The most common places for NETs to form in the GI tract are:
Small bowel NETs are increasing in incidence and are now the most common primary malignancies of the small intestine.
The GI tract consists of organs that help digest food, which are:
Stomach: The stomach stores swallowed food and liquid, mixes the food and liquid with digestive juices, and slowly empties it into the small intestine.
Small intestine: The muscles of the small intestine mix food with digestive juices from the pancreas, liver, and sometimes the gallbladder, while absorbing vitamins and nutrients from food. The small intestine is made up of three sections: the duodenum, jejunum, and ileum.
Large intestine: Helps to break down food while absorbing liquid from the materials and forming waste product (stool). The colon is part of the large intestine.
Rectum: The rectum stores stool until it is pushed it out during a bowel movement.
Some GI NETs may not cause any signs or symptoms. A GI NET may cause symptoms when it overproduces and releases hormones into the bloodstream or grows large enough to cause blockages in the GI tract.
NETs can occur throughout the body, but most commonly form in the GI tract, pancreas, lungs and adrenal glands.