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Lymphangioleimyomatosis (LAM)

  • Definition

    Lymphangioleimyomatosis (LAM), also known as lymphangiomyomatosis or pulmonary lymphangiomyomatosis (honeycomb lung) is a rare progressive, fatal disorder that primarily affects the lungs of women of childbearing age. LAM affects about 300 women in the U.S.


    LAM is characterized by an unusual type of muscle cell that invades the tissue of the lungs, including the airways, blood and lymph vessels. Over time, these muscles cells form into bundles (cysts or blebs) and grow into the walls of the airways, causing them to become obstructed thereby blocking the flow of air, blood, lymph (the fluid which is derived from connective tissue and tissue between organs) to and from the lungs. This blockage prevents the lungs from providing oxygen to the rest of the body.

    This disorder also may affect the smooth muscle tissue of the thoracic duct, lymph nodes, the liver, and in very rare cases, the lymphatic vessels of the legs.


    While the exact cause of this disorder is not known, the fact that it occurs only in women leads researchers to believe that it may be transmitted as a sex-linked trait or genetic disposition (a person may carry a gene for a disease but it may not be expressed unless something in the environment triggers the disease). Hormone therapy given to women to combat other medical problem(s) has also been implicated as another possible cause.


    The symptoms of LAM include:

    • Shortness of breath (in early stages of LAM, shortness of breath occurs only during strenuous exercise. As the disease progresses there may be shortness of breath while resting)
    • chest pain (due to excessive fluid [pleural effusion] or air [pneumothorax] in the chest cavity)
    • Coughing up small amounts of blood or blood-stained sputum
    • Difficulty breathing
    • Collapsed lung ( symptoms include sudden, sharp chest pain; difficult rapid breathing; rapid heart beat; low blood pressure; profuse sweating; dizziness; lack of normal chest movement)
    • Weight loss
    • abdominal pain and discomfort (due to fluid collection in the walls of the abdomen)
    • Cloudy urine

    The early symptoms of LAM are similar to those of other lung diseases such as asthma, emphysema or bronchitis. Therefore the doctor must run a battery of tests to accurately diagnose LAM. These tests include a chest x-ray, pulmonary function tests, blood tests, and a computed tomography (CT) scan. If these tests are inconclusive the doctor will perform a lung biopsy.

    A biopsy is a diagnostic test in which tissue or cells are removed from the body for examination under the microscope. In the case of LAM, lung tissue can removed via at least three different procedures.

    The first is open lung biopsy (tissue is removed through an incision made in the chest wall between the ribs).

    The second is thoracoscopy (a small incision is made through which a small lighted tube called an endoscope is inserted). This instrument allows the doctor to view the lung and remove the tissue.

    The third procedure is transbronchial biopsy (tissue is removed through a long, narrow flexible tube called a bronchoscope which is inserted down the windpipe and into the lungs).

    After the lung tissue is removed, the laboratory will look for the presence of abnormal muscle cells and cystic changes.


    Treatment of LAM is directed at controlling the symptoms of the disease.

    • For persons with excess fluid in the lungs, there are at least two methods to reduce the fluid. The first method is the insertion of shunts (tubes) in the lungs. The other method is the surgical insertion of a sterile irritant, such as the antibiotic tetracycline, into the space surrounding the lungs. This method not only reduces the fluid, but also helps in reducing the size of the chest cavity.
    • For minor breathing problems, the doctor may prescribe a bronchodilator drug that relaxes the muscles around the bronchioles and assists in widening the airways in the lungs. For major breathing problems, oxygen therapy may be necessary if the disease continues to worsen and lung function is impaired.
    • In response to the theory that estrogen production may be a causative factor of LAM, doctors may opt to pharmaceutically or surgically reduce estrogen production.
    • Removal of the abnormal lung tissue.
    • Lung transplantation is considered as a last resort.

    In the early stages of the disease, most LAM patients have a normal lifestyle (school, work, minimal physical activities) but as the disease progresses the LAM patient may have very limited ability to move around and may require oxygen full-time. pregnancy and traveling to remote areas are not advised.


    Is the diagnosis LAM or another lung disease?

    How fast is the disease progressing?

    What type of treatment will you be recommending?

    If drugs are prescribed, what are the side effects?

    If surgery is recommended, what are the risks, complications and recovery time?

    What is the prognosis?