Radiotherapy for idiopathic inflammatory orbital pseudotumor. Indications and results.

Supervoltage radiotherapy was used in 21 orbits of 19 patients with idiopathic inflammatory orbital pseudotumor. Seventeen orbits (15 patients) were initially treated with systemic corticosteroids, but recurrence of orbital inflammation during dosage tapering was the most frequent indication for radiotherapy. Fifteen orbits (14 patients) responded favorably, as judged by reduced proptosis, decreased lid edema and conjunctival injection, improved ocular motility, and increased visual acuity. Six orbits (five patients) did not improve with radiotherapy. Patients who were successfully treated with radiotherapy have been free of recurrence for a mean follow-up period of 25.05 months; these patients have not required further corticosteroid treatment or additional radiotherapy. Low-dose (1,000 to 2,000 rad) supervoltage radiotherapy seems to have a definite role in the management of idiopathic orbital pseudotumor in the following instances: (1) when corticosteroids fail or systemic complications are unacceptable (2) when signs and symptoms recur during decreasing corticosteroid dosage, and (3) when systemic corticosteroids are medically contraindicated.