Pulmonary interstitial emphysema due to respiratory syncytial virus infection.

Pulmonary interstitial emphysema (PIE) primarily affects premature infants on positive pressure ventilation. PIE is rarely reported in infants and children in the absence of mechanical ventilation and/or associated respiratory infection. We report a case of PIE in a 22-month-old girl who had severe respiratory distress due to respiratory syncytial virus infection. Chest computed tomography showed cystic lung lesions mimicking congenital cystic adenomatoid malformation. The cystic lesions spontaneously resolved after conservative treatment. Based on the clinical course and the chronological changes on imaging, the cystic lung lesions were diagnosed as localized persistent PIE.