A 56-year-old male patient presents with 'edema for 2 months'. The renal biopsy pathology report shows: 35 glomeruli with diffuse thickening of the glomerular basement membrane, segmental spike formation, subepithelial fuchsinophilic deposits, focal atrophy of tubular epithelial cells, and interstitial infiltration by lymphocytes and monocytes. The pathological diagnosis is: