Delayed cardiac metastasis from phyllodes breast tumor presenting as cardiogenic shock

Malignant metastases to the heart and pericardium, which occur far more often than do primary cardiac neoplasms, typically lead to fatal outcomes. The phyllodes tumor is a rare, predominantly benign fibroepithelial breast neoplasm with variable malignancy potential. Herein, we describe the case of a 35-year-old woman who, 3 years after undergoing a simple mastectomy for a rapidly enlarging breast neoplasm, presented with cardiogenic shock and was found to have a large right ventricular tumor that obstructed the right ventricular outflow tract. Despite successful resection of the ventricular mass and a right atrial mass of organized thrombus, the patient died 8 days postoperatively of multiorgan failure due to severe right ventricular dysfunction. Histopathologic analysis determined that the right ventricular mass was a malignant, metastatic phyllodes tumor. To our knowledge, this is only the 2nd reported case of a phyllodes tumor that metastasized to the heart and presented as an intracavitary mass with cardiogenic shock. In addition to discussing our patient's case, we review the pertinent medical literature.