Carcinoid tumors are a type of slow-growing cancer that can arise in several places throughout your body. Carcinoid tumors, which are one subset of tumors called neuroendocrine tumors, usually begin in the digestive system (gastrointestinal tract, stomach, appendix, small intestine, colon, rectum) or in the lungs. See Gastrointestinal Carcinoid Tumor for signs, symptoms and treatments.
