Carcinoid tumours are rare, slow-growing tumours that originate in cells of the diffuse neuroendocrine system. They occur most frequently in tissues derived from the embryonic gut. Foregut tumours account for up to 25% of cases and arise in the lung, thymus, stomach, or proximal duodenum. Midgut tumours account for up to 50% of cases and arise in the small intestine, appendix or proximal colon. Hindgut tumours account for approximately 15% of cases and arise in the distal colon or rectum. Other sites include the gallbladder, kidney, liver, pancreas, ovary and testis.1
This is a companion discussion topic for the original article at https://patient.info/doctor/carcinoid-tumours