Synchronous Occurrence of Thyroglossal Duct Cyst-Derived Papillary Carcinoma and Papillary Thyroid Carcinoma: A Case Report and Literature Review

The thyroglossal duct (TGD) normally regresses; when it persists, a thyroglossal duct cyst (TGDC) may form.Malignancy in a TGDC is rare.Papillary thyroid carcinoma (PTC) is the most common differentiated thyroid cancer, and the concurrent occurrence of papillary carcinoma of the TGDC (TGDC-PC) and PTC is uncommon.We report one such synchronous case.A young woman presented with neck discomfort and a foreign-body sensation.Imaging revealed a TGDC; the thyroid appeared normal.Intraoperative frozensection examination confirmed TGDC-PC.On this basis, she underwent a Sistrunk procedure, total thyroidectomy (TT), and regional lymph node dissection.Postoperative pathology identified PTC with lymph node metastasis.When papillary carcinoma arises in a TGDC, a hidden thyroid lesion should be suspected despite normal imaging, and treatment should proceed accordingly.