Figure 1.

Acute tubular injury in kidney biopsies of patients with COVID-19. (A) Acute tubular injury with retraction of glomerular capillaries, tubular lumen with proteinaceous cylinders, and regenerative changes in the tubular epithelium and syncitial cells (periodic acid–Schiff, ×10). (B and C) Tubular lumen with pigmented casts and loss of brush borders (hematoxylin and eosin, ×40 and Masson trichrome, ×40). (D) Tubular isometric vacuolization with debris in tubular lumen (Masson trichrome, ×40).