Orbital Inflammatory Disease.

Idiopathic orbital inflammatory syndrome (IOIS) is a diagnosis of exclusion, requiring an evaluation to rule out other causes of orbital disease. Orbital MRI is the test of choice, but serologic studies are necessary to exclude a systemic etiology. Biopsy is usually not indicated at presentation, as the risk of causing damage to vital structures within the orbit outweighs the benefits. Patients unresponsive to therapy or those with multiple recurrences should be biopsied. The first-line treatment is corticosteroids, which may be tapered over several months. Although data is limited, radiotherapy is indicated for patients who fail to respond to steroids, or who have a rapidly progressive course. For those patients who are refractory to both corticosteroids and radiotherapy, anecdotal reports have supported the use of chemotherapeutic agents such as cyclophosphamide, methotrexate, and cyclosporine.