Colonic adenocarcinoma metastatic to the thyroid gland : A case report with immunohistochemical investigation

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 imm unohistochemical findings. A 68-year-old woman with a history of Dukes' sta ge B colon carcinoma presented a mass in the thyroid gland. The tumor was c onfirmed to be metastatic adenocarcinoma from the colon. The immunohistoche mical findings demonstrated positive staining for cytokeratin 20, low-molec ular-weight cytokeratin, villin and carcinoembryonic antigen, but stains we re negative for cytokeratin 7 and thyroglobulin.