[A case of pulmonary alveolar proteinosis which initially deteriorated rapidly with exacerbation of pulmonary nocardiosis, responded promptly to treatment of the pulmonary nocardiosis].

A 37-year-old man was admitted with complaints of continuous cough and sputum production for 1 month. Computed tomography (CT) of the chest revealed a solitary mass with a cavity in the apex of the left lung and bilateral ground-glass opacities (GGO). Thereafter, the patient complained of fever, and an increase in the mass shadow size and expansion of the ground-glass opacities were observed on serial CT. The patient was given diagnoses of pulmonary nocardiosis and pulmonary alveolar proteinosis by bronchoscopic examination. Serum anti-GM-CSF antibody tests were positive. On the basis of these findings, we diagnosed autoimmune pulmonary alveolar proteinosis. After beginning antituberculosis drugs and antibiotics, the tumor shadow and GGO reduced. The pulmonary alveolar proteinosis rapidly worsened on exacerbation of the pulmonary nocardiosis, but prompt overall improvement was obtained after treating the latter. We believe this to be a valuable case for examining the time progression of autoimmune pulmonary alveolar protein syndrome, because of the clinical course of the exacerbation, and the improvement in the pulmonary alveolar proteinosis after treatment of pulmonary nocardiosis.