Right Ventricular Lipoma With an Aneurysm-Like Appearance: A Case Report of Successful Surgical Resection.

Cardiac lipomas are rare benign tumors, comprising ~8.4% of all benign primary cardiac tumors. They can arise in various cardiac chambers, though right ventricular (RV) involvement is uncommon. While most cardiac lipomas are asymptomatic and detected incidentally, those originating in the RV may present with unusual features, including pseudoaneurysmal appearances. Such anomalous structural changes can increase right atrial and ventricular pressures, placing the patient at risk of progressive hemodynamic compromise and rupture. We report a case of an RV lipoma initially diagnosed as a pseudoaneurysm that was successfully resected. An 81-year-old man with an incidentally detected RV mass was admitted to our hospital. Contrast-enhanced computed tomography (CT) showed that the mass contained a large amount of fatty tissue with a pseudoaneurysmal appearance, suggesting it to be an RV lipoma. Transthoracic echocardiography revealed to-and-fro blood flow between the RV and the aneurysm through the slits. Although the patient was asymptomatic, considering that the right atrial pressure and RV end-diastolic pressure (RVEDP) were 12 and 25 mmHg, respectively, based on right heart catheterization, we decided to perform surgical resection to avoid the risk of future enlargement or rupture. A fat-covered mass was found in the anterior aspect of the RV and resected. The residual RV and slits were closed using a patch. The patient had a good postoperative course with normalized right heart pressure and was discharged on the postoperative day 14. While the indications for surgery in asymptomatic patients remain unclear due to the rarity of this condition, these findings suggest that early surgical intervention may be considered in cases presenting with structural compromise and elevated right-sided pressures.