An adenocarcinoma arising in the anal canal epithelium, including the mucosal surface, the anal glands, and the lining of fistulous tracts. The prognosis is related to the stage at diagnosis. The disease is anus adenocarcinoma (Monarch Disease Ontology id MONDO_0002652). Also known as: adenocarcinoma of anus, adenocarcinoma of the anus, anal adenocarcinoma.