Composite cerebral neuroblastoma and astrocytoma. A mixed central neuroepithelial tumor

This report describes an exceptional example of cerebral neuroblastoma in association with neoplastic glial cells, which were frequently arranged in clusters around the supporting blood vessels. The neuroblastic nature of the tumor was confirmed by the presence of numerous dense-core vesicles in the cell processes. The glial nature of the associated cells was confirmed by their positivity for glial fibrillary acid protein by immunoperoxidase staining and by the presence of abundant cytoplasmic filaments of intermediate size on electron microscopy. Of particular interest was the presence of dense-core vesicles in some of the glial cells, and that of a basal lamina underlying the perivascular glial cells. The tumor was interpreted as a composite cerebral neuroblastoma and astrocytoma. No undifferentiated neuroepithelial stem cells could be identified. The cytogenesis of this mixed neuroepithelial neoplasm is uncertain.