Oligodendroglioma NOS

Case contributed by A.Prof Frank Gaillard

Patient Data

Age: 30 years
Gender: Male
MRI

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.

Conclusion:

Appearance is most consistent multifocal low-grade glioma.

Pathology

MICROSCOPIC DESCRIPTION

Paraffin sections show a variably hypercellular oligodendroglioma. Tumour 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. Tumour is centred 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.

IMMUNOHISTOCHEMISTRY

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

DIAGNOSIS

Oligodendroglioma (WHO Grade II)

 

Case Discussion

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

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Case information

rID: 30083
Case created: 17th Jul 2014
Last edited: 20th May 2017
Inclusion in quiz mode: Included

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