Should the patient be tested for AQP4-IgG?, n (%)Yes, this patient has a core clinical characteristic of NMOSD associated with area postrema lesions on MRI.No, this patient does not have a core clinical characteristic of NMOSD, and false positive serological testing is common in this setting.Yes, although this patient does not fulfill criteria for an area postrema syndrome.No, this patient has a typical syndrome of MS. Here, AQP4 is linked to myeloid sarcoma.