PMC7463376_01
A punch biopsy of skin involved by a brisk acute small vessel neutrophilic vasculitis that extends from the papillary to midreticular dermis. There is prominent associated fibrinoid necrosis of vessel wall, leukocytoclasis, purpura, and epidermal degeneration. Original magnification: 4X in (a) and 40X in (b).
CRIN2020-8828336.001.jpg
PMC7463376_01_CRIN2020-8828336.001.jpg
fig1
Two days after admission, a skin biopsy of the lower shin was performed, showing leukocytoclastic vasculitis (Figure 1) with intravascular deposition of IgA and C3 (not shown), consistent with HSP.
Findings of initial kidney biopsy: (a) a representative glomerulus with global endocapillary proliferation on periodic acid-Schiff stain; (b) a glomerulus with segmental mesangial and endocapillary proliferation (right side) and intracapillary pseudothrombi (<); (c) immunofluorescence staining of IgA shows global granular mesangial and capillary wall staining and a few intracapillary pseudothrombi (<); (d) electron microscopy shows many electron dense mesangial and subendothelial deposits with severe foot process effacement. Original magnification: 400X in (a-c) and 5000X in (d).
CRIN2020-8828336.002.jpg
PMC7463376_01_CRIN2020-8828336.002.jpg
fig2
A kidney biopsy showed diffuse global endocapillary and focal segmental mesangial proliferative glomerulonephritis with IgA-dominant mesangial and capillary wall deposition, consistent with active HSPN (Figure 2).
Clear cell renal cell carcinoma, low grade of partial nephrectomy (a). In adjacent nonneoplastic kidney, several glomeruli show segmental to global endocapillary proliferation with segmental necrotizing lesion (*) in (b) and rare glomeruli show large glomerular deposits (<) in (c). Original magnification: 40X in (a) and 400X in (b) and (c).
CRIN2020-8828336.003.jpg
PMC7463376_01_CRIN2020-8828336.003.jpg
fig3
A few crescentic lesions were identified in the nonneoplastic kidney of the partial nephrectomy specimen (Figure 3).
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).
CRIN2020-8828336.004.jpg
PMC7463376_01_CRIN2020-8828336.004.jpg
fig4
The biopsy revealed diffuse cellular and fibrocellular crescents and minimal IgA deposition along glomerular capillary wall (Table 1; Figures 4(a) and 4(b)). The renal biopsy showed only chronic changes with fibrous crescents and negligible IgA deposition in nonsclerotic glomeruli (Figures 4(c)-4(f)).
Immunofluorescence staining of KM55 shows global, granular, mesangial, and capillary wall as well as intracapillary pseudothrombi staining on initial kidney biopsy (a) and diminished/minimal glomerular capillary wall staining on sequential kidney biopsies three weeks (b) and five months (c) after surgical resection of clear cell renal cell carcinoma. Original magnification: 400X in all.
CRIN2020-8828336.005.jpg
PMC7463376_01_CRIN2020-8828336.005.jpg
fig5
KM55 displayed similar staining pattern and intensity to IgA in all biopsies (Figure 5). Diffuse global granular capillary wall staining and segmental granular mesangial staining for Gd-IgA1, similar to IgA, were observed on the first biopsy, while dramatically decreased Gd-IgA1 and IgA staining along the capillary wall and in mesangium were seen on the follow-up kidney biopsies (Figure 5).