Anaplastic astrocytoma - thalamic glioma

Case contributed by A.Prof Frank Gaillard

Presentation

Memory loss and behavioural changes.

Patient Data

Age: 65 years
Gender: Female

The right thalamus demonstrates high T2 signal with expansion, with extension of abnormal signal into the medial aspect of the left thalamus along the thalamic adhesion, and antrosuperiorly into the superior part of caudate and anterior lentiform nucleus across the anterior limb of the internal capsule. These areas demonstrate elevated cerebral blood volume, areas of a reduced ADC values (particularly the medial aspect of the thalami: 670 x 10-6 mm^2/s) and a spectroscopic trace consisting of elevated choline and reduced NAA. No calcification evidence of hemorrhage. This is an isolated abnormality other than and a small focal region of high T2 signal in the postcentral gyrus on the left which is nonspecific and almost certainly unrelated. Anterior caudate main courses through the area of signal abnormality on the right. No other abnormal flow voids noted elsewhere. Posterior fossa is unremarkable. MR venography demonstrates patency of the internal cerebral veins and dural venous sinuses.

Conclusion: The features are almost certainly those of a diffuse glioma, possibly a diffuse midline glioma H3 K27MX96 mutant. Enhancement, high cellularity is indicated by low ADC values, and MRS and CBV all support this to be a high-grade tumor (at least WHO grade III).

Case Discussion

The patient went on to have a stereotactic biopsy.

Histology

Paraffin sections show cores of a densely cellular glial tumor. Tumor cells have fibn'llary astrocytic morphology, show moderate nuclear and cellular pleomorphism and are arranged in diffuse sheets. Moderate numbers of mitotic figures are identified (5 in 10 HPF). There is no multilayering of atypical cells around vessel Iumena and no necrosis is identified.

IMMUNOHISTOCHEMISTRY:

  • GFAP positive
  • Nogo A positive in native oligodendrocytes
  • IDH-1 R132H negative (not mutated)
  • ATRX positive (not mutated)
  • P53 positive
  • P16 CDKNZA negative
  • Topoisomerase labeling index: Approximately 15%.

FINAL DIAGNOSIS: Anaplastic astrocytoma, IDH wild-type (WHO Grade III).

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Case information

rID: 59709
Published: 22nd Apr 2018
Last edited: 22nd Apr 2018
Inclusion in quiz mode: Included

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