Glioblastoma NOS (mimics parafalcine meningioma)

Case contributed by Royal Melbourne Hospital


This elderly patient presenting with short term memory loss, confusion and a change in personality.

Patient Data

Age: 70 years
Gender: Female

In the anterior midline is a rounded mass with heterogeneous contrast enhancement, which is more prominently peripheral. There is very extensive vasogenic oedema, also involving the genu of the corpus callosum, which also appears enlarged. 

Case Discussion

This is a difficult case, due to the location of the tumour. 

The finding which draws one away from the diagnosis of a GBM is the midline location and the fact that the anterior cerebral arteries are located posterior to the mass and anterior to the corpus callosum. Thus this is not a genu mass, and one could be mistaken in thinking that it arose from the falx. One should remember that the falx, this far anteriorly, is usually a thin strip descending towards the crista galli. 

The patient was taken to theatre and resection performed. The mass was more reminiscent of a glioblastoma (GBM) and frozen section confirmed the diagnosis (subsequently further confirmed with histology). 


The sections show features of a densely cellular astrocytic tumour. The tumour cells show elongated, angulated and hyperchromatic nuclei. Some appear pleomorphic xanthoastrocytoma-like, being more epithelioid with abundant amounts of cytoplasm.  Scattered mitotic figures are identified. There are foci of endothelial cell hyperplasia. Areas of palisaded necrosis are present.  The features are those of glioblastoma multiforme. The tumour cells are GFAP and nestin positive. The Ki-67 index is about 30%.

FINAL DIAGNOSIS: Glioblastoma (WHO Grade IV).

Note: IDH mutation status is not provided in this case and according to the current (2016) WHO classification of CNS tumours, this tumour would, therefore, be designated as a glioblastoma NOS

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Case information

rID: 13680
Published: 7th May 2011
Last edited: 16th Jul 2018
Inclusion in quiz mode: Included

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