The vast majority of PanNETs are sporadic, but approximately 17% are associated with an inherited syndrome, the most common being Multiple Endocrine Neoplasia type 1 (MEN1), von Hippel–Lindau (VHL) syndromes, Neurofibromatosis type 1 (NF1), and Tuberous Sclerosis Complex (TSC) [2,3]. This evidence concerns the gene MEN1 and multiple endocrine neoplasia type 1.