GNAS and carcinoma: It may occur alone or in association with KRAS activating mutations and could define a specific progression pathways in IPMN-associated carcinoma.[15–17]GNAS-activating mutations are reported in both IPMN and MCAS, and IPMN is a MCAS associated lesion.[18,19] This emphasizes the important role of GNAS in pancreatic tumorigenesis.[5]GNAS- driven pancreatic tumorigenesis is associated with IPMN intestinal phenotype[8] and colloid pancreatic adenocarcinoma,[16] and a less aggressive disease, with better long-term outcome.[20] IPMN occur most of the time as a sporadic disease.