A primary pericardial undifferentiated sarcoma invading the right atrium and superior vena cava.

Primary undifferentiated cardiac sarcomas are rare. The literature demonstrated that 81% of primary cardiac undifferentiated sarcomas arose in the left atrium. We reported herein a case of 56-year-old male farmer with a primary pericardial undifferentiated sarcoma, which was revealed only on echocardiography but not computed tomography. The tumor, which invaded the right atrium and superior vena cava, was not completely resected.