Until 2000, only 10% of PGLs were considered of genetic origin and linked to hereditary syndromes: von Hippel Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN2) and neurofibromatosis type 1 (NF1), due respectively to a germ line mutation in tumor-suppressor gene VHL [46, 47], protooncogene RET [48–52] and tumor-suppressor gene NF1 [53]. Here, RET is linked to multiple endocrine neoplasia type 2.