[Rational diagnostics and differential diagnosis in IgG4-related disease].

Area of Science:

• Rheumatology
• Immunology
• Pathology

Background:

• Immunoglobulin G4 (IgG4)-related diseases (IgG4-RD) are systemic disorders characterized by fibrosing inflammation and IgG4-positive plasma cell infiltration.
• These conditions can affect virtually any organ system, presenting with diverse manifestations such as autoimmune pancreatitis, sclerosing cholangitis, lymphadenopathy, retroperitoneal fibrosis, and inflammatory orbitopathy.

Purpose of the Study:

• To highlight the heterogeneous nature of IgG4-related diseases.
• To emphasize the diagnostic challenges posed by IgG4-RD due to their mimicry of other conditions.
• To underscore the importance of a structured diagnostic approach for accurate identification and management.

Main Methods:

• Review of typical clinical manifestations and histopathological features of IgG4-RD.
• Emphasis on the diagnostic necessity of excluding malignant and other inflammatory conditions.
• Highlighting the integration of laboratory findings, histopathology, and radiological imaging.

Main Results:

• IgG4-RD present with a wide spectrum of clinical scenarios, often mimicking other diseases.
• Diagnosis is complex and requires a high index of suspicion and thorough exclusion of differential diagnoses.
• A multimodal diagnostic strategy is essential for accurate diagnosis.

Conclusions:

• Accurate diagnosis of IgG4-related diseases necessitates careful exclusion of mimics and a comprehensive multimodal approach.
• A structured diagnostic algorithm and interdisciplinary collaboration are critical for avoiding misdiagnosis and ensuring timely, appropriate treatment.