CONGENITAL CYSTIC ADENOMATOID MALFORMATION OF THE LUNG

Abstract

Two new cases of congenital cystic adenomatoid malformation of the lung are reported. Both patients died shortly after birth, one at 36 hours and the other on the tenth postnatal day. Cystic adenomatoid malformation is a special form of cystic lung disease characterized by large and small cysts lined variably by a bronchial-type (respiratory) and by cuboidal epithelium. In spite of the bronchial-type epithelium in some of the cysts, bronchial wall elements such as cartilage and mucoserous glands were not demonstrated. There was much elastic tissue in these cysts, of a degree having no counterpart in normal lung. These observations together with the topographic interposition of the cysts with normal appearing alveolar structures suggest a developmental malformation affecting those segments of the lungs normally destined to become the terminal bronchioles, respiratory bronchioles, and alveolar ducts. In one case, groups of alveoli were lined with a tall mucogenic epithelium morphologically resembling that seen in pulmonary adenomatosis of man and jaagsiekte of sheep. The finding is considered the result of alveolar cell metaplasia.