FAMILIAL MEDULLARY THYROID CARCINOMA
This is a relatively infrequent clinical subtype of MEN 2, believed to represent 5–10 % of all MEN 2 cases. FMTC is characterized by familial later-onset MTC without evidence of PC or HPT (Farndon et al. 1986). Given our current knowledge of the genetics of MEN 2, it is believed that FMTC and MEN 2A are artificially divided subtypes and may be on a continuum but representing phenotypes resulting from different penetrance (Zbuk and Eng 2007).