Cancerous Left Atrial Mass: A Rare Case Report of Cardiac Sarcoma in a 71-Year-Old Woman

Background: Diagnosing cardiac masses is inherently complex due to overlapping differential diagnoses, including thrombi, vegetations, artifacts, and tumours. Primary cardiac tumours are exceptionally rare, with a prevalence between 0.001% and 0.3%. Approximately 25% of these are malignant, with cardiac sarcomas being a rare but aggressive subset. These tumours may manifest with symptoms such as arrhythmias, obstruction of blood flow, and systemic signs, necessitating timely and precise differentiation for optimal patient management. Methods: This report examines a case of malignant cardiac sarcoma in the left atrium of a 71-year-old woman. Diagnostic modalities included electrocardiography, transthoracic echocardiography, transesophageal echocardiography, and CT, with biopsy confirming the diagnosis. Key clinical approaches, imaging findings, and management strategies are detailed in this article. Results: The patient presented with gastrointestinal symptoms, pneumonia, and heart block. Imaging revealed a 3 × 4.2 cm immobile mass in the left atrium. Initial differentials included thrombus and benign tumours, but further investigations confirmed malignancy. Biopsy established the final diagnosis of high-grade sarcoma. Given the advanced stage, palliative care was selected. Discussion: Differentiating cardiac masses, including thrombi and benign and malignant tumours, requires a multimodal imaging approach complemented by histopathological analysis. Early diagnosis and a multidisciplinary care strategy are pivotal, though prognosis for cardiac sarcomas remains poor due to their aggressive nature.