Key Facts

  • LAM is caused by abnormal growth of cells in the lungs and other organs.
  • LAM is very rare, affecting only 3 to 8 of every million women, usually when they are of childbearing age.
  • Lung damage from LAM often results in pneumothorax, which can ultimately help doctors with diagnosis. A lung transplant may be considered for advanced cases.
  • Recent advances in treatment are making progress in slowing lung damage and improving lung function.

What Causes LAM

LAM is caused by the mutations in two genes, Tuberous sclerosis complex (TSC)1 and TSC2. The first form is hereditary and occurs in patients who have tuberous sclerosis. This is much more common than the second form, which is not linked to tuberous sclerosis. This second form is not hereditary and the reason for the mutation is unknown.

How LAM Affects Your Body

In people who have LAM, abnormal muscle-like cells begin to grow out control in the lungs, lymph nodes, kidneys and sometimes other organs. This can lead to organ tissue damage and impair function. In the lungs, LAM cells block the airways and also result in the formation of “cysts” on your lungs. The combination of these two types of lung damage makes breathing difficult and reduces the body’s ability to take in oxygen. If a cyst ruptures, it can create a hole in the lung that allows air into the body cavity and may result in pneumothorax (collapsed lung).

In the most advanced cases, the loss of lung function can be so bad that a lung transplant may be needed. In addition, LAM can cause blockage in the lymphatic system, allowing fluid to build up in the chest and abdomen that will require draining.

Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel.

Page last updated: November 17, 2022

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