UNILATERAL OPTIC NEUROPATHY REVEALING AN OPTIC NERVE MENINGIOMA

Optic nerve sheath meningioma (ONSM) is a rare orbital tumor that can mimic inflammatory optic neuropathies. We report the case of a 32-year-old woman presenting with rapidly progressive unilateral visual loss, pain with eye movements, and papilledema. MRI revealed an enhancing perioptic meningeal lesion extending into the optic canal, consistent with ONSM. Visual evoked potentials and electroretinography confirmed marked right sided dysfunction, while systemic evaluations were unremarkable. Given the acute decline and suspected inflammatory component, high-dose intravenous corticosteroid therapy was initiated. The patient showed significant visual improvement and MRI demonstrated clear regression of the optic canal lesion after one month, with stabilization at 11-month follow-up. This case emphasizes the importance of considering meningioma in atypical optic neuropathies, particularly in young women with hormonal exposure, and highlights the potential benefit of corticosteroids when peritumoral edema is present.