A rare case of incidentally diagnosed primary papillary carcinoma of thyroglossal duct cyst.

Thyroglossal duct cysts are the most common congenital abnormality of thyroid development. Seventy percent of thyroglossal duct cysts are diagnosed during childhood and 7% are diagnosed in adulthood. Less than 1% of these cases are malignant with most being papillary in nature. It is often diagnosed incidentally after surgical excision. Incidentally discovered, well-differentiated thyroid carcinoma of the thyroglossal duct, in the presence of a clinically and radiologically normal thyroid gland, can be managed adequately by the Sistrunk operation. We present a rare case of primary papillary carcinoma of thyroglossal duct cyst, with normal thyroid gland, in a 28-year-old female that was diagnosed incidentally on histopathological examination. A Sistrunk procedure was performed on the patient to remove the thyroglossal duct cyst and patient is doing well at regular follow up.