Fig. 2.

Histologic features. (A) Low-power view of hematoxylin and eosin (H&E) stained section. The tumor was heavily fragmented and mineralized. Large areas were hypocellular and showed numerous hyalinized vessels (asterisk) while other areas were more cellular (arrow). The adjacent brain parenchyma showed reactive piloid gliosis (not shown). (B) Higher-power view. The tumor was composed of a gangliocytic component and a smaller neurocytic component. Mitotic activity was not prominent and there was no endothelial proliferation or necrosis. Cytologic atypia was focally increased (not shown). (C and D) Immunohistochemical staining for neurofilament and synaptophysin, respectively. The gangliocytic cells showed variable somal positivity for neurofilament. Synaptophysin highlights a neuropil background and was weakly to moderately positive in both the gangliocytic and smaller neurocytic components.