To analyze the clinical, morphological, and immunohistochemical features of gliosarcoma (GS).

The clinical and pathologic findings for five cases of GS diagnosed at Taian City Central Hospital were evaluated. Hematoxylin and eosin staining, reticulin staining, and immunohistochemistry were performed on archival paraffin sections.

Among the five patients, 4 were male and 1 was female; 4 had primary GS, and 1 had secondary GS to intracranial glioblastoma. The average age was 54.2 years. The main symptoms were headache, nausea, blurred vision, numbness of limbs and dysphoria, indistinct speech and so on. Histologic examination showed a biphasic pattern in all cases, and 4 cases were mainly composed of sarcoma while the gliomatous component was intertwined with the sarcomatous component, so it was not easy to recognize the gliomatous component. In 1 case, the two components were clearly divided into two parts, so they could be easily recognized. All cases were negative for EGFR, and 4 cases were P53(+ ). The gliomatous component was positive for GFAP and Olig-2, while the sarcomatous component was positive for Vim, with reticular fibers around each cell. The Ki-67 index ranged from 30% to 70%. Five patients had follow-up data available. Two patients were disease-free for 4.5-21.0 months and three patients died of the disease at 3 to 10 months after the operation (mean duration of survival of 6 months).

GS with distinct gliomatous and sarcomatous components is a distinct entity of IDH-1 wild-type glioblastoma. GFAP immunostaining and reticulin staining are helpful in confirming the diagnosis. The incidence of TP53 mutation in gliosarcoma is very high while there are few EGFR and IDH-1 mutations.