Mucoid impaction of a stem bronchus

Persistent atelectasis of the left lung was the chief finding in an elderly woman who had no background of chronic lung disease. At operation lower lobectomy was necessary because of irreversible parenchymal changes, but it was possible to salvage the upper lobe. Pathologically, the process was found to be mucoid impaction of the bronchi (MIB). Although this condition rarely involves an entire lung, its recognition is important because treatment with intrabronchial acetylcysteine may be definitive and surgery, if required, should be conservative.