Granulomatous glomerulonephritis in Wegener's granulomatosis

Review of the kidneys in 24 autopsy cases of Wegener's granulomatosis revealed a significant granulomatous glomerular lesion in eight of the cases. To gain a better understanding of this peculiar lesion, focusing on its pathogenesis, we attempted a thorough investigation on both glomerular and vascular lesions of the kidneys. Semiquantitative analysis of the glomerular lesions indicated that existence of a severe glomerular damage probably constitutes a necessary condition in the development of granulomatous glomerulonephritis, because the granulomatous glomerular lesion was typically seen in company with a widely distributed glomerular lesion represented by thrombotic and necrotic occlusion of capillary tufts and crescent formation. Necrotizing vasculitis in the kidney was always encountered, especially in small branches of renal arteries and vasa recta. A serial section study of the two most typical cases indicated that granulomatous inflammation apparently originated in hilar arteriolitis , which extended along the pericapsular space and developed into diffusely circumferential periglomerular inflammation. We conclude that two factors are jointly at work, one inside and the other outside of the glomerulus in the pathogenesis of granulomatous glomerulonephritis: there is a thrombotic and necrotic lesion of the glomerular tuft, on the one hand and pericapsulitis originating in hilar arteriolitis on the other.