Pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (abbreviated PAP), is a rare lung disease in which abnormal accumulation of pulmonary surfactant occurs within the alveoli, interfering with gas exchange. PAP can occur in a primary form or secondarily in the settings of malignancy (especially in myeloid leukemia), pulmonary infection, or environmental exposure to dusts or chemicals. Rare familial forms have also been recognized, suggesting a genetic component in some cases.