Figure 1: Renal biopsy specimen showing focal necrotizing glomerulonephritis in a patient with antineutrophil cytoplasmic antibody (ANCA)-associated microscopic polyangiitis. Kain et al.

It is often perinuclear staining pattern (p)-ANCA positive. Yearly incidence is between one and three per million, with peak incidence in the fourth decade of life and there is a roughly equal sex ...