Other CNS AIDs such as autoimmune encephalitis (AE) and rare demyelinating diseases (RDD), including AQP4‐IgG+ neuromyelitis optica spectrum disorder (NMOSD) and MOG antibody‐associated disease (MOGAD), are characterized by specific circulating CNS‐directed antibodies [6, 7]. Here, AQP4 is linked to sinus histiocytosis with massive lymphadenopathy.