[Idiopathic pulmonary alveolar proteinosis: report of three cases and literature review].

To describe the clinical, radiological and pathological characteristics of idiopathic pulmonary alveolar proteinosis (I-PAP) and to evaluate the methods of diagnosis and treatment. Three patients were successfully diagnosed and treated in our hospital and the literature on the subject was reviewed. Three patients, two males and one female (mean age 46 years), were diagnosed averagely in 4 months. Two severe patients presented with progressive dyspnea and type I respiratory failure, and one mild patient only with dry cough and hypoxemia. Chest X-ray radiographs all showed perihilar "butterfly" shadow and chest CT scans showed diffused ground-glass opacities (GGO), typically with "map" changes and "crazy paving" patterns. All the patients underwent bronchoscope, branchoalveolar lavage fluid (BALF) had grossly opaque and/or milky appearance and its sediment was periodic acid-Schiff stain positive. Trans-bronchoscopic lung biopsy (TBLB) specimens were obtained and under light microscopy alveoli and some of the small bronchioles were filled with eosinophilic proteinaceous material with needle-like clefts. By electron microscopy numerous cellular debris and extracellular multilamellated bodies were found. Two severe patients were successfully treated with sequential whole-lung lavage and one required repeated lavages. I-PAP is rare and prone to be misdiagnosed. The radiological features may indicate the diagnosis and examinations of TBLB and BALF can make the accurate diagnosis. Whole-lung lavage is the most effective therapy by now and granulocyte-macrophage colony-stimulating factor (GM-CSF) may be beneficial in some patients.