Successful Long-Term Treatment of Pediatric Relapsing Idiopathic Optic Neuritis with Mycophenolate Mofetil

<b>Background:</b> Pediatric optic neuritis (ON) is a rare but severe condition characterized by acute visual impairment, with 3-5% of relapsing cases lacking identifiable markers for associated conditions, such as neuromyelitis optica spectrum disorder (NMOSD) or multiple sclerosis (MS); these cases are thus classified as relapsing idiopathic optic neuritis (RION). Corticosteroids are typically used for acute management; however, their prolonged use in children poses significant risks, including central obesity, hypertension, and growth impairment, underscoring the need for nonsteroidal, long-term treatment options. Current strategies for preventing recurrence in pediatric RION are limited due to a lack of data on immunosuppressive efficacy and safety. Given its rarity and the challenges of long-term immunosuppression in children, identifying optimal therapeutic approaches remains critical. <b>Case Presentation:</b> We report a case of a six-year-old girl with RION, who was initially treated with intravenous methylprednisolone (IVMP) and prednisolone (PSL) tapering, and who experienced recurrence eight months post-treatment. Additional corticosteroids and intravenous immunoglobulin (IVIg) were administered during relapse, but, due to adverse effects, treatment was transitioned to mycophenolate mofetil (MMF), enabling early PSL tapering. <b>Conclusions:</b> With MMF, the patient maintained stable vision and achieved a five-year recurrence-free period without notable side effects. In conclusion, this case suggests MMF's efficacy as a long-term management option for pediatric RION, potentially reducing corticosteroid-related risks.