Extracapillary Proliferation Superimposed on Primary Membranous Glomerulonephritis: A Case Report

We report the case of a 34-year-old patient with no significant medical history who was followed for primary membranous glomerulonephritis confirmed by renal biopsy, initially revealed by nephrotic syndrome and preserved renal function. After nine months of conservative treatment, the patient presented with progressive deterioration of renal function and increased proteinuria, leading to the initiation of immunosuppressive therapy. Persistent renal deterioration prompted a second biopsy, which revealed extracapillary proliferation in addition to membranous nephropathy. The clinical course was rapidly unfavorable, with oligoanuria, fluid overload, and respiratory distress requiring urgent hemodialysis. Despite optimal care and several dialysis sessions, no renal recovery was observed, and the patient progressed to end-stage renal failure. This case illustrates the rare occurrence and severity of crescentic transformation in primary membranous glomerulonephritis, highlighting the importance of close monitoring and rapid reassessment in the event of rapid disease progression.