High carcinoembryonic antigen level following cancer surgery: another way to detect thyroid medullary carcinoma

Thyroid medullary carcinoma is usually detected in the presence of an isolated thyroid nodule or in the context of a family disease: familial thyroid medullary carcinoma or multiple endocrine neoplasia type 2A. Here we report a third means of detection: an unexplained rise in carcinoembryonic antigen levels after cancer surgery. In each case, the carcinoembryonic antigen increase led to the assessment of the caicitonin plasma level and to a thyroid echography being performed. Thyroid medullary carcinoma was confirmed in every case after surgery. Even though the association of thyroid follicular carcinoma with familial adenomatous polyposis is common, the association of thyroid medullary carcinoma with breast or colonic carcinoma remains exceptional and probably accidental. Due to the seriousness of the thyroid medullary carcinoma, it is mandatory to look for it in the event of an unexplained rise in the carcinoembryonic antigen level, by assessing the calcitonin plasma level.