Abstract
Gliosarcoma is a malignant glial neoplasm which consists of both gliomatous and sarcomatous components. It arises commonly in the cerebral hemispheres of middle-aged individuals and shows a characteristic “biphasic” histopathological appearance. The gliomatous component usually shows the features similar to those of glioblastoma, and the sarcomatous component exhibits an appearance of spindle cell sarcoma resembling fibrosarcoma. Cytogenetic studies have revealed that gliosarcoma is a variant of primary （de novo） glioblastoma. The histogenesis of gliosarcoma has been controversial for a long time, but it has been established in recent years that the sarcomatous component of gliosarcoma is derived from the “heterodifferentiation” （or “neometaplasia”） of glioblastoma cells. It has also been presumed that the “epithelial-mesenchymal transition” phenomenon plays an important role in the histogenesis of gliosarcoma.
