MEN1 and neurofibromatosis type 1: PNETs are a rare and heterogeneous neoplasm with an incidence of five cases per million.9,10 In contrast, the prevalence rate in autopsy cases has been reported to be as high as 10%.11 Although most PNETs occur sporadically, about 10% are due to hereditary syndromes, including multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 4 (MEN4), von Hippel–Lindau disease (VHL), neurofibromatosis type 1 (NF1), and TSC.12