Pulmonary alveolar proteinosis. Occurrence with metastatic melanoma to lung.

Pulmonary alveolar proteinosis is characterized by excessive accumulation of surfactant-like material in the alveoli, resulting in part from defective alveolar clearance by macrophages. We present a case of alveolar proteinosis in a patient with malignant melanoma metastatic to lung and discuss possible alteration in macrophage function in the pathogenesis of these two concomitant processes.