Immune-Mediated Macular Edema After Intravitreal Methotrexate in Primary Vitreoretinal Lymphoma.

PURPOSE: To report a case of cystoid macular edema in a patient with primary vitreoretinal lymphoma (PVRL) following intravitreal methotrexate (MTX) and lymphoma remission.

METHODS

Case report.

RESULTS

A 76-year-old man was diagnosed with PVRL after a 9-month history of bilateral floaters and progressive blurred vision. Vitreous biopsy revealed CD20-positive large B cells, a MYD88 (L265P) mutation, and interleukin IL-10/IL-6 ratio of 1.76 at diagnosis. Systemic involvement was initially excluded but metachronous brain lesions emerged, prompting systemic chemotherapy.Macular edema developed after 2 and 6 weeks of MTX in the left and right eyes, respectively, coinciding with inversion of the IL-10/IL-6 ratio to 0.01. Edema was refractory to topical therapy and required intravitreal dexamethasone and aflibercept.

DISCUSSION: The simultaneous inversion of the IL-10/IL-6 ratio with edema onset suggests a cytokine shift unmasking an inflammatory response previously suppressed by malignant lymphoproliferation. This pattern supports an immune reconstitution inflammatory syndrome-like mechanism as the most likely cause.