IgG4‐related disease: review of the histopathologic features, differential diagnosis, and therapeutic approach

Immunoglobulin G4‐related disease (IgG4‐RD) is an uncommon disorder that demonstrates characteristic clinicopathologic features including sclerosing lesions with storiform fibrosis, increased IgG4+ plasma cells with an increased IgG4+/IgG+ plasma cell ratio, obliterative phlebitis, and often an increased serum IgG4 level. This review summarizes the characteristic histopathologic and clinical features of IgG4‐RD with detailed discussion of the...