Glioblastoma IDH wild-type

Case contributed by A.Prof Frank Gaillard

Patient Data

Age: Elderly
CT

CT brain

4.5cm heterogeneous mass arising from the genu and body of the corpus callosum. There is associated minor bilateral superior frontal vasogenic oedema. The ventricles are age appropriate. Basal cisterns are not effaced. 

CT

Mild enhancement is noted of the corpus callosum mass. 

The patient went on to have an MRI (movement degraded, not shown) and a craniotomy and debulking of the tumour. 

Histology

MICROSCOPIC DESCRIPTION:

Paraffin sections show fragments of a densely hypercellular astrocytic glioma. Tumour cells show marked nuclear and cellular pleomorphism. Frequent mitotic figures are identified. There is multifocal microvascular proliferation with accumulation of endothelial-like cells in vessel walls. Foci of necrosis are also identified. Tumourcells show patchy strong immunostaining for GFAP and strong diffuse staining for nestin. No staining for IDH-1 is seen. The features are of glioblastoma multiforme. The topoisomerase labelling index is >50%.

FINAL DIAGNOSIS: Glioblastoma  (WHO Grade IV)

Note: Although this tumour is entirely consistent with IDH wild-type molecular subtype, strictly speaking, to conclusively establish this, IDH would need to be sequenced to ensure that a non-IDH1 R132H mutation was present. In practice, an IDH1 R132H negative tumour in an individual over 55-years-of-age makes the possibility of this being IDH mutant remote (<1%), and sequencing is not felt to be necessary by many institutions, and not recommended by the WHO classification of CNS tumours (2016). 

 

Case Discussion

Involvement of the corpus callosum is rare in metastases, and the vast majority of such cases represent high grade gliomas or CNS lymphoma. Central necrosis / non-enhancement is uncommon in lymphoma in the absence of treatment or immunosuppression (e.g. AIDS) and as such one can be confident in the diagnosis of high grade glioma on imaging grounds alone. 

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Case information

rID: 23040
Case created: 16th May 2013
Last edited: 6th Jun 2017
Inclusion in quiz mode: Included

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