Authors: Anca Florian1, Christophe Van De Weghe2, Jan Bogaert3 Institution: Departments of Cardiology1 and Radiology3, UZ Leuven, Belgium; AZ Nikolaas Hospital2, St-Nikolass, Belgium
Background: A 57 year old woman with a family history of premature coronary artery disease and a prolonged history of exertional chest pain underwent an exercise stress test and multislice CT coronarography which were negative for myocardial ischemia and obstructive coronary artery disease. Although there were no significant coronary stenoses, the cardiac CT showed a mass (21x16x17mm) in the right ventricular (RV) free wall with a mean-density of -60 Hounsfield units (HU) (Figure 1a, 1b). The patient was referred to our center for a cardiac magnetic resonance imaging (MRI) study for further characterization of the hypodense mass. Of note, the initial transthoracic echocardiogram showed no structural abnormalities.
Cardiac MRI: A well-defined ovoid mass (19x13x17mm) was demonstrated residing within the RV free wall. This mass appeared hyperintense on T1-weighted fast spin-echo MRI (Figure 1c, 1d) and hypointense on T1-weighted fat suppressed sequences (Figure 1e). On T2-weighted short-inversion-time inversion-recovery (STIR) fast spin-echo MRI the mass was hypointense (Figure 1f). All these findings were diagnostic for a benign cardiac lipoma. No impact on global or regional RV function and intracavitary blood flow was demonstrated (Movie 1).
Summary: Given the above images the diagnosis of cardiac lipoma was made. It was felt that this finding was not related to the patient's chest pain syndrome and other noncardiac diagnosis were entertained. As these tumors have a very low growth rate, clinical follow up was suggested and the patient will undergo a repeat cardiac MRI in 12 months.
Perspective: Primary cardiac tumors are extremely rare with 75% of them being benign1. Among benign tumors, myxomas are the most common, followed by lipomas and rhabdomyomas2. Cardiac lipomas account for 8.4% of the primary benign tumors of the heart and pericardium. Most reported cases of cardiac lipomas are described in adults and consist in single lesions. These tumors are usually incidental findings but secondary cardiac conduction disturbances and arrhythmias, including sudden death, are described3,4. In rare cases their mass effect can cause intracavitary or coronary blood flow obstruction. In symptomatic patients surgical removal of the tumor is the treatment of choice while in asymptomatic patients serial follow-up is preferred6.
CT and MRI have a great specificity for not only identifying and locating the tumor but also making a tissue-specific diagnoses based on the findings of fat attenuation and signal intensity. In addition, MRI can provide detailed information regarding the relationship of the mass to the coronary arteries (essential when preoperative planning is intended) along with information about its impact on regional and global myocardial function5.