Carcinoid tumors

Symptoms and causes

Carcinoid tumors are a type of slow-growing cancer that can arise in several places throughout your body. Carcinoid tumors, which are one subset of tumors called neuroendocrine tumors, usually begin in the digestive tract (stomach, appendix, small intestine, colon, rectum) or in the lungs.

Carcinoid tumors often don't cause signs and symptoms until late in the disease. Carcinoid tumors can produce and release hormones into your body that cause signs and symptoms such as diarrhea or skin flushing.

Treatment for carcinoid tumors usually includes surgery and may include medications.

Some carcinoid tumors don't cause any signs or symptoms. When they do occur, signs and symptoms are usually vague and depend on the location of the tumor.

It's not clear what causes carcinoid tumors. In general, cancer occurs when a cell develops mutations in its DNA. The mutations allow the cell to continue growing and dividing when healthy cells would normally die.

The accumulating cells form a tumor. Cancer cells can invade nearby healthy tissue and spread to other parts of the body.

Doctors don't know what causes the mutations that can lead to carcinoid tumors. But they know that carcinoid tumors develop in neuroendocrine cells.

Neuroendocrine cells are found in various organs throughout the body. They perform some nerve cell functions and some hormone-producing endocrine cell functions. Some hormones that are produced by neuroendocrine cells are histamine, insulin and serotonin.

Factors that increase the risk of carcinoid tumors include:

• Older age. Older adults are more likely to be diagnosed with a carcinoid tumor than are younger people or children.
• Sex. Women are more likely than men to develop carcinoid tumors.
• Family history. A family history of multiple endocrine neoplasia, type 1 (MEN 1), increases the risk of carcinoid tumors. In people with MEN 1 multiple tumors occur in glands of the endocrine system.

The cells of carcinoid tumors can secrete hormones and other chemicals, causing a range of complications including:

• Carcinoid syndrome. Carcinoid syndrome causes redness or a feeling of warmth in your face and neck (skin flushing), chronic diarrhea, and difficulty breathing, among other signs and symptoms.
• Carcinoid heart disease. Carcinoid tumors may secrete hormones that can cause thickening of the lining of heart chambers, valves and blood vessels. This can lead to leaky heart valves and heart failure that may require valve-replacement surgery. Carcinoid heart disease can usually be controlled with medications.
• Cushing syndrome. A lung carcinoid tumor can produce an excess of a hormone that can cause your body to produce too much of the hormone cortisol.