Congenital lobar overinflation (CLO), previously called congenital lobar emphysema, is a congenital lung abnormality that results in progressive overinflation of one or more lobes of a neonate lung. Various mechanisms have been postulated including an obstructive check valve mechanism at the bronchial level. It usually presents with respiratory distress, mostly during the neonatal period. 

Left upper lobe is most commonly affected (40-45%), followed by right middle lobe (30%)-as in our case, followed by right upper lobe. More than one lobe affection is uncommon (5%). 

Treatment includes follow up in mildly symptomatic patients. However, lobectomy can be considered in severe cases.