Anti-aquaporin-4 antibody-seronegative NMO spectrum disorder with Baló's concentric lesions

A 34-year-old woman developed simultaneous bilateral severe optic neuritis and subsequent myelitis. Two months after the first attack, she developed a headache and dysesthesia in the left arm. Brain magnetic resonance imaging revealed multiple hyperintense lesions in the white matter of the right hemisphere, some of which were Baló-like concentric lesions. Our diagnosis was neuromyelitis optica spectrum disorder with Baló's concentric sclerosis (BCS), although the patient was negative for anti-aquaporin-4 (anti-APQ4) antibodies. Our case suggests that Baló's concentric sclerosis overlaps with neuromyelitis optica spectrum disorder and that this overlapping is caused by a mechanism that does not involve anti-AQP4 antibodies.