The Convergence of Vasculopathy and Vasculitis: Computer Mapping Analysis of 2 Renal Biopsies in a Patient with both Systemic Sclerosis and ANCA-Related Vasculitis

Abstract

Scleroderma vasculopathy and ANCA (antineutrophil cytoplasmic antibodies)-associated glomerulonephritis have rarely been reported to occur simultaneously in one patient. Herein, we report a patient who presented with a classic constellation of clinical and laboratory findings of systemic scleroderma and was subsequently found to be positive for p-ANCA. Two renal biopsies, performed 5 months apart, demonstrated typical changes of the two entities in both acute and "healed" phases, which were analyzed by computer mapping techniques. The two renal biopsies were serially sectioned and stained routinely, and with CD31 and CD34 as endothelial markers. The slides were digitized, aligned and analyzed. Each glomerular tuft was sequentially studied in terms of total area (µm²) and each biopsy was individually profiled. All arterial vessels were sequentially studied with whole vessel and luminal areas delineated and ratios calculated. The initial biopsy contained 32 glomeruli almost all with extensive fibrinoid necrosis and destruction of the capillary network. The arterial vessels (interlobular and arcuate) showed intimal edema with luminal occlusion. CD31/CD34 stains showed variable endothelial intactness but demonstrated the luminal size shifts. The second biopsy had 37 glomeruli that were either segmentally or globally sclerotic with no active changes. The vessels were now normally patent. Each glomerular tuft and arterial vessel in both biopsies was analyzed as a serial section histogram documenting these changes. These studies depict the rare occurrence of two entities together, the scleroderma kidney vasculopathy and the glomerulonephritis of ANCA-associated vasculitis syndrome both in an acute and healing phase, profiled by computer mapping techniques.

Keywords: Antineutrophil cytoplasmic antibodies-related vasculitis; Computer mapping; Renal biopsy; Systemic sclerosis; Vasculitis; Vasculopathy.

Fig. 1

Glomerular and vascular changes in biopsy (H&E). a The extensive glomerular destruction and fibrin deposition are well seen in the Masson trichrome preparation. Endothelial marker (CD34) stains (b) delineate the disruption of the glomerular capillary network with endothelial loss/fragmentation. The arterial intima edema is well seen (H&E, c; Masson trichrome, d), and the CD34 stain (e) demarcates the narrowed arterial lumen and shows fragmented endothelium.

Fig. 2

Top: composite of sequential glomerular area histograms from each biopsy (each horizontal line on the vertical axis = 20,000 μm²). In biopsy 1, profiles are seen which demonstrate the very large glomerular tufts present and the incomplete histograms because of size constraints. On the other hand, histograms in biopsy 2 illustrate smaller glomeruli with more complete histograms. Bottom: bar graph representing maximal size from glomerular histograms. Biopsy 1 (upper) shows the overall marked enlargement of the glomeruli; smaller values in biopsy 1 were related to a single glomerular tuft, which was normal, and incomplete representation of these large glomeruli. The highest values in biopsy 2 (lower) are likely related to hypertrophic changes, the smallest global sclerosis.

Fig. 3

Top: individual histograms are seen with segmented and profiled glomeruli (PAS, CD31) and vessels (H&E); bars indicate source of the image from profile (biopsy 1, left; biopsy 2, right). Bottom: the segmentation of arterial vessels presented problems (few numbers and orientation). In biopsy 1 (left), a single vessel retained its cross-sectional profile in multiple levels, showing a dramatically diminished lumen. In biopsy 2 (right), a vessel is shown with numerous profiles shifting from a full cross-section to an oblique conformation.