Glioblastoma IDH wild-type (unusual)

Case contributed by A.Prof Frank Gaillard

Presentation

Headache and right sided weakness.

Patient Data

Age: 65 years

A large left parietal mass with evidence of internal coarse calcification. Extensive surrounding oedema. No bony hyperostosis or involvement. 

A large heterogeneous mass with vivid enhancement in the left parietal region contains mixed low and high T2 signal with some peripheral cystic areas and contains multiple large flow voids. Surrounding vasogenic oedema. It is difficult to be entirely sure whether this mass is intra or extra-axial. Certainly it has a broad dural abutment with a dural tail of enhancement, however, on coronal sequence, its deeper portion does not have intervening cortex between lesion and white matter. There is left-sided sulcal and lateral ventricular effacement with 7 mm midline shift toward the right but no uncal herniation. No left temporal horn dilation to suggest entrapment.

Conclusion: Large left frontal/parietal mass is favoured to be either an intraaxial partially exophytic mass (e.g. glioblastoma) or an extra-axial mass which has invaded brain parenchyma (e.g. atypical meningioma).

DSA (angiography)

The mass in the left frontoparietal region is markedly hypervascular, with supply predominantly from pial vessels of the angular and parietal branches of the middle cerebral artery, with contribution from the anterior cerebral artery, with only minor supply from a normal calibre left middle meningeal artery. The striking feature is the neoangiogenesis around the periphery of the tumour, particularly on the deep aspect, with primary drainage into a central large dysplastic-appearing vein which passes to the convexity and then to the superior sagittal sinus. A smaller second vein is shown. There is rapid arteriovenous shunting. 

Conclusion: The appearance is that of a tumour and not a vascular malformation despite the marked arteriovenous shunting. The degree of hypervascularity and shunting is most unusual, particularly for a standard glioblastoma. Differential diagnoses would include astroblastoma (which can have both shunting enlarged intratumoral veins), a hypervascular metastasis such as a renal cell carcinoma (although this is not considered likely on the MRI findings of such a large solitary lesion), and haemangioblastoma. A hypervascular parenchymal tumour with drainage into an incidental developmental venous anomaly could also explain these appearances. Although there is an extra-axial component, haemangiopericytoma or atypical meningioma are virtually excluded by the angiographic pattern.

Case Discussion

The patient went on to have surgery.

Histology

MICROSCOPIC DESCRIPTION: Sections show fragments of a markedly hypercellular astrocytic glioma. Tumour cells show marked nuclear and cellular pleomorphism. Scattered mitotic figures are identified. There is prominent microvascular proliferation with multi-layering of atypical cells around vessel lumena. Extensive areas of palisaded tumour necrosis are also present.

Immunohistochemistry results show tumour cells stain:

  • GFAP: Positive
  • Nestin: Positive (high)
  • NogoA: Negative
  • IDH-1 R132H: Negative (non-mutated)
  • ATRX: Positive (non-mutated)
  • MGMT: Negative (likely methylated)
  • p53: Positive
  • p16 CDKN2A: Positive
  • Topoisomerase labelling index: 20%.
  • BRAF: No mutation detected.

Conclusion: Histologically the differential diagnoses include glioblastoma and anaplastic pleomorphic xanthoastrocytoma, however, the absence of a BRAF mutation strongly favours glioblastoma.

FINAL DIAGNOSIS: IDH-1 wild type Glioblastoma (WHO Grade IV).

PlayAdd to Share

Case information

rID: 50835
Case created: 24th Jan 2017
Last edited: 21st May 2017
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.