RET and multiple endocrine neoplasia type 2B: Multiple endocrine neoplasia type 2 (MEN 2) is a rare hereditary cancer syndrome caused by germline variants in the REarranged during Transfection (RET) proto-oncogene [1,2,3,4,5] and is subdivided into MEN 2A and MEN 2B, with a point prevalence of 13–24 per million and 0.9–1.65 per million [6,7,8,9], respectively.