Alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare disease of unknown cause. It is characterized by the deposition of insoluble phospholipid-rich protein in the alveoli, and the clinical symptoms are mainly shortness of breath, cough and sputum. The chest X-ray showed diffuse lung infiltration shadows in both lungs. Pathological examination was characterized by alveoli filled with protein-like substances that were positive for periodate Schiff (PAS) staining. The disease was first reported by Rosen in 1958. Alveolar proteinosis can be divided into primary, secondary, and congenital depending on the cause.