Diagnosis and management of orbital pseudotumor.

Orbital pseudotumor, also known as idiopathic orbital inflammatory syndrome (IOIS), may have protean clinical manifestations. Some presentations of IOIS may mimic common conditions such as orbital cellulitis and optic neuritis. IOIS should be considered a diagnosis of exclusion, with evaluation directed toward eliminating other causes of orbital disease. Orbital magnetic resonance imaging is the single most important diagnostic test, but serologic studies are necessary to exclude a systemic cause. Biopsy is usually not performed at presentation, as the risk of producing damage to vital structures within the orbit outweighs the benefits. Patients with multiple recurrences, or those unresponsive to therapy, should have biopsy samples taken. Corticosteroids are the mainstay of therapy and are administered for several months to ensure remission. Radiotherapy may be used in 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 suggested the use of chemotherapeutic agents such as cyclophosphamide, methotrexate, and cyclosporine.