Immunophenotype characterization of different mucinous BTCs, showed that the gastro-intestinal phenotype (MUC2+, MUC5AC+ and MUC6+) was more frequently seen in MCN-L and IPMN than in benign mucinous cystadenomas. The gene discussed is MUC5AC; the disease is pancreatic intraductal papillary-mucinous neoplasm.