Learn About Lymphangioleiomyomatosis (LAM) | American Lung Association

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Learn About Lymphangioleiomyomatosis (LAM)

LAM is a progressive disease that can affect your lungs, kidneys and lymphatic system. The lymphatic system is a system of tiny channels that run through the body carrying cells that maintain your immunity and regulate the nutrients in your blood. The cause of LAM is unknown, but hormones may play a role, as LAM almost always occurs in females and very rarely develops before puberty or after menopause.

The main finding associated with LAM is the presence of "cysts" in your lungs. A cyst is a round space or "hole" with a thin border that is surrounded by normal tissue.

Key Facts

  • LAM is a rare disease affecting women of child-bearing age, usually in their 30s and 40s.
  • There are no behavioral conditions or risk factors that are known to cause LAM.
  • Although female hormones and pregnancy can aggravate LAM, this is not considered a cause or risk factor for the development of LAM.

What Is LAM?

The hallmark of LAM is the thickening of the areas surrounding the blood vessels, breathing tubes and lymph channels, as well as the lining of the lung. This is the result of an abnormal growth of smooth muscle cells.

LAM is not contagious. When associated with another condition called tuberous sclerosis complex (TSC), LAM is part of an inherited disorder that occurs when one of the parents pass on an abnormal gene to their children. When LAM occurs alone, it is related to the alterations of certain genes that are an important part of cell growth. In rare cases, these alterations can happen at random (in approximately 3 to 7 out of 1 million women).

How LAM Affects Your Body

LAM primarily affects your lungs and your breathing. Occasionally, it is associated with tuberous sclerosis complex (TSC). When LAM is a part of TSC, it is more common to have kidney tumors called angiomyolipomas and other benign tumors in the abdomen and, in rare instances, involvement of the brain that may cause seizures and require monitoring.

How Serious Is LAM?

LAM can shorten your lifespan, though over the last few decades, some patients are living longer than ever before. It is possible that LAM can make you lose your lung function to the point of needing a lung transplant.


    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.


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