Kidney Week

Abstract: SA-PO0722

Fibrillary Glomerulonephritis in a Patient with Appendiceal Carcinoma

Session Information

• Glomerular Diseases: Complement-Mediated Glomerulopathies and Infection-Related GN
  October 24, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Khiraoui, Noora, University of Miami Health System, Miami, Florida, United States

Noora Khiraoui, DO

• Saroop, Satesh, University of Miami Health System, Miami, Florida, United States

Satesh Saroop, DO

• Alexander, Brooke, University of Miami Health System, Miami, Florida, United States

Brooke Alexander, DO

• Kima, Elias Deffang, University of Miami Health System, Miami, Florida, United States

Elias Deffang Kima, MD, MPH

• Contreras, Gabriel, University of Miami Health System, Miami, Florida, United States

Gabriel Contreras, MD, MPH

• Munoz Mendoza, Jair, University of Miami Health System, Miami, Florida, United States

Jair Munoz Mendoza, MD, FASN

• Mechery, Vinodh, University of Miami Health System, Miami, Florida, United States

Vinodh Mechery, MD

Introduction

Fibrillary glomerulonephritis (FGN) is a rare glomerular disease with a prevalence of less than 1% on renal biopsies. It is characterized by a proliferative GN on light microscopy with electron microscopy showing the deposition of non-congophilic, randomly arranged 10-30nm straight fibrils that stain for polyclonal IgG, complement and DNAJB9. Currently, the prognosis is poor with limited data for therapeutic options. In this case, we describe a possible paraneoplastic association of Fibrillary GN with metastatic appendiceal adenocarcinoma that improved with chemotherapy and rituximab.

Case Description

A 50-year-old female with history of discoid lupus and stage 4 appendiceal adenocarcinoma on her fourth cycle of FOLFOX plus bevacizumab presented with uncontrolled hypertension, a rapidly progressing AKI (Cr 7.42 mg/dL from baseline 0.9 mg/dL) with UPCR 1.12 g/g, and an active urine sediment. She did not respond to fluid resuscitation, prompting a renal biopsy with empiric high-dose steroids for three days. Biopsy IF revealed mesangial IgG, C3, kappa and lambda staining; EM showed randomly arranged fibrils (18.5–25 nm) with DNAJB9 positivity on immunohistochemistry, consistent with fibrillary glomerulonephritis. Renal function improved on discharge on a steroid taper with outpatient creatinine stabilizing at 1.3–1.5 mg/dL. She received two doses of rituximab with reduction in proteinuria (UPCR 272 mg/g; UACR 95.2 mg/g). At 7 months, her Fibrillay GN remained in remission with a creatinine of 1.15 mg/dL and UACR < 1.2 mg/g.

Discussion

Diagnosing FGN as paraneoplastic requires temporal association with malignancy, polyclonal immune complex deposition driven by tumor antigens, exclusion of other etiologies, and demonstration of renal improvement following cancer-directed therapy. Most reported associations between FGN and malignancy are considered coincidental, with only rare cases demonstrating improvement in kidney function following treatment of the underlying cancer. Data regarding rituximab use has only demonstrated stabilization of creatinine with minimal improvement in proteinuria. Since the etiology of FGN remains largely unknown, this case highlights its role as a possible paraneoplastic glomerulopathy.