Evolution of carcinoma in the extrahepatic bile ducts.

The histopathology of 43 cases of carcinoma in the extrahepatic bile ducts was reported. All four cases of noninfiltrating carcinoma were papillary or polypoid in gross shape. Only one of the eight cases of papillary or polypoid cancers penetrated beyond the fibromuscular layer of the bile ducts, while most cases of nodular or flat cancers spread deeper than the fibromuscular layer. Adenomatous residue was found in 9 (21.4%) of the total 43 cases, and was particularly frequent in papillary or polypoid cancers (6 [75.0%] of 8 cases). It is likely that early cancers were usually polypoid or papillary in gross shape and that most carcinomas arose from a pre-existing adenoma. Carcinoma associated with a choledochal cyst was found in two cases. Multiple carcinomas were seen in one case. Three cases of carcinoma in the extrahepatic bile ducts were associated with carcinoma of the gallbladder.