When the Primary Malignancy Is in the Heart
A 46-year-old man with no significant prior medical history or cardiovascular risk factors initially presented with nonexertional chest pain. Electrocardiogram showed no abnormality (Figure 1). Transthoracic echocardiography performed in an outpatient office showed normal biventricular and valvular function but noted a largely homogenous mass in the left atrium measuring 2.3 x 3 cm with no visualized stalk from the interatrial septum (Figure 2). Transesophageal echocardiogram demonstrated 2.6 x 3.3 cm mass in the left atrium protruding into the left upper pulmonary vein (Figure 3). Pre-surgical coronary angiogram revealed normal coronary arteries. Given the location and frequency of left atrial mass, the preoperative diagnosis was left atrial myxoma.
Figure 1: Electrocardiogram on Initial Presentation
The patient underwent endoscopic robotic resection of the mass performed with extended endarterectomy of the left pulmonary veins origin and an extensive endothelial-intima resection of the entire left atrium down to the mitral valve leaflets. The extensive resection produced incompetency of the mitral valve that required replacement with a 27 mm bioprosthetic mitral valve. The pathology specimen showed high-grade, undifferentiated sarcoma with spindle and epithelioid morphology (Figure 4), with tumor extension to the inked edges that conferred a positive margin. The patient was started on monthly adjuvant systemic chemotherapy (adriamycin, ifosfamide, and mesna) and completed a total of 6 cycles of adjuvant chemotherapy, with a cumulative doxorubicin 150 mg/m2, ifosfamide 15 g/m2, and mesna 15 g/m2. He also received dexrazoxane 250 mg/m2 for 2 doses to mitigate potential anthracycline cardiotoxicity. Serial imaging surveillance with cardiac magnetic resonance imaging (MRI) and computed tomography of the chest performed every 3 months initially showed no evidence of residual or metastatic disease until cardiac MRI performed 12 months later found small punctate myocardial scar along the mid anterior wall. Another MRI 6 months later revealed new myocardial mass in the mid anterior wall (2.8 x 1.6 cm) with central necrosis (Figure 5), findings consistent with recurrent primary cardiac sarcoma. Cardiothoracic surgeons determined that he was not a candidate for reoperation given the extent and location of the recurrent sarcoma.
What is the most common malignant cardiac tumor?