AQP4 and myeloid sarcoma: As with silent spinal cord lesions, accumulation of silent brain lesions during remission, as frequently seen in MS, is widely absent in AQP4-IgG-positive NMOSD (5%) (and also rare in MOG-EM/MOGAD [4% in a mixed adult and pediatric cohort, 12% in an exclusively pediatric cohort]) [21, 37].