Barrett adenocarcinoma (MONDO_0004405, a Monarch Disease Ontology identifier) is an adenocarcinoma arising from Barrett metaplastic epithelium in the esophagus. There is evidence supporting the idea that the Barrett adenocarcinomas develop through a stepwise progression through intestinal metaplastic epithelium to epithelial dysplasia to malignancy. Adenocarcinomas arising in the setting of Barrett esophagus are typically papillary and/or tubular. In terms of grading, they are well or moderately differentiated adenocarcinomas. -- 2002. Also known as: Barrett's adenocarcinoma, adenocarcinoma arising in Barrett's mucosa.