Diagnose This! (August 7, 2017)

What is your diagnosis?

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The images show a proliferative glomerulonephritis with numerous polymorphonuclear cells infiltrating the glomerular tuft and extensive C3 deposits by immunofluorescence. These findings are most suggestive of an infection-associated glomerulonephritis. Infection-associated glomerulonephritis encapsulates several subcategories with described morphologies such as postinfectious glomerulonephritis, endocarditis-associated glomerulonephritis, and IgA dominant infection-associated glomerulonephritis as well as others. The images shown are most suggestive of a postinfectious glomerulonephritis, especially should additional IgG staining and subepithelial hump formation is identified.