ABSTRACT
Background Epidemiology Medullary thyroid carcinoma (MTC) is a neoplasm of the parafollicular C cells and belongs to the neuroendocrine tumor group. MTC represents 5-10% of thyroid cancers.1
C cells secrete calcitonin (Ct), other polypeptides and glycoproteins, such as carcinoembryonic antigen (CEA), vasoactive intestinal polypeptide, and somatostatin. MTC may occur sporadically or in a hereditary form as familial MTC that includes multiple endocrine neoplasia type IIA, type IIB, and isolated familial MTC.2 Germline mutations in the RET protooncogene have been identified in families with these syndromes, and genetic screening has become integrated to the clinical management.1 Both sporadic and familial MTC are characterized by relatively slow tumor growth but early lymphatic metastatic spread. Metastases are already present in 35% of patients at the time of initial diagnosis.3
