ABSTRACT
Leiomyosarcoma is an extremely rare mass of the heart. A 50 years-old female complained of palpitation and dyspnea was diagnosed as myxoma. The tumour is removed in an urgent operation and leiomyosarcoma was pathologicaly diagnosed. Post-operative CT scan revealed no metastases. Three months after the surgery, dyspnea and palpitation became resymptoms of her. Transthoracic and transesophageal echocardiography revealed a mobile left atrial mass. And she was reoperated 3 months after first operation. There was a mobile gelatinous mass in the left atrium stretching through to the mitral valve. The tumor was resected and mitral valve replaced.