A 61-year-old woman presented with dementia, 7 years after an operation for retroperitoneal leiomyosarcoma. Magnetic resonance imaging (MRI) revealed enhanced masses with perifocal edema in the bilateral frontal regions and a very small mass in the right medial frontal region. The tumors in the bilateral frontal regions were completely removed surgically, and γ-knife radiotherapy was administered for the very small tumor in the right medial frontal region. The histological diagnosis was metastatic leiomyosarcoma. Postoperatively, an MRI showed that the perifocal edemahad decreased, and the symptoms gradually improved. Cerebral metastasis from a retroperitoneal leiomyosarcoma is very uncommon. Ideally, the tumors should be surgically removed because radiotherapy and chemotherapy are apparently ineffective. A combination of complete surgical removal and γ-knife radiotherapy may be effective in prolonging patient survival.