Colon carcinoma metastasis to the thyroid gland: report of a case with a review of the literature.

Metastasis of colon cancer to the thyroid gland is very rare and we would like to report a case we have experienced, with a review of the literature. A 66-year-old woman noticed a swelling in the anterior neck area and sought medical attention at our department in August 2003. At age 63, she had undergone surgery for cancer of the ascending colon, but subsequently the cancer metastasized to the liver and she underwent an outer hepatic segmentectomy. Fine-needle aspiration cytology indicated adenocarcinoma with characteristic tall columnar cells, confirming our suspicion that metastasis from the ascending colon cancer had already occurred. Furthermore, lung metastasis was also suspected, because several nodules were found in the lungs. On August 13, resection of the left lobe of the thyroid gland and dissection of the cervical lymph nodes were performed. Histopathology showed metastasis of the ascending colon cancer to the thyroid and lymph nodes.