Lymphangioleiomyomatosis (LAM) is a rare, slowly progressive growth of smooth muscle cells throughout the lungs.
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) for no apparent reason. Sometimes fluid collects in the sac that covers the lungs (pleura).
Pulmonary function tests (see Pulmonary Function Testing (PFT)) show that the amount of air the lungs can hold is below normal.
A chest x-ray and computed tomography (CT) are usually needed for diagnosis. If the results of imaging tests are unclear, doctors may remove small pieces of lung tissue for examination under a microscope (lung biopsy). They may remove the tissue while examining the airways using a viewing tube (bronchoscopy—see Bronchoscopy).
The disorder tends to progress slowly, but eventually lung function deteriorates into respiratory failure. The rate of progression varies widely, but progression may accelerate during pregnancy.
Sirolimus, a drug normally used to suppress the immune system after a kidney transplant, is being studied and seems to slow the decline in lung function. Lung transplantation may cure the disorder. However, sometime LAM recurs in the transplanted lung.
Last full review/revision October 2013 by Harold R. Collard, MD