Fibrillary Glomerulonephritis and Multiple Myeloma: A Case Report and Literature Review

Abstract

Introduction: Fibrillary glomerulonephritis (FGN) is a rare form of immune complex-mediated primary glomerular disease frequently coexisting with malignancies or autoimmune diseases. The kidney prognosis is extremely poor, with approximately 50% of patients progressing to end-stage kidney disease within 2-4 years after diagnosis. However, no established treatment currently exists.

Case presentation: Here we describe a rare case of FGN diagnosed in a patient progressing from monoclonal gammopathy to multiple myeloma. The histopathological findings of the kidney biopsy were consistent with classical FGN and revealed no evidence of myeloma cast nephropathy. Albumin-dominant, Bence Jones protein-negative proteinuria further supported this diagnosis. The patient was successfully treated with anti-myeloma chemotherapies including autologous stem cell transplant, resulting in significant improvement in kidney function.

Conclusion: Based on our experience, secondary FGN associated with plasma cell neoplasms may represent a rare entity that responds favorably to anti-myeloma therapies. Initial investigations to rule out coexistent plasma cell neoplasms are crucial for the optimal management of FGN patients.

Keywords: Fibrillary glomerulonephritis; Kidney biopsy; Monoclonal gammopathy of undetermined significance; Multiple myeloma; Plasma cell neoplasms.

Fig. 1.

Clinical course of the present case of fibrillary glomerulonephritis (FGN) associated with multiple myeloma (MM), demonstrating significant improvement in kidney function, hematuria, and proteinuria after anti-myeloma therapy. Following intensive anti-myeloma chemotherapy, the patient achieved an immunophenotypic complete response for MM and partial response for FGN. Mel, melphalan; ASCT, autologous stem cell transplantation.

Fig. 2.

Urine protein electrophoresis at the time of fibrillary glomerulonephritis (FGN) diagnosis. Urine total protein was 1,358 mg/g Cre, and the proportion of albumin (1), α1-globulin (2), α2-globulin (3), β-globulin (4), and γ-globulin (5) were 78.1%, 2.4%, 3.5%, 6.2%, and 9.8%, respectively, without evidence of M peak formation.

Fig. 3.

Kidney biopsy findings at the time of fibrillary glomerulonephritis (FGN) diagnosis. a Glomeruli exhibit mesangial cell proliferation and increased mesangial matrix (periodic acid-Schiff [PAS]; original magnification, ×400). b Glomeruli exhibit double-contoured glomerular capillary walls (periodic acid-silver methenamine [PAM]; original magnification, ×400). c Direct fast scarlet 4BS (DFS) staining is negative in glomeruli (original magnification, ×400). d IF staining for IgG is positive in the mesangium (original magnification, ×400). e On electron microscopy, deposits are seen in the mesangium and the subendothelial zone of the glomerular capillary walls (scale bar indicates 2.0 μm). f, g On higher magnification, the deposits are composed of fibrils that are 15–20 nm in diameter, randomly arranged, straight, non-branching, and lacked hollow centers (scale bar indicates 500.0 nm in f; 200.0 nm in g).