Light microscopy showing the evolution of crescentic glomerulonephritis

Light microscopy of crescentic glomerulonephritis showing different stages of crescent formation in the same patients (silver stain).
(A) Early stage showing necrosis of the capillary wall before development of extracapillary proliferation.
(B) Large necrotic area with onset of crescent formation involving proliferation of parietal epithelial cells.
(C) Circumferential cellular crescent.
(D) Late stage showing a large area of disruption of the Bowman's capsule.