Radiation-induced glioblastoma

Case contributed by Dr Bruno Di Muzio


Patient treated for a medulloblastoma 30 years ago (ressection and neuroaxis radiation).

Patient Data

Age: 48
Gender: Male
Modality: MRI

There is a mass in the left precentral gyrus with thick and nodular peripheral enhancement measuring approximately 2 x 2.5 cm. There is adjacent white matter high FLAIR signal with no mass-effect on the lateral ventricles and no midline shift. There is a small amount of diffusion restriction which appears related to the anteromedial wall. Spectroscopy demonstrated slight reduction in NAA and slight elevation of choline with no significant lactate rise. The peripheral enhancing component has increased cerebral blood volume.

No further contrast enhancing lesion.

Prominent periventricular white matter high FLAIR signal. Prior posterior fossa craniotomy. A large focus of calcification is seen in the left cerebellar hemisphere. Further focal calcification or cavernoma is seen in the right temporal parietal region as well as further scattered tiny areas of susceptibility artefact. These are stable when compared to previous examinations. Exvacuo-dilatation of the left lateral ventricle again demonstrated.

IMPRESSION: Overall, findings favour tumour with increased cerebral blood flow and peripheral diffusion restriction concerning for high grade glioma. Metastasis is a less likely differential diagnosis.

Modality: Pathology

MICROSCOPIC DESCRIPTION: The sections show fragments of unremarkable cerebral cortex and white matter and separate fragments of a densely hypercellular glial tumour. Tumour cells are a mixture of pleomorphic, astrocytic and oligodendroglial cells arranged in diffuse sheets. Scattered mitotic figures are identified and there are several foci of microvascular proliferation with multilayering of atypical cells around vessel lumena. Scattered small foci of necrosis are also seen. IMMUNOHISTOCHEMISTRY: GFAP positive in tumour astrocytes; negative in oligodendroglial cells Nogo A positive in tumour oligodendrocytes; negative in tumour astrocytes. Nestin positive (high) IDH-1 R132H negative (not mutated) ATRX negative (likely mutated) MGMT negative (likely methylated) p53 negative p16 negative Topoisomerase labelling index: Approximately 35% The features are of glioblastoma multiforme with an oligodendroglioma component (WHO Grade IV).

DIAGNOSIS: Brain tumour: Glioblastoma multiforme with an oligodendroglioma component (WHO Grade IV).

Case Discussion

This patient received radiation therapy as part of a treatment for medulloblastoma when he was an adolescent. More than 30 years after this treatment brain imaging shows a diffuse cerebral atrophy as a post radiation treatment effect and a left frontal lobe tumour corresponding to a glioblastoma

Although the patient has all the requisites to fit his new tumour as a radiation-induced glioma, the lesion could also represent a de novo tumour. 

Cahan et al.1 have defined radiation-induced malignancies as those tumours which fulfill the following criteria: 

  • tumour in a previously irradiated area
  • sufficient latency time between the original and new tumors
  • new tumour must has a distinct histology from the original
  • no history of disease predisposing to tumour development
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Case Information

rID: 34943
Case created: 15th Mar 2015
Last edited: 1st Sep 2015
Tag: rmh
Inclusion in quiz mode: Included

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