Gliosarcoma
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Gliosarcoma | ||||
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![]() Axial MRI of Gliosarcoma | ||||
Tumor Class | Astrocytoma | |||
Cell of origin | Glial | |||
WHO Grade | IV | |||
Survival | 6 Months | |||
Treatment | Surgery, Radiation, Chemotherapy | |||
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Radiographic Features |
Contents |
Definition
Gliosarcoma is a histological variant of Glioblastoma multiforme (GBM) characterized by a biphasic tissue pattern with alternating areas of glial and mesenchymal differentiation. Gliosarcoma corresponds to WHO Grade IV astrocytoma.
Epidemiology
Gliosarcoma accounts for about 2% of all GBMs. The mean age of occurrence is 53 years. There is a male predominance (1.8:1).
Localization
Gliosarcomas are most often supratentorial, occurring in descending frequency in the temporal, frontal, parietal and occipital lobes.
Clinical presentation
Most patients present with new-onset seizure or paresis.
Imaging
Angiographic examination demonstrates a mixed dural and pial vascular supply. On MRI, these lesions may be mistaken for a meningioma or hemangiopericytoma.
Macroscopy
Gliosarcomas are biphasic lesions composed of a firm, sarcomatous component, often located superficially, and a more typical gliomatous component.
Histopathology
A biphasic tissue pattern displaying gliomatous and mesenchymal (e.g. neoplastic spindle cells imbedded in a reticulin-positive stroma) components is necessary for diagnosis.
Molecular genetics
Gliosarcomas possess a complement of molecular mutations similar to those seen in GBMs (see Molecular genetics of Gliomagenesis), but generally lack evidence of EGFR amplification of overexpression.
Prognosis
Large trials have failed to demonstrate a difference in outcomes for gliosarcoma and GBM.