[From 'malignancy' to IgG4-related systemic disease].

IgG4-related systemic disease is a new clinical entity with a large variety of clinical symptoms that can affect almost all organs. The best known manifestations are retroperitoneal fibrosis and autoimmune pancreatitis. We present 3 patients aged 71, 83 and 70 years, with malaise, fatigue and swellings suggestive of a malignancy.