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Axial MRI of Gliosarcoma
|Cell of origin||Glial|
|Treatment||Surgery, Radiation, Chemotherapy|
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.
Gliosarcoma accounts for about 2% of all GBMs. The mean age of occurrence is 53 years. There is a male predominance (1.8:1).
Gliosarcomas are most often supratentorial, occurring in descending frequency in the temporal, frontal, parietal and occipital lobes.
Most patients present with new-onset seizure or paresis.
Angiographic examination demonstrates a mixed dural and pial vascular supply. On MRI, these lesions may be mistaken for a meningioma or hemangiopericytoma.
Gliosarcomas are biphasic lesions composed of a firm, sarcomatous component, often located superficially, and a more typical gliomatous component.
A biphasic tissue pattern displaying gliomatous and mesenchymal (e.g. neoplastic spindle cells imbedded in a reticulin-positive stroma) components is necessary for diagnosis.
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.
Large trials have failed to demonstrate a difference in outcomes for gliosarcoma and GBM.