Gliosarcoma: report of four cases with immunohistochemical findings.

Gliosarcoma (GSa) is a rare primary central nervous system neoplasm (CNS) characterized by biphasic histological pattern with both glial and sarcomatous components. Our objective is to describe the clinical, morphological and immunohistochemical features of four cases of GSa and to discuss its pathogenetic mechanisms. The male:female ratio was 3:1. The mean age was 39 years, ranging from 19 to 48. Headache was the commonest clinical symptom. All patients underwent craniotomy with microsurgery and total resection of the tumor. Diagnosis was suspected due to microscopic architecture and confirmed by detection of reticulin fibers through histochemical techniques. Immunohistochemical analysis was positive for p53 in both glial and sarcomatous cells in all four cases. EGFR was focally positive in glial cells in one case. Our findings support monoclonal origin of GSa involving the TP53 tumor-suppressor gene. However, alternative pathways cannot be ruled out.