Figure 4: Histological and immunohistochemical observations of the T2 spinal cord tumor. (a) Pathology sections of Hematoxylin and Eosin stain show moderate to high cellularity composed of neoplastic cells harboring round nuclei with mild-to-moderate atypia, and salt-and-pepper chromatin. (b–d) The immunohistochemical staining discloses that the neoplastic cells are positive for synaptophysin (b). (c) Glial fibrillary acidic proteins are expressed in astrocytic interstitial cells. (d) The Ki-67 labeling index is around 20%. Together with morphology and immunohistochemical studies, it is consistent with pineal parenchymal tumor with intermediate differentiation