Cysts within the lung are one of the more common pulmonary pathological findings seen in an active pediatric surgical pathology service. Of both developmental and acquired origin, they may present as respiratory distress in infants or may be asymptomatic lesions incidentally discovered by images studies of the thoracic for "non-pulmonary" reasons. The most frequently seen developmental cysts of the lung are those of Congenital Pulmonary Airway Malformations, types 1, 2 & 4. Other congenital cystic lesions include bronchogenic cysts (usually in older patients) and some of the enteric duplication lesions that contain cysts. Acquired cystic lung lesions include acute and persistent pulmonary interstitial emphysema, postinfarction peripheral cysts, postinfectious pulmonary cysts, and the cystic form of pleuropulmonary blastoma.