Cardiac metastases are rare. Herein, we report a case of a 37-year-old female patient with a history of borderline breast phyllodes tumor (PT) treated by surgery, admitted to our department for concomitant cardiac and pulmonary metastases of malignant PT. Cardiac metastasis occurred through direct extension from pulmonary metastasis to the left atrium via the right inferior pulmonary vein, causing severe mitral valve obstruction. Although the total surgical removal of metastases, the patient had a huge relapse of the mediastinal metastasis resulting in her death.