An instance of neuroendocrine tumor of the small intestine that is caused by an inherited modification of the individual's genome. The disease is hereditary neuroendocrine tumor of small intestine (MONDO_0018698). Also known as: hereditary neuroendocrine tumor of small bowel, hereditary neuroendocrine tumor of the small intestine, hereditary neuroendocrine tumour of small bowel, hereditary neuroendocrine tumour of the small intestine, hereditary small intestine neuroendocrine neoplasm.