Papillary Glioneuronal Tumor Research Articles

Glioneuronal tumors of the central nervous system.

Advances in the immunohistochemical detection of neuron-specific and neuronal-associated antigens have resulted in the discovery of neuronal elements in certain primary human brain tumors. The results have been not only to expand what neuropathologists commonly recognize as gangliogliomas, including the tumors now known as glioneurocytic tumor with neuropil rosettes and papillary ganglioneuroma, but also to expand the spectrum of tumor types to now include tumors such as central neurocytoma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile ganglioglioma. These discoveries have helped us to better understand the biology of these tumors and to refine our classification of them. Distinctions among these tumors include sites of predilection, such as the temporal lobe with the dysembryoplastic neuroepithelial tumors, and a spectrum of clinical aggressiveness that spans indolent "quasi-hamartomatous" lesions, such as the dysembryoplastic neuroepithelial tumor, to high-grade, highly aggressive tumors, such as the supratentorial primitive neuroectodermal tumor (World Health Organization Grade IV). Many of these tumors also commonly exhibit a glial component, as determined by both their histologic appearance and their immunoreactivity for glial fibrillary acidic protein. This review covers these recently described lesions, including the desmoplastic infantile ganglioglioma, the dysembryoplastic neuroepithelial tumor, the papillary glioneuronal tumor, the glioneuronal tumor with neuropil rosettes, and the mixed glioblastoma-cerebral neuroblastoma (supratentorial primitive neuroectodermal tumor), as well as the known tumors, ganglioglioma, medulloepithelioma, and medulloblastoma. For pathologists confronted by this growing array of tumors and subtypes, it is appropriate to focus on them and understand the differential diagnosis to be considered when confronted by them.

Review of the World Health Organization classification of tumors of the nervous system

(Conclusion) Classifications of the nervous system tumors should be neither static nor definitive. The most recent, third, current WHO classification of nervous system tumors was published in 2000. Many substantial changes were introduced. New entities include the chordoid glioma of the third ventricle, the atypical teratoid/rhabdoid tumor, cerebellar liponeurocytoma (the former lipomatous medulloblstoma of the cerebellum), solitary fibrous tumor and perineurioma. The new tumor variants include the large cell medulloblastoma, tanacytic ependymoma and rhabdoid meningioma. Several essential changes were introduced in the meningiomas regarding histological subtypes, grading and proliferation index. In addition to new entities described in the 2000 WHO classification there are newly brain tumor entities and tumor variants, which are not included in the current classification due to the insufficient number of reporeted cases, for example papillary glioneuronal tumor, rosetted glioneuronal tumor, lipoastrocytoma and lipomatous meningioma. They will be probably accepted in the next WHO classificaton. In the current WHO classification the importance of cytogenetic and molecular biologic investigation in the understanding and further classifications of these tumors has been emphasized.

Papillary glioneuronal tumor: a new variant of mixed neuronal-glial neoplasm.

We describe the clinicopathologic features of nine cases of a unique papillary glioneuronal tumor (PGNT) exhibiting astrocytic as well as extensive and varied neuronal differentiation. The four male and five female patients studied ranged in age from 11 to 52 years (mean 27.7 years). They either presented with mild neurologic symptoms or were asymptomatic. Magnetic resonance imaging showed demarcated cystic, 1.5-cm to 7-cm contrast-enhancing masses; five involved the temporal lobe, two the parietal, and two the frontal. All but one were totally resected. No recurrence was noted despite a follow-up period of 3 years. Two microscopic components were evident: 1) compact pseudopapillae composed of hyalinized vessels covered by a single layer of glial fibrillary acid protein (GFAP)-positive astrocytes and 2) synaptophysin-positive neuronal cells of varying size, including neurocytes, ganglioid cells, and ganglion cells within neuropil. Immunostains for chromogranin-A were negative, as was in situ hybridization for chromogranin-A mRNA. Ultrastructurally, neuronal cells featured microtubule-containing processes and aberrant synaptic terminals, but dense core granules were rare. Overall, cellularity was moderate and atypia was minimal. No mitotic activity or necrosis was noted. The proportions of the two components varied, but essential morphologic findings were identical in all cases. In that the clinical, radiographic, and morphologic characteristics of PGNT are distinctive, it appears to represent a previously undescribed form of mixed neuronal-glial tumor of the central nervous system.