RESUMO
A 71-year-old woman developed sudden, painful, decreased vision in the left eye accompanied by progressive instability. Initial examination revealed left optic disc edema, and macular optical coherence tomography confirmed the presence of intraretinal and subretinal fluid, as well as hyperreflective material under the retinal pigment epithelium. Subsequent investigations, including brain magnetic resonance imaging and a comprehensive serological analysis, ruled out infectious and autoimmune causes, further complicating the diagnostic picture. The patient's vision in both eyes continued to deteriorate, prompting empirical corticosteroid treatment. While the vision improved, the case took an unexpected turn with worsening neurological symptoms. Ultimately a brain biopsy was consistent with diffuse large B-cell lymphoma.