PMC5828087_01
(a) and (b) Bilateral diffuse ground-glass opacities with thickened interlobular septae were seen in multiple sections of the lungs on HRCT.
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fig1
There is no convincing evidence of interstitial lung disease, nor any signs of air trapping that would suggest an obstructive etiology (Figure 1).
(a) Papanicolaou-stained smear of BAL fluid (lower magnification). (b) Papanicolaou-stained smear of BAL fluid (higher magnification) showing amorphous globules and alveolar histiocytes (likely macrophages) with dense intracellular proteinaceous material. (c) Paucicellular, amorphous globules staining orange, green, and green with orange centre under Papanicolaou-stain (higher magnification).
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fig2
Amorphous green, orange, and orange-centred globules and histiocytes containing dense proteinaceous material were seen on Papanicolaou-stained smears of BAL fluid (Figure 2).
Diff-Quick stain of BAL fluid showing densely blue, basophilic globules.
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fig3
These globules appeared densely dark blue and basophilic under Diff-Quick stain and were periodic acid-Schiff- (PAS-) positive and diastase-resistant (Figures 3 and 4), consistent with the diagnosis of PAP.
(a) PAS stain of BAL fluid. Globules were PAS-positive. (b) The globules were diastase-resistant.
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fig4
These globules appeared densely dark blue and basophilic under Diff-Quick stain and were periodic acid-Schiff- (PAS-) positive and diastase-resistant (Figures 3 and 4), consistent with the diagnosis of PAP.
H&E stain of lung wedge biopsy sections at 100x (a), 200x (b), and 400x (c) magnifications showing intact alveolar walls, normal interstitium, and amorphous, eosinophilic granular material in the airspace.
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fig5
H&E stains of the wedge biopsy showed intact alveolar structure filled with amorphous granular eosinophilic material and no interstitial pathology, confirming the diagnosis of PAP (Figure 5).