RESUMEN
PURPOSE: To report a case of progressive outer retinal necrosis treated by combined intravitreal foscarnet and ganciclovir. CASE SUMMARY: A 11-year-old male with a history of chemotherapy and cord blood transplantation due to precursor T-cell leukemia developed Herpes zoster lesion on his forehead and rapidly progressing peripheral retinal necrosis without vasculitis in the right eye. Varicella-Zoster virus was confirmed in his cerebrospinal fluid using polymerase chain reaction (PCR); and the patient was diagnosed with progressive outer retinal necrosis. Despite combined treatment with intravenous acyclovir and foscarnet and intravitreal foscarnet, retinal necrosis progressed to retinal detachment and total retinal necrosis. During follow-up, new retinal necrosis was observed in his left eye. The patient was started on combined intravenous and intravitreal foscarnet and ganciclovir; retinal necrosis in the left eye regressed and posterior pole was spared. With subsequent oral valganciclovir and intravitreal foscarnet and ganciclovir, the remaining retina was preserved with maintained vision.