Cancer A to Z Gastrointestinal Carcinoid Tumors Gastrointestinal Carcinoid Tumors About Gastrointestinal Carcinoid Tumors Gastrointestinal carcinoid tumors most often begin in neuroendocrine cells in the gastrointestinal (GI) tract, primarily in the appendix, Read More 2 500 June 19, 2018 0 2 500