An adenocarcinoma that arises from the extrahepatic bile ducts. It is characterized by the presence of extracellular mucin that constitutes more than fifty-percent of the tumor. The disease is extrahepatic bile duct mucinous adenocarcinoma (Monarch Disease Ontology term MONDO_0002739). Also known as: bile duct colloid carcinoma, bile duct colloidal carcinoma, bile duct mucinous adenocarcinoma, colloid adenocarcinoma of bile duct, colloid adenocarcinoma of extrahepatic bile duct, colloid adenocarcinoma of the bile duct, colloid adenocarcinoma of the extrahepatic bile duct, colloid bile duct adenocarcinoma.