a Example images of lung sections showing the epithelial (top; hematoxylin and eosin stains), vascular (middle; left hematoxylin and eosin stain, right fibrin-Lendrum (MSB) stain), and fibrotic (bottom; left hematoxylin and eosin stain, right Verhoeff-van Gieson stain) pattern of lung injury in COVID-19. In the top panels, atypia and detachment of type II pneumocytes (closed arrowheads), hyaline membrane formation (closed arrow), an interstitial inflammatory response (open arrowhead), and denudation of bronchiolar epithelium (open arrow) are indicated. In the middle panels, intracapillary hyaline thrombi (arrows), acute fibrinous and organizing pneumonia (closed arrowheads), and edema (open arrowhead) are indicated. In the bottom panels, notable intra-alveolar fibroelastosis (closed arrowheads) with pre-existing alveolar septal elastin (arrows) are indicated, possibly representing fibrosing organizing pneumonia. Images were obtained from autopsies of COVID-19 patients performed at the Erasmus Medical Center. For low power images, see Supplementary Figures S1–S3. b Venn diagram summarizing the histological patterns of lung injury in 78 COVID-19 patients.