Pathology of pineal parenchymal tumors.

Tumors of the pineal region can arise from multiple cellular origins and thus represent a very heterogeneous group of pathologies. Such tumors include pineal parenchymal tumors, germ cell tumors, astrocytomas, ependymomas, and papillary pineal tumors. Within the subgroup of pineal parenchymal tumors, there is a histopathologic spectrum ranging from pineocytoma to pineal parenchymal tumors of intermediate differentiation to pineoblastoma. The current World Health Organization classification and the pathologic features of each of the pineal parenchymal tumor subtypes are reviewed in this article.