Ann Thorac Surg 2009;88:1337-1339. doi:10.1016/j.athoracsur.2009.02.052
© 2009 The Society of Thoracic Surgeons
Case Reports
Giant Cardiac Lipoma in the Ventricular Septum Involving the Tricuspid Valve
Hiroyuki Nishi, MDa,
Masataka Mitsuno, MDa,
Masaaki Ryomoto, MDa,
Hiroyuki Hao, MDb,
Seiichi Hirota, MDb,
Yuji Miyamoto, MDa,*
a Department of Cardiovascular Surgery, Hyogo College of Medicine, Hyogo, Japan
b Department of Pathology, Hyogo College of Medicine, Hyogo, Japan
Accepted for publication February 17, 2009.
* Address correspondence to Dr Miyamoto, Department of Cardiovascular Surgery, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 661-8501, Japan (Email: y-miyamo{at}hyo-med.ac.jp).
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Abstract
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We report a case with a primary giant cardiac lipoma in the right ventricle attached to the interventricular septum that involved the chordae of the septal leaflet of the tricuspid valve. As the potential for malignancy was low, tricuspid valve replacement and minimum tumor resection were performed to obtain a suitable route to the right ventricular outflow tract.
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Introduction
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The incidence of cardiac lipoma is reported as 8.4% of primary cardiac tumors [1], whereas true lipoma, particularly in the interventricular septum, is extremely rare [2–6]. Herein, we report a patient with a giant cardiac lipoma in the right ventricle that arose from the interventricular septum and involved the chordae of the septum leaflet of the tricuspid valve.
A 70-year-old woman was admitted to our hospital as a huge mass was found in her right ventricle during an investigation for chest pain and dyspnea on effort. On auscultation, an ejection systolic murmur was heard at the third left intercostal space, which weakened on inspiration. An enhanced computed tomographic (CT) scan and magnetic resonance imaging showed a 5-cm diameter tumor, which had a broad-based attachment to the right side of the interventricular septum and occupied most of the right ventricular cavity space. On CT scan, the tumor had a very low radio density similar to that of fat (Fig 1a). A magnetic resonance imaging revealed a high-signal intensity mass in T1-weighted image, which was uniformly suppressed in the fat-suppression mode. A right-sided ventriculogram showed the huge mass protruding into the right ventricular outflow tract, and a coronary arteriogram revealed a significant stenosis at the mid-left anterior descending coronary artery (LAD). Thus, an operation involving coronary artery bypass grafting and resection of the tumor was electively planned.
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Fig 1. (a) Preoperative enhanced computed tomographic scan showed 5-cm diameter tumor, which had a broad-based attachment to the right side of the interventricular septum. (b) The tumor was seen through a right atrium incision. The lobulated yellowish mass was broadly attached on the ventricular septum and occupied the right ventricular cavity (white arrow). (c) A postoperative enhanced computed tomographic scan revealed volume reduction of the tumor. (d) After resection of the tumor with the septal leaflet of the tricuspid valve, ventricular septum (blue arrow) was seen. The remaining tumor was integrated with the ventricular septum and was also partly immersed into it.
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After establishing cardiopulmonary bypass, the left internal thoracic artery was anastomosed to the left anterior descending artery. The tumor was seen through a right atrium incision. The lobulated yellowish mass broadly attached on the ventricular septum and occupied the right ventricular cavity (Fig 1b). The tumor was integrated with chordae and papillary muscle of the tricuspid septal leaflet, as well as right ventricular trabecular muscle. Intraoperative histologic diagnosis showed no apparent sign of the malignancy. The tumor was excised with the septal leaflet of the tricuspid valve to obtain a wide route to the right ventricular outflow tract, and a tricuspid valve replacement was performed with a bioprosthesis. It was impossible to remove the entire tumor, because it was integrated with and partly immersed into the ventricular septum (Fig 1d). A postoperative enhanced CT scan revealed volume reduction of the tumor (Fig 1c). Although a low-density tumor in the ventricular septum remained, the patient was asymptomatic at 6 months after surgery.
The tumor was removed in pieces with the septal leaflet of the tricuspid valve, including part of the chordae and papillary muscle group (Fig 2a). Intraventricular lipoma was defined by histopathology, and was composed of a cluster of mature adipose cells with connective tissue and capillary vessels (Fig 2b). A high-power view of the tumor (Fig 2b, inset) demonstrated mature adipose cells without atypia. Massive infiltration of mature adipose cells with displacement of pre-existing myocardial cells was predominant in removed tumor sections (Fig 2c). Some adipose tissue infiltrated into the chordae (Fig 2d).
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Fig 2. (a) Gross appearance of surgically resected part of lipoma with the septal leaflet of the tricuspid valve and part of the chordae and papillary muscles. (b) The tumor was removed in pieces, and involvement of chordae and papillary muscle of tricuspid valve is evident. Microphotograph showing surface area of the tumor composed of mature adipose cells. Inset indicates high-power view of adipose cells without malignant features. (c) Muscle cells were encountered by mature adipose tissue. (d) The histologic feature of infiltrating adipose tissue was dominant in the removed tumor. A few adipose tissues were infiltrated into the chordae of the tricuspid valve. [(b–d) Hematoxylin & eosin; bars, 500 µm. (b) Inset: Hematoxylin & eosin; bar, 50 µm.]
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Comment
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The symptoms of cardiac lipomas depend on the tumor location and size [3]. In the present case, the patient had a systolic murmur that weakened at inspiration, which seemed due to right ventricular outflow obstruction by the tumor. The mass had a broad-based attachment to the right side of the interventricular septum and occupied most of the right ventricle space. There are no previous reports describing intracardiac lipoma involving the chordae and papillary muscle of the tricuspid valve.
As diagnosing techniques, the CT scan and magnetic resonance imaging are useful for identifying a tumor, in addition to delineating its shape, dimension, and relationship to surrounding tissue [2, 5, 6]. In the present case, the tumor was identified as fat tissue by the radiodensity in the enhanced CT scan and the suppression of the tumor in the lipid-suppression mode of the magnetic resonance imaging.
Surgical removal of a tumor is warranted in symptomatic patients, although it is difficult to distinguish lipomas from well-differentiated liposarcomas. Thus, surgical resection remains the best option for final assessment [2]. In the present case, separation of the tumor from the surrounding tissue was difficult due to integration of the lipoma and the myocardium. Furthermore, we had to consider the possibility of serious complications including complete atrioventricular block and ventricular septal perforation. Intraoperative histologic findings are also important for making a final decision. In the present case, minimum resection to obtain a suitable route to the right ventricular outflow tract was performed, as the potential for malignancy was low. However, we could not avoid excising the septal leaflet of the tricuspid valve, followed by tricuspid valve replacement, which we could not have predicted before the operation. Although complete resection was not performed, the patient did not have complete atrioventricular block or ventricular septal perforation. The postoperative enhanced CT scan showed the remaining tumor in the ventricular septum requiring long-term, careful observation.
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References
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- Reece IJ, Cooly DA, Frazier OH, Hallman GL, Powers PL, Montero CG. Cardiac tumors: Clinical spectrum and prognosis of lesions other than classical benign myxoma in 20 patients J Thorac Cardiovasc Surg 1984;88:439-446.[Abstract]
- Ozaki N, Mukohara N, Yoshida M, Shida T. Cardiac lipoma in the ventricular septum—a case report Thorac Cardiovasc Surg 2006;54:356-357.[Medline]
- Miralles A, Bracamonte L, Souncul H, et al. Cardiac tumors: clinical experience and surgical results in 74 patients Ann Thorac Surg 1991;52:886-895.[Abstract/Free Full Text]
- Kamiya H, Ohno M, Iwata H, et al. Cardiac lipoma in the interventricular septum: Evaluation by computed tomography and magnetic resonance imaging Am Heart J 1990;119:1215-1217.[Medline]
- Dooms GC, Hricak H, Sollitto RA, Higgins CB. Lipomatous tumors and tumors with fatty component: MR imaging potential and comparison of MR and CT results Radiology 1985;157:479-483.[Abstract/Free Full Text]
- Arslan S, Gundogdu F, Acikel M, Kantarci AM. Asymptomatic cardiac lipoma originating from the interventricular septum diagnosed by multi-slice computed tomography Int J Cardiovasc Surg 2007;23:277-279.
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Abstract
Introduction
