Immunoglobulin G4-related Systemic Disease: Pictorial Review of the Pancreatic and Extrapancreatic Manifestations

Immunoglobulin G4-related systemic disease (IgG4-RSD) is a newly recognised and emergent condition, which was initially thought to manifest only as autoimmune pancreatitis. As the knowledge about this disease grows, it is now known that it also manifests in various extrapancreatic organs. Some of the appearances can mimic neoplasms leading to unnecessary surgery and anxiety. This pictorial review presents the characteristic radiological features of IgG4-RSD in various organs with different imaging modalities. We hope to raise awareness of this new disease entity and assist the differentiation of lesions due to IgG4-RSD from other pathologies.