Patients with NMO or MS often have accompanying autoantibodies and autoimmune diseases [3], [4], most commonly, but not limited to, Sjögren syndrome (SS) or a related profile of autoantibodies including antinuclear antibody (ANA), extractable nuclear antigen antibodies (SSA/SSB), rheumatoid factor (RF), anticardiolipin antibodies (ACA), and anti-double-stranded DNA antibody (A-ds DNA) [5] and AQP4 antibody. Here, AQP4 is linked to synovial sarcoma.