Gastrointestinal Neuroendocrine (Carcinoid) Tumors

Carcinoid tumors are the most common type of neuroendocrine tumor, the majority occuring within the gastrointestinal system, notably the appendix (35%), ileum (part of the small intestine) (28%), and rectum (13%). 

Gastrointestinal neuroendocrine (carcinoid) tumors form from a type of neuroendocrine cell (a cell that is like a nerve cell and a hormone-making cell). These cells are scattered throughout the chest and abdomen, but most are found in the GI tract. Neuroendocrine cells make hormones that help control digestive juices and the muscles used in moving food through the stomach and intestines. A GI carcinoid tumor may also make hormones and release them into the body. These tumors usually grow slowly and are classified as low-grade tumors, but in some cases may begin to grow rapidly.

The following is syndicated content from the National Cancer Institute (NCI).