Pleomorphic xanthoastrocytoma: report of two cases and brief review of the literature.

Two cases of pleomorphic xanthoastrocytoma (PXA) involving the temporal lobe are reported, both occurring in adolescents. This neoplasma is a recently described, rare variant of astrocytoma affecting the superficial cerebral cortex and meninges of children and young adults. The tumor is considered to arise from the subpial astrocytes of the superficial cortex. Electron microscopic examination and immunoperoxidase stains for glial fibrillary acidic protein (GFAP) are helpful in making a definitive histologic diagnosis. Despite its pleomorphic appearance, this type of supratentorial glioma appears to have a much better prognosis than other tumors from which it must be distinguished, such as high grade gliomas and meningeal sarcomas. In contrast to malignant gliomas, the pleomorphic xanthoastrocytoma does not appear to require aggressive postoperative radiation therapy or chemotherapy. Therefore, it is important to recognize and identify this type of glioma as a distinct entity.