PMC6787412_01
Computed tomography kidney findings at onset. Diffuse enlargement of the kidneys was observed. The longest diameter of the kidneys was > 12 cm.
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Whole-body CT and magnetic resonance imaging showed no pleural effusion, ascites, lymph node swelling, or enlargement of organs, except for diffuse enlargement of the kidneys (Fig. 1).
Renal biopsy findings. a Normal glomeruli and storiform fibrosis, which is specific to IgG4-related kidney disease, were observed in the interstitium on light microscopy (Azan staining, x100). b Diffuse infiltration of abundant mononuclear cells and plasma cells (marked by arrows) was observed in the interstitium (hematoxylin and eosin staining, x200). c, d The immunohistochemical findings of IgG4 (c) and IgG (d) are shown. IgG4-positive plasma cells were markedly observed in the interstitium (> 10 IgG4-positive plasma cells/high-power field), and the ratio between IgG4-positive and IgG-positive plasma cells (marked by arrows) was > 90'. e Slight linear deposition of C3 was observed in the tubules on immunofluorescence microscopy.
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Slight linear deposition of C3 was observed in the tubules on immunofluorescence microscopy, and no electron-dense deposits were observed (Fig. 2a, b). Immunohistochemically, IgG4-positive plasma cells were markedly observed in the interstitium (> 10 IgG4-positive plasma cells/high-power field), and the ratio of IgG4-positive plasma cells to IgG-positive plasma cells was > 90' (Fig. 2c, d).