Congenital pulmonary alveolar proteinosis is a very rare primary interstitial lung disease due to pulmonary surfactant accumulation within the alveolar macrophages and alveoli, characterized by a variable clinical course ranging from an asymptomatic clinical presentation and spontaneous remission, to symptoms such as dyspnea and cough, or to severe respiratory failure. The disease is hereditary pulmonary alveolar proteinosis (MONDO_0012580). Also known as: congenital PAP, congenital pulmonary alveolar proteinosis, inborn error of pulmonary surfactant metabolism, inborn error of surfactant metabolism.