Figure 5a:

(a) Radiologic-pathologic correlation in patient 1, a 67-year-old woman. Gross pathology findings show interlobular septal edema, congestion, thickened bronchial walls (arrow), and consolidation (arrowhead). The corresponding CT in sagittal plane discloses bronchial wall thickening (arrow) and dystelectasis in the posterior parts of the lower lobes (arrowhead). Photomicrographs show bronchopneumonia in the left lower lobe (top left and right), thickened bronchial walls (bottom left), and microthrombosis (bottom right, immunohistochemistry for fibrin polyclonal antibody [A0080; Dako]; other photomicrographs, hematoxylin-eosin [H&E] stain, magnification not available [N/A]). (b) Radiologic-pathologic correlation in patient 2, a 66-year-old man. Gross findings document interlobular septal edema and segmental hemorrhage in the anterobasal segment of the left lower lobe (arrow), while CT scan shows peripherally pronounced ground-glass opacity (GGO) in the left lower lobe. Inserted minimum intensity projection reveals some focal bronchial dilatation in association to GGOs. Photomicrograph reveals hyaline membranes as remnants of acute exudative (arrowhead) and intra-alveolar fibroblastic proliferations as signs of proliferative diffuse alveolar damage (DAD) (arrows) . Furthermore, capillaries show extensive congestion (*). (H&E stain, magnification N/A.) (c) Radiologic-pathologic correlation in patient 3, a 73-year-old man. Gross findings show interstitial edema, congestion, and chronic pulmonary embolism in the left upper lobe that was not disclosed by imaging due to unenhanced acquisition (insert). CT scan discloses extensive GGO in transition to consolidation in the left lower lobe (arrow) as well as lingula. Photomicrograph reveals hyaline membranes as a correlate of acute exudative DAD predominantly in the left lower lobe (arrow). (H&E stain, magnification N/A.)