The case of a 65-year-old female patient with a pedunculated left atrial angiosarcoma is presented. Histologically, the tumor was composed of vascular spaces lined by atypical cells with similar cells in the solid portion of the tumor. Immunohistochemical stain for factor VIII-related antigen was positive in the cells forming vascular spaces. Immunoperoxidase stain for Ulex Europaeus I lectin was positive in cells lining vascular lumina and in individual cells in the solid portion of the tumor. Cardiac angiosarcomas characteristically occur in men, arise in the right atrium, are large mural masses that infiltrate widely at the time of presentation, and are usually rapidly fatal. Review of the literature reveals that this case of cardiac angiosarcoma is unusual by virtue of its occurrence in a female, left atrial location as a polypoid lesion, and prolonged symptom-free survival after surgical resection alone. Cardiac angiosarcoma may clinically and radiologically simulate myxoma.