A syndrome caused by a carcinoid tumor. This tumor usually arises in the digestive tract, anywhere between the stomach and the rectum, though 90% arise in the appendix. The tumor may metastasize (spread) to the liver, and may produce and release large amounts of various hormones into the bloodstream. Symptoms may include flushing, rapid pulse, facial swelling, swelling around the eyes, low blood pressure, abdominal pain, weight loss and diarrhea.

the most common systemic clinical manifestation of carcinoid tumours; usually develops after a carcinoid tumour has metastasised, usually to the liver, and there is a substantial concentration of the hormones released by a tumour in the systemic circulation

(KAR-sin-oyd) A combination of symptoms caused by the release of serotonin and other substances from carcinoid tumors of the gastrointestinal tract. Symptoms may include flushing of the face, flat angiomas (small collections of dilated blood vessels) of the skin, diarrhea, bronchial spasms, rapid pulse, and sudden drops in blood pressure.