Early diffuse alveolar damage

Photomicrograph shows early diffuse alveolar damage with minimal alveolar septal thickening, hyperplasia of pneumocytes, and eosinophilic hyaline membranes (arrow).

High-power photomicrograph shows alveoli containing capillaries within a narrow interstitium. The alveoli are lined with thin, elongated type I pneumocytes (arrow) and smaller numbers of cuboidal type II pneumocytes (dashed arrow).