A Case of Medullary Microcarcinoma in the Setting of Cowden's Syndrome.

Cowden's syndrome (CS) is a rare inherited condition characterized by hamartomas in various organs including the thyroid and mucocutaneous tissues as one of the most distinctive features. We present a rare case of Cowden's syndrome with medullary microcarcinoma of the thyroid, in a 56 year old male with a history of hamartomatous colon polyps, papillomas of the tongue, skin tags, learning disability in the spectrum of autism and macrocephaly. This was evident on immunohistochemical examination of a nodule in the right thyroid lobe. Calcitonin and carcinoembryonic antigen (CEA) positivity along with C-cell hyperplasia were consistent with a medullary microcarcinoma. Total thyroidectomy was performed. Post-operatively margins were uninvolved by carcinoma. Perineural and lymphatic invasion was not identified. Considering the rarity of this condition and the unique presentation of our patient we believe that reporting this case would add more information to the existing fund of knowledge.