Abstract 14737: A Case of an Intracardiac Sarcoma Arising From Metastatic Spread of a Primary Phyllodes Tumor of the Breast

Abstract

Background: Malignant phyllodes tumors with cardiac involvement are rare, presenting diagnostic and management challenges. The benefits of medical and surgical therapies remain unclear. Large-bore aspiration devices are currently only approved for retrieval of venous thromboemboli but may present a valid option for diagnosis and treatment of intracardiac masses in high risk patients. Case Summary: We present the case of a 57-year-old female with a malignant phyllodes tumor of the breast and bilateral pulmonary emboli who presented with an incidental complex intracardiac mass on transthoracic echocardiography (1). A follow-up transesophageal echocardiogram demonstrated masses within the superior vena cava, right atrium, and right ventricle (2a-2b). Aspiration thrombectomy was performed given clinical stability and concern for thrombi with high risk of worsening clot burden. A large-bore aspiration device was used to retrieve the masses in multiple passes (3), which were pathologically consistent with spindle cell sarcoma. A cardiac MRI was completed following aspiration, and multiple mobile masses persisted in the right ventricle (4). The patient was discharged on day nine of hospitalization with therapeutic chemotherapy planned. She had one session of chemotherapy before a fatal cardiac arrest from unknown cause three months after discharge. Discussion: Phyllodes tumors rarely metastasize to the heart, and effective modalities for their diagnosis and management are unclear. Treatment strategies include wide surgical resection of the primary tumor, however mortality remains high in the setting of metastatic spread. Current guidelines recommend following principles of soft tissue sarcomas with chemotherapy. Large-bore aspiration devices may be an effective way to resect intracardiac tumors for both diagnostic and therapeutic purposes as an alternative to invasive surgical intervention for high-risk patients.