What is carcinoid syndrome?

What is carcinoid syndrome?

Carcinoid syndrome, once called carcinoid tumors, is a set of symptoms that might be signs you have neuroendocrine tumors. Neuroendocrine tumors (NETs) are tumors that start in specialized cells in your neuroendocrine system. These neuroendocrine cells are scattered throughout your body, making and releasing hormones. Hormones are chemicals that coordinate different body functions, let your body know what to do and when to do it.

NETs happen when your neuroendocrine cells begin to rapidly divide and multiply. Carcinoid syndrome happens when NETs in your gastrointestinal tract (NETs of GI) flood your system with the hormone serotonin and other substances.