The answer to the image quiz of Feb 17: "crescentic glomerulonephritis". Slide 1 is a low power light micrograph, PAS stain, which shows the diffuse nature of the condition (most glomeruli are involved with some degree of "extracapillary proliferation“ (crescent formation) outside the tuft but inside Bowman's capsule. Slide 2 is a higher power light micrograph, again with PAS staining, that shows details of the cellular composition of the crescent. Notice mostly mononuclear cells (monocytes, epithelioid cells, proliferated parietal epithelial cells from Bowman's capsule, some polymorphonuclear neutrophils) in the crescent and the collapsed, fragmented capillary tuft, as highlighted by the PAS positive basement membranes (center and right). Slide 3 shows fibrin staining by immunofluorescence. The slide illustrates the distribution of fibrin within the crescent. This finding is constant, regardless of the mechanism of crescent formation.
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Slide 1 (click over image to enlarge)
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Slide 2
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Slide 3
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