ABSTRACT
We report a case of a 24-year-old woman who presented with orthopnea, in whom an echocardiographic exam showed a very large mass in the left atrium. We diagnosed this as cardiac failure due to the tumor occupying it. Although the tumor malignancy remained unclear, we had to perform emergency surgery to excise the tumor. The tumor was excised in its entirety, including the interatrial septum and a large segment of the left atrial wall. We reconstructed them with the autologous pericardium. The pathological diagnosis was undifferentiated pleomorphic sarcoma. Conventional adjuvant chemotherapy and radiotherapy was performed. Primary cardiac malignant tumor prognosis is very poor, but she has survived over 1 year without recurrent symptoms after complete excision and adjuvant therapy. In addition to reporting this case, we discussed the diagnosis and treatment of undifferentiated pleomorphic sarcoma.