We describe a composite glio-neuronal tumor comprising pleomorphic xanthoastrocytoma (PXA) and ganglioglioma identified in a left temporal biopsy. The 32-year-old male patient underwent surgery following a clinical history of persistent headaches of 6 years' duration. Immunohistochemical double labeling with antibodies to synaptophysin, beta-tubulin isotype III, GFAP and CD44H demonstrated neoplastic neurons and astrocytes in the ganglioglioma, while coexpression of glial and neuronal markers was found in a subset of PXA tumor cells variously showing giant cell or spindle cell morphology. There were gradual transitions between the two neoplastic populations. These findings raise the possibility of ganglioglioma having evolved by differentiation of bipotential PXA tumor cells along astrocytic and neuronal lineages. The PXA may, therefore, be closely related to desmoplastic neuroepithelial tumors of infancy, a group of neoplasms of presumed embryonal origin.