IgG4-related disease in gastroenterology: from pathogenesis to clinical management and long-term outcomes

IgG4-related disease is a rare, immune-mediated, multisystem fibroinflammatory condition. It is characterized by elevated serum IgG4 concentrations and tissue infiltration of IgG4-positive plasma cells with distinctive histopathological features, including storiform fibrosis and obliterative phlebitis. Gastroenterological involvement is diverse and represents a critical diagnostic consideration, encompassing the pancreas, bile ducts, liver, esophagus, stomach, and intestine. In this review, we summarize the current understanding of genetic susceptibility and environmental risk factors underlying this disease, and systematically describe the clinical presentations, histopathological characteristics, imaging findings, and serological profiles of each major gastroenterological manifestation. We further review evidence-based treatment regimens ranging from glucocorticoids and conventional immunosuppressants to emerging biologic therapies, discuss organ-specific therapeutic responses, and identify predictors of disease relapse along with long-term surveillance strategies. From a gastroenterologist's perspective, this review aims to provide a practical and integrated framework to facilitate early recognition, accurate differentiation from mimicking conditions such as pancreaticobiliary malignancies, and optimized long-term management of this complex yet treatable disease.