IPMNs are known to have a wide spectrum of histological variations associated with clinicopathological characteristics.[4] There are 3 epithelial types as follows: gastric, intestinal, and pancreatobiliary.[14] Intestinal-type IPMNs produce abundant mucin and typically involve MPD, with less invasiveness and a favorable prognosis.[14] Interestingly, the intestinal-type of IPMN in this patient, which was distributed in the branch duct and showed relatively rapid progression, ultimately resulted in a pancreaticobiliary fistula. The gene discussed is MUC5AC; the disease is pancreatic intraductal papillary-mucinous neoplasm.