IgG4-related disease is a fibroinflammatory pathology which gathers several disorders with common histological, serological and clinical features. The disease usually manifests itself as a diffuse or localized enlargement of one or several organs that reveals upon histology a dense lymphoplasmatic infiltrate with IgG4 positive plasma cells, a storiform fibrosis and obliterative phlebitis. Serum IgG4 are often but not always increased. Diagnostic criterias were published in 2011. Lesions caused by the disease might become irreversible without treatment. Currently, glucocorticoids are the first line of treatment. However, other immunosuppressants such as rituximab are sometimes used.