- Term applied to a constellation of symptoms mediated by various humoral factor released from well-differentiated NETs.
- More than 90% of patients with carcinoid syndrome have metastatic disease from a small bowel primary NET - typically to the liver.
- Monoamine oxidase in the liver can generally detoxify substances - thus is patient symptomatic = liver metastasis.
- Can occur with very large retroperitoneal tumours
- Symptoms of carcinoid occur due to serotonin, tachykinins (substance P), prostaglandins, PDGF.