Carcinoma in thyroglossal duct remnants.

Two cases of carcinoma arising in thyroglossal duct remnants are reported to add to the previously documented 78 cases in the literature. This rare lesion, which occurs is less than 1% of thyroglossal duct abnormalities, pathologically and clinically is similar to primary tumors arising in the thyroid gland. Papillary adenocarcinomas constitute 75-85% of all cases reported and most are confined to the duct remnant itself with metastasis being infrequently recorded. Therapy consists of wide excision of the tumor-bearing tissue (Sistrunk procedure) in those cases localized to the duct remnant itself. In instances where metastasis or additional lesions are detected in the thyroid gland, thyroid ablation and neck dissections are indicated. Additional modalities such as suppressive thyroid therapy, radioactive iodine, and external radiation have been employed. Distant metastasis is rare and the long-term prognosis is very favorable.