RESUMO
Thyroglossal duct carcinoma is a rare midline neck carcinoma that is usually diagnosed postoperatively. Its incidence is about 1-1.5%. This article presents two cases of thyroglossal duct cyst carcinoma and their diagnosis and the management methods are described. Our patients were 24 and 16 year old ladies that referred to Khalili hospital with chief complaint of midline neck mass in 1379, 1377. Their para-clinical tests were negative for malignancy but papillary carcinoma was detected after surgery. They have only been followed up for few years without any thyroidectomy and radioiodine therapy. There is high false negativity in fine needle aspiration and sonography for ruling out malignancy in thyroglossal cyst; therefore, para clinical tests cannot rule out malignancy and excisional biopsy is the only definite way for ruling out thyroglossal cyst carcinoma. On the other hand, severe controversy exists in managing of thyroglossal cyst carcinoma. While some surgeons are interested in total thyroidectomy and radioiodine ablation, it is not necessary to do thyroidectomy if the thyroid gland, lymph nodes and excised mass margins are free of malignancy because excellent prognosis of thyroglossal cyst carcinoma and probable thyroid involvement can be found by close follow up