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Cancer Health Center

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Carcinoid Syndrome: Causes, Symptoms, Treatments

Carcinoid syndrome is a group of symptoms that result from a rare type of tumor called a carcinoid tumor. This tumor grows slowly, starting most often in cells that line the digestive tract or lung.

Carcinoid syndrome occurs in fewer than 20% of those with a carcinoid tumor. The symptoms of carcinoid syndrome can affect many different parts of your body. You can take steps to improve these symptoms.

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Causes of Carcinoid Syndrome

Doctors don't know very much about what causes carcinoid tumors. You may be at greater risk if you:

  • Are African-American
  • Have a certain genetic syndrome
  • Have a condition that affects the stomach's ability to produce acid

Carcinoid syndrome results when a carcinoid tumor is advanced and releases large amounts of hormonal substances such as serotonin or other substances.

Symptoms of Carcinoid Syndrome

In many cases, carcinoid tumors often cause no symptoms. In advanced cases, when the tumor has spread, the increased release of hormonal substances can cause a diverse set of symptoms. These may include:

Other symptoms -- such as abdominal pain or intestinal bleeding -- may also depend on the location of the carcinoid tumor. Symptoms may worsen over time as a result of complications, such as damage to heart valves, leading to shortness of breath and heart murmur.

To diagnose a carcinoid tumor, your doctor will ask you about your history of symptoms, perform a physical exam, and order lab tests, imaging tests or scans, and an endoscopy to confirm a diagnosis or help locate a carcinoid tumor.

Factors such as stress, infection, drugs, alcohol, or certain medical procedures can trigger symptoms.

Seek immediate medical care if you have severe symptoms, because this may signal life-threatening carcinoid crisis. Severe symptoms include:

Treatment for Carcinoid Syndrome

The type of treatment your doctor suggests depends on many factors. These include your symptoms and the location and size of the tumor or tumors.

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