Adenomiosis of Vater's papilla is an organospecific dysplastic process, clearly linked to age and not dependent on other pathological processes of the biliary axis. The reasons for which it is diagnosed in preoperative biopsies with a frequency lower than should be expected on the basis of investigations performed on cadavers are stated. In particular, pathogenetic weight is stressed as a cause of Vaterian stenosis, especially in elderly subjects cholecystectomized many years earlier.