Papillary carcinoma in a supra hyoid thyroglossal duct cyst - an unusual presentation

Carcinomatous transformation of ectopic thyroid elements within the thyroglossal tract is a rare entity. We report a case of primary papillary carcinoma of thyroid presenting within the thyroglossal duct cyst in a 23 year old gentleman. The patient presented to us, as a case of suprahyoid thyroglossal cyst with sub-lingual involvement and he underwent surgical excision of the entire thyroglossal tract by Sistrunk's approach. The post-operative histopathological diagnosis was of a papillary carcinoma within the thyroglossal duct cyst. Hence, the patient was evaluated for a malignant focus in the thyroid which proved negative. He was counseled regarding the possibility of developing Carcinoma in the thyroid gland and offered two options of further management viz., total thyroidectomy followed by life long thyroid suppression or watchful observation and follow up. As the patient belonged to the low risk group, he opted for the second option. He is presently kept under meticulous follow up and remains asymptomatic till date. We present the pre- and post-operative imaging, intra-operative findings, histo-pathological features and review the present world literature on this rare entity.