When Heart Failure Hides a Sarcoma

Cardiac sarcomas are rare and highly aggressive primary cardiac tumors characterized by rapid growth, local invasion, and early metastasis, most commonly to the lungs, liver, and brain. Clinical presentation is nonspecific and largely depends on tumor location. Diagnosis relies on imaging, with transthoracic echocardiography as the first-line modality, while cardiac magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET) provide complementary information for staging, surgical planning, and treatment monitoring. Surgical resection remains the cornerstone of therapy. Chemotherapy, radiotherapy, and emerging targeted or immunotherapies have shown limited benefit, highlighting the need for novel treatment strategies. We describe the case of a 71-year-old woman with multiple comorbidities, including heart failure with preserved ejection fraction, who presented with dyspnea, nocturnal breathlessness, edema, and cough. She was initially treated for decompensated heart failure with good short-term improvement. Echocardiography unexpectedly revealed a 50 × 30 mm left atrial mass infiltrating the mitral valve and septa, producing severe mitral stenosis and regurgitation. Cardiac MRI confirmed a sarcomatous lesion, considered unresectable due to extensive involvement. Staging CT identified an osteolytic lesion in the D12 vertebral body. A biopsy confirmed high-grade sarcoma, and PET showed no further spread. Given the rapid progression and recurrent heart failure, systemic therapy was not initiated, and the patient was transitioned to palliative care, passing away five months after diagnosis. This case highlights the diagnostic and therapeutic challenges of primary cardiac sarcomas. Primary cardiac sarcomas should be considered in patients with unexplained heart failure or intracardiac masses. Multidisciplinary management, improved systemic strategies, and timely palliative care are essential to address the aggressive biology and limited treatment options of this disease.