GFAP and teratoma: These neuroglial elements were composed of glial cells that expressed GFAP or Olig2 (100% of cases), and neurons that expressed ChromoA (10/17 [59%] NMDAR-E and 6/12 [50%] control teratomas) or neurofilament F (7/17 [41%] NMDAR-E and 7/13 [54%] control teratomas; Table 3).