Figure 1

Diagnosis of alveolar proteinosis was suspected based on typical radiological picture in chest x-ray and CT with ground-glass attenuation and interstitial thickening, resulting in crazy paving pattern (Figure. 1 A, B). Figure. 1 E shows CT after whole lung lavage of the right lung. Macroscopic appearance (Figure. 1 G) and light microscopy of BAL fluid stained with PAS (Figure. 1 C, magnification x400) showed extracellular positive proteinaceous material, lipid-laden macrophages (Figure. 1 H, MGG stain, magnification x1000), and after exclusion of infectious or metabolic causes or malignancy, PAP was confirmed by histology (right lower lobe). HE stained tissue demonstrated alveolar filling with eosinophilic material (Figure. 1 F) which was positive in periodic acid stain (PAS)(Figure. 1 I), intraalveolar cholesterol clefts (Figure. 1 H, arrows) and characteristic oval bodies (Figure. 1 H, open arrow).