A Case of Transmural Lipoma of the Right Atrium

Abstract

Primary cardiac tumors are a relatively rare disease. About 75% of primary cardiac tumors are benign. The most common histological type is myxoma, followed by cardiac fibroma, lipoma, etc. We report a case of a 53-year-old female patient admitted to the hospital due to "repeated palpitations and tightness of breath for 5 years, worsened for 2 days." Preoperative transthoracic echocardiography revealed a hypoechoic mass approximately 3.1 cm x 3.0 cm in size within the right atrium, suggesting an intracardiac mass: nature? Chest computed tomography (CT) indicated a fat-density nodule within the right atrium, with a larger cross-sectional size of about 3.0 cm x 2.5 cm, suggesting a lipoma. The patient underwent excision of the right atrial mass under cardiopulmonary bypass. Intraoperative transesophageal echocardiography (TEE) revealed a mass within the right atrium, closely connected to the atrial wall, with no signs of tricuspid valve obstruction. Exploration during surgery revealed a yellow, smooth-surfaced mass approximately 3.0 cm x 3.0 cm in size, penetrating the right atrial wall, from which the mass and an additional 2mm margin of the right atrial wall were completely excised. A suitable-sized bovine pericardial patch was used to repair the defect in the right atrial wall. Postoperative TEE showed the disappearance of the right atrial mass. The postoperative pathological result indicated a lipoma. Cardiac lipoma is a rare benign primary cardiac tumor. The common sites of occurrence of this tumor are the right atrium, left ventricle, and pericardium. Based on their location, cardiac lipomas can be divided into three types: subepicardial, intramyocardial, and subendocardial lipomas, with subendocardial lipomas being the most common, accounting for over 50% of primary cardiac lipomas. Clinical symptoms largely depend on the size and growth location of the tumor, and it is generally believed that most cardiac lipomas are asymptomatic. Symptomatic lipomas can be treated with curative surgical excision. Transmural lipomas of the right atrium are relatively rare, and such lipomas may affect adjacent structures both inside and outside the atrial wall. Although the lipoma in this case did not significantly affect valve function or blood flow, the patient experienced repeated symptoms of palpitations and tightness of breath. Despite being a benign tumor, the lipoma in this case exhibited transmural growth within the right atrium, showing a certain degree of invasiveness, making surgical excision an effective treatment method.