LAM lung disorder is caused by overgrowth of smooth muscle
DEAR DR. ROACH: A woman in my town wears oxygen and has something called “LAM.” What is LAM, and when should one get evaluated for it? — A.L.
ANSWER: Lymphangioleiomyomatosis is a rare disorder (a few people per million will have it) that can affect many organs, but most commonly the lung. It is found mostly in women.
It is neoplastic (meaning “new growth”), which makes it a relative of cancer. It can be associated with another condition, tuberous sclerosis. The underlying problem in LAM is the unregulated growth of smooth muscle cells, especially in the lungs, kidneys and lymph vessels.
The lion’s share of LAM diagnoses are made in people in their 30s and 40s. The most common symptom is shortness of breath during exercise, and it may be misdiagnosed as asthma or COPD. Cysts may be seen on films, and these can burst, causing a pneumothorax, which is an emergency. The diagnosis traditionally has been made with CT scans and biopsy, but a new blood test, VEGF-D, may reduce the need for biopsy.