AQP4 and neuromyelitis optica: It is interesting that, unlike the circumventricular areas, the PCTs do not have high AQP4 expression; nevertheless, we believe the unique PCT involvement extending from the brainstem to the MCPs may be similar to longitudinal brain abnormalities commonly involving the CST from the internal capsule to the cerebral peduncle, providing new evidence for symmetrical MCP T2 hyperintensities in patients with AQP4‐IgG‐seropositive NMO.