**1. Introduction**

The region of the ampulla of Vater is an anatomical and functional complex, a separate entity, mainly comprising the biliopancreaticoduodenal confluence area. The ampulla territory includes in its structure the terminal portion of the choledoch, including the Oddi sphincter and the main duct of Wirsung, forming the papilla at the duodenal level. In 85% of cases, the openings of the main bile duct and the pancreatic canal are common. The terminal choledoch, after crossing the duodenal wall, next to the duct of Wirsung, opens in the ampulla of Vater. The choledoch implants in the papilla is variable. In most cases, the choledoch has a tangential implantation through the duodenal wall, reaching the level of the ampulla, the choledoch ends differently, either with a highly developed sphincter in the case of a small ampulla or with a much less developed sphincter in the case of a well-highlighted ampulla [1].

The localization of the papilla at the duodenum level is in most cases on the medial contour of the descending duodenum, at the junction of the middle third

with the lower third, but ectopic positions of the papilla are known, cranial at 1–2 cm below the bulb level, or caudal at the lower duodenal knee level [1].

A special place is occupied by the cancers of the ampulla of Vater, which are distinct entities, separate from those of the duodenum, although the anatomical location of the ampulla of Vater is at the level of the descending duodenum, due to their embryological origins and the different histological structures [1].

Neoplasms of the vaterian region, also known as vaterian ampulloma, may have as a starting point the cylindrical choledochal epithelium, the Wirsungian cubic epithelium, or the glandular epithelium of the papilla. Due to their origin in an epithelial type tissue structure, histopathologically these tumors are adenocarcinomas [1].
