Patient A Hematoxylin and Eosin staining. Two surgical samples were taken from the upper and the lower left lobes. The sample from the upper lobe (a, b) shows limited architectural changes, with centrilobular inflammation and fibrosis. Fibroblastic foci and small aggregates of multinucleated giant cells engulfing cholesterol clefts are visible in centrilobular areas. Granular pink material is visible in some alveolar spaces (b). The sample from the lower lobe (c, d) shows diffuse microcysts, fibrosis and smooth muscle proliferation, without residual normal tissue. Fibroblastic foci and bronchiolar metaplasia are prominent (d). (a) magnification 2x, scale bar 0,5 cm; (b) magnification 10x, scale bar 200 micron; (c) magnification 2x, scale bar 0,5 cm; (d) magnification 20x, scale bar 30 micron.