High-grade glioma spreading along the corticospinal tract and corpus callosum

Case contributed by Dalia Ibrahim
Diagnosis certain

Presentation

Seizures and left sided weakness.

Patient Data

Age: 25 years
Gender: Male

Right frontal large infiltrative space-occupying lesion is seen spreading along the genu and body of the corpus callosum reaching the contralateral left frontal lobe and also spreading along the right corticospinal tract. The lesion elicits isointense signal on T1 WI and heterogeneous high signal on T2 WI showing small necrotic cystic areas at the genu of the corpus callosum and at the right deep frontal region. The lesion shows patches of diffusion restriction mainly seen the genu of the corpus callosum, corticospinal tract and the high frontal region.

Linear track of cystic and hemorrhagic signal, and patchy contrast enhancement is seen at the right anterior frontal region, representing sequel of stereotactic intervention.

The lesion is surrounded by vasogenic edema and exerting positive mass effect.

Based on the radiological features of the lesion especially the extension of the lesion along the corticospinal tract and corpus callosum, as well as the aggressive features including necrotic cystic areas and patchy contrast enhancement, high-grade glioma was considered most likely with gliomatosis growth pattern. 

Pathology after stereotactic biopsy revealed anaplastic astrocytoma WHO Grade III

The first sagittal image shows spread of the tumor along the corticospinal tract and corpus callosum (Yellow arrows)

The second and third images demonstrate areas of diffusion restriction mainly at the genu of the corpus callosum, corticospinal tract and the right frontal lobe.

 

Case Discussion

The case illustrates features of gliomatosis, especially spreading along the condensed white matter tracts such as corticospinal tracts and corpus callosum to involve the contralateral hemisphere.

Aggressive features such as areas of necrosis and patchy diffusion restriction suggest a diagnosis of glioblastoma. Areas of diffusion restriction helps to identify ares of high-grade transformation and to discriminate the lesion from the surrounding vasogenic edema.

The biopsy results of only grade III tumor most likely represents under-grading due to sampling bias. 

Glioblastomas have traditionally been divided into primary and secondary; the former arising de novo (90%) without a pre-existing lower grade diffuse astrocytoma and they tend to occur in older individuals, whereas the latter developed from a pre-existing lower grade diffuse astrocytoma (10%), they tend to occur in younger patients, and of uncertain significance, they have a predilection for the frontal lobes.

Anaplastic astrocytomas are WHO grade III lesions, with imaging appearances and prognosis between those of diffuse low-grade astrocytomas (WHO grade II) and glioblastomas (WHO IV). 

Lack of IDH status means this tumor should be regarded as an anaplastic astrocytoma NOS (although glioblastoma is most likely). 

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