Orbital pseudotumor.

Orbital pseudotumor is a benign condition that accounts for approximately 10% of all orbital mass lesions. Any part of the orbit may be involved. The etiology is unknown. The presentation may be either acute or subacute. Patients may present with a palpable mass, a swollen eyelid, congestion, pain, diminished ocular motility, and/or decreased visual acuity. Approximately, 25% of patients present with bilateral disease. A modest proportion of patients experience resolution of their symptoms without treatment. Biopsy is indicated for those who do not respond to, or relapse after, first-line therapy. Oral corticosteroids are the initial treatment and approximately 80% of patients respond. Roughly half of those who respond to corticosteroids relapse. Second-line therapy consists of either low-dose radiotherapy (20-30 Gy at 2 Gy per fraction), cytotoxic chemotherapy, or immunosuppressive agents. Radiotherapy results in long-term local control rates of 50% or higher. Limited lesions may be successfully resected. A small subset of patients may experience inexorable progression to a fixed, painful, sightless eye and require orbital exenteration.