Solitary cardiac metastasis is rarely recognized. We report a case of solitary cardiac metastasis from a rectal adenocarcinoma that was manifested as superior vena cava (SVC) syndrome. Invasion of the deep cardiac structures was so severe that only its palliative resection and right atrial reconstruction were performed using a cardiopulmonary bypass to release the SVC obstruction. The postoperative course was uneventful and the patient was discharged home without any complications. Adjuvant chemotherapy could not be performed because of the renal dysfunction. Eleven months later, the patient died from multiple metastasis of adenocarcinoma. Even though the surgery was not curative, it might be effective for release from symptoms and for elongating life expectancy.