Abstract
Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor arising from the parafollicular C cells. This tumor can be sporadic or familial in 25% of the cases. When hereditary, it is associated with the multiple endocrine neoplasia type 2 syndrome (MEN2), an autosomal dominant disorder caused by germline mutations of the RET proto-oncogene, classified in 2 subtypes: MEN2A e MEN2B. The hi…