MUC5AC and intrahepatic cholangiocarcinoma: This type, among three gross types of ICC, is an entity described in recent years and designated as mucin-producing ICC or intrahepatic IPMN-B [4,8,11,17,18], which corresponds to a malignant form of IPMN-B, or papillary cholangiocarcinoma; the other mass-forming and periductal infiltrative types, which are more common and typical, could be called non-papillary cholangiocarcinoma.