MOG and myeloid sarcoma: So far, the histopathology associated with MOG-IgG in humans is based on only a few reported cases: two patients with recurrent longitudinally extensive transverse myelitis (LETM) plus tumefactive brain lesions (16, 21), two patients with ON plus clinical or subclinical brain involvement (39), two patients with ADEM (40), and one patient whose initial diagnosis was clinically isolated syndrome suggestive of MS (hemiparesis, impaired coordination, and headache) (41).