[IgG4-related orbital inflammation]

Serum immunoglobulin G4 (IgG4)-related systemic disease is a newly found entity and should be considered as a further differential diagnosis to the big pool of unspecific orbital inflammation. We describe clinical appearance and treatment options.

We retrospectively analyzed all patients with the diagnosis IgG4-related orbital inflammation who were examined in our outpatient clinic. We compared symptoms, clinical and histological findings and therapy.

In the last 17 months five patients were diagnosed with IgG4-related orbital disease. Biopsies were performed of most affected areas as seen in the computerised tomography scan. Histology revealed marked infiltration with IgG4-positive plasma cells. Serum IgG4-levels were partly significantly elevated. Based on these findings diagnosis of an IgG4-related disease was agreed and treatment with oral prednisone installed. In one patient a therapy with Rituximab was successfully started.

Extended unspecific orbital inflammation, especially when bilateral and associated with systemic disease should be considered to be IgG4-related. Histological proof of IgG4-positive plasma cells and elevated IgG4 serum levels do confirm this diagnosis. Strict follow-up and interdisciplinary work-up is recommended.