Neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody (MOG-IgG)-associated disorder (MOGAD) are antibody-mediated inflammatory disorders of the CNS distinct from multiple sclerosis (MS) (Jarius et al., 2018; Lennon et al., 2005; Wingerchuk et al., 2015). Here, MOG is linked to myeloid sarcoma.