Pulmonary alveolar proteinosis developing during steroid treatment in a patient with organizing pneumonia in association with atypical chronic myeloid leukemia

Pulmonary alveolar proteinosis (PAP) is an uncommon disease characterized by the accumulation of surfactant proteins and phospholipids within the alveolar spaces.1, 2 Acquired PAP is divided into two forms based on its clinical features: idiopathic PAP and secondary PAP (sPAP). sPAP most commonly occurs in association with hematologic malignancies.3 Organizing pneumonia (OP) has also been reported as a rare complication in patients with hematologic malignancies.4 To our knowledge, there have been no reports of the development of both OP and PAP in the same patient. We herein report a case of hematologic malignancy‐associated PAP with a poor outcome that developed during steroid treatment for OP.