PMC8531272_01
Light, immunofluorescence, electron, and immune-electron microscopy findings in Case 1. (A) Immunofluorescence studies revealed bright lambda staining in the segmental mesangial area and along capillary walls (x400). (B) Light microscopy showed a mesangial proliferative pattern of injury (periodic acid-silver methenamine + Masson trichrome staining, x400). (C) Electron microscopy revealed electron-dense deposits in segmental mesangial and subendothelial regions (x800). (D) Immunoelectron microscopy demonstrated lambda deposition in the mesangial area and segmental subendothelial regions (x8,000).
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F1
Electron microscopy revealed electron-dense deposits in the subendothelial area and along segmental GBM, which were prominent lambda under immunoelectron microscopy (Figures 1A-D).
Light, immunofluorescence, electron, and immunoelectron microscopy findings in Case 2. (A) Immunofluorescence staining revealed bright kappa deposition in the mesangial area and along capillary walls (x400). (B) Light microscopy revealed a membranoproliferative pattern of injury (periodic acid-silver methenamine + Masson trichrome staining, x400). (C) Electron microscopy demonstrated electron-dense deposits in subendothelial and mesangial regions (x8,000). (D) Immunoelectron microscopy showed kappa deposition in the mesangial area and inner GBM (x8,000).
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F2
After consulting the hematology physician, his treatment was changed to lenalidomide (25 mg daily, days 1 through 21 of each 28-day cycle) and dexamethasone (20 mg once weekly) (Rd therapy). After eight cycles of Rd therapy, his hematological response achieved partial remission (kappa/lambda ratio 0.28, kappa 35.4 mg/L, lambda 125 mg/L), his nephrotic syndrome achieved partial remission (UTP 2.7 g/d, Alb 35.1 g/L), and impaired renal function was restored (eGFR 77.541 ml/min/1.7 m2) (Figure 2).
PMC8531272_02
Clinical course of Case 1. After treatment with lenalidomide, the renal impairment and proteinuria caused by LCDD was improved. BCD: bortezomib (2 mg, once weekly), cyclophosphamide (200 mg, once weekly), and dexamethasone (20 mg, once weekly); Rd: lenalidomide (25 mg daily, on Days 1 through 21 of each 28-day cycle) and dexamethasone (20 mg once weekly).
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F3
GBM, mesangial area, and endolysosome of renal tubular epithelial cells, which were prominent kappa under immunoelectron microscopy (Figures 3A-D). Given his outstanding anemia, the diagnosis of multiple myeloma was suspected but unproven.
Clinical course of Case 2. After treatment with lenalidomide, the renal impairment and proteinuria caused by LCDD was aggravting. BCD: bortezomib (2 mg, once weekly), cyclophosphamide (200 mg, once weekly), and dexamethasone (20 mg, once weekly); Rd: lenalidomide (25 mg daily, on Days 1 through 21 of each 28-day cycle) and dexamethasone (20 mg once weekly).
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F4
After four courses of Rd therapy, his free light chain ratio showed improvement (kappa 1185 mg/L, lambda 42.4 mg/L, kappa/lambda ratio 27.9), but his nephrotic syndrome and anemia both aggregated (UTP 9.07 g/d, Alb 23.1 g/L, and Hgb 49 g/L) with relatively preserved renal function (eGFR 59.911 ml/min/1.73 m2) (Figure 4).