Papillary carcinoma of thyroid in a thyroglossal cyst.

Thyroglossal duct cyst (TDC) is the most common congenital anomaly of the thyroid gland and the most common congenital cervical abnormality in childhood. Carcinoma arising from a TDC is rare, which composes only 1% of TDC cases. Here, we are reporting a case of 50-year-old male with a swelling in the upper left neck region which was progressively increasing in size over 5 years. Ultrasonography report showed a large lobulated cystic mass. Internal echoes with calcification and there were no neck nodes. Thyroid gland was normal. In the present study, the Sistrunk procedure was used to excise a TDC. Papillary carcinoma was confirmed with the histopathological examination following the surgery. The patient was treated with radioactive iodide and thyroid suppression therapy was given as adjuvant treatment. The patient has been following for 2 years without any metastasis.