Kidney Week

Abstract: TH-PO1157

Tubulointerstitial Nephritis Associated with IgG4-Related Disease

Session Information

• Onconephrology: Emerging Biomarkers, Preclinical Models, Clinical Challenges, and Therapeutic Strategies
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Onconephrology

• 1600 Onconephrology

Authors

• Roberto, Lucas Enock Vieira, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Lucas Enock Vieira Roberto, MD

• Bianchini, Daniel Riva, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Daniel Riva Bianchini

• Ledesma, Felipe Lourenco, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Felipe Lourenco Ledesma

• Lutf, Luciana Gil, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Luciana Gil Lutf, MD

• Caires, Renato A., Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Renato A. Caires, MD

• Mattedi, Francisco Zanotelli, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Francisco Zanotelli Mattedi, MD

• Kassar, Liliana M L, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Liliana M L Kassar, MD

• Segura, Gabriela C., Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Gabriela C. Segura, MD

• Silva, Wellington, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Wellington Silva, MD, PhD

• Costa e Silva, Veronica Torres, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, São Paulo, SP, Brazil

Veronica Torres Costa e Silva, MD, PhD

Introduction

IgG4-Related Disease (IgG4-RD) is a systemic fibroinflammatory condition that mimics malignancy. This report describes the case of a patient with a history of Diffuse large B-cell lymphoma (DLBCL) and a late diagnosis of IgG4-RD with important kidney involvement.

Case Description

Male patient, 75 years old, diagnosed with DLBCL, achieving complete remission in 2009 after treatment with R-CHOP (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine). Between 2012 and 2024, he developed recurrent lymphadenopathies with increased uptake on PET-computed tomography (CT). Five lymph node biopsies demonstrated only reactive alterations. In January 2025, PET-CT showed diffuse uptake in the pancreas corresponding to a 2.8 cm solid pancreatic lesion, and a pancreatic biopsy demonstrated non-neoplastic tissue. In April 2025, the patient developed prostatic symptoms, an increase in serum creatinine (Scr) (2.1 mg/dL, from a baseline of 0.8 mg/dl), and left hydronephrosis with periaortic tissue on CT. Following transurethral resection and double-J stenting, Scr improved to 1.3 mg/dL, and prostatic pathology revealed chronic prostatitis with plasmacytosis. In December 2025, the patient developed proteinuria (1.25 g/day) and a recurrent increase in Scr (2.6 mg/dL). The kidney biopsy revealed chronic interstitial nephritis with 80% storiform fibrosis and numerous IgG4-positive plasma cells (IgG4:IgG ratio 2/3, >70 cells/HPF), supporting a diagnosis of IgG4-RD (Figure), further corroborated by highly elevated serum IgG (>12,056 mg/dL). Corticosteroid therapy (prednisone 40 mg/day) was initiated in February 2026, resulting in progressive improvement of Scr (1.3 mg/dL) after 2 weeks of therapy.

Discussion

Tubulointerstitial nephritis can be observed in up to 15% of IgG4-RD cases and should be included in the differential diagnosis in the context of mass-forming lesions and lymphadenopathies.