What is it?

Carcinoid tumor is a type of neuroendocrine tumor that grows from neuroendocrine cells. Neuroendocrine cells receive and send messages through hormones to help the body function. Neuroendocrine cells are found in organs throughout the body. This tumor can be either benign, non-cancerous, or malignant.
Carcinoid tumors often grow very slowly. In children and young adults, carcinoid tumors are most often found in the appendix, called appendiceal carcinoid tumors, or in the lungs, called bronchial tumors. In adults, carcinoid tumors are most often found in the digestive tract. This tumor may spread to other parts of the body but does so more often in adults than children.