Abstract
Lung underdevelopment is a rare congenital anomaly with variable clinical significance and presenting symptoms. It usually manifests during childhood. We present two cases of developmental lung anomaly subtypes and discuss clinical presentation and outcomes in such patient populations. LEARNING POINTS: Pulmonary underdevelopment is a challenging diagnosis and should be considered in patients with unilateral opacification on chest radiograph.Childhood developmental history is critical for diagnosis as delayed, or misdiagnoses are common. Definitive diagnosis can be made by computed tomography scan.Management is watchful waiting with close monitoring, with long term prognosis remaining unclear.