[Blood vessels as a target organ: from Ormond's disease to immunoglobulin G4-related diseases].

Immunoglobulin G4-related disease (IgG4-RD) is a rare and clinically diverse entity with an estimated incidence of 0.8-1.4 per 100,000 person-years. Typical sites of manifestation include the head and neck area, the hepato-pancreato-biliary system, and the retroperitoneum. Perhaps the best-known variant is retroperitoneal fibrosis, formerly known as Ormond's disease. Biopsy and histological examination are of great diagnostic importance, as relying solely on serum IgG4 is problematic and not sufficiently specific. Therapeutically, in addition to the initial administration of glucocorticoids, treatment with B cell-directed antibodies, particularly rituximab, has become clinically established. Initial studies demonstrate the effectiveness of other therapies targeting B cells. Although the disease has received more clinical attention in recent years, it is still necessary to further increase awareness of IgG4-RD to enable optimal treatment for patients.