Work

A case of IgG4-related disease misdiagnosed as perirenal abscess: Case report and literature review

Year: 2025

Type: article

Abstract: RATIONALE: Immunoglobulin G4-related disease (IgG4-RD) is a chronic immune-mediated fibroinflammatory condition that can mimic infection or malignancy. Renal involvement may present as a perirenal mass suggestive of an abscess. This case highlights a diagnostic pitfall and a favorable response to therapy. PATIENT CONCERNS: A 48-year-old man had a persistent fever for over 20 days. Imaging revealed a left renal mass. Empirical antibiotics were initiated without improvement, and he was transferred for further evaluation. DIAGNOSES: Laboratory tests showed elevated inflammatory markers, including C-reactive protein and interleukin-6, positive proteinase 3 antineutrophil cytoplasmic antibody, and markedly increased serum immunoglobulin G4 (IgG4). Computed tomography and magnetic resonance imaging demonstrated renal and pulmonary abnormalities. Renal biopsy confirmed dense infiltration of IgG4-positive plasma cells. The final diagnosis was IgG4-RD involving the kidneys and lungs, initially misdiagnosed as a perirenal abscess. INTERVENTIONS: Systemic corticosteroid therapy was started. OUTCOMES: The patient experienced rapid resolution of fever and clinical improvement, with reductions in serum IgG4 and interleukin-6 levels. LESSONS: IgG4-RD should be considered in patients with unexplained fever and space-occupying renal lesions unresponsive to antibiotics. Timely recognition and immunosuppressive therapy can lead to favorable outcomes and help prevent irreversible organ damage.

Source: Medicine

DOI: 10.1097/md.0000000000045898