Oligodendroglioma NOS

Case contributed by Dr Bruno Di Muzio

Presentation

History of migraine.

Patient Data

Age: 21-year-old
Gender: Female
MRI

MRI Brain

 

Technique: Multiplanar, multisequence imaging has been obtained through the brain including pre and post contrast sequences, MR perfusion and MR spectroscopy.

Comparison: Outside scan from one month ago. 

Findings:  An area of signal change on the FLAIR and T2 with slight positive mass effect is identified in the medial and anterior aspect of the superior left frontal gyrus. Signal change extends into the cortex which is also is thickened.

A leading-edge of signal abnormality extending down to the ventricle is not clearly identified but would necessitate high-resolution 3-D FLAIR imaging

No contrast-enhancement in associated with the lesion. No raised cerebral blood volume (CBV). MR spectroscopy shows a decrease of metabolites without increased choline and without increased myoinositol peak.

No other lesions are identified

Conclusion: An area of signal abnormality with mass effect is present within the superior frontal gyrus on the left. Differential diagnosis lies between cortical dysplasia and low-grade glioma. Spectroscopic findings would favour cortical dysplasia.

Pathology

MICROSCOPIC DESCRIPTION: The sections show cerebral cortex and white matter. Cortical laminar architecture is preserved with no features of cortical dysplasia seen. There is prominent perineuronal secondary structuring. White matter contains a population of atypical glial cells with oligodendroglial morphological features - enlarged round and oval hyperchromatic nuclei, some with perinuclear clearing and a paucity of processes. Several groups of overlapping nuclei are noted. No mitotic figures are identified. There is no microvascular proliferation and no necrosis is seen. A population of reactive astrocytes is also present.

IMMUNOHISTOCHEMISTRY: GFAP negative in atypical oligodendroglial cells; positive in reactive astrocytes. NogoA positive in atypical oligodendroglial cells. IDH-1 R132H positive (mutated) ATRX positive (not mutated) p53 negative MGMT positive (likely unmethylated) p16 CDKN2A positive Topoisomerase labelling index: Approximately 1%. The features are of IDH-1 mutated diffuse glioma (WHO II) strongly favouring oligodendroglioma.

DIAGNOSIS: IDH-1 mutated diffuse glioma (WHO II) with features strongly favouring oligodendroglioma. ​

Case Discussion

This case demonstrates a small cortical lesion that is a real challenging for radiologists, even with all the MRI advanced sequences available. The histology confirmed a diffuse glioma most likely representing an oligodendroglioma (WHO grade II). 

Typical MRI features for this kind of tumour were not present, and the appearance was indistinguishable from a cortical dysplasia. 

Note: This case predates the recent (2016) revision WHO classification of CNS tumours, and thus molecular markers (IDH mutation and 1p19q co-deletion) are not available. As such, this tumour would now be classified as an oligodendroglioma NOS.

PlayAdd to Share

Case information

rID: 43093
Case created: 23rd Feb 2016
Last edited: 20th May 2017
Tag: rmh
Inclusion in quiz mode: Included

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.