Abstract: Immunoglobulin G4(IgG4)-related disease is a kind of new systemic entity characterized by mass-forming lesions in various organs that consist of lymphoplasmacytic infiltrates and fibrosclerosis with numerous IgG4-positive plasma cells. PET/CT has been widely used in clinical as a whole body examination that earned plenty of successful experience, especially in multiple locations and organs cancer such as lymphoma. PET/CT also has a potential application in IgG4-related diseases as its feature of systemic.