Figure legends:
Figure 1: Radiologic findings of the primitive neuroectodermal tumor. (A) T1-weighted MRI showing a mass with mixed isointense to hypointense signals in left frontoparietal lobe. (B) CT scan demonstrating a large mass with isodensity signals. (C, D) Post-contrast MRI showing a mass with heterogeneous enhancement in the left frontoparietal lobe.
Figure 2: Histopathologic findings. (A) An undifferentiated and densely cellular tumor. (B, C) Small, round, uniform cells infiltrating the brain tissue. (D) Round cells with scant cytoplasm. (E, F) Diffuse membranous positivity for CD99. Scale bars: 100 μm (A), 50 μm (B, C, E). 20 μm (D, F)