Thyroglossal duct cyst (TGDC) generally arises from the remnant of the thyroglossal duct that connects the foramen cecum of the tongue to the thyroid gland. We describe a rare case of TGDC associated with small calcification grains in the cystic cavity.
A 39-year-old man was referred to our hospital for further evaluation of a tumor in the submental region. At presentation, the tumor, which measured 4 cm in diameter, was found in the subhyoid region as a rounded, well-circumscribed, painless, mobile, and elastic-soft mass. He had no clinically significant family or medical history of TGDC. Ultrasonography demonstrated a poorly-demarcated cystic lesion about 2 cm in diameter with a heterogeneous internal echo pattern that was partly hyperechoic. Computed tomography and magnetic resonance imaging also showed a demarcated and round cystic mass with a diameter of 2 cm. A clinical diagnosis of TGDC was made, and we performed surgical removal of the tumor with the Sistrunk procedure under general anesthesia. Histopathologically, the cyst was covered with pseudostratified ciliated columnar epithelium within stratified squamous epithelium in some areas. In addition, lamellar-structured small calcification grains were found within the cystic cavity. A histopathological diagnosis of TGDC was made. These small calcification grains apparently developed by a process similar to the generating mechanism of a sialolith. Recurrence of the original TGDC was not found 3 years or more after surgery.
