A case of a large primary cardiac sarcoma on the left ventricular free wall is reported. Although the definitive diagnosis of this tumor was not made preoperatively, total excision was planned for rapid diagnosis and optimal procedure. However, the operation was discontinued due to intraoperative diagnosis of malignancy. As a result, the patient suffered from the symptoms of cardiac tamponade caused by the large tumor. We discuss the surgical strategy to provide therapeutic benefit for possible patients in the future. In conclusion, an aggressive attempt at volume reduction such as cardiac autotransplantation may relieve the symptoms, even though such surgery would only be palliative.