A 51-year-old woman presented with a rare case of temporal gliosarcoma manifesting as a 2-month history of headache that rapidly penetrated the middle fossa floor postoperatively and metastasized to the lung. The tumor included an anteroinferior component consisting of a sarcomatous lesion adjacent to the middle fossa floor, and a posterosuperior component consisting of a gliomatous lesion. The MIB-1 index of the sarcomatous component was 47.5%, and that of the gliomatous component was 36.5%. In addition to the highly proliferative nature of the sarcomatous component, the craniotomy with partial excision of the dura mater might have accelerated the tumor penetration through the temporal base and the hematogenous metastasis to the lung.