Pericardial Constriction Caused by a Giant Lipoma
We report the case of a 52-year-old woman who was referred to our center for an unusually large constrictive pericardial mass. Her medical and surgical history included obstructive sleep apnea, reduction mammoplasty, breast cancer, obesity (body mass index = 44.63 kg/m2), and latex allergy. She complained of exercise intolerance and progressive dyspnea (New York Heart Association class III) for 6 months. Physical examination revealed low heart sounds without paradoxal pulse. Her chest x-ray showed an enlarged cardiac silhouette (Figure 1A), and her ECG was in sinus rhythm with low QRS voltage in leads aVL and III (Figure 1C). On cardiac CT scan, we observed a very large, well-delimited, noninvasive lipidic mass (20×17×15 cm) surrounding a normal-size heart (Figure 2A). No additional anomaly was found. Transthoracic echocardiography was challenging, with obesity and the fatty mass limiting echocardiographic windows. Therefore we performed a cardiac MRI, which showed normal biventricular size and function and no significant valvular disease. Cardiac MRI depicted a well-delimited intrapericardial mass with high signal intensity on T1-weighted images (Figure 3). The mass signal was fully nulled with application of fat saturation, confirming a diagnosis of giant intrapericardial lipoma. There was no gadolinium enhancement in the myocardium, pericardium or mass. Pericardial thickness was normal. On real-time cine imaging, there was an inspiratory inversion of the interventricular septum curvature toward the left ventricle, indicating ventricular interdependence and suggesting that the giant pericardial lipoma caused pericardial constriction (Movie I in the online-only Data Supplement). Pericardial constriction was further confirmed at cardiac catheterization (Figure 4). The left and right ventricular end-diastolic pressures were equal without a “dip and plateau” aspect. The pulmonary artery pressure was normal (36/21/28 mm Hg), but the right atrial pressure (17 mm Hg) and the pulmonary capillary wedge pressure (18 mm Hg) were elevated. There was an inspiratory drop in left ventricular systolic pressure suggesting ventricular interdependence (Figure 4). The coronary arteries were normal, without aberrant vasculature and blood supply to the mass. We concluded that the patient’s dyspnea was caused by pericardial constriction attributable to a giant pericardial lipoma, and we advised surgical intervention to remove this tumor. We proceeded through a median sternotomy. Intraoperative transesophageal echocardiography showed a normal size heart with a circumferential and hypoechogenic mass (Figure 2B). The inferior vena cava was fixed and dilated (24 mm) before opening of the pericardium. Protrusion of fat lobules through the pericardial incision suggested cardiac compression by high pericardial pressure. The lipoma was pediculized in the posterior pericardium, with attachment just above the left atrial appendage. It proved easy to remove it entirely. The inferior vena cava size normalized on intraoperative transesophageal echocardiography after mass extraction, suggesting successful relief of pericardial constriction. Macroscopic inspection showed a multilobulated fatty mass of 2.4 kg (Figure 5A). Histology revealed mature adipocytes and confirmed the diagnosis of benign giant lipoma (Figure 5B). The patient’s postoperative course was uneventful and she was discharged home after 4 days. At 2 months follow-up, the patient’s exercise tolerance was improved and she had resumed her usual activities without limitations.
Intrapericardial lipomas are the least common benign cardiac tumors1 To our knowledge, fewer than 10 cases of constrictive pericardial lipomas have been reported in the literature.2 Patients remain asymptomatic for years, and the incidence of pericardial lipoma is not well known. Pericardial lipomas may be congenital and they could arise from intra or extracardiac fat. Their growth is very slow and they only cause cardiac constriction3 if very large and intrapericardial, as in our case (2.4 kg). Our case illustrated clinical presentation, multimodality imaging, invasive hemodynamics, and surgical intervention for a giant intrapericardial lipoma presenting with pericardial constriction. Although echocardiography and CT scan can suggest the diagnosis, cardiac MRI proved itself a key examination for evaluation of this disease,4 overcoming difficult imaging windows. On MRI, a lipoma presents as an unenhancing mass with high signal intensity on T1-weighted images that characteristically suppresses with fat saturation. Cardiac MRI provides information about tissue composition (difference with liposarcoma), involvement of cardiac structures, and hemodynamic significance. Interestingly, low voltage on the lateral ECG derivations (aVL) corresponded to the areas of maximal tumor thickness. ECG voltage increased after surgical mass resection (Figure 1D). Postoperative prognosis appears excellent for pericardial lipomas. Despite the absence of reported recurrence, we plan follow-up every 5 years with a chest X-ray and echocardiogram.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.115.020318/-/DC1.
- © 2016 American Heart Association, Inc.