Left Atrial Leiomyosarcoma Extending into the Posterior Mediastinum and Mimicking a Left Atrial Myxoma

<p><strong>Background:</strong> Intracardiac malignancies are extremely rare and hard to detect or differentiate preoperatively.</p><p><strong>Case Report:</strong> We present a 48-year-old female patient who was diagnosed primarily with left atrial myxoma and taken into emergency surgery. The tumor extended into the pulmonary veins and infiltrated the atrial endocardium, and the histopathologic diagnosis was leiomyosarcoma. The left atrial endocardium was successfully peeled off with the tumor and complete resection was achieved.</p><p><strong>Conclusion:</strong> The possible malignant nature of intracardiac masses should be kept in mind, especially in middle-aged patients. The extent of the tumor must be determined in elective cases to establish the proper strategy for complete resection, which is the only chance of successful treatment for this lethal disease entity. Endocardial peeling is warranted for successful removal of the tumor mass in leiomyosarcoma.</p>