About 2 out of 3 people with carcinoid tumors will have signs or symptoms that will lead to the diagnosis of the disease. But because carcinoids tend to grow slowly, they may not cause symptoms for several years in some people, or they may be found when tests are done for other reasons.
Most carcinoid tumors start in the large bronchial tubes leading into the lung. Symptoms can include:
Large carcinoids can cause partial or complete blockage of an air passage, which can lead to pneumonia (an infection in the lung). Sometimes a doctor may suspect a tumor only after treatment with antibiotics doesn’t cure the pneumonia.
Some tumors start in the smaller airways toward the outer edges of the lungs. They rarely cause any symptoms unless there are so many of them that they cause trouble breathing. Usually they are found as a spot on a chest x-ray or CT scan that is done for an unrelated problem.
Some carcinoid tumors can make hormone-like substances that are released into the bloodstream. Lung carcinoids do this far less often than gastrointestinal carcinoid tumors.
Carcinoid syndrome: Rarely, lung carcinoid tumors release enough hormone-like substances into the bloodstream to cause symptoms. This causes carcinoid syndrome. Symptoms can include:
Many people with carcinoid syndrome find that stress, heavy exercise, and drinking alcohol can bring on these symptoms or make them worse.
Over a long time, these hormone-like substances can damage heart valves, causing:
Cushing syndrome: In rare cases, lung carcinoid tumors may make a hormone called ACTH. This causes the adrenal glands to make too much cortisol (a steroid hormone) and other hormones. This can lead to:
The symptoms and signs above may be caused by lung carcinoid tumors, but they can also be caused by other conditions. Still, if you have any of these problems, it’s important to see your doctor so the cause can be found and treated, if needed.
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Last Revised: August 28, 2018