Health A-Z

What is carcinoid syndrome?

Carcinoid syndrome is a rare condition that happens if you have neuroendocrine tumors. Neuroendocrine tumors (NETs) are tumors that start in specialized cells in your neuroendocrine system.

NETs develop when your neuroendocrine cells begin to rapidly divide and multiply, creating tumors that release unusually large amounts of serotonin and other substances. When that happens, you develop carcinoid syndrome symptoms. Sometimes, a carcinoid syndrome diagnosis is the first indication you have a neuroendocrine tumor.

Very rarely, people with carcinoid syndrome have carcinoid crises, a potentially life-threatening condition that can happen if your carcinoid syndrome goes undiagnosed or untreated.

What are carcinoid syndrome symptoms?

Studies suggest the most common symptoms include:

• Uncomfortable flushing of your head and neck.
• Wheezing and shortness of breath (dyspnea).
• Abdominal cramping and explosive, frequent diarrhea.
• Fatty poops that smell bad.
• Edema or swelling of your feet and legs. This can be a symptom of heart failure.
• Some people might lose interest in sex or have erectile dysfunction.
• Jaundice, which is when your skin and the whites of your eyes turn yellow.
• Dizziness or feeling faint. This can be a sign of low blood pressure.
• Feeling like your heart is racing.

How is carcinoid syndrome treated?

Neuroendocrine tumors cause carcinoid syndrome, so treating the tumors also treats the syndrome.

Those treatments include:

• Surgery: Surgery to remove or reduce the size of the neuroendocrine tumors.
• Somatostatin analogs: Somatostatin analogs are drugs that may stop your body from making too many hormones. This may slow down the growth of the tumor when cancer cells spread to other parts of your body.
• Targeted therapy: Targeted therapy is a type of treatment that uses drugs that target certain genes or proteins to kill cancer cells.
• Chemotherapy: This treatment uses drugs that destroy cancer cells.
• Embolization: Embolization kills tumors by blocking or closing a blood vessel that feeds the tumor

How is carcinoid syndrome diagnosed?

Healthcare providers may use the following tests to diagnose carcinoid syndrome:

• Urine test: This test checks on certain hormone levels.
• Physical exam and medical history: Many carcinoid syndrome symptoms are similar to other less serious illnesses. Your healthcare provider will ask questions about specific symptoms, how long you’ve had the symptoms and if your symptoms are getting worse.
• Blood tests: These tests check on the amounts of substances that your organs and tissues release into your blood. Substance levels that spike or fall might be signs of disease.
• Neuroendocrine positron emission tomography (PET) scan: This test tracks neuroendocrine tumors with a dye called Gallium 68 dotatate.
• Computed tomography (CT) scan: CT scans use X-rays and a computer to produce 3D images of organs and bones.
• Ultrasound: Ultrasounds use sound waves to develop images of organs and bones.
• Magnetic resonance imaging (MRI): This uses a computer, radio waves and a large magnet to create images of the inside of your body.
• Endoscopy: For this test, a provider inserts a long thin tube with a camera and a light into your body.