment line and could not be visualized. Residual cysts embedded within the lingual muscles were identified by intraoperative ultrasonography, and “core out” was performed to excise the cysts completely. Most cases of TDC involve solitary cysts that occur caudal to the hyoid bone; multiple cysts are extremely rare. In cases involving multiple cysts, particularly small cysts within the lingual muscles, changes in the positional relationship between the hyoid bone and cysts may occur during surgery, leading to the possibility of cyst remnants at the usual detachment line. In such cases, intraoperative ultrasonography is useful for identifying cysts and fistulas within the lingual muscles.