case_images: PMC10723809_01
case_images: Renal biopsy findings. a PAS staining demonstrated diffuse endocapillary hypercellularity, that was mainly constituted by histiocytes/macrophages CD68-KP1 positive; original magnification x400. b Immunofluorescence on fresh tissue showed irregular, strong positivity for IgG in the cytoplasm of intracapillary glomerular histiocytes and along basement membranes; original magnification x200. c Direct immunofluorescence on fresh material; original magnification x400. d Immunohistochemistry performed on fixed paraffin-embedded material revealed strong glomerular positivity only for kappa light chains; original magnification x200. e-h Electron microscopy demonstrated several structured electron-dense deposits with the atypical organization: some microtubular deposits with electron-lucent lumen organized in parallel arrays, some triangular or square deposits in cross-sections, others atypical structures in vortex. Original magnification x1,900 (e), original magnification x27,500 (f-h). i The proximal tubules did not show electron-dense deposits (original magnification x3,810).
case_images: cnd-2023-0013-0001-533913_F01.jpg
case_images: PMC10723809_01_cnd-2023-0013-0001-533913_F01.jpg
case_images: F1
case_images: Glomerular capillary lumina were occluded by several histiocytes/macrophages (CD68-KP1 positive) (Fig. 1a, b) with cytoplasm filled with amorphous material with the reactivity of immune deposits on special stainings (PTAH, AFOG, trichrome). Glomeruli demonstrated on immunofluorescence a moderate positivity for kappa chains (2+) (Fig. 1c, d) and weak staining for lambda (1+). Deposits showed various structuration: microtubules with a diameter of 50-52 nm, focally organized in parallel arrays, but on cross-sections with an unusual triangular or square shape, and other types of deposits with an atypically concentric "vortex" arrangement (Fig. 1e-h).
case_images: Changes in renal function. a Changes of serum creatinine from baseline to posttreatment. b Changes of proteinuria from baseline to posttreatment. Chemotherapy with thalidomide, dexamethasone, and bortezomib was started in July 2021 and ASCT in December 2021. ASCT, autologous stem cell transplantation.
case_images: cnd-2023-0013-0001-533913_F02.jpg
case_images: PMC10723809_01_cnd-2023-0013-0001-533913_F02.jpg
case_images: F2
case_images: Last laboratory tests (March 2022) (Fig. 2a, b) confirm stable renal function, with normal proteinuria (0.11 g/24 h), undetectable BJP, and decreasing serum monoclonal protein (=0.6%) and FLC ratio (=1.3).