Glioblastoma IDH wild-type (multifocal)
Seizure, first episode.
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There is a large region of FLAIR hyperintensity involving grey and white matter in the right temporal, parietal and occipital lobes and extending into the right insula, posterior limb of internal capsule and splenium of the corpus callosum.
Within this region of high FLAIR signal are multiple enhancing components with central necrosis. The largest is centred in the right posterior temporal lobe, abutting temporal horn and trigone with what is presumably subependymal spread along the right occipital horn. This lesion demonstrates peripheral restricted diffusion and contains susceptibility artefact suggesting haemorrhagic foci. There is a further peripherally enhancing mass superficially located in the right parieto-occipital lobes. There is a punctate enhancing focus in the medial right occipital lobe and small nodular enhancing foci in the lateral aspect of the right splenium.
A separate small T2 hyperintense region at the right paramedian vertex involving the precentral gyrus does not contain contrast enhancement.
Spectroscopy in the right temporal enhancing mass demonstrates elevated choline:creatine, depressed NAA and a lactate peak. The enhancing lesions exhibit elevated cerebral blood volume.
Mass effect characterised by partial effacement of the right lateral ventricle, sulcal effacement and 2 mm leftward midline shift is unchanged compared to the CT. No hydrocephalus.
Conclusion: The appearances are in keeping with high-grade glioma associated with mass effect as described above.
This case illustrates typical imaging features of a high-grade glial tumour: extensive FLAIR abnormalities with mass effect and vasogenic oedema, irregular contrast enhancement, restrict diffusion, elevated areas of CBV and tumour trace on spectroscopy.
The patient went on to have surgery.
MICROSCOPIC DESCRIPTION: The sections show features of a densely cellular astrocytic tumour. The tumour cells have elongated, angulated and hyperchromatic nuclei. Scattered mitotic figures are identified. There are foci of microvascular proliferation. Areas of palisaded necrosis are present. The features are those of glioblastoma. The tumour cells are focally p53 positive. They are IDH-1 and MGMT immunostains negative. There is no loss of ATRX staining.
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, however, an IDH1 R132H negative tumour in an elderly individual makes the possibility of this actually being IDH mutant remote, and sequencing is not felt to be necessary by many institutions.