Atypical extraventricular neurocytoma with oligodendroglioma-like spread and an unusual pattern of chromosome 1p and 19q loss

Hum Pathol. 2004 Sep;35(9):1156-9. doi: 10.1016/j.humpath.2004.05.005.


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.

Publication types

  • Case Reports

MeSH terms

  • Brain Neoplasms / classification
  • Brain Neoplasms / genetics*
  • Brain Neoplasms / pathology*
  • Chromosomes, Human, Pair 1
  • Chromosomes, Human, Pair 19
  • Diagnosis, Differential
  • Female
  • Gene Dosage
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Loss of Heterozygosity
  • Microscopy, Electron
  • Middle Aged
  • Neurocytoma / classification
  • Neurocytoma / genetics*
  • Neurocytoma / pathology*
  • Oligodendroglioma / classification
  • Oligodendroglioma / pathology*
  • Oligodendroglioma / ultrastructure