(6 HE, 4 PAS, 4 MST)
Microscopic Summary: One core of renal tissue consisting entirely of cortex contains seventeen glomeruli of which two are globally sclerotic. There is a focal segmental and global, proliferative, necrotizing and sclerosing glomerulonephritis, with crescent formation involving five (30%) of the nonsclerotic glomeruli. One glomerulus with an early global crescent shows multiple capillary basement membrane breaks with extravasation of red blood cells and fibrin into Bowman's space and a break in Bowman's capsule. Another glomerulus contains a segmental necrotizing lesion with an associated partial cellular crescent. A third glomerulus with extensive necrosis and hemorrhage is associated with a global cellular crescent, shown both on H&E and methenamine silver-trichrome (MST) stains. The tubules are remarkable for focal acute tubular epithelial injury and many of the tubules contain red blood cells casts. The interlobular sized arteries present in the specimen show a necrotizing and granulomatous vasculitis.
Direct immunofluorescence using a panel of ten anti-sera (IgG, IgM, IgA, C3, C1q, C4, albumin, fibrinogen, kappa and lambda)
is performed on a portion of renal tissue containing two non-sclerotic glomeruli and one sclerotic
glomerulus, two arteries and one arteriole. Minimal immunoglobulin and complement (pauci-immune) staining is seen. A separate non-sclerotic glomerulus contains a fibrin crescent.
|Connective tissue||1+||1+ (focal)||0||0||0||0||2+||0||1+||1+|
Two glomeruli are examined ultrastructurally. One glomerulus contains a portion of a crescent with fibrin and partially degenerated, swollen epithelial cells in the urinary space. No electron dense deposits are seen. One of the capillary loops contains a fibrin thrombus. The surrounding basement membrane has a transmural break, and the overlying epithelial cell is herniating into the capillary lumen.