Gliosarcoma: clinical experiences and additional information with MR spectroscopy.

Gliosarcomas represent about 2% of glioblastoma multiforme (WHO grade IV). They have mixed features of glial and sarcomatous components. The clinical presentation and prognosis are similar to glioblastoma. Between 1997 and 2006, 16 patients with intracranial gliosarcoma were treated in the Department of Neurosurgery in Kiel, Germany. Median age was 63 years (52-79 years). Eleven patients were men and five were women. Six tumors were in the frontal lobe, four in the temporal lobe, three parietal, two in the thalamic area and one in the occipital lobe. Pre-operatively, in two patients, we could perform magnetic resonance (MR) spectroscopy. There was lactate peak, which is a sign of local necrosis and hypoxia. Median survival time in our patient group was 7 months (2-11 months). On histological examination, we found glial fibrillary acid protein positive cells surrounded by sarcomatous tissue and reticular fibers. The proliferation index MIB-1 was between 20 and 70%. The prognosis in this patient group is still poor. MR spectroscopy and location of the tumor adjacent to the dura with inhomogeneous contrast enhancement might give hints pre-operatively for the differential diagnosis of gliosarcoma. Further works with adjuvant chemotherapy are necessary.