[Epithelial neoplasms of Vater's ampulla: anatomico-clinical and immunohistochemical study]

3 adenomas and 5 carcinomas of the ampulla of Vater are studied to evaluate their histogenesis and diagnostic significance of the antigen defined by the monoclonal antibody CA 19/9. In the adenomas, some dysplastic glands show a faint positivity for CA 19/9 antigen, whereas in the ampullomas this antigen is present in adenomatous residue and in well differentiated adenocarcinomatous areas. The present observations indicate that the endoscopical and macro-microscopical examinations are fundamental to evaluate the location of the ampullary neoplasia. Moreover, the immunohistochemical finding of the CA 19/9 antigen in adenomas and carcinomas suggests their histogenetic relationship, but it is not useful in their differential diagnosis.