Thyroglossal duct cysts are usually located in the midline of the neck. The coexistence of carcinomas in thyroglossal duct cysts is extremely rare, with most being papillary carcinomas. Usually, the diagnosis is only made postoperatively after excision of the cyst. Although the Sistrunk procedure is often regarded as adequate, controversies exist concerning the need for thyroidectomy depending on histopathological findings. We report the case of a 31-year-old man diagnosed with papillary carcinoma within a thyroglossal duct cyst, who underwent total thyroidectomy as has been recommended for differentiated papillary cancer.