Medically Reviewed by Kumar Shital
If you or someone you know has been diagnosed with carcinoid tumors in the lung, you may wonder what they are and how they’re different from other types of lung cancer.
Carcinoid tumors are a rare type of lung cancer. Only 1% to 2% of lung cancers are carcinoid tumors. They usually grow slowly. They are a type of neuroendocrine tumor, meaning that they start in special cells, called neuroendocrine cells, that are found in the lungs and throughout the body.
Types of Carcinoid Tumors
It’s important for you to know what kind of carcinoid tumor you have to get the best treatment. Carcinoid tumors are divided in two types: typical and atypical.
Typical carcinoid tumors are the most common. About 9 out of 10 carcinoid tumors are called typical. They grow slowly, and they don’t usually spread outside of the lungs.
Atypical carcinoid tumors grow faster, and they’re more likely to spread, or metastasize, outside of the lungs.
Doctors also refer to lung carcinoid tumors based on their location. If your tumors are in the walls of the large airways of your lungs, they’re central carcinoids. If they’re found in the smaller airways closer to the edges of your lungs, they’re peripheral carcinoids.
The outlook is often good. Among people with typical carcinoid tumors of the lung, about 85% to 90% live another 5 years or more, as do 50% to 70% of those with atypical carcinoids.
Causes and Risk Factors
Researchers don’t really know the causes of carcinoid tumors in the lung. They have found that typical carcinoids don’t seem to be linked to smoking, but atypical carcinoid tumors are found more often in people who do smoke.
You may be at a higher risk for these rare tumors with:
Age. You can get carcinoid tumors at any age, but they happen most often in people 45 to 55 years old.
Gender. Carcinoid tumors are more common in women than in men.
Race/ethnicity. These tumors are more common in whites than in other racial and ethnic groups.
Family history. Your risk is higher if you have family members with carcinoid tumors.
Multiple endocrine neoplasia type 1. This inherited syndrome raises your chances of getting lung carcinoid tumors, as well as tumors in the pancreas and the pituitary and parathyroid glands.
You may not have any symptoms. Around 25% of people with these tumors don’t. Your doctor may discover them when you have tests for something else.
Carcinoid tumors in the lung may cause:
Coughing, sometimes with blood
Shortness of breath
Sometimes carcinoid tumors cause a condition called carcinoid syndrome. That’s due to the hormones released by the cells in the tumors. Symptoms may include flushing of your face and neck, diarrhea, fast heart rate, and weight gain.
Your doctor will ask you questions about your medical history (that includes your family history) and examine you, listening to your lungs.
These tests can help diagnose carcinoid tumors:
Chest X-rays may show whether any tumors are in your lungs. Some may be too small or in locations that can’t be seen with standard X-rays.
CT scans use X-rays and a computer to give a cross-section view of your lungs and can also show if any tumors have spread to other organs, such as your liver.
Blood and urine tests may find substances that carcinoid tumors sometimes release. Serotonin or chromogranin-A in the blood may be a sign of a typical carcinoid tumor. The level of 5-HIAA, a byproduct of serotonin, can show up in your pee.
A biopsy is a sample of tissue taken from your tumor and checked under a microscope. It can be done two ways. If you have a nonsurgical biopsy, you’ll probably be sedated. Your doctor may insert a bronchoscope, a type of thin, flexible camera, into your lungs to look at the tissue. If you have a surgical biopsy, you’ll have anesthesia and need to stay in the hospital. It will take longer to recover, too. Your doctor will have to make small surgical cuts in your chest to get the sample of tissue.