Glioblastoma IDH-1 wildtype

Case contributed by Dr David Mitchell

Presentation

Confusion

Patient Data

Age: 70 years
CT

CT

Single rim enhancing lesion centered on the left basal ganglia with surrounding hypodense white matter changes.
MRI

MRI

A heterogeneous lesion with irregular rim enhancement which is centered on the left lentiform nucleus with substantial surrounding T2/FLAIR hyperintense signal change. The rim enhancement incompletely surrounds the lesion, attenuated on side of the left lateral ventricle without subependymal enhancement to suggest intraventricular spread. There are moderately low ADC values and elevated CBV corresponding to areas of enhancement. ADC values in the central non-enhancing region are, however, quite low. On MR spectroscopy, the enhancing components demonstrate elevated choline and depressed NAA. 2 mm midline shift to the right and partial effacement of the left lateral ventricle.

Conclusion:

Rim enhancing lesion in the left basal ganglia with substantial surrounding T2/FLAIR hyperintense change. The differential includes high-grade glioma. Infection is also a consideration given the central non-enhancement associated with low ADC values, including atypical organisms such as toxoplasmosis, particularly if there is a history of immunosuppression.

Pathology

The sections show pieces of cellular glial tumor composed of enlarged atypical glial cells with irregularly shaped nuclei. Abnormal mitotic figures are seen within the specimen. There is plentiful necrosis. 

Immunohistochemistry results show tumor cells stain:

  • GFAP Positive
  • Nestin Positive (moderate)
  • NogoA Negative
  • IDH-1 R132H Negative (not mutated)
  • ATRX Positive (not mutated)
  • p53 Negative
  • p16 CDKN2A Negative
  • Topoisomerase labeling index: Approximately 10%

FINAL DIAGNOSIS: Glioblastoma, IDH-1 wildtype.

Case Discussion

There is a wide differential for a rim enhancing lesion. Although this turned out to be a GBM, the central non-enhancing component with low ADC values raised the possibility of infection, which would make this a clinical emergency.
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Case information

rID: 60648
Published: 28th May 2018
Last edited: 18th Jun 2018
Inclusion in quiz mode: Included

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