- Villous adenomas of the upper gastrointestinal tract are rare , residing mostly in the duodenum (80%) and ampulla of Vater (15%). Villous adenomas of the extrahepatic bile ducts are exceptional and only a few cases have been reported in the medical literature worldwide . The adenomatous polyp to carcinoma on the large bowel sequence is well known. However, in the absence of evidence of this sequence in the biliary duct a conclusion cannot be drawn from one case report on the adenoma-carcinoma sequence. We present a case of cholangiocarcinoma of the common bile duct arising from a villous adenoma.