Malignant Phyllodes Tumor With Left Atrial and Bilateral Pulmonary Metastases Treated Surgically: A Case Report

We report a rare case of a malignant phyllodes tumor with left atrial and bilateral pulmonary metastases. A woman in her 40s had undergone a tumorectomy for a benign phyllodes tumor of the right breast. Two years later, she developed local recurrence diagnosed as a malignant phyllodes tumor and underwent total mastectomy. At follow-up two years after surgery, computed tomography (CT) revealed bilateral pulmonary metastases with tumor extension into the pulmonary veins and left atrium. Echocardiography showed a mobile left atrial mass. Due to the risk of cardiac complications, surgical resection was performed. The patient underwent left atrial tumor resection, right lower lobectomy, and left upper lobe partial resection. Histopathological findings confirmed metastatic malignant phyllodes tumor in all specimens. Postoperatively, she received five cycles of doxorubicin, but the disease progressed, and she passed away six months after surgery. Intracardiac metastasis from a malignant phyllodes tumor is extremely rare and often fatal. Prompt surgical intervention may be beneficial in select cases. In the future, with the development of effective drug therapy for malignant phyllodes tumors, long-term survival may be expected with multidisciplinary treatment, including surgery, even in cases of distant metastasis.