Teaching neuroimages: neuromyelitis optica misdiagnosed as spinal cord tumor.

A 17-year-old girl presented with acute-onset cervical pain, followed by left arm weakness and gait disturbances. Spinal cord astrocytoma was diagnosed by MRI performed at an outpatient facility (figure, A and B). The patient was admitted to the neurosurgery department to undergo spinal cord biopsy. A second neurologic evaluation indicated neuromyelitis optica (NMO) as the most likely diagnosis, which was confirmed by NMO-immunoglobulin G seropositivity. The patient was treated with rescue plasmapheresis with substantial clinical and radiologic (figure, C) improvement.