An inflammatory condition with different faces: Immunoglobulin G4-Related disease

Background: Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition with involvement of different organs. The pathophysiological mechanism is unclear, but fibrosis is the hallmark of this disease. Early recognition is critical to avoid irreversible organ damage. Recently improved histological testing boosts the diagnostic yield. We present three cases of patients with IgG4-RD to emphasise the broad clinical presentation of this disease.
Case descriptions: Patient A, a 63-year-old male with bilateral orbital swelling due to IgG4-RD, was shown to suffer from IgG4-RD in a multifocal pattern as demonstrated by PET scanning. Patient B, a 53-year-old male with a long-standing abdominal mass of unknown origin, eventually proved to have IgG4-RD. Patient C was a 32-year-old male admitted with pleural effusion and pericardial tamponade. Histological diagnosis after pericardiectomy confirmed IgG4-RD.
Discussion: IgG4-RD has many faces and may mimic other conditions, such as malignancy and infectious diseases. Knowledge of this disease is needed to avoid unnecessary diagnostics and delay in treatment. IgG4-RD may be suspected based on specific clinical findings such as elevated serum IgG4 levels, but the diagnosis can only be established histologically. Although corticosteroids are an effective first choice of therapy, the relapse rate after this treatment remains high. The role of disease-modifying antirheumatic drugs in the treatment of IgG4-RD has not been outlined yet, but there is increasing evidence that rituximab might be an effective second-line therapy.
Conclusion: IgG4-RD is a disease with many faces requiring early recognition and therapy to avoid permanent damage of the organs.