A Case of Acute Biphenotype Leukemia after Diagnosis of Pulmonary Alveolar Proteinosis

We present the case of a 34-year-old man with acute biphenotype leukemia that co-expressed B-lymphoid and myeloid antigen after the diagnosis of pulmonary alveolar proteinosis (PAP). The diagnosis of PAP was established by Periodic Acid-Schiff reaction staining on the Video Associated Thoracoscope guided lung biopsy and biphenotype leukemia was revealed by immunohistochemical stains of the blasts harvested from the bone marrow biopsy. Supposedly, PAP follows a hematologic malignancy, yet this case shows the reverse sequence.