Carcinoid syndrome

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What is carcinoid syndrome?

Carcinoid syndrome can affect your quality of life and occasionally put you in danger. Our experienced specialists can offer relief, including effective carcinoid tumor treatment and safeguards for your health.

Carcinoid syndrome refers to a set of symptoms tied to tumors called carcinoids and the release of the hormone serotonin.

Carcinoids are a type of neuroendocrine tumor (NET), found in cells that resemble nerves but which can also release hormones. Many carcinoids are benign (noncancerous), but they can also turn malignant (cancerous). They develop most often in the gastrointestinal (GI) tract but can also form in the lungs and airways. Occasionally, they develop in other areas of the body.

Up to 40 percent of GI carcinoids result in carcinoid syndrome. A much smaller percentage of lung carcinoids cause this complication.

Carcinoid syndrome symptoms

Carcinoid syndrome can cause a handful of symptoms. Some people develop a single symptom, while others get a mix.

Symptoms include:

  • Flushing: Roughly four in five people with carcinoid syndrome experience flushing. It causes the face and neck to turn red and feel warm. It can also cause hypotension (drop in blood pressure) and tachycardia (fast heart rate).
  • Diarrhea: Up to half of people with carcinoid syndrome develop diarrhea, typically watery and persistent. You may also get belly cramps and not feel like eating.
  • Wheezing: Some people experience trouble breathing, with their lungs making a whistling sound.
  • Spider veins: Thin veins can appear on the lips and nose and turn purple.

Symptoms can get worse when you feel stressed, exercise intensely, drink alcohol or eat a large meal. You may also experience additional symptoms directly from the tumor if it presses on other tissue or blocks the GI tract.

What triggers carcinoid syndrome?

Some carcinoids — most commonly from tumors in the small intestine, appendix and start of the colon — make and release serotonin. Occasionally, carcinoids in the lungs and ovaries do, too.

Serotonin from carcinoids in the lungs or ovaries goes straight to the bloodstream, where it can trigger symptoms.

For GI tumors, the extra serotonin typically gets processed by the liver, with no effect on the body. Eventually, though, tumors can metastasize (spread) to the liver and interfere with its function, allowing serotonin into the blood. Liver metastases may also release additional serotonin.

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