LAM

Lymphangioleiomyomatosis or LAM is a rare lung disease that almost exclusively affects women of childbearing age. It is caused when the benign growth of smooth muscle tissue starts to intrude on lung tissue, resulting in constriction of the airways, breathing difficulties, pneumothorax, pleural effusion, and reduced lung volume.
LAM is usually misdiagnosed as its symptoms resemble more prosaic illnesses such as asthma. The progression of the disease is very slow, even though it will eventually result in death if untreated. Even if suspected, on scans it resembles langerhans cell histiocytosis, emphysema and sarcoidosis. It's often found together with tuberous sclerosis.
In its early stages, the disease can be treated with drugs that suppress estrogen, which appears to play a role in the progression of the disease. However, all of the possible treatments have serious side effects, and may even speed the progression of the disease. In advanced stages, a lung transplant may be the only option.
LAM at Wikipedia