Early case of idiopathic pulmonary alveolar proteinosis positive for serum anti-GM-CSF antibody

An asymptomatic 56-year-old woman who had never smoked and had been healthy was admitted to our hospital because of abnormal shadows on a chest X-ray film taken on a medical check-up. Chest CT showed ground-glass opacities in the right upper lung field. No abnormality on chest X-ray had been pointed out on any annual medical check up until then. As bronchofiberscopy (BAL and TBLB) could not reveal any diagnostic information, VATS biopsy was performed. Histological findings showed that alveolar spaces were filled with PAS-positive granular materials, and fused membrane structures and amorphous material were demonstrated by electron microscopy. Anti-GM-CSF antibody of serum was also positive (7.908 microg/ml). Based on these findings, we decided this was an early case of idiopathic pulmonary alveolar proteinosis.