A case of primary intraocular lymphoma resistant to methotrexate therapy

Background: Treatment by methotrexate (MTX) for primary intraocular lymphoma (PIOL) has attracted attention in recent years. Case-report: A 51-year-old woman visited our hospital with binocular vitreous opacity that was unresponsive to therapy with corticosteroids. We diagnosed PIOL by the cytological findings and intraocular IL-10 level. Although her vitreous opacity disappeared by intravitreal MTX injection initially, in the course of repeated injections, MTX gradually became ineffective and subretinal tumor appeared, which did not respond to subsequent high-dose MTX therapy. Finally, by radiation therapy, the tumor cleared and her visual function improved. Conclusion: MTX therapy including high-dose MTX treatment may not be effective against PIOL.