Giant Interventricular Septal Lipoma: From Silent Mass to Sudden Cardiac Arrest

Cardiac lipomas are rare benign tumors with symptoms that vary with location, although most are asymptomatic.

A 31-year-old man, under follow-up for 10 years for an asymptomatic cardiac lipoma, was referred after an out-of-hospital resuscitated cardiac arrest while boxing. Echocardiography, computed tomography, and cardiac magnetic resonance revealed a large interventricular septal mass extending into both ventricles, with fat tissue characteristics, no ¹⁸F-fluorodeoxyglucose avidity on positron emission tomography, and with minimal growth over the past 10 years. Coronary angiography was normal. Holter monitoring showed 5 runs of nonsustained ventricular tachycardia.

Resection of such a large tumor poses major surgical challenges. A decision was made to proceed with extravascular implantable cardioverter-defibrillator placement for secondary prevention, with surgical resection or heart transplantation to be considered in the future in case of recurrent malignant ventricular arrhythmias.

This case illustrates the challenges of managing a large cardiac lipoma and underscores the importance of careful long-term follow-up.