Monarch Disease Ontology identifier MONDO_0003388 (ampulla of vater clear cell adenocarcinoma) is a carcinoma with glandular differentiation arising from the ampulla of Vater. Morphologically, it is characterized by the presence of glycogen-rich cells with hyperchromatic nuclei. Also known as: ampulla of Vater clear cell adenocarcinoma, hepatopancreatic ampulla clear cell adenocarcinoma.