Medullary Thyroid Carcinoma with Hepatic Metastasis Presenting as Watery Diarrhea for about 1.5 Years: A Case Report

Medullary thyroid carcinoma (MTC) is a rare cause of chronic diarrhea. When systemic symptoms such as diarrhea occur, distal metastasis often exists. The most common clinical presentation of MTC is solitary thyroid nodule. It was uncommon that chronic diarrhea as initial presentation of MTC without visible thyroid nodule. A 66-year-old woman suffered from watery diarrhea for 4 months. Irritable bowel syndrome was impressed initially. Water diarrhea persisted for another one year under medical treatment. Abdominal echography showed a 6.9cm non-cirrhotic hepatic tumor unexpectedly. Finally, core-needle biopsy for the hepatic tumor revealed metastatic medullary thyroid carcinoma. Physical examination revealed a palpable nodule in left thyroid lobe. Further thyroid ultrasonography disclosed multiple nodular goiter and the largest left thyroid nodule had punctate microcalcification. Fine needle aspiration cytology confirmed the diagnosis of MTC. Palliative surgery with total thyroidectomy, and liver bi-segmentectomy were done. After palliative surgery, watery diarrhea was partially improved. (J Intern Med Taiwan 2014; 25: 25-29)