Oral and Lower Extremity Ulcers as the Initial Presentation of Granulomatosis with Polyangiitis

Figure 3

Light microscopy of a renal biopsy with multiple cores of renal tissue, of which approximately 40% is represented by cortex. Eighteen glomeruli are present, none of which are globally sclerotic. In up to four glomeruli, there are segmental cellular crescents, associated with fibrinoid necrosis and rupture of the capillary loops. Intact glomeruli do not show significant endocapillary hypercellularity. The tubulointerstitial compartment is marked by tubular injury, with tubular dilatation and epithelial simplification. There is mild and patchy inflammatory infiltrate, mixed. Multiple red blood cell casts are present throughout the biopsy. Occasional neutrophilic casts are also seen. There are mild interstitial fibrosis and tubular atrophy which comprise approximately 20% of the cortex. Arteries are marked by mild intimal fibrosis. Arterioles do not show significant hyalinosis. Toluidine blue-stained sections contain four intact glomeruli.