Certain signs and symptoms might suggest that a person may have a lung carcinoid tumor, but tests are needed to confirm the diagnosis.

Signs and symptoms

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 by medical tests done for other reasons.

Central carcinoid tumors start in the large bronchial tubes leading into the lung. People with these tumors may have a cough or cough up bloody sputum, or they may have wheezing symptoms like asthma. Other possible symptoms include shortness of breath and chest pain, especially when taking deep breaths. Large carcinoids can cause partial or complete blockage of a large air passage, leading to a lung infection called post-obstructive pneumonia. Sometimes a doctor may suspect a tumor only after treatment with antibiotics fails to cure the pneumonia.

Peripheral carcinoids rarely cause any symptoms unless there are so many of them they interfere with breathing. Usually they are found as a spot on a chest x-ray taken for an unrelated problem.

Some carcinoid tumors can produce hormone-like substances that are released into the bloodstream. Lung carcinoids do this far less often than gastrointestinal carcinoid tumors.

Carcinoid syndrome: In less than 1 out of 20 cases, lung carcinoid tumors release enough hormone-like substances into the bloodstream to cause symptoms. This results in the carcinoid syndrome. Symptoms include facial flushing (redness and warm feeling), severe diarrhea, wheezing, and fast heartbeat. Many patients find that stress, heavy exercise, and drinking alcohol may make these symptoms worse. Over a long time, these hormone-like substances can damage heart valves, causing shortness of breath, weakness, and a heart murmur (an abnormal heart sound).

Cushing syndrome: In rare cases, lung carcinoid tumors may produce ACTH, a substance that causes the adrenal glands to make too much cortisol and other hormones. This can cause weight gain, weakness, secondary diabetes, and increased body and facial hair.

Although the symptoms and signs above may be caused by lung carcinoid tumors, they can also be caused by other conditions. Still, if you have any of these problems, it's important to see your doctor right away so the cause can be found and treated, if needed.

Medical history and physical exam

If you have any signs or symptoms that suggest you might have a lung carcinoid tumor, your doctor will want to take a complete medical history, including your family history, to check for symptoms and possible risk factors. You will also be asked about your general health.

A physical exam provides information about your general health, possible signs of lung carcinoid tumor, and other health problems. During your physical exam, your doctor will pay close attention to your chest and lungs.

If symptoms and/or the results of the physical exam suggest a lung carcinoid tumor might be present, more involved tests will likely be done. These might include imaging tests, lab tests, and other procedures.

Imaging tests

Imaging tests use x-rays, radioactive particles, or other means to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, including to help find a suspicious area that might be cancerous, to learn how far cancer may have spread, and to help determine if treatment has been effective.

Chest x-ray

A chest x-ray may be the first imaging test a doctor orders if he or she suspects a lung problem. It may be able to show if there is a tumor in the lung. However, some carcinoids that are small or are in places where they are covered by other organs in the chest may not show up on a chest x-ray. If your doctor is still suspicious or if a vague abnormality appears on the chest x-ray, a CT scan may be ordered.

Computed tomography (CT) scan

The CT scan is an x-ray procedure that produces detailed cross-sectional images of your body. Instead of taking one picture, like a regular x-ray, a CT scanner takes many pictures as it rotates around you while you are lying on a narrow platform. A computer then combines these into images of slices of the part of your body that is being studied. Before the scan, you may be asked to drink a contrast solution and/or get an intravenous (IV) injection of a contrast dye that helps better outline abnormal areas in the body.

You may need an IV line through which the contrast dye is injected. The injection can cause some flushing (redness and warm feeling). Some people are allergic and get hives or, rarely, more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays.

You need to lie still on a platform while the scan is being done. During the test, the platform moves in and out of the scanner, a ring-shaped machine that completely surrounds it. You might feel a bit confined by the ring you have to lie in while the pictures are being taken.

Spiral CT (also known as helical CT) is now available in many medical centers. This type of CT scan uses a faster machine. The scanner part of the machine rotates around the body continuously, allowing doctors to collect the images much more quickly than standard CT. As a result, you do not have to hold your breath for as long while the image is taken. This lowers the chance of blurred images occurring as a result of breathing motion. It also lowers the dose of radiation received during the test. The slices it images are thinner and more detailed.

CT scans can have several uses:

• CT scans of the chest can spot very small lung tumors and help determine the exact location and extent of the tumors.

• CT scans can be helpful in staging a cancer (determining the extent of its spread). For example, CT scans of the abdomen can show if the cancer has spread to the liver or other organs. This can help to determine if surgery is a good treatment option.

• CT scans can also be used to guide a biopsy needle precisely into a suspected tumor or metastasis. For this procedure, called a CT-guided needle biopsy, the patient remains on the CT scanning table, while a radiologist advances a biopsy needle through the skin and toward the location of the mass. CT scans are repeated until the needle is within the mass. A biopsy sample is then removed and looked at under a microscope.

Radionuclide scans

Scans using small amounts of radioactivity and special cameras may be helpful in looking for carcinoid tumors. They can help determine the extent of the tumor, as well as help locate it if doctors aren't sure where it is in the body.

The most commonly used scan is somatostatin receptor scintigraphy (SRS), also known as the OctreoScan. It uses octreotide, a hormone-like substance that attaches to carcinoid cells, which is bound to radioactive indium-111. A small amount of this substance is injected into a vein. It travels through the blood and is attracted to carcinoid tumors. About 4 hours after the injection, a special camera can be used to show where the radioactivity has collected in the body. More scans may be done in the following few days as well.

Another test, known as an I-131 MIBG scan, is used less often. This test uses a chemical called MIBG to which radioactive iodine (I-131) is attached. This is injected into a vein, and the body is scanned several hours or days later with a special camera to look for areas that picked up the radioactivity. These would most likely be carcinoid tumors, although other kinds of neuroendocrine tumors will also pick up this chemical.

Positron emission tomography (PET): A PET scan is another imaging test that uses low levels of radioactivity to look for tumors. PET scanning for carcinoid tumors usually uses a radioactive form of 5-hydroxytryptophan, a chemical that is taken up and used by carcinoid cells. A special camera can detect the radioactivity. The usefulness of this test for lung carcinoid tumors is still being studied.

Biopsy

Even if an imaging test such as a chest x-ray or CT scan finds a mass, it is often hard for doctors to tell if the mass is a carcinoid tumor, another type of lung cancer, or a localized infection. In many cases, the only way to know for sure is to remove cells from the tumor and look at them under a microscope. This procedure is called a biopsy. There are several ways to take a sample from a lung tumor.

Bronchoscopic biopsy

This approach is used to view and sample tumors of large airways, such as central carcinoids. The doctor passes a long, thin, flexible, fiber-optic tube called a bronchoscope down the throat to look at the lining of the lung's main airways. You will be sedated for this. If a tumor is found, the doctor can take a small sample of the tumor through the tube. The doctor can also take a brushing sample through the bronchoscope by wiping a tiny brush over the surface of the tumor. Brushing samples are sometimes a helpful addition to the bronchial biopsy, but they are not as helpful in diagnosing carcinoids as they are with lung carcinomas.

An advantage of this type of biopsy is that no surgical incision or hospital stay is needed, and you are ready to return home within hours. One disadvantage is that a bronchial biopsy may not always be able to remove enough of a sample to be certain the tumor is a carcinoid. But with recent advances in the lab testing of lung tumors, doctors can usually make an accurate diagnosis even with very small samples.

Bleeding from a carcinoid tumor after a biopsy is rare but it can be a serious problem. If bleeding becomes a problem, doctors can inject drugs through the bronchoscope into the tumor to narrow its blood vessels, or they can seal off the bleeding vessels with a laser aimed through the bronchoscope.

Needle biopsies

Tumors that are not near the large airways are often sampled by needle biopsy. A long, hollow needle is passed through the skin in the chest between the ribs and into the lung. CT scan images are used to guide the needle into the tumor so that a small sample can be removed and looked at under the microscope. This procedure is also done without a surgical incision or overnight hospital stay.

A possible complication of this approach is the buildup of air between the lung and the chest wall, which is known as a pneumothorax. In some cases this can lead to the collapse of part of a lung, causing shortness of breath. If this happens, it can be treated by temporarily placing a suction tube through the skin and into the chest, which will re-expand the lung.

Surgical biopsies

In some cases, neither a bronchoscopic biopsy nor a needle biopsy can provide enough tissue to identify the type of tumor, and your doctor may need to do surgery to get a biopsy sample. Different types of operations may be used.

Thoracotomy: For a thoracotomy, the surgeon makes an incision in the chest wall between the ribs to get access to the lungs and to the space between the lungs and the chest wall. In some cases if the doctor strongly suspects a carcinoid or some other type of lung cancer, he or she may do a thoracotomy and remove the entire mass without first doing a bronchoscopic biopsy or needle biopsy.

Thoracoscopy: This is a less invasive procedure to look at the space between the lungs and the chest wall. Most often it is done in the operating room while you are under general anesthesia (in a deep sleep). The doctor inserts a thin, lighted scope with a small video camera on the end through a small cut made in the chest wall to view the space between the lungs and the chest wall. (Sometimes more than one cut is made.) Using this, the doctor can see potential areas of cancer and remove small pieces of tissue to look at under the microscope. Thoracoscopy can also be used to sample lymph nodes and fluid and assess whether a tumor is growing into nearby tissues or organs.

Mediastinoscopy: If imaging tests such as a CT scan suggest that the cancer may have spread to the lymph nodes between the lungs, the doctor may do a procedure called a mediastinoscopy. This is done in an operating room while you are under general anesthesia (in a deep sleep). A small cut is made in the front of the neck above the breastbone (sternum) and a thin, hollow, lighted tube is inserted behind the sternum. Special instruments can be passed through this tube to take tissue samples from the lymph nodes along the windpipe and the major bronchial tube areas.

Blood and urine tests

Because carcinoid tumors can secrete hormone-like chemicals into the blood, the tumor can sometimes be detected by simple blood or urine tests. This is especially true if you have symptoms of the carcinoid syndrome, which is caused by excessive levels of these substances in the blood.

Serotonin is a substance made by some carcinoid tumors, and probably causes some of the symptoms. It is broken down by the body into 5-hydroxyindoleacetic acid (5-HIAA), which is released into the urine. A commonly used test to look for carcinoid syndrome measures the levels of 5-HIAA in a urine sample collected over 24 hours. Measuring the serotonin levels in the blood or urine may also give useful information. These tests can help diagnose some carcinoid tumors, but they are not always accurate. Some other medical conditions, as well as foods and medicines, can affect the results, and some carcinoid tumors may not release enough of these substances to give a positive test result.

Other tests commonly used to look for carcinoids can include blood tests for chromogranin A (CgA), neuron-specific enolase (NSE), cortisol, and substance P. Depending on where the tumor might be located and on the patient's symptoms, doctors may do other blood tests as well.

Abnormal lab test results are not as likely to be seen with lung carcinoid tumors as they are with carcinoid tumors that start elsewhere in the body.

Pulmonary function tests

Pulmonary function tests (PFTs) are often done after a lung carcinoid diagnosis to see how well your lungs are working. This is especially important if surgery is an option in treating the cancer. Because surgical removal of part or all of the lung results in lower lung capacity, it's important to know how well the lungs are working beforehand. These tests can give the surgeon an idea of whether surgery is a good option, and if so, how much lung can safely be removed.

There are a few different types of PFTs, but they all basically have you breathe in and out through a tube that is connected to different machines.

Last Medical Review: 03/09/2009
Last Revised: 03/09/2009