[A case with poorly differentiated follicular carcinoma of the thyroid produced and secreted CEA]

Detection of thyroglobulin, CEA, and calcitonin in serum and tissue is very useful to make differential diagnosis among papillary, follicular, and medullary carcinoma of the thyroid. The case was a 70-year-old woman with a nodule of the thyroid, presenting elevated serum level of thyroglobulin and CEA (22.0 ng/ml). Both serum level of thyroglobulin and CEA decreased after surgery. One year and nine months after surgery, she died from systemic metastases of thyroid carcinoma. Histological examination of the tumor presented to be poorly differentiated type of follicular carcinoma, presenting positive of both thyroglobulin and CEA, and negative of calcitonin in the cytoimmunochemistry. This case was identified to be a rare case that tumor cells of poorly differentiated follicular carcinoma produced and secreted both thyroglobulin and CEA.