MUC5AC and hepatocellular carcinoma: This is based on the presence of positive staining patterns for markers such as MUC5AC, which is usually positive in all IPMN subtypes and is helpful in rule out an intraductal tubulopapillary neoplasm (typically MUC5AC negative); MUC6, for the differential diagnosis with the other IPMN subtypes (usually MUC6 negative in particular gastric and intestinal subtypes); and Hep Par-1, a cytoplasmic marker which is also positive in hepatocellular carcinoma and other cancer types composed of cells rich in mitochondria [1,2].