Diagnose This (January 24, 2022)

In a patient with RPGN and this morphological finding on biopsy, what is the most likely diagnosis?

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The biopsy shows necrotizing arteritis and a glomerulus with segmental fibrinoid necrosis and crescent formation. This combination of findings is typically seen in ANCA-associated vasculitis. Anti-GBM disease is another cause of RPGN with crescentic glomerulonephritis; however, necrotizing arteritis is not present, unless there are concomitant ANCAs. To learn more about this, visit https://www.arkanalabs.com/anca-associated-vasculitis-aav/.