Neuromyelitis optica (NMO) is an inflammatory disorder of the central nervous system characterized by optic neuritis and transverse myelitis. The identification of NMO IgG ab led to the definition of NMO spectrum disorders. There have been a few reports of NMO spectrum disorders in association with cancers. The present case study describes a woman diagnosed with metastatic breast cancer and leptomeningeal spread who presented with bilateral optic neuritis and who was found to have the NMO-IgG. Reports such as this show that the potential para-neoplastic association should be considered when seeing a patient with an NMO spectrum disorder and in the appropriate clinical setting investigating an underlying cancer might be important. Studies of the diverse presentations of NMO in different clinical settings could lead to a better understanding of the underlying disease mechanisms and can potentially provide targets for therapeutic intervention.