ABSTRACT
Congenital cystic lung lesions are a group of congenital lung diseases with low incidence. These include congenital cystic adenomatoid malformation,bronchogenic cyst,congenital lobar emphysema and pulmonary sequestration. These malformations occur during the period of lung development stimulated by various factors. Manifestations of the diseases are very similar,but the pathogenesis and pathology are very different. Congenital cystic adenomatoid malformations are thought to be the results of the cessation of bronchiolar maturation with overgrowth of mesenchymal elements and without development of alveoli. There are 5 pathological types of congenital cystic adenomatoid malformations. Bronchogenic cysts are the results of abnormal budding from a segment of the tracheobronchial tree during embryo development,and the buds with no communication with normal tracheobronchial tree. Congenital lobar emphysema is a term reserved for hyperinflation of alveoli from idiopathic reasons or extrinsic compression,as well as pathological changes of the bronchial wall. Pulmonary sequestrations account for parts of nonfunctioning lung tissue that mostly do not communicate with normal bronchoalveolar tree and vascularized by a systemic artery,two types(intralobar and extralobar sequestration)are described.