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Arthur & Sonia Labatt Brain Tumour Research Centre

Oligodendroglial tumour and mixed gliomas

Oligodendroglioma image

These tumours are not common in children and are slow growing. Oligodendrogliomas develop from glial cells called oligodendroglia and are often treated with surgery followed by radiation therapy. Genetic alterations in oligodendrogliomas differ significantly from those commonly found in diffuse astrocytomas. Loss of heterozygosity (LOH) in chromosome 1p And 19q are characteristic genetic signature of Oligodendroglioma.



Anaplastic Oligodendroglioma image


Anaplastic Oligodendroglioma
An oligodendroglioma with focal or diffuse signs of anaplasia in the form of increased cellularity, nuclear atypia, cellular pleomorphism and high mitotic activity. Microvascular proliferation and necrosis may be present. According to WHO, anaplastic oligodendroglioma corresponds histologically to WHO grade III.



Mixed Gliomas
Mixed gliomas, also called mixed type tumours, are composed of two or more distinct neoplastic counterparts of the normal glial cell, usually astrocytes and other glial cell types. Their treatment generally is the appropriate therapy for the most anaplastic or malignant tumour cell found in the mix. A mixed tumour composed of oligodendroglioma and anaplastic astrocytoma, for example, would be treated as if it were a pure anaplastic astrocytoma.

Oligoastrocytoma image


Oligoastrocytoma (WHO grade II)
The tumour composed of two distinct neoplastic cell types morphologically resembling the tumour cells in oligodendroglioma or low-grade diffuse astrocytoma of WHO grade II. The oligodendroglial and astroglial components may either be diffusely intermingled or separated into distinct areas.

Anaplastic Oligoastrocytoma (WHO grade III)
Anaplastic oligoastrocytomas are rapidly growing tumours that correspond histologically to WHO grade III. They are predominantly hemispheric tumours mainly in the frontal and temporal lobe.