A carcinoma that arises from glandular epithelial cells of the hepatopancreatic ampulla. The disease is ampulla of vater adenocarcinoma (MONDO_0002670, a Monarch Disease Ontology term). Also known as: adenocarcinoma of ampulla of Vater, ampulla of Vater adenocarcinoma, ampullary adenocarcinoma, hepatopancreatic ampulla adenocarcinoma, invasive adenocarcinoma of the ampullary region.