AQP4 and myeloid sarcoma: Monophasic tumefactive demyelinating lesions (not fulfilling MS criteria) on the one hand and recurrent TDL (tumefactive lesions that relapse as tumefactive lesions in the same or in different regions) on the other, are disease entities not fully investigated; there is a lack of tissue biopsy biomarkers for differentiating them from classical MS, but there are distinct immunopathology patterns when compared to MOG and AQP4 associated disease.