Diffuse astrocytoma NOS (gemistocytic)

Case contributed by Dr Bruno Di Muzio


Left lower limb weakness.

Patient Data

Age: 56
Gender: Male

MRI Brain

Fiducial markers identified at bifrontal regions.

A large cortical-based mass is present within the right parietal lobe, involving the right postcentral and superior parietal gyri. The mass has ill defined margin. It is predominantly solid and demonstrates multiloculated cystic component in its medial aspect in the parafalcine region. Mass also demonstrates susceptibility artefacts indicating the presence of either calcification or blood products. Minimal patchy enhancement is noted after contrast administration.

Despite its large size, the mass incites minimal vasogenic edema. Positive mass effect is exerted onto the adjacent right lateral ventricle but no midline shift is noted. The postero-medial margin of the mass is close to the superior sagittal sinus, the sinus however still maintains its normal flow void and does not appear to be encased or compressed by the mass.

The rest of the brain is unremarkable.

Conclusion: Large cortical based mass within right parietal lobe with involvement of the right postcentral gyrus. Appearance is in keeping with a neoplastic lesion, primary tumor favored over secondary. It is likely to be at least anaplastic astrocytoma and probably glioblastoma multiforme.

Case Discussion

The pathological diagnosis was: Gemistocytic astrocytoma (WHO grade II)

Comment: Although the features are in keeping with a grade II tumor, a significant proportion of gemistocytes (as in this case) tends to progress more rapidly than ordinary fibrillary astrocytoma.

Gemistocytic astrocytoma is a histologic subtype of low-grade astrocytoma, with a poorer prognosis than other matched WHO grade tumors, and with no specific imaging features, however, they are typically presented with features that suggest higher grade tumors. 

Note: IDH mutation status is not provided in this case and according to the current (2016) WHO classification of CNS tumors, this tumor would, therefore, be designated as a diffuse astrocytoma NOS.

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Case information

rID: 38796
Published: 12th Aug 2015
Last edited: 14th Aug 2019
Tag: rmh
Inclusion in quiz mode: Included

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