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Abstract: TH-PO676

ANCA Glomerulonephritis: Uncommon Presentation as Renal Masses

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Al-Sawajneh, Suhaib F M, The University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Monk, Brian, The University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Hassanein, Mohamed, The University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Syed, Bushra, The University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Dossabhoy, Neville R., The University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Obi, Yoshitsugu, The University of Mississippi Medical Center, Jackson, Mississippi, United States
Introduction

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) can manifest with diverse systemic symptoms and commonly affects the kidneys, causing necrotizing glomerulonephritis (GN). Here, we report a rare case of AAV presenting as renal cortical masses.

Case Description

A 70-year-old male presented with fatigue, loss of appetite, and a 50-lb weight loss over six months. Initial laboratory workup was unremarkable including normal serum creatinine and urinalysis. CT scan showed non-specific bilateral pulmonary nodules and a `rind’ of abnormal soft tissue surrounding the abdominal aorta. Three months later, follow-up CT scan revealed worsening peri-aortic soft tissue thickening (max 3 cm) and the development of bilateral renal cortical masses (largest measuring 2.5 cm). Further workup showed positive p-ANCA with elevated MPO levels (>8.0 U; ref. <0.4 U), CRP (72 mg/dL; ref. <0.5 mg/dL), and mildly elevated IgG4 (137 mg/dL, ref. 2.4–121 mg/dL). Two kidney biopsies were obtained. The standard core biopsy showed plasma cell-rich infiltrates without IgG4 positivity, while the fine needle aspiration (FNA) to a renal mass showed focal necrotizing and crescentic GN with granulomatous vasculitis. Induction therapy with high-dose steroids and rituximab was initiated. Steroid dosage was tapered over a year, and maintenance rituximab doses were adjusted based on CD19+/CD20+ cell counts and MPO-ANCA titers. The patient has remained in clinical remission, without hematuria, proteinuria, or elevated serum creatinine over 4 years.

Discussion

AAV can form inflammatory masses in various organs, including kidneys, pancreas, orbit, and peri-aortic soft tissue, akin to IgG4-related disease. In a recent case series, patients with ANCA-associated renal masses often had elevated serum IgG4 levels or increased tissue IgG4+ plasma cells. Few cases had normal urinalysis and serum creatinine despite biopsy findings of crescentic GN, as in our case. Our case is particularly unique: (1) repeated CT scans confirmed rapid development and progression of renal masses and peri-aortic soft tissue thickening; and (2) crescentic GN was detected in FNA of the renal mass but not in the core biopsy. In patients with suspected AAV and renal masses, kidney biopsy is essential to establish the diagnosis and rule out cancer and infection before starting immunosuppression.