When Cancer Reaches the Heart: Imaging Unravels a Rare Sarcoma Metastasis

In a striking reminder that cancer can infiltrate even the body’s most protected organs, clinicians have documented the case of a 36-year-old man whose soft-tissue sarcoma spread to his heart, forming a large mass in the left atrium that partially blocked the veins returning oxygenated blood from his lungs. The report, published in Clinical Case Reports, details how a carefully sequenced combination of echocardiography, cardiac magnetic resonance imaging, and computed tomography allowed physicians to characterize the tumor, understand its hemodynamic consequences, and guide treatment decisions in a situation where surgery was no longer feasible. The case offers a vivid illustration of both the rarity and the diagnostic complexity of cardiac metastasis, a complication that autopsy studies suggest occurs in only about 2.3 to 18.3 percent of cancer patients.

Soft-tissue sarcomas, a heterogeneous family of malignancies arising from connective tissues such as muscle, fat, and blood vessels, are known to have a comparatively high propensity for spreading to the heart via the bloodstream. Yet cardiac involvement often remains clinically silent until the tumor reaches a critical size or occupies a strategically damaging location. In this patient, four years after an initial diagnosis treated with surgery, radiotherapy, and chemotherapy, the first warning signs were progressive shortness of breath and intermittent chest pain over several weeks. He had no prior cardiovascular history, which made the eventual findings all the more consequential. On examination he was hemodynamically stable, with a heart rate of 88 beats per minute, blood pressure of 128 over 76 millimeters of mercury, and oxygen saturation of 94 percent on room air. A soft systolic murmur was heard at the apex of the heart, and breath sounds were diminished over the right lower lung field, hinting at pathology within the chest rather than a primary cardiac disorder.

The diagnostic journey began with the simplest tools. An electrocardiogram showed sinus rhythm with nonspecific ST-T changes, findings that are easy to dismiss but consistent with myocardial stress. A chest X-ray revealed an enlarged cardiac silhouette and a mass in the right lung, prompting the team to proceed to transthoracic echocardiography. That ultrasound-based study proved pivotal. It demonstrated mild-to-moderate left ventricular systolic dysfunction, with the heart’s ejection fraction reduced to between 40 and 45 percent, meaning the main pumping chamber was operating well below its normal capacity of roughly 55 to 70 percent. The chambers and valves were otherwise structurally normal apart from mild mitral and tricuspid regurgitation, minor backflows of blood through the valves that often accompany altered cardiac loading conditions.

The echocardiogram’s decisive finding was a large, heterogeneous mass measuring approximately 2.7 by 3.2 centimeters within the left atrium, the chamber that receives oxygenated blood from the lungs before passing it to the left ventricle. Critically, the mass was intruding upon the right pulmonary veins, the vessels that deliver blood from the right lung into the atrium. This anatomical relationship explained much of the patient’s symptomatology: by obstructing pulmonary venous return, the tumor reduced the filling of the left ventricle, compounding the ventricle’s already weakened pumping function and contributing to breathlessness and chest discomfort. A slightly elevated pulmonary artery pressure was also noted, plausibly a secondary response to the underlying lung pathology and the left-sided hemodynamic burden.

To define the mass’s full extent and tissue characteristics, the clinicians turned to cardiac magnetic resonance imaging, the gold standard for characterizing cardiac masses. The CMR scans, acquired using steady-state free precession sequences, confirmed a far larger lesion than the echocardiogram alone suggested: a mass of 120 by 95 millimeters extending from the right lung into the left atrium through the pulmonary vein. The tissue was heterogeneous, showing mild perfusion and enhancement after contrast administration, a pattern typical of metastatic tumors and one that helps distinguish viable tumor from avascular structures such as thrombus. The imaging also revealed multiple metastatic nodules scattered through the left lung, painting a picture of widespread disease.

CMR added functional detail that proved equally important. The right ventricle, the chamber that pumps blood to the lungs, showed mildly reduced function with a right ventricular ejection fraction of 43 percent, although the chamber itself remained of normal size, indicating that some compensatory reserve persisted. The scans also detected a localized increase in T1 signal within the myocardium, the heart muscle itself, a finding the authors interpreted as possible chemotherapy-induced cardiomyopathy, a well-recognized late toxicity in patients treated with cardiotoxic agents. Trivial aortic insufficiency was also noted. Together these observations underscored that the patient’s heart was being assaulted on multiple fronts: by direct tumor invasion, by obstruction of venous return, and by the residual cardiac cost of his earlier cancer therapy.

A computed tomography scan of the chest completed the multimodal picture, confirming multiple pulmonary metastases with the dominant right-sided lesion extending directly into the left atrium. The concordance of findings across echocardiography, CMR, and CT was essential, because the differential diagnosis of a cardiac mass is broad and consequential. The clinicians systematically considered primary cardiac tumors such as atrial myxoma, the most common benign tumor of the left atrium, which can appear heterogeneous on imaging but typically does not invade surrounding structures, and rhabdomyosarcoma, a rare primary malignancy. They also weighed lung cancer metastasis, intracardiac thrombus, which lacks enhancement on CMR, infective endocarditis with its vegetations, cardiac sarcoidosis, fatty tumors such as lipoma and liposarcoma, hemangioma, and pericardial cysts. The patient’s sarcoma history, combined with the invasive growth pattern and enhancement characteristics on CMR, strongly favored metastatic disease, and the diagnosis was supported by clinical progression.

With the disease too extensive for surgical resection, the case was referred to a multidisciplinary tumor board comprising oncologists, cardiologists, and radiologists. The panel opted for palliative chemotherapy combined with targeted radiation therapy aimed at symptomatic relief. The outcome was encouraging: the patient experienced reduced dyspnea and chest pain, and follow-up imaging and clinical assessments documented improved cardiac function. This response aligns with recent evidence suggesting that continued antitumor therapy can improve survival even in patients with cardiac metastases, a population once considered to have uniformly dismal prospects. The authors emphasize that the positive trajectory followed directly from early detection and coordinated, multidisciplinary management rather than from any single intervention.

The broader lessons of the case extend beyond this single patient. Cardiac metastasis is rare but increasingly recognized as advances in imaging and cancer therapy extend survival long enough for late complications to emerge. Symptoms such as progressive breathlessness and chest pain in a patient with a known malignancy, particularly one of the sarcoma family, should prompt a low threshold for cardiac evaluation rather than attribution to more common causes. Transthoracic echocardiography remains the accessible first-line test, but its field of view can underestimate tumor extent, as it did here, where CMR revealed a mass several times larger than the initial measurement. The integration of multiple modalities, each contributing complementary anatomical, tissue-characterization, and functional information, was pivotal in establishing the diagnosis, mapping the disease, and steering therapy. As the authors conclude, early recognition and a coordinated multidisciplinary strategy remain essential to improving outcomes, even when metastatic disease is extensive, and the case stands as a testament to how modern cardiac imaging can turn a diagnostic dilemma into an actionable treatment plan.

Subject of Research: Cardiac metastasis from soft-tissue sarcoma diagnosed with multimodal imaging

Article Title: Metastatic Soft Tissue Sarcoma With Cardiac Involvement: A Case Study on the Role of Multimodal Imaging in Diagnosis and Management

Article References: Alizadehasl, A., Akhavan, S., Jebelli, S. F. H., najmabadi, A. F., Marzbali, N. A., Yousefimoghaddam, F., Haghazali, M., & Rafiei, S. (2026). Metastatic Soft Tissue Sarcoma With Cardiac Involvement: A Case Study on the Role of Multimodal Imaging in Diagnosis and Management. Clinical Case Reports, 14(9), Article e72112. https://doi.org/10.1002/ccr3.72112

Image Credits: AI Generated

DOI: 10.1002/ccr3.72112

Keywords: cardiac metastasis, soft-tissue sarcoma, echocardiography, cardiac MRI, computed tomography, left atrial mass, pulmonary veins, multidisciplinary care, palliative chemotherapy, case report, oncology, heart failure