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Last Update: June 11, 2014.

LAM, or lymphangioleiomyomatosis (lim-FAN-je-o-LI-o-MI-o-ma-TO-sis), is a rare lung disease. It mostly affects women of childbearing age.

What Is LAM?

LAM, or lymphangioleiomyomatosis (lim-FAN-je-o-LI-o-MI-o-ma-TO-sis), is a rare lung disease that mostly affects women of childbearing age.

In LAM, abnormal, muscle-like cells begin to grow out of control in certain organs or tissues, especially the lungs, lymph nodes, and kidneys.

Over time, these LAM cells can destroy the normal lung tissue. As a result, air can’t move freely in and out of the lungs. In some cases, this means the lungs can’t supply the body’s other organs with enough oxygen.


There are two forms of LAM. Sporadic LAM occurs for unknown reasons. LAM also can occur in women who have a rare disease called tuberous sclerosis complex (TSC). Women who have TSC often have a milder form of LAM.

About 50 percent of women who have LAM develop pneumothorax (noo-mo-THOR-aks), or collapsed lung. In this condition, air leaks out of the lung and into the space between the lung and chest wall (the pleural space).

A collapsed lung can cause pain and shortness of breath. Sometimes one lung will collapse over and over again. Pneumothorax is a serious condition. It usually requires treatment and might be life threatening.

Figure A shows the location of the lungs and airways in the body. The inset image shows a cross-section of a healthy lung. Figure B shows a view of the lungs with LAM and a collapsed lung (pneumothorax). The inset image shows a cross-section of a lung with LAM.

Many women who have LAM get tumors called angiomyolipomas (AN-je-o-my-o-li-PO-mas), or AMLs, in their kidneys. Women who have LAM also may develop:

  • Growths in other organs, including the liver and brain
  • Large tumors in their lymph nodes
  • A buildup of fluid in their chests, abdomens, or pelvic areas


LAM has no cure, and the disease tends to worsen over time. How quickly the disease worsens varies from woman to woman. LAM may lead to death from respiratory failure. Lung transplant is a treatment option for women whose lungs have been damaged by LAM.

Not long ago, doctors thought women who had LAM wouldn't live more than 8–10 years following diagnosis. They now know that some women may survive longer (as long as 20 years following diagnosis, although this is rare).

Doctors have learned a lot about LAM in recent years. They're now able to diagnose the condition earlier. Support services also are now available to help improve the quality of life for women who have LAM.

Researchers continue to explore and test new treatments for LAM.

What Causes LAM?

The cause of LAM and why it mainly affects women isn’t known. Recent studies show that sporadic LAM has some of the same traits as another rare disease called tuberous sclerosis complex (TSC). This information has provided some valuable clues about what causes LAM.

The common features of sporadic LAM and TSC are:

  • Kidney growths. People who have TSC get growths in their kidneys. These growths are the same as the angiomyolipomas that many women who have LAM get in their kidneys.
  • Lung cysts. Some women who have TSC get cysts in their lungs. These cysts are the same as the ones that women who have sporadic LAM get in their lungs. When a woman who has TSC gets cysts in her lungs, the lung disease is called TSC-associated LAM or TSC–LAM.

TSC is a genetic disease. A defect in one of two genes causes the disease. These genes are called TSC1 and TSC2. They normally make proteins that control cell growth and movement in the body. In people who have TSC, the genes are faulty. The proteins that the genes make can’t control cell growth and movement.

Women who have LAM also have abnormal TSC1 and TSC2 genes. Researchers have found that these genes play a role in causing LAM. This finding is leading to new treatments for LAM.

Because LAM affects women, the hormone estrogen also may play a role in causing the disease.

Who Is at Risk for LAM?

LAM is a rare disease that mostly affects women of childbearing age. Many women who develop LAM are between the ages of 20 and 40 when they begin to have symptoms. LAM can occur in older women as well, although this is less common.

Some women might have LAM and not know it. Many of LAM’s signs and symptoms are the same as those of other diseases, such as asthma, emphysema (em-fih-SE-ma), and bronchitis (brong-KI-tis).

LAM affects about 3 out of every 10 women who have tuberous sclerosis complex (TSC). Some of these women may have mild cases of LAM that don’t cause symptoms. Not everyone who has TSC and LAM has lung symptoms.

In rare cases, LAM has been reported in men.

What Are the Signs and Symptoms of LAM?

The uncontrolled growth of LAM cells and their effect on nearby body tissues causes the signs and symptoms of LAM. The most common signs and symptoms are:

  • Shortness of breath, especially during activity. At first, shortness of breath may occur only during high-energy activities. Over time, you may have trouble breathing during simple activities, such as dressing and showering.
  • Chest pain or aches. This pain might be worse when you breathe in.
  • Frequent cough. This may occur with bloody phlegm (a sticky fluid).
  • Wheezing (a whistling sound when you breathe).

Other signs and symptoms of LAM include:

  • Pneumothorax, or collapsed lung. In LAM, a pneumothorax can occur if lung cysts rupture through the lining of a lung. Air that collects in the space between the lung and chest wall must be removed to reinflate the lung.
  • Pleural effusions. This condition can occur if bodily fluids collect in the space between the lung and the chest wall. Often the fluid contains a milky substance called chyle (kile). The excess fluid in the chest may cause shortness of breath because the lung has less room to expand.
  • Blood in the urine. This sign may occur in women who have kidney tumors called angiomyolipomas.
  • Enlarged lymph nodes. These usually occur in the abdomen or the chest. Very rarely, enlarged lymph nodes may occur in locations where they can be felt, such as the neck or under the arms.
  • Abdominal swelling, sometimes with pain.
  • Swelling in the legs, ankles, or feet.

Other diseases also can cause many of these signs and symptoms. If you’re having any of these problems, see your doctor. He or she can help find the cause of your symptoms.

How Is LAM Diagnosed?

Methods for diagnosing LAM have improved. It's now possible for doctors to diagnose the disease at an early stage.

LAM is diagnosed based on your signs and symptoms and the results from tests and procedures. If you have LAM, you may need to see a pulmonologist. This is a doctor who specializes in lung diseases and conditions.

Signs and Symptoms

Your doctor will ask about your signs and symptoms related to LAM. He or she may ask how long you’ve had symptoms, and whether they’ve become worse over time.

Many of LAM’s signs and symptoms are the same as those of other diseases, such as asthma, emphysema, and bronchitis. Your doctor will want to rule out those conditions before making a final diagnosis.

Diagnostic Tests and Procedures

Your doctor may recommend tests to show how well your lungs are working and what your lung tissue looks like.

These tests can show whether your lungs are delivering enough oxygen to your blood. You also may have tests to check for complications of LAM.

Tests for Lung Function

Lung function tests. For lung function tests, you breathe through a mouthpiece into a machine called a spirometer (spi-ROM-eh-ter). The spirometer measures the amount of air you breathe in and out.

Other lung function tests can show about how much air your lungs can hold and how well your lungs deliver oxygen to your blood.

Blood tests. Your doctor may take a blood sample from a vein in your arm to look at your blood cells and blood chemistry.

Pulse oximetry. For this test, a small sensor is attached to your finger or ear. The sensor uses light to estimate how much oxygen is in your blood.

Tests To Check for Complications or Detect LAM Cells

Chest x ray. A chest x ray creates a picture of the structures in your chest, such as your heart and lungs. The test can show a collapsed lung or fluid in your chest. In the early stages of LAM, your chest x rays may look normal. As the disease gets worse, the x rays may show cysts in your lungs.

High-resolution CT (HRCT) scan. The most useful imaging test for diagnosing LAM is an HRCT scan. This test creates a computer-generated picture of your lungs. The picture shows more detail than the pictures from a chest x ray.

An HRCT scan can show cysts, shadows of cell clusters, excess fluid, a collapsed lung, and enlarged lymph nodes. The test also can show how much normal lung tissue has been replaced by the LAM cysts.

HRCT scans of your abdomen and pelvis can show whether you have growths in your kidneys, other abdominal organs, or lymph nodes.

Procedures To Look for LAM Cells

The results from the above tests—along with information about your signs, symptoms, and medical history—might be enough for your doctor to diagnose LAM.

However, if your doctor needs more information, the most useful method involves looking at samples of your lung tissue for LAM cells.

You may want to see a doctor who specializes in LAM for this test. Several procedures can be used to get a sample of lung tissue.

Video-assisted thoracoscopy (tho-rah-KOS-ko-pe). In this procedure, also called VAT, your doctor inserts a small, lighted tube into little cuts made in your chest wall. This lets him or her look inside your chest and snip out a few small pieces of lung tissue.

VAT is done in a hospital. The procedure isn’t major surgery, but it does require general anesthesia (that is, you’re given medicine to make you sleep during the procedure).

Open lung biopsy. In this procedure, your doctor removes a few small pieces of lung tissue through a cut made in your chest wall between your ribs. An open lung biopsy is done in a hospital. You’ll be given medicine to make you sleep during the procedure.

Open lung biopsies are rarely done anymore because the recovery time is much longer than the recovery time from VAT.

Transbronchial biopsy. In this procedure, your doctor inserts a long, narrow, flexible, lighted tube down your windpipe and into your lungs. He or she then snips out bits of lung tissue using a tiny device.

This procedure usually is done in a hospital. Your mouth and throat are numbed to prevent pain.

The amount of tissue that your doctor removes is very small, so this test doesn’t always provide enough information.

Other biopsies. Your doctor also can diagnose LAM using the results from other tissue biopsies, such as biopsies of lymph nodes or lymphatic tumors called lymphangiomyomas.

Other Tests

If you’re diagnosed with sporadic LAM, your doctor may advise you to have a computed tomography (CT) scan or magnetic resonance imaging (MRI) scan of your head. These tests can help screen for underlying tuberous sclerosis complex (TSC).

CT and MRI scans will reveal TSC in only a small number of people who are initially diagnosed with sporadic LAM.

Researchers are exploring other tests that may help diagnose LAM. These tests include blood tests for the LAM cells or a blood vessel growth factor called VEGF-D.

How Is LAM Treated?

Currently, no treatment is available to stop the growth of the cysts and cell clusters that occur in LAM. Most treatments for LAM are aimed at easing symptoms and preventing complications.

The main treatments are:


Medicines That Help You Breathe Better

If you’re having trouble breathing, your doctor may prescribe bronchodilators. These medicines relax the muscles around the airways. This helps the airways open up, making it easier for you to breathe.

Lung function tests can sometimes show whether these medicines are likely to help you.

Medicines That Prevent Bone Loss

Women who have LAM are at risk for a bone-weakening condition called osteoporosis (OS-te-o-po-RO-sis). This is in part because many LAM therapies block the estrogen action needed to keep bones strong.

To prevent osteoporosis, your doctor may measure your bone density. If you have lost bone density, your doctor may prescribe medicines to prevent bone loss. He or she also may prescribe calcium and vitamin D supplements.

Rapamycin (Sirolimus)

Sirolimus was originally developed to prevent the immune system from rejecting kidney transplants. However, studies have shown that the medicine helps regulate the abnormal growth and movement of LAM cells.

Research suggests that sirolimus may shrink tumors in the kidneys of women who have LAM.

A recent study funded in part by the National Institutes of Health showed that sirolimus also helps stabilize lung function, reduce symptoms, and improve quality of life for people who have LAM.

Sirolimus does have side effects, some of which can be serious. If you have LAM, talk with your doctor about the benefits and risks of this medicine, and whether it’s an option for you.

Oxygen Therapy

If the level of oxygen in your blood is low, your doctor may suggest oxygen therapy. Oxygen usually is given through nasal prongs or a mask. At first, you may need oxygen only while exercising. It also may help to use it while sleeping. Over time, you may need full-time oxygen therapy.

A standard exercise stress test or a 6-minute walk test can show whether you need oxygen while exercising. A 6-minute walk test measures the distance you can walk in 6 minutes. An exercise stress test measures how well your lungs and heart work while you walk on a treadmill or pedal a stationary bike.

You also may need a blood test to show your blood oxygen level and how much oxygen you need.

For more information, go to the Health Topics Oxygen Therapy article.

Procedures To Remove Air or Fluid From the Chest or Abdomen

Several procedures can remove excess air or fluid from your chest and abdomen. These procedures also help prevent air or fluid from building up again.

Removing fluid from your chest or abdomen may help relieve discomfort and shortness of breath. The procedure to remove fluid from the chest is called thoracentesis (THOR-ah-sen-TE-sis). The procedure to remove fluid from the abdomen is called paracentesis (PAR-ah-sen-TE-sis).

Your doctor often can remove the fluid with a needle and syringe. If large amounts of fluid build up in your chest, your doctor may have to insert a tube into your chest to remove the fluid.

Removing air from your chest may relieve shortness of breath and chest pain caused by a collapsed lung. Your doctor usually can remove the air with a tube. The tube is inserted into your chest between your side ribs. Often, the tube is attached to a suction device. If this procedure doesn't work, or if your lungs collapse often, you may need surgery.

If fluid and air often leak into your chest, your doctor may inject a chemical at the site of the leakage. The chemical fuses your lung and chest wall together. This removes the space for leakage.

Your doctor may do this procedure at your bedside in the hospital. You will be given medicine to prevent pain. The procedure also can be done in an operating room using video-assisted thoracoscopy. In this case, you will be given medicine to make you sleep during the procedure.

Procedures To Remove or Shrink Angiomyolipomas

AMLs often don't cause symptoms, but sometimes they can cause ongoing pain or bleeding. If this happens, you may need surgery to remove some of the tumors.

If bleeding isn't too severe, a radiologist often can block the blood vessels feeding the AMLs. This may cause them to shrink.

Lung Transplant

Lung transplants can improve lung function and quality of life in patients who have advanced LAM.

However, lung transplants have a high risk of complications, including infections and rejection of the transplanted lung by the body.

Studies suggest that more than three-quarters of women with LAM who receive a lung transplant survive for at least 3 years.

In a few cases, doctors have found LAM cells in the newly transplanted lungs and other parts of the body. However, the LAM cells don't seem to stop the transplanted lung from working.

For more information, go to the Health Topics Lung Transplant article.

Hormone Therapy

Estrogen is thought to play a role in causing LAM. Thus, your doctor may want to treat you with hormone therapy that limits the effects of estrogen on your body. Hormone therapy is given in pill form or as injections.

Some doctors also suggest surgery to remove the ovaries. This causes menopause and greatly reduces estrogen levels in the body.

Unfortunately, at this time, no clear evidence shows that this type of treatment works for women who have LAM.

Living With LAM

In the early stages of LAM, you usually can do your normal daily activities. These may include attending school, going to work, and doing common physical activities such as walking up stairs.

In the later stages of LAM, you may find it harder to be active. You also may need oxygen therapy full time.

Ongoing Care

Getting ongoing medical care is important. You may need to see a pulmonologist. This is a doctor who specializes in treating lung diseases and conditions.

Take steps to care for your lungs. For example, talk with your doctor about getting a yearly flu shot and pneumonia vaccine.

Lifestyle Changes

If you have LAM, taking good care of your health is important. Follow a healthy eating plan, be as physically active as you can, and get plenty of rest.

If you smoke, quit. Talk to your doctor about programs and products that can help you quit smoking.

If you have trouble quitting smoking on your own, consider joining a support group. Many hospitals, workplaces, and community groups offer classes to help people quit smoking. Ask your family members and friends to support you in your efforts to quit.

For more information about how to quit smoking, go to the Health Topics Smoking and Your Heart article and the National Heart, Lung, and Blood Institute's (NHLBI’s) "Your Guide to a Healthy Heart." Although these resources focus on heart health, they include basic information about how to quit smoking.

Also, check with your doctor before traveling by air or traveling to areas where medical attention isn't readily available. Also, talk to your doctor before traveling to places where the amount of oxygen in the air is low.

Pregnancy and Birth Control

If your lung function is normal, pregnancy might be an option. However, hormones during pregnancy can worsen LAM. Thus, you should discuss a possible pregnancy with both a pulmonologist who specializes in LAM and your obstetrician.

Most doctors don't recommend birth control pills containing estrogen to women who have LAM. Talk to your doctor about birth control options.

Emotional Issues and Support

Living with LAM may cause fear, anxiety, depression, and stress. Talk about how you feel with your health care team. Talking to a professional counselor also can help. If you’re very depressed, your doctor may recommend medicines or other treatments that can improve your quality of life.

Joining a patient support group may help you adjust to living with LAM. Information about patient support groups is available from the NHLBI Health Information Center at 301–592–8573 or the National Institutes of Health/NHLBI Pulmonary Vascular Medicine Branch at 1–877–NIH–LUNG (1–877–644–5864), extension 3.

Support from family and friends also can help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.

Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. For example, this research has uncovered some of the causes of chronic lung diseases, as well as ways to prevent and treat these diseases.

Many more questions remain about chronic lung diseases, including LAM. The NHLBI continues to support research aimed at learning more about these diseases. For example, NHLBI-supported research on LAM includes studies that explore:

  • The disease processes involved in LAM, and how to develop better treatments based on these processes
  • How bacteria and toxins found in the lungs, mouth, and digestive system contribute to LAM and other lung diseases

Much of the NHLBI’s research depends on the willingness of volunteers to take part in clinical trials. Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions.

For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you may gain access to new treatments before they’re widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don’t directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You’ll learn about treatments and tests you may receive, and the benefits and risks they may pose. You’ll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you’ll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to LAM, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:

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