Preoperative identification of intraatrial tumor is uncommon. A 23-year-old woman presented with local recurrence and pulmonary metastases after previous resection of a clavicular sarcoma. Evaluation by computed tomography revealed bilateral pulmonary masses. Due to the size and proximal location, magnetic resonance imaging and transesophageal echocardiography were performed, revealing a large intraatrial mass. She then underwent staged surgical excision without intraoperative complications. We summarize this case and review risk factors for intracardiac extension and prevention of tumor emboli.