Manifest interstitial and vascular pathology in anti-neutrophil cytoplasmic antibody-associated renal disease

Rapidly progressive renal failure in anti-neutrophil cytoplasmic antibody (ANCA)- associated renal disease customarily implies crescentic glomerulonephritis with approximately 50% of the glomeruli will have crescents. The tubulointerstitial inflammation is often proportionate to the glomerular inflammation and may have granulomatous pattern adjacent to the glomeruli or an inflamed vessel. A 77-year-old male with rapidly progressive renal failure was myeloperoxidase-ANCA positive, and renal histopathology revealed thrombotic microangio-pathy, significant interstitial inflammation, interstitial granulomas, and arteritis. Pathology is unique for the paucity of the classical crescents and the myriad of extraglomerular features. His renal function improved and stabilized after induction with cyclophosphamide and maintenance with azathioprine.