title: Congenital cystic adenomatoid malformation of the lung.
abstract: Ultrastructural study of a congenital cystic adenomatoid malformation of the lung revealed a persistence of type 2 pneumocytes lining the alveolar and gland-like spaces. The larger cystic areas were lined by normal bronchiolar-type epithelium and were surrounded by a few smooth muscle cells. The interstitium contained undifferentiated mesenchymal cells. No cartilage or bronchial glands were present. These features suggest that this lesion is developmental in nature, with a failure of maturation resulting from an insult occurring early in embryonic life, prior to the onset of cartilaginous differentiation within the lungs.
mesh_terms: D004848:Epithelium / Q000473:pathology; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000002:abnormalities* / Q000473:pathology; D008297:Male; D009130:Muscle, Smooth / Q000473:pathology; D011650:Pulmonary Alveoli / Q000473:pathology; D012127:Respiratory Distress Syndrome, Newborn / Q000473:pathology