Merck Manual

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Joyce Lee

, MD, MAS, University of Colorado School of Medicine

Last full review/revision Jun 2021| Content last modified Jun 2021
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Lymphangioleiomyomatosis (LAM) is a rare, slowly progressive growth of smooth muscle cells throughout the lungs.

Lymphangioleiomyomatosis (LAM) is rare. It occurs only in women, usually women between the ages of 20 and 40 years. The cause is unknown.

Affected women usually have shortness of breath. Sometimes cough, chest pain, and coughing up blood (hemoptysis) also occur. Symptoms may worsen during pregnancy. Sometimes the first indication of the disease is when a lung collapses (pneumothorax Pneumothorax A pneumothorax is the presence of air between the two layers of pleura (thin, transparent, two-layered membrane that covers the lungs and also lines the inside of the chest wall), resulting... read more Pneumothorax ) for no apparent reason. Sometimes fluid collects in the sac that covers the lungs (pleura).

The disorder tends to progress slowly, but eventually lung function deteriorates into respiratory failure Respiratory Failure Respiratory failure is a condition in which the level of oxygen in the blood becomes dangerously low or the level of carbon dioxide in the blood becomes dangerously high. Conditions that block... read more . The rate of progression varies widely, but progression may accelerate during pregnancy.

Diagnosis of Lymphangioleiomyomatosis

  • Chest computed tomography

  • Blood testing

A chest x-ray and computed tomography (CT) are usually needed for diagnosis of lymphangioleiomyomatosis.

A blood test that measures the level of vascular endothelial growth factor D (VEGF-D) is often done. VEGF-D levels are usually elevated in women who have LAM.

If the results of imaging and blood tests are unclear, doctors may remove pieces of lung tissue for examination under a microscope (lung biopsy).

Treatment of Lymphangioleiomyomatosis

  • Sirolimus

  • Lung transplantation

Sirolimus, a drug normally used to suppress the immune system after a kidney transplant, seems to slow the decline in lung function in people with LAM.

More Information

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • LAM Foundation: General information on lymphangioleiomyomatosis, including research discoveries and support programs

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