Fig. 1

(a) The figure shows pleomorphic tumor cells with nuclear atypia and multinucleated giant cells of the ependymal tumor; the bizarre nuclei were eye-catching; (b) The figure shows the high cellularity of the tumor, with crowding of the tumor cells; (c) The figure shows brisk mitosis in the tumors, with mitotic events counted in 2 mm² high-power fields; (d) The figure shows microvascular proliferation, which often presents with a glomeruloid appearance; (e) The figure shows tumor necrosis, but palisading necrosis is easily seen; and (f) The figure shows the high Ki67 index in the ependymal tumors