A neuroepithelial tumor showing combined histological features of dysembryoplastic neuroepithelial tumor and pleomorphic xanthoastrocytoma--a case report and review of the literature.

A neuroepithelial tumor showing combined histological features of dysembryoplastic neuroepithelial tumor (DNT) and pleomorphic xanthoastrocytoma (PXA) is described. The patient was a 60-year-old male with a long-standing temporal lobe tumor and seizures. After a long, dormant period, the tumor, which had been localized in the left uncus, re-grew rapidly and extended into the subarachnoidal space and brain stem. The post-operative specimens disclosed two distinct components: an intra-cortical, cystic lesion containing mucinous materials and an extra-cortical, nodular lesion involving the leptomeninges. The former contained oligodendroglia-like small, round cells placed along axonal processes, plus mature neurons situated against mucinous materials (DNT-like component, WHO Grade I). The latter contained spindle and/or pleomorphic cells expressing glial fibrillary acidic protein, having bizarre nuclei and atypical mitotic figures. A reticulin network was developed among the tumor cells (PXA-like component, WHO Grade III). This case illustrates an unusual composite brain tumor, combined DNT and PXA.