MOG and myeloid sarcoma: Inflammatory demyelinating diseases of the central nervous system (CNS) are a group of autoimmune diseases targeting oligodendrocytes or support cells (such as astrocytes); these diseases are characterized by inflammatory infiltration, demyelination, and axonal damage, and examples include multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein (MOG) antibody-associated demyelinating disease [1–4].