PRIMARY PAPILLARY CARCINOMA OF THE THYROGLOSSAL DUCT CYST MASQUERADING AS BENIGN CYSTIC SWELLING: A RARE ENTITY

Carcinoma arising primarily from thyroglossal duct cyct is an extremely rare occurance, with only a few cases being reported till date in world wide literature. Majority of malignancies arising from the thyroglossal duct cyst (TDC) is due to thyroid remnants. Ectopic thyroid tissue has been found in most cases of primary cancers arising in the TDC. Here we present a rare case of primary papillary carcinoma of the thyroglossal duct (TD) in a thirty-nine year old female who presented with a painless midline neck swelling over a period of three months. Imaging revealed a 1.9 cm diameter space occupying lesion (SOL) with normal thyroid and absent lymphadenopathy, following which fine needle aspiration cytology (FNAC) was done, which showed papillary thyroid carcinoma. Subsequently, the patient underwent Sistrunk operation as a part of treatment protocol for midline neck swellings. Postoperative histopathological examination confirmed papillary thyroid carcinoma along with the presence of ectopic thyroid tissue at the periphery of the lesion.