Oligodendroglioma NOS

Case contributed by Assoc Prof Frank Gaillard



Patient Data

Age: 30 years
Gender: Male

A sharply defined zone of abnormal slightly heterogeneous signal in the left parietal lobe extends to involve the medial cortex of the superior parietal lobule. Inferiorly it abuts and distorts the cingulate gyrus. Superiorly it is significantly posterior to the precentral gyrus and slightly posterior to the left post central gyrus. Posterior and laterally it extends to and distorts the left intraparietal sulcus. It extends to within 1 cm of the parieto-occipital fissure postero-medially, slightly posteriorly bowing it. It exhibits no restricted diffusion and no pathological contrast enhancement. It does show slightly elevated choline to creatine ratio, reduced NAA and a few small lactate peaks. It shows reduced relative cerebral blood volume (CBV) and relative cerebral blood flow (CBF) on perfusion studies.

Case Discussion

The patient went on to have a resection. 



Paraffin sections show a moderately hypercellular glial tumor involving cerebral cortex and white matter. Tumor cells have pleomorphic round and oval nuclei, some with perinuclear clearing. These are arranged in diffuse sheets intersected by delicate capillaries. Moderate numbers of minigemistocytes and gliofibrillary oligodendrocytes are noted. No mitotic figures are identified and there is no endothelial cell hyperplasia or necrosis.


  • Nogo-A: positive
  • IDH1: positive
  • MGMT negative (likely methylated)
  • p16 positive
  • p53 negative

Topoisomerase labeling index approximately 3%.

DIAGNOSIS: Oligodendroglioma (WHO Grade II)

Note: This case predates the recent (2016) revision WHO classification of CNS tumors, and as 1p19q co-deletion status is not available this tumor would now be classified as an oligodendroglioma NOS.

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Case information

rID: 32960
Published: 25th Dec 2014
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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