bronchiolitis obliterans

Definition of bronchiolitis obliterans
National Cancer Institute

bronchiolitis obliterans

(BRONG-kee-oh-LY-tis ob-LIH-teh-ranz)
A condition in which the bronchioles (tiny branches of air tubes in the lungs) become inflamed and blocked. It may be caused by breathing in gases or particles that irritate the bronchioles. This irritation causes scar tissue to form, and makes breathing difficult. Bronchiolitis olbiterans may be caused by other factors, and can also occur after a transplant with an organ or stem cells from a matched donor.

Source: NCI Dictionary of Cancer Terms