Abstract
Two cases of congenital cystic lesion in the thyroid gland were reported. Case 1, a 74-year-old male, was surgically treated for a cyst which was located in the thyroidal isthmus and surrounded by normal thyroid tissue. The inner surface was covered with a single flat epithelium.
Case 2, a 6-year-old female, visited us because of a gradually increasing tumor in the right anterior neck. The cyst wall, 2mm in thickness, was lined with columnar ciliated epithelium. Many lymph follicles were observed in the subepithelial layer. The boundary from the normal thyroid tissue was not clear. The content consisted of many lymphocytes. The postoperative course of these two patients were uneventful.
Embryonal development of the thyroid gland and surrounding tissues are complicated. Congenital cysts in this region originate from the 3rd or 4th pouches, ultimobranchial body or thyroglossal duct.
We diagnosed these two cases as thyroglossal duct cysts based on the clinical findings and histological examination.
