Giant bullous cysts of the lung.

Emphysematous bullae of the lung may be single or multiple; they are usually of pathological interest rather than of clinical importance, except when they rupture into the pleura and cause a tension pneumothorax. They are an expression of underlying bronchial disease, either in the form of inflammation or scarring, whereby air passes during inspiration into the area of lung supplied by the bronchus or bronchiole more easily than it can escape during expiration. Over-inflation, occurs, with the formation of an air cyst, and it is. possible that pleural adhesions may play a part; this point will be considered liter. Observations on a very few patients led to the idea that these cysts might themselves give rise to symptoms apart from any disability for which their initial cause might be responsible.