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What Is Carcinoid Syndrome?

What Is Carcinoid Syndrome?

Carcinoid syndrome may be caused by neuroendocrine tumors that produce too much serotonin.

Your body’s cells communicate with each other through hormones. Cells and glands located throughout the body produce hormones. These hormones control functions like metabolism, appetite, and even your emotions. The system in your body that produces hormones is known as the endocrine system.

Some nerve cells communicate with chemicals, too. Those are called neuro (for nerve) endocrine cells.

When a cell grows abnormally, it forms a tumor. Tumors are classified as cancer when they can spread within an organ or to other organs. In the neuroendocrine system, the cancer is called a neuroendocrine tumor, or NET. When hormone-producing NETs spread to the liver, they can cause symptoms that can make daily life difficult. In fact, carcinoid syndrome doesn't necessarily mean your tumor is getting worse. In some cases, patients with carcinoid syndrome have stable disease.

There are about 14,000 people in the US diagnosed with carcinoid syndrome


What is carcinoid syndrome and what causes it?


  • When a cell grows abnormally, it can form a tumor. Tumors are classified as cancer when they have the potential to spread within an organ or to other organs.
  • Some nerve cells communicate with hormones. When cancer occurs in the neuroendocrine system, it is called a neuroendocrine tumor or NET.
  • When NETs spread they can release extra serotonin into your bloodstream. Serotonin is a hormone that helps control your mood and digestion. Extra serotonin in your gut can cause carcinoid syndrome.

“I am hoping to see more awareness of this disease.”

Patient with carcinoid syndrome

About 1,500 people in the US are diagnosed with carcinoid syndrome each year