VIP and pancreatic neoplasm: Rare functioning pancreatic neoplasms (rf-pNENs) comprise glucagonomas, vasoactive intestinal polypeptide (VIP) producing pNENs (VIPomas), calcitoninomas, somatostatinomas, as well as pNENs secreting parathyroid hormone related peptide, gonadotropin relasing hormone , adrenocorticotropic hormon, renin, luteinising hormone, erythropoietin and insulin-like growth factor II1,2.