Congenital pulmonary lymphangiectasis: report of an autopsy case masquerading as pulmonary interstitial emphysema.

We describe the clinicopathologic features of a case of congenital pulmonary lymphangiectasis (CPL). A male Japanese infant born prematurely at 34 weeks of gestation developed a severe moaning sound, dyspnea, and prominent respiratory acidosis about 10min after delivery. A chest X-ray film showed bilateral frosted glass-like infiltrates with an air bronchogram and an air leak around the cardiac shadow, suggesting pneumomediastinum. The patient died of hypoxemic respiratory failure 13h after birth. The death was complicated by bilateral pneumothorax, despite the initiation of artificial ventilation and administration of a surfactant. At autopsy, small cystic lesions were noted in the visceral pleura, interlobular septa, and hilum of both lungs. A histologic examination of the lungs showed diffuse and marked dilation of the lymphatic channels in the subpleural, peribronchial, interlobular, and hilar areas. The channels were lined with flattened endothelium, which was immunohistochemically positive for D2-40. In addition, lymphangiectasis was found around the thymus and intra-abdominal organs, but no cardiovascular anomalies were seen. The findings conformed to a primary form of CPL, Noonan Group 3. Although pulmonary interstitial emphysema (PIE) was considered an important differential diagnosis because of the overlapping clinicopathologic features, a giant cell reaction surrounding the interstitial cystic lesions, a histologic hallmark of PIE, was absent in the present case.