Pulmonary alveolar proteinosis as a terminal complication in myelodysplastic syndromes: a report of four cases detected on autopsy.

Secondary pulmonary alveolar proteinosis (PAP) is one of the complications of hematologic malignancy and immunosuppressive diseases. We encountered four cases of myelodysplastic syndrome (MDS) associated with PAP detected on autopsy. They consisted of two refractory anemia (RA) and two patients with refractory anemia with excess blasts in transformation (RAEBt) at the time of MDS diagnosis, but all of them developed leukemic phase and were resistant to chemotherapy at the time of pulmonary episodes. Of the four MDS patients, two also had pulmonary aspergillosis. Previously, 69 patients with PAP associated with hematologic disorders have been reported, but there have been only seven cases with MDS, including our four patients. Of the 69 reported cases of PAP in hematologic malignancies, 24/63 (38%) informative patients with infection had fungal infections of the lung; 2/7 (29%) MDS cases had fungal infection. We should, therefore, pay careful attention to this possibility in cases of MDS with lung complications, including PAP, especially in patients in the leukemic phase of MDS.