Galactose-Deficient IgA1 Deposits in Clear Cell Renal Cell Carcinoma-Related Henoch–Schönlein Purpura Nephritis

Figure 4

Findings of the second and third kidney biopsies, at three weeks (a, b) and five months (c–f) after surgical resection of clear cell renal cell carcinoma, respectively. Sequential biopsies demonstrate progression and transition from active lesions (a, b) to sclerosing lesions (e, f), and dramatic clearance of glomerular IgA deposits following tumor resection (c, d). (a) A representative glomerulus shows endocapillary hypercellularity and a nearly circumferential cellular crescent with necrosis. (b) Segmental large subendothelial deposits (right half of the glomerulus) are visible by light microscopy. (c) Immunofluorescence staining of IgA shows only modest glomerular mesangial and capillary wall IgA deposition. (d) Electron microscopy shows a small number of electron dense deposits mainly in mesangium. (e) Nonsclerosed glomeruli show only mild mesangial hypercellularity without endocapillary hypercellularity. (f) Representative glomeruli with fibrous crescents, one globally sclerotic (the lower glomerulus) and the other segmentally scarred (the upper glomerulus). The third biopsy shows significant chronic changes with approximately 35% global glomerulosclerosis and additional 35% glomeruli with fibrous crescents and segmental sclerosis. There is severe tubulointerstitial scarring. Original magnification: 400X in (a–c) and (e), 8000X in (d), and 200X in (f).

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