IgG4-related Disease from Head to Toe

Area of Science:

• Immunology
• Pathology
• Radiology

Background:

• Immunoglobulin G4 (IgG4)-related disease is a recently identified clinical-pathologic entity characterized by IgG4-positive plasma cell infiltration.
• Recognized as a systemic disease in 2003, it affects numerous organ systems, including the pancreas, biliary tree, salivary glands, lungs, and kidneys.
• The pathogenesis remains unclear, but it exhibits features of both autoimmune and allergic disorders.

Purpose of the Study:

• To highlight the importance of imaging in diagnosing IgG4-related disease.
• To emphasize the need for whole-body examinations to detect multi-organ involvement.
• To inform radiologists about the clinical and imaging manifestations to prevent diagnostic delays and unnecessary surgeries.

Main Methods:

• Histopathologic analysis is definitive for diagnosis.
• Imaging plays a critical role in identifying organ infiltration and enlargement.
• Whole-body imaging is recommended to assess systemic involvement.

Main Results:

• IgG4-related disease presents as fibro-inflammatory lesions with IgG4-positive plasma cells, often with elevated serum IgG4 levels.
• The disease can affect virtually any organ system, presenting as masses or diffuse enlargement mimicking neoplastic processes.
• A significant response to corticosteroid therapy is typical.

Conclusions:

• Radiologists must be familiar with IgG4-related disease manifestations to ensure accurate and timely diagnosis.
• Early diagnosis through comprehensive imaging can lead to prompt treatment with corticosteroids.
• Recognizing IgG4-related disease can prevent delays in diagnosis and avoid unnecessary surgical interventions.