The Clinicopathologic Spectrum of IgG4-Related Disease

Abstract

Immunoglobulin G4-related disease is a fibroinflammatory systemicdisease that is characterized by focal or diffuse organ infiltration byimmunoglobulin G4-bearing plasma cells. Immunoglobulin G4-relateddisease may affect any organ, and a high index of suspicion is necessaryfor early detection to avoid irreversible fibrosis, organ dysfunction,and death. Tumor-forming lesions are common radiological featuresof immunoglobulin G4-related disease that need to be differentiatedfrom malignancies. The diagnostic approach requires the integrationof clinical, biochemical, and radiographic manifestations withclassic histopathologic features, which remain crucial to diagnosis.The histology of immunoglobulin G4-related disease is determinedby a dense lymphoplasmacytic infiltrate, storiform fibrosis, andobliterative phlebitis in the presence of increased immunoglobulinG4-positve plasma cells. Although immunoglobulin G4-relateddisease forms a distinct, clinically independent disease category,many questions and problems remain unanswered, especially on itspathogenesis and the role of immunoglobulin G4. Advances in theunderstanding of immunoglobulin G4-related disease are likely tochange the diagnostic approach in the future and create potentialtargets for therapeutic purposes. Here we describe the concept ofimmunoglobulin G4-related disease and the most recent knowledge inthe clinico-pathological characteristics on this emerging disease. Thisstudy can guide clinicians in early diagnosis and prevent unnecessarysurgical resections.