Abstract
Clinically evident metastases of carcinomas to the thyroid gland are rare,
particularly from a colorectal primary tumor. We present a case of colonic
adenocarcinoma metastatic to the thyroid gland with histopathologic and
immunohistochemical findings. A 68-year-old woman with a history of Dukes' stage
B colon carcinoma presented a mass in the thyroid gland. The tumor was confirmed
to be metastatic adenocarcinoma from the colon. The immunohistochemical findings
demonstrated positive staining for cytokeratin 20, low-molecular-weight
cytokeratin, villin and carcinoembryonic antigen, but stains were negative for
cytokeratin 7 and thyroglobulin.