RET and Cowden syndrome 1: Hereditary syndromic forms include Multiple Endocrine Neoplasia type 1, type 2 A and B and type 4 (MEN1, MEN2A, MEN2B and MEN4), von Hippel Lindau (VHL), hereditary Paraganglioma/Pheochromocytoma syndromes (PGL/PCC), Hyperparathyroidism-Jaw Tumor syndrome (HPT-JT), Cowden syndrome (CS), Carney Complex (CNC), Tuberous Sclerosis (TSC), and Neurofibromatosis type 1 (NF1).