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| Detailed Guide: Lung Carcinoid Tumor |
How Are Lung Carcinoid Tumors Diagnosed? |
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Signs and Symptoms
Central carcinoid
tumors start in the large bronchial tubes leading into the lung. If you
have 1 of these, you may have a cough, may cough up bloody sputum, or
may have wheezing symptoms like asthma. When a large carcinoid causes
partial or complete blockage of a large air passage, you may develop a
lung infection called post-obstructive
pneumonia. Sometimes your doctor may suspect a tumor only
after treatment with antibiotics fails to cure the pneumonia.
Peripheral carcinoids
rarely cause 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
(10% to 20% of the time) than gastrointestinal carcinoid tumors. The carcinoid syndrome
results from the effect of these substances. Symptoms include facial flushing (redness
and warm feeling that may last hours to days), sweating, diarrhea, and
a fast heartbeat. Some carcinoid tumors may produce adrenocorticotropic
hormone (ACTH), a hormone that stimulates your adrenal gland to produce
excessive amounts of cortisol and related hormones. Symptoms of
excessive amounts of these hormones include weight gain, weakness,
secondary diabetes, and increased body and facial hair.
If you have 1 or more symptoms that suggest this you may have this a
lung carcinoid tumor, your doctor will ask about other symptoms such as:
- cough
- chest pain
- wheezing
- asthma
- blood-tinged sputum
- pneumonia that is not cured by antibiotics
- recent weight gain
- facial flushing (redness)
- diarrhea
A thorough physical exam will provide information about signs of
carcinoid tumor, such as the carcinoid syndrome, and other health
problems.
Imaging Tests
Imaging tests produce pictures or images of the inside of the body and
are useful in finding carcinoid tumors and determining how far they
have spread.
Chest x-rays:
This will be done to look for a lung tumor. 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):
The CT scan is an X-ray procedure that produces detailed
cross-sectional images of your body. Instead of taking one picture,
like a conventional x-ray, a CT scanner takes many pictures as it
rotates around you. A computer then combines these pictures
into an image of a slice of your body. The machine will take pictures
of multiple slices of the part of your body that is being studied.
CT scans are often used to find small lung tumors. The CT scan can help
to determine if surgery is a good treatment option.
This test can help tell if your cancer has spread into your liver or
other organs. Often after the first set of pictures is taken you will
receive an intravenous injection of a "dye" or radiocontrast agent
that helps better outline structures in your body. Then a second set of
pictures is taken.
CT scans can also be used to guide a biopsy needle into a suspected
tumor or metastasis. For this procedure, called a CT-guided needle biopsy,
you remain on the CT scanning table while a radiologist (a doctor who
specializes in reading x-rays) advances a biopsy needle toward the
location of the mass. CT scans are repeated until the doctors are
confident that the needle is within the mass. A fine needle biopsy
sample (tiny fragment of tissue) or a core needle biopsy sample (a thin
cylinder of tissue about ½ inch long and less than 1/8 inch in
diameter) is removed and examined under a microscope.
CT scans are more tiring than regular x-rays because they take longer
and you need to lie still on a table while they are being done. But
just like other computerized devices, they are getting faster and your
stay might be pleasantly short. Also, you might feel a bit confined by
the ring you lie within when the pictures are being taken.
You will have an IV (intravenous) line through which the contrast "dye"
is injected. The injection can also cause some flushing. 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.
Somatostatin Receptor
Scintography: This is a scan technique that uses
radioactive octreotide (octreotide is a hormone that when injected into
the body, attaches to carcinoid tumors). A small amount of
this radioactive hormone-like substance is injected into a vein. A
special radioactivity-detecting camera is used to show where the
radioactivity accumulates. This test is useful in detecting spread of
lung carcinoid tumors to other areas of the body.
A similar test uses radioactive meta-iodobenzylguanidine
(MIBG). MIBG is another chemical that is taken up by
carcinoid tumors. The MIBG is attached to radioactive iodine and
injected into the bloodstream. If there is a carcinoid tumor, the
radioactivity will go there and the scanner will detect it.
About one-third of carcinoids are diagnosed by accident, in people
without any symptoms that suggest a carcinoid. In these cases, a chest
x-ray done to evaluate an unrelated medical problem finds a lung mass.
Even if imaging tests such as a chest x-ray and/or CT scan find a mass,
these imaging tests cannot show if the mass is a carcinoid tumor, a
lung carcinoma, or a localized infection. The only way to know for sure
is to remove cells from the tumor and examine them under a microscope.
This procedure is called a biopsy.
Bronchoscopy and Biopsy
There are several ways to take a sample from a lung tumor. Tumors of
large airways, such as central carcinoids, can be found and sampled by bronchoscopic biopsy.
The doctor passes a long, thin, flexible, lighted tube called a bronchoscope down
the throat to look at the lining of the lung's main airways. You will
be sedated for this. When a tumor is found, the doctor can take a small
sample of the tumor through the tube.
The advantages of this approach are that no surgical incision is
needed, no 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 tissue to be certain the tumor is a
carcinoid. But, thanks to recent advances in laboratory testing of lung
tumors, doctors can usually make a more 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 beam
aimed through the bronchoscope.
Doctors can also take a brushing sample through the bronchoscope. They
wipe a tiny brush over the surface of the tumor. The cells removed by
the brush are smeared onto a microscope slide and examined in the lab.
Brushing samples are sometimes a helpful addition to the bronchial
biopsy but are not as helpful in diagnosing carcinoids as they are with
lung carcinomas.
Tumors that are not near the large airways are often sampled by needle
biopsy. A long needle is passed between the ribs into the lung. CT scan
images are used to guide the needle into the tumor so that a small
tissue sample can be removed for examination under the microscope. This
procedure is also done without a surgical incision or overnight
hospital stay. You may experience a collapse of one lung, called pneumothorax, after
this procedure. But this complication can be treated by temporarily
placing a suction tube into the chest. This will reexpand the lung.
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 surgically open your chest cavity. This procedure is called
a thoracotomy.
In other cases, when the doctors strongly suspect a carcinoid or some
other type of lung cancer, they may do a thoracotomy and remove the
entire mass without first doing a bronchoscopic biopsy or needle
biopsy.
Recently, a less invasive procedure for removing small lung tumors has
been developed. This is called video-assisted
thoracic surgery. A small hollow tube with a video camera
attached to the end can be placed through a small hole in the chest to
help the surgeon see the tumor. Only small incisions are needed, so
there is a little less pain after the surgery.
Other Tests
Because the carcinoid tumor sometimes secretes chemicals into the blood
like the ones that cause the carcinoid syndrome, the tumor can often be
detected by simple laboratory tests. These abnormal substances are
excreted in the urine and can be found by urine tests. Sometimes, blood
tests may be done to detect some of the hormone-like substances
produced by carcinoids, particularly if you have symptoms of the carcinoid syndrome,
caused by excessive levels of these substances in the blood. Although
these substances are often made by carcinoid tumors that start
elsewhere in the body, they are uncommon in people with lung carcinoids. Last Revised: 08/07/2006
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