AQP4 and myeloid sarcoma: There is clinical and radiological overlap between MS, MOGAD, AQP4-IgG NMOSD, and antibody-negative NMOSD.9, 10, 11However, the different pathophysiological mechanisms of these diseases carry different prognoses and treatment demands, which makes their precise distinction imperative.12Overall, antibody-mediated demyelinating diseases, especially MOGAD, have a low prevalence, even lower than that of MS.13Unfortunately, the autoantibody test for these diseases is costly and not universally available.