MUC5AC and pancreatic intraductal papillary-mucinous neoplasm: Intraductal papillary mucinous neoplasm (IPMN) of the pancreas are tumors that grow in the main pancreatic duct (MPD) or branch duct (BD) with different papillary features and atypical mucin production, as well as segmentary or diffuse dilatation of the MPD, cystic dilatation of the secondary branch, or both.[1] MPD-involved IPMNs were defined as a dilation of the MPD ≥ 5 mm, either segmental or diffuse, without identifiable reason for a duct obstruction and with or without signs of BD dilation.