Oligodendroglioma NOS

Case contributed by Frank Gaillard
Diagnosis certain

Patient Data

Age: 30 years
Gender: Male

Cortical and subcortical T2 hyperintensity and expansion is again identified in the left paramedian frontal lobe, with no enhancement but containing a small region of diffusion restriction. Spectroscopy trace in the left frontal lesion demonstrates increased choline and reduced NAA but no lactate peak. No convincing CBV increase.

A smaller focal region of cortical and subcortical T2 hyperintensity in the paramedian right parietal lobe demonstrates more pronounced diffusion restriction. There is no pathological contrast enhancement.

6 mm focus of T2 hyperintensity in right temporoparietal white matter is non-specific. No further abnormality identified. No hydrocephalus.


Appearance is most consistent multifocal low-grade glioma.



Paraffin sections show a variably hypercellular oligodendroglioma. Tumor cells show mild nuclear pleomorphism and are arranged in diffuse sheets. Areas with a vaguely lobular pattern are noted with lobules enclosed by thin-walled vessels. An occasional mitotic figure is identified. There is no microvascular proliferation and no necrosis is seen. Tumor is centered largely within white matter but focally extends into cortex where there is prominent perineuronal and perivascular secondary structuring. No breach of the pia-arachnoid is seen.


GFAP positive in reactive astrocytes and gliofibrillary oligodendrocytes; negative in oligodendroglial cells. NogoA positive in oligodendroglial tumor cells. IDH-1 R132H positive MGMT positive (likely unmethylated) p53 negative p16 positive Topoisomerase labeling index: Approximately 3%.


Oligodendroglioma (WHO Grade II)


Case Discussion

Note: This case predates the recent (2016) revision WHO classification of CNS tumors, and without 1p19q co-deletion status this tumor would now be classified as an oligodendroglioma NOS, even though histology and immunohistochemistry with Nogo-A is highly suggestive. 

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