A: thick hyaline membranes (arrow), H&E stain, original magnification 400x; B: hemorrhagic areas (arrows), H&E stain, original magnification 20x; C: type II pneumocyte hyperplasia and syncytial cells (white arrows), and casts of desquamated respiratory epithelium (black arrow) in the alveoli, H&E stain, original magnification 400x; D: viral cytopathic effect with multinucleated cells (white arrow) and giant mononucleated cells (black arrows), H&E stain, original magnification 400x; E: perivascular multinucleated cells (arrow), H&E stain, original magnification 400x; F: endotheliitis - reactive endothelial cells (white arrows) and areas of endothelial desquamation (black arrow), H&E stain, original magnification 400x; G: focal fibroblast proliferation and alveolar space obliteration - organizing pneumonia (arrow), H&E stain, original magnification 100x; H: degenerative and necrotic changes in peripheral arterioles (arrows), H&E stain, original magnification 400.
H&E: hematoxylin and eosin.