PMC10372288_01
Pathological findings from biopsied skin tissue. Neutrophilic inflammation with fibrinoid necrosis and fragmented neutrophilic nuclei (A: x40; B: x100).
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Pathological findings from a skin biopsy revealed neutrophilic inflammation, with fibrinoid necrosis and fragmented neutrophilic nuclei, which are typical features of leukocytoclastic vasculitis (Fig. 1).
Histopathological findings from biopsied renal tissue. Histopathological findings revealed proliferation of mesangial cells, the mesangial matrix, endocapillary cells, and lobulated glomeruli, as well as duplication of the glomerular basement membrane (A, B:  x400). Immunofluorescence revealed immune deposits of IgG in the capillary walls and mesangial cells (C, x400), positivity for complement C3 (D, x400) and negativity for IgM (E, x400). Immunofluorescence on formalin-fixed paraffin-embedded tissue after a protease digestion analysis revealed positivity for IgM in the capillary wall and in mesangial cells (F, x200). Histopathological findings revealed lymphoepithelial lesions infiltrated by small-to-medium-sized atypical lymphoid cells (G, x40). The lymphoma cells were positive for CD20 (H, x40).
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Destruction of the Bowman's capsule by atypical lymphocytes was observed, as was proliferation of mesangial cells, the mesangial matrix, and endocapillary cells, accompanied by lobulated glomeruli and a double-contour appearance of the glomerular basement membrane (Fig. 2A, B). Immunofluorescence analyses revealed deposition of IgG in the capillary wall and in mesangial cells (Fig. 2C), as well as positivity for complement C3 (Fig. 2D). IgM due to the poor condition of the samples (Fig. 2E, sclerosed glomeruli were observed). Immunofluorescence on formalin-fixed paraffin embedded tissue after a  digestion analysis revealed positive findings for IgM in the capillary wall and mesangial cells (Fig. 2F). Histopathological findings from biopsy tissue also revealed infiltration of lymphoepithelial lesions by small-to-medium-sized atypical lymphoid cells (Fig. 2G). The lymphoma cells were positive for CD20 (Fig. 2H) and CD79a but negative for CD3.
Histopathological findings from biopsied gastric tissue. Histopathological analyses revealed lymphoepithelial lesions infiltrated by small-to-medium-sized atypical lymphoid cells (A, x40; B, x100). The lymphoma cells were positive for CD20 (C, x100) and IgM (D, x40). A, B: Hematoxylin and Eosin staining.
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Histopathological findings of the biopsied gastric mucosa revealed MALT lymphoma expressing IgM (Fig. 3); the patient was negative for anti-HP IgG antibodies in serum.
Clinical course. U-protein: urine-protein
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After treatment, serum IgM, serum-free kappa light chain (14.4 mg/L), and urinary protein levels decreased concurrent with amelioration of the systemic edema and skin eruptions (Fig. 4).