case_images: PMC11412746_01
case_images: PMC11412746_02
case_images: Case 1: pathology slides. (a) Immunofluorescence (IF) microscopy demonstrates C3 granular mesangial and subendothelial deposits of high intensity. (b) IF demonstrates IgG deposits with the same pattern as C3 deposits. (c) Light microscopy shows the PAS membranoproliferative pattern of injury. Nodular mesangial expansion, endocapillary proliferation, subendothelial deposits, and glomerular basement membrane double contour are noted. (d) IF fixation of kappa light chain was negative. (e) IF demonstrates lambda deposits with the same pattern as C3 deposits. (f) Light microscopy Masson's trichrome stain shows the membranoproliferative pattern of injury.
case_images: CRIN2024-5556426.002.jpg
case_images: PMC11412746_02_CRIN2024-5556426.002.jpg
case_images: fig2
case_images: A renal biopsy was done (Figure 2), confirming a diagnosis of monoclonal membranoproliferative glomerulonephritis.
case_images: PMC11412746_03
case_images: Case 2: pathology slides. (a) Light microscopy shows numerous PAS-positive hyaline pseudothrombi (arrows) as well as a fibrin thrombus (star) (PAS 400x). (b) PAS-positive hyaline pseudothrombi filling the glomerular capillary lumen (PAS 600x). (c) Fibrin thrombosis at the glomerular vascular pole (Jones 200x). (d) Immunofluorescence microscopy demonstrates intracapillary and mesangial staining for kappa light chain. Intracapillary fixation was also noted for IgM, C3, and C1q but not for the lambda light chain. (e) Immunofluorescence microscopy shows fixation of fibrinogen in the glomerular vascular pole, compatible with the thrombosis. (f) Electron microscopy shows unorganized immune-type deposits of intracapillary and subendothelial localisation. Intracapillary fibrin deposits were also noted.
case_images: CRIN2024-5556426.003.jpg
case_images: PMC11412746_03_CRIN2024-5556426.003.jpg
case_images: fig3
case_images: Renal biopsy demonstrated endocapillary proliferative glomerulonephritis associated with the presence of numerous monotypic IgM/kappa intracapillary pseudothrombi (Figure 3).
case_images: PMC11412746_04
case_images: PMC11412746_05
case_images: PMC11412746_06
case_images: PMC11412746_07