Lymphocytic orbital tumor of unknown origin.
Painful, moderately severe inflammatory reactionwith eyelid swelling, chemosis, and unilateral or bilateral exophthalmos. Involvement of the ocular muscles results in limited motility with diplopia.
The CT and MR imageswill show diffuse soft-tissue swelling. A biopsy is required to confirm the diagnosis.
Occasionally the CT image will simulate an infiltrative tumor.
Various disorders should be excluded. These includeGraves’ disease and orbital cellulitis, which is usually bacterial. Special forms of orbital pseudotumor include myositis and Tolosa–Hunt syndrome (pain-ful total ophthalmoplegia produced by an idiopathic granuloma at the apex of the orbit).
High-dosesystemic cortisone(initially 100 mg of prednisone)usually leads to remission. Orbital radiation therapy or surgical intervention may be indicated in cases that fail to respond to treatment.