[IgG4-associated diseases : Essentials for pathologists and radiologists]

Immunoglobulin G4-associated (IgG4) autoimmune diseases are systemic multiorgan diseases with variable clinical presentation. Principally, all organs can be affected. All IgG4-associated diseases have the same morphological correlate in common, which includes lymphoplasmacellular inflammation with abundant IgG4-positive plasma cells, obliterative phlebitis and storiform fibrosis, each with a variable manifestation. The exact pathogenesis is not yet completely understood; however, as in most cases glucocorticoids induce a prompt clinical response to therapy, this new multisystemic disease must be taken into consideration not only by pathologists but also by radiologists.