Lymphangioleiomyomatosis, or LAM, is a disorder which causes uncontrolled growth of smooth muscle cells. These cells invade lung tissue and grow, forming cysts that block the airways and impair the flow of blood and lymph fluid. The condition can cause an accumulation of fluid in the spaces of the lungs (pleural effusion), lung collapse (pneumothorax) and respiratory failure. About 40 percent of patients are found to have a benign type of kidney tumor called angiomyolipoma.

LAM occurs almost exclusively in women. Hormones appear to play a role. The disease usually appears sometime during puberty and menopause and often progresses during pregnancy. The exact incidence is unknown. It is sometimes associated with an inherited condition, called tuberous sclerosis. The LAM Foundation estimates 40 to 50 percent of women with tuberous sclerosis have a form of LAM. LAM can also occur sporadically (is not inherited). Between 30,000 and 50,000 people worldwide are believed to have the sporadic form of LAM.

Diagnosis of LAM may be difficult. Since the disease is very uncommon, physicians may not be aware of it. Women may go undiagnosed or misdiagnosed with asthma, bronchitis or emphysema. Signs may not be visible on a chest X-ray. A high resolution CT scan or lung biopsy may be needed to make a diagnosis.

Treating LAM

Currently there is no known method to stop the growth and proliferation of abnormal smooth muscle cells associated with LAM. Treatments, like medication, oxygen therapy and removal of fluid in the chest, are aimed at easing symptoms. In severe cases, a lung transplant may be needed.

Vera Krymskaya, Ph.D., a Pulmonary Researcher with the University of Pennsylvania School of Medicine, discovered LAM is associated with the loss of tuberous sclerosis complex protein, which normally controls the growth of the LAM muscle cells. In further research, she found an anti-rejection drug for transplant patients, called rapamycin, could inhibit the growth of LAM cells by mimicking the activity of the tuberin protein. Several researchers are now trying to determine if rapamycin can be an effective treatment to restore lung function in patients with LAM.

For general information on Lymphangioleiomyomatosis (LAM):

The LAM Foundation

American Lung Association

American Thoracic Society

National Heart, Lung and Blood Institute