Aquaporin-4–positive myelitis associated with Sjögren syndrome and colonic adenocarcinoma

Neuromyelitis optica (NMO) is an inflammatory disorder of the CNS with prominent involvement of the optic nerve and the spinal cord. An autoantibody against aquaporin-4 (AQP4), a water channel abundant on astrocytic foot processes, is the biomarker of the disease.1