MUC5AC and appendix adenocarcinoma: For this reason, goblet cell carcinoid has been regarded as a distinctive entity, and is classified and staged as appendiceal adenocarcinomas.[17] In 2019 World Health Organization, GCA became the preferred terminology for this appendiceal tumor.[20] In our present case, the tumor was composed of signet-ring-like cells on confluent growth model and copious mucin was produced as well.