title: Atypical extraventricular neurocytoma with oligodendroglioma-like spread and an unusual pattern of chromosome 1p and 19q loss.
abstract: An insular cortex tumor in a 54-year-old woman showed unequivocal neurocytic features, including open nuclei, distinct nucleoli, and strong synaptophysin immunoreactivity. Ultrastructurally, there were neuritic-type processes with microtubules and hillock-like attachments, and there were dense-core granules. Atypical features were mitotic activity, prominent vasculature, and small foci of necrosis. Peripherally, there was oligodendroglia-like histology with single-cell infiltration of white matter and perineuronal spread in cortex. Fluorescence in situ hybridization analysis with chromosome 1 and 19 probes showed 3 copies of 1q and 2 copies of 1p and showed 2 copies of 19q and 4 copies of 19p. This yielded a 1p-19q loss of heterozygosity pattern similar to that seen in oligodendrogliomas, although the actual chromosomal abnormality is distinct. This tumor, best classified as an atypical neurocytoma with oligodendroglia-like spread, supports suggestions of a close histogenic relationship between oligodendroglial and neurocytic tumors. This case also illustrates the limitations of relying exclusively on loss of heterozygosity analysis for tumor classification.
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Littlle Rock, AR 72205, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Mrak
authors.forename: M Gazi
authors.initials: MG
authors.lastname: Yasargil
authors.forename: Gayatry
authors.initials: G
authors.lastname: Mohapatra
authors.forename: James
authors.initials: J
authors.lastname: Earel
authors.forename: David N
authors.initials: DN
authors.lastname: Louis
mesh_terms: D001932:Brain Neoplasms / Q000145:classification / Q000235:genetics* / Q000473:pathology*; D002878:Chromosomes, Human, Pair 1; D002888:Chromosomes, Human, Pair 19; D003937:Diagnosis, Differential; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D019656:Loss of Heterozygosity; D008854:Microscopy, Electron; D008875:Middle Aged; D018306:Neurocytoma / Q000145:classification / Q000235:genetics* / Q000473:pathology*; D009837:Oligodendroglioma / Q000145:classification / Q000473:pathology* / Q000648:ultrastructure