Intralesional or intraorbital rituximab injection for the management of biopsy-proven idiopathic orbital inflammation involving the lacrimal gland.

Objective: To evaluate the efficacy of intralesional rituximab injection for the management of idiopathic orbital inflammation (IOI) involving the lacrimal gland, which is the most common subtype.

Method: Eighteen consecutive patients with biopsy-proven IOI involving the lacrimal gland were included. Rituximab (50 mg/5 mL) was injected intralesionally at monthly intervals.

Results: Clinically, all patients presented with upper eyelid swelling and ptosis. Most patients (56%) had periocular pain and a palpable superotemporal mass. Biopsies showed chronic inflammation without fibrosis in 14 patients (78%) and chronic inflammation and fibrosis in 4 patients (22%). Intralesional rituximab was injected once in 1 patient (6%) because of complete response after the first injection, twice in 11 patients (61%), and 3 times in 6 patients (33%) because of partial response after 2 injections. After a mean follow-up of 33 months (median, 33 months; range, 11-59 months), 16 patients (89%) showed a clinical response, including 14 patients (78%) a complete response (i.e., disappearance of all lesions) and 2 patients (11%) with a partial response (i.e., ≤30% decrease in lesion diameter). Two patients (11%) did not respond after 3 injections and were placed on systemic corticosteroid and methotrexate therapies. Two patients (11%) with a complete response developed subsequent recurrence 12 and 49 months after their last injections. Both were treated with 2 additional rituximab injections, 1 month apart, and showed complete response when examined 27 and 11 months after treatment, respectively.

Conclusion: Intralesional rituximab injection may be an effective treatment for IOI involving the lacrimal gland, achieving a 78% complete response rate in this series. Local treatment with rituximab has the potential to avoid the ocular and systemic side effects of corticosteroid and systemic immunosuppressive treatment.