Orphanet_264675 (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. Also known as: Congenital PAP.