Cardiac involvement in metastatic breast cancer

Metastatic disease is the most common cause of death in breast cancer. Although cardiac involvement has been reported in 12% to 30% of cases, intra-atrial involvement is rare. In this report we describe a 41-year-old woman with metastatic breast cancer whose left atrium was invaded by a metastatic tumor that resulted in intermittent left ventricular in-flow obstruction. Such a presentation has not been described previously in metastatic breast cancer. The pertinent literature is reviewed.