Orbital inflammation in IgG4-related sclerosing disease.

IgG4-related sclerosing disease is a recently described systemic inflammatory disease that should be considered when evaluating patients with nonspecific orbital inflammation (pseudotumor). Orbital biopsy is necessary to establish a diagnosis and demonstrates lymphoplasmacytic infiltration, fibrosis, obliterative phlebitis of medium and small veins, and variable degrees of eosinophilia. We report the clinical and histopathological findings of 2 patients who developed chronic orbital inflammation as a manifestation of IgG4-related sclerosing disease. The 2 cases illustrate the widely varying clinical characteristics of this elusive disease.