Congenital cystic adenomatoid malformation of the lung

Abstract

In 8 of 10 infants with congenital cystic adenomatoid malformation of the lung, the pregnancy was complicated by hydramnios. Two were stillborn, all the others died within 3 h of birth and showed respiratory distress. Seven were hydropic. The lesion was always confined to one side, affecting 1 lobe (in 8 cases) and 2 lobes (in 2 cases). The remaining lobe(s) on the same side and the contralateral lung were hypoplastic. On gross examination the appearances were either solid or mixed solid and cystic. Microscopically the solid areas were composed of an ‘adenomatoid’ increase in terminal respiratory structures, which resembled the developing lung of the embryo. The cysts were lined by papillary mucosa. Mucin-secreting epithelium was seen in 5 cases. It was concluded that congenital cystic adenomatoid malformation of the lung is a distinct pathological entity, and separable from other cases of the ‘congenital cystic lung’.