Methods

SUMMARY Surgical specimens of carcinoma in the papilla of Vater were studied histologically. Adenomatous residue which suggested that the carcinoma was derived from a pre-existing adenoma was found in 18 cases (81.8%) out of 22. The histological transition of adenoma into carcinoma was also frequently seen. The malignant potentialities of adenomas in the am-pulla of Vater have been noted, ' 3 although benign neoplasms of the extrahepatic bile ducts are rare.4 At least in a small number of cases adenoma of the ampulla of Vater may be related to carcinoma. Most carcinomas in the large intestine arise from aden-omatous polyps, though this is not so often the case with gastric carcinomas. The present study aims to assess how frequently carcinomas of the ampulla of Vater arise from adenoma by histological exam-ination of adenomatous residue in the cancerous ampulla of Vater