Carcinoma arising from villous adenoma of the ampullary bile duct: Report of a case.

Adenocarcinoma arising from the villous adenoma of the ampullary biliary epithelium is an extremely rare disorder. The preoperative diagnosis and treatment of the disease represent a major difficulty. A 67-year-old woman was admitted to the hospital with a chief complaint of jaundice. Preoperative investigations revealed obstructive type jaundice due to a 2-cm mass at the end of common bile duct. She was operated on and after undergoing a sphincterotomy, small, yellowish, grape-like particles fell down from the ampullar orifice. A frozen-section examination of these particles revealed villous adenoma. Next, a transduodenal resection of ampulla and reconstruction were performed. The frozen-section examination of the resected material also revealed a villous adenoma. The patient was discharged uneventfully. The histological examination revealed a villous adenoma arising from the biliary epithelium and some adenocarcinoma foci. The surgical margins were tumor free. Nevertheless, she developed hepatic metastases 15 months after surgery. This case shows the importance of surgeons to keep in mind the fact that frozen examinations may sometimes miss a malignancy and they therefore cannot be relied upon to rule out malignancy in villous adenoma of the ampullary bile duct.