rectal neuroendocrine tumor (Monarch Disease Ontology id MONDO_0015068) is a well differentiated, low or intermediate grade tumor with neuroendocrine differentiation that arises from the rectum. Also known as: neuroendocrine tumor of rectum, well differentiated, low or intermediate grade, rectal well differentiated neuroendocrine neoplasm, rectal well-differentiated neuroendocrine neoplasm.