Orbital inflammatory pseudotumors: etiology, differential diagnosis, and management.

Orbital inflammation is typically an idiopathic process that occasionally may be identified with a specific local or systemic disease as the causative agent. Orbital inflammatory pseudotumor (also known as idiopathic orbital inflammation syndrome, orbital pseudotumor, nonspecific orbital inflammation, and orbital inflammatory syndrome) is defined as an idiopathic tumor-like inflammation consisting of a pleomorphic cellular response and a fibrovascular tissue reaction. Various rheumatologic disorders are associated with orbital inflammation and must be ruled out in cases of orbital inflammatory pseudotumor, including Wegener's granulomatosis, giant cell arteritis, systemic lupus erythematosus, dermatomyositis, and rheumatoid arthritis. The mainstay of therapy is corticosteroid therapy, although there is an increasing trend toward use of antimetabolites, alkylating agents, cytotoxic agents, and other immunosuppressive agents.