umls-concept:C0220620 | skos:definition | NCI: An indolent (slow-growing) cancer that forms in cells that make hormones in the lining of the gastrointestinal tract (the stomach and intestines). It usually occurs in the appendix (a small fingerlike pouch of the large intestine), small intestine, or rectum. Having gastrointestinal carcinoid tumor increases the risk of forming other cancers of the digestive system.,NCI: A usually small, slow-growing, well differentiated neuroendocrine tumor arising from the gastrointestinal system. It is composed of islands of rounded, oxyphilic, or spindle-shaped cells of medium size, with small vesicular nuclei. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent. The tumor can occur anywhere in the gastrointestinal system; approximately 90% arise in the appendix. | lld:umls |