Squamous cell carcinoma arising in a thyroglossal duct cyst.

Carcinoma arising in a thyroglossal duct cyst is a rare event, occurring in less than 1% of abnormalities of the thyroglossal duct. To date, there have been approximately 100 cases reported, with papillary carcinoma accounting for the vast majority. Squamous cell carcinoma, on the other hand, is an even rarer event. Its clinical course in the elderly, consisting of recurrent drainage and suppuration, may distinguish it from other neoplastic conditions of thyroglossal duct cyst. We present a 65-year-old man with squamous cell carcinoma in a recurrently discharging thyroglossal duct cyst to illustrate important distinguishing clinical features of this condition.