Teaching NeuroImages: Leber hereditary optic neuropathy masquerading as neuromyelitis optica.

A 22-year-old woman presented with photopsia, sensory loss, and paresthesia over both lower extremities, visual scotomas, and painless binocular vision loss over 5 months. MRI showed T2 hyperintensities near the optic chiasm (figure 1, B and C), floor of the fourth ventricle and the colliculi (figure 2, A–F), and central gray matter of the spinal cord (figure 1A). CSF analysis was notable for elevated glucose and lactate; oligoclonal bands, immunoglobulin G index, and aquaporin-4 antibodies were negative. Hermaternal uncle has Leber hereditary optic neuropathy (LHON) and a genetic analysis confirmed an m.3460 G>Amitochondrial DNA point mutation.