An asymptomatic 67-year-old woman was found to have renal tumors by chance on a screening abdominal ultrasound examination. Although surgical resection was planned for both a diagnostic purposes and treatment, she suddenly developed hemorrhage from the cerebral metastasis in the left thalamus, and the surgical procedure was postponed. Irradiation with a gamma knife was performed to treat the cerebral metastasis; however, the patient's general condition quickly worsened, and she died six months after diagnosis. An autopsy showed typical spindle cells in the primary lesion with multiple metastases. Renal spindle cell carcinoma is a relatively rare type of the renal carcinoma that is both very aggressive and exhibits a poor prognosis, with few established treatments. Hence, obtaining an early diagnosis on abdominal ultrasound is important in such cases.