The teratoma, seen in about 20% of adults and few children,24, 25, 30 is likely to be a site of immunization as it contains dense infiltrations of T cells and B cells31 and its removal can hasten recovery.19, 24 Indeed, a recent paper showed that lymphocytes—both B cells and plasma cells—within the teratoma have the capacity to produce NR1‐directed autoantibodies, and the cystic teratoma fluid contains higher levels of NMDAR‐antibodies than serum.31 The gene discussed is GRIN1; the disease is teratoma.