MUC5AC and pancreatic intraductal papillary-mucinous neoplasm: An intraductal papillary mucinous neoplasm (IPMN) of the pancreas is characterized by the production of mucin with a dilated pancreatic duct.1-3 This category of pancreatic tumor was first conceptualized in the 2nd section of the World Health Organization classification in 1996, which made clinicians aware of IPMN as a differential diagnosis.