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Polypoid (Pedunculated) Subepicardial Lipoma
CASE REPORT
Polypoid (Pedunculated) Subepicardial Lipoma: A Cardiac Lesion Resembling the Epiploic Appendage J. Fernando Val-Bernal, MD, PhD, Fernando Villoria, MD, and Fidel A. Fernández, MD, PhD Anatomical Pathology Department, Marqués de Valdecilla University Hospital, Medical Faculty, University of Cantabria, Santander, Spain
ⴙⴙ This report describes a 75-year-old woman with an asymptomatic pedunculated lipoma involving the epicardium of the right atrium. The lipoma was an incidental finding at autopsy. The twisted lesion showed many similarities with the infarcted epiploic appendages observed in the visceral peritoneum. Cardiovasc Pathol 2000;9:55–57 © 2000 by Elsevier Science Inc.
Cardiac benign lesions of fatty tissue include: diffuse lipomatous infiltration, lipomatous hypertrophy of the interatrial septum, lipomatous hamartoma of cardiac valves, and lipoma (1). A lipoma is a well-circumscribed mass composed of mature fat cells. Lipoma of the heart is very rare. It represents 0.83% of the benign tumors of the heart (two cases in 242 benign tumors) (1). The tumor may appear in subendocardial, intramyocardial and subepicardial location; and may be solitary or multiple. The intracavitary or subepicardial lesions may be sessile or pedunculated. Association with tuberous sclerosis has been described in some cases of lipoma of the heart (1). Most lipomas are subepicardial and single lesions. The signs and symptoms of cardiac lipomas are mainly dependent upon their location and size. The majority of patients are asymptomatic (2). Large or multiple lipomas may be fatal (3,4) or may impair cardiac function resulting in dyspnoea, fatigue, anginal pain by compressing the coronary arteries, and various arrhythmias (5–8). We report our recent experience with an asymptomatic infarcted subepicardial pedunculated lipoma that showed similarities with the infarcted epiploic appendices observed in the peritoneum.
Manuscript received September 17, 1999; accepted October 18, 1999. Address for correspondence: J. Fernando Val-Bernal, MD, PhD, Departamento de Anatomía Patológica, Hospital Universitario Marqués de Valdecilla, Avda. Valdecilla, 1, 39008 Santander, Spain. Tel.: ⫹34 - 942 202599; Fax.: ⫹34 - 942 - 201903; Email:. Cardiovascular Pathology Vol. 9, No. 1, January/February 2000:55–57 2000 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
Case Report A 75-year-old obese woman died of tetanus. At autopsy the heart weighed 380 g, showing mild hypertrophy of the left ventricle (wall thickness 1.6 cm) and excessive subepicardial adipose tissue. On opening the pericardium, a soft, yellow to orange, 1.0 ⫻ 0.5 ⫻ 0.5 cm nodule was noted. It was attached by a 0.5 cm stalk to the epicardial adipose tissue on the anterior aspect of the right atrium (Figures 1A and 1B). The stalk was thin and pale yellow. There was no pericardial effusion. The pericardium was perfectly smooth. Microscopically, the lesion consisted of mature fat cells surrounded by a thin fibrous tissue covering and an outer layer of mesothelial cells. This lesion showed zonation with infarcted, mummified adipose tissue in the central portion. More peripherically fat necrosis, lipophagic granulomas with giant cells, fibrosis (Figures 1C and 1B) and hemosiderin deposition were present. In the pedicle there was venous engorgement.
Discussion The valid explanation of the case may be the following. The tumor found in epicardial location was a twisted polypoid, pedunculated lipoma altered by fat necrosis. The torsion produced disruption of fat cells accompanied by hemorrhage and an influx of macrophages. Progression of the process was marked by the formation of multinucleated histiocytes and hemosiderin deposition. Demarcation fibrosis
1054-8807/00/$–see front matter PII S1054-8807(99)00032-0
56
VAL-BERNAL ET AL. PEDUNCULATED EPICARDIAL LIPOMA
Cardiovasc Pathol Vol. 9, No. 1 January/February 2000:55–57
Figure 1. (A) View of the anterior aspect of the right atrium cordis showing a polypoid lipoma. (B) Close-up view of the pedunculated lipoma after dissection of the lesion. (C) Histologic section of transected lipoma. Its outer portion consists of fibrous tissue covered by mesothelial cells. Interior consists of necrotic mummified fat cells (Masson’s trichrome stain, original magnification ⫻10). (D) Fat necrosis, lipophagic macrophages, giant cells, and fibrosis can be seen in the periphery of the lesion (hematoxylin and eosin stain, original magnification ⫻64).
developed peripherally enclosing the necrotic and demolition area. This sequence of facts can also be seen in a twisted epiploic fringe in the peritoneal cavity. Epiploic appendices are pedunculated, mesothelial-covered collections of adipose tissue on the lateral aspects of the colon. The stalks of these accumulations are thin and tenuous and may occasionally twist and lead to infarct or even amputation forming loose bodies within the peritoneal cavity. These lesions may become calcified (9,10). In theory, a twisted pedunculated lipoma of the pericardium may undergo amputation and turn into a detached bit that has become free. This pericardial (body) “mouse” might be found floating in the pericardial fluid mimicking a similar body that occasionally appears in the peritoneal cavity. However, we have not found such case upon literature review. The so-called cardiac MICE (11) is a small fleshy mass that may be found free floating within the pericardial sac (12). The MICE is a benign lesion comprising a mixture of histiocytes, mesothelial cells, inflam-
matory cells and fibrin. Therefore, this lesion differs substantially from bonafide subendocardial lipoma and probably represents a focus of nodular mesothelial hyperplasia. In conclusion, we have reported a rare case of asymptomatic pedunculated subepicardial lipoma that showed many similarities with the infarcted epiploic appendices observed in the visceral peritoneum.
References 1. Burke A, Virmani R. Tumors of the heart and great vessels. Atlas of Tumor Pathology, 3rd series, fascicle 16. Washington DC: Armed Forces Institute of Pathology, 1996;1–11:91–98. 2. Shirani J, Roberts WC. Epicardial lipoma. Am Heart J 1993;126:1030. 3. Ashar K, van Hoeven KH. Fatal lipoma of the heart. Am J Cardiovasc Pathol 1992;4:85–90 4. Li J, Ho SY, Becker AE, Jones H. Multiple cardiac lipomas and sud-
Cardiovasc Pathol Vol. 9, No. 1 January/February 2000:55–57
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Figure 1. (Continued)
5.
6. 7.
8.
den death: A case report and literature review. Cardiovasc Pathol 1998;7:51–55. Graham TR, Chalmers JAC, Aldren C. A large epicardial lipoma. An insight into the surgical anatomy of the interatrial septum. Int J Cardiol 1989;25:119–121. Eng J, Ruiz K, Kay PH. Giant epicardial lipoma. Int J Cardiol 1992;37:115–117. Cooper MJ, deLorimier AA, Higgings CB, Van Hare GF, Enderlein MA. Atrial flutter-fibrillation resulting from left atrial compression by an intrapericardial lipoma. Am Heart J 1994;127:950–951. Lang-Lazdunski L, Oroudji M, Pansard Y, Vissuzaine C, Hvass U. Successful resection of giant intrapericardial lipoma. Ann Thorac Surg 1994;58:238–241.
9. Elliot GB, Freigang B. Aseptic necrosis, calcification and separation of appendices epiploicae. Ann Surg 1962;155:501–505. 10. Vuong PN, Guyot H, Moulin G, Houissa-Vuong S, Berrod JL. Pseudotumoral organization of a twisted epiploic fringe or “hardboiled egg” in the peritoneal cavity. Arch Pathol Lab Med 1990;114:531–533. 11. Veinot JP, Tazelaar HD, Edwards WD, Colby TV. Mesothelial/monocytic incidental cardiac excrescences: cardiac MICE. Mod Pathol 1994;7:9–16. 12. Luthringer DJ, Virmani R, Weiss SW, Rosai J. A distinctive cardiovascular lesion resembling histiocytoid (epithelioid) hemangioma. Evidence suggesting mesothelial participation. Am J Surg Pathol 1990;14:993–1000.
Polypoid (Pedunculated) Subepicardial Lipoma: A Cardiac Lesion Resembling the Epiploic Appendage J. Fernando Val-Bernal, MD, PhD, Fernando Villoria, MD, and Fidel A. Fernández, MD, PhD Anatomical Pathology Department, Marqués de Valdecilla University Hospital, Medical Faculty, University of Cantabria, Santander, Spain
ⴙⴙ This report describes a 75-year-old woman with an asymptomatic pedunculated lipoma involving the epicardium of the right atrium. The lipoma was an incidental finding at autopsy. The twisted lesion showed many similarities with the infarcted epiploic appendages observed in the visceral peritoneum. Cardiovasc Pathol 2000;9:55–57 © 2000 by Elsevier Science Inc.
Cardiac benign lesions of fatty tissue include: diffuse lipomatous infiltration, lipomatous hypertrophy of the interatrial septum, lipomatous hamartoma of cardiac valves, and lipoma (1). A lipoma is a well-circumscribed mass composed of mature fat cells. Lipoma of the heart is very rare. It represents 0.83% of the benign tumors of the heart (two cases in 242 benign tumors) (1). The tumor may appear in subendocardial, intramyocardial and subepicardial location; and may be solitary or multiple. The intracavitary or subepicardial lesions may be sessile or pedunculated. Association with tuberous sclerosis has been described in some cases of lipoma of the heart (1). Most lipomas are subepicardial and single lesions. The signs and symptoms of cardiac lipomas are mainly dependent upon their location and size. The majority of patients are asymptomatic (2). Large or multiple lipomas may be fatal (3,4) or may impair cardiac function resulting in dyspnoea, fatigue, anginal pain by compressing the coronary arteries, and various arrhythmias (5–8). We report our recent experience with an asymptomatic infarcted subepicardial pedunculated lipoma that showed similarities with the infarcted epiploic appendices observed in the peritoneum.
Manuscript received September 17, 1999; accepted October 18, 1999. Address for correspondence: J. Fernando Val-Bernal, MD, PhD, Departamento de Anatomía Patológica, Hospital Universitario Marqués de Valdecilla, Avda. Valdecilla, 1, 39008 Santander, Spain. Tel.: ⫹34 - 942 202599; Fax.: ⫹34 - 942 - 201903; Email:
Case Report A 75-year-old obese woman died of tetanus. At autopsy the heart weighed 380 g, showing mild hypertrophy of the left ventricle (wall thickness 1.6 cm) and excessive subepicardial adipose tissue. On opening the pericardium, a soft, yellow to orange, 1.0 ⫻ 0.5 ⫻ 0.5 cm nodule was noted. It was attached by a 0.5 cm stalk to the epicardial adipose tissue on the anterior aspect of the right atrium (Figures 1A and 1B). The stalk was thin and pale yellow. There was no pericardial effusion. The pericardium was perfectly smooth. Microscopically, the lesion consisted of mature fat cells surrounded by a thin fibrous tissue covering and an outer layer of mesothelial cells. This lesion showed zonation with infarcted, mummified adipose tissue in the central portion. More peripherically fat necrosis, lipophagic granulomas with giant cells, fibrosis (Figures 1C and 1B) and hemosiderin deposition were present. In the pedicle there was venous engorgement.
Discussion The valid explanation of the case may be the following. The tumor found in epicardial location was a twisted polypoid, pedunculated lipoma altered by fat necrosis. The torsion produced disruption of fat cells accompanied by hemorrhage and an influx of macrophages. Progression of the process was marked by the formation of multinucleated histiocytes and hemosiderin deposition. Demarcation fibrosis
1054-8807/00/$–see front matter PII S1054-8807(99)00032-0
56
VAL-BERNAL ET AL. PEDUNCULATED EPICARDIAL LIPOMA
Cardiovasc Pathol Vol. 9, No. 1 January/February 2000:55–57
Figure 1. (A) View of the anterior aspect of the right atrium cordis showing a polypoid lipoma. (B) Close-up view of the pedunculated lipoma after dissection of the lesion. (C) Histologic section of transected lipoma. Its outer portion consists of fibrous tissue covered by mesothelial cells. Interior consists of necrotic mummified fat cells (Masson’s trichrome stain, original magnification ⫻10). (D) Fat necrosis, lipophagic macrophages, giant cells, and fibrosis can be seen in the periphery of the lesion (hematoxylin and eosin stain, original magnification ⫻64).
developed peripherally enclosing the necrotic and demolition area. This sequence of facts can also be seen in a twisted epiploic fringe in the peritoneal cavity. Epiploic appendices are pedunculated, mesothelial-covered collections of adipose tissue on the lateral aspects of the colon. The stalks of these accumulations are thin and tenuous and may occasionally twist and lead to infarct or even amputation forming loose bodies within the peritoneal cavity. These lesions may become calcified (9,10). In theory, a twisted pedunculated lipoma of the pericardium may undergo amputation and turn into a detached bit that has become free. This pericardial (body) “mouse” might be found floating in the pericardial fluid mimicking a similar body that occasionally appears in the peritoneal cavity. However, we have not found such case upon literature review. The so-called cardiac MICE (11) is a small fleshy mass that may be found free floating within the pericardial sac (12). The MICE is a benign lesion comprising a mixture of histiocytes, mesothelial cells, inflam-
matory cells and fibrin. Therefore, this lesion differs substantially from bonafide subendocardial lipoma and probably represents a focus of nodular mesothelial hyperplasia. In conclusion, we have reported a rare case of asymptomatic pedunculated subepicardial lipoma that showed many similarities with the infarcted epiploic appendices observed in the visceral peritoneum.
References 1. Burke A, Virmani R. Tumors of the heart and great vessels. Atlas of Tumor Pathology, 3rd series, fascicle 16. Washington DC: Armed Forces Institute of Pathology, 1996;1–11:91–98. 2. Shirani J, Roberts WC. Epicardial lipoma. Am Heart J 1993;126:1030. 3. Ashar K, van Hoeven KH. Fatal lipoma of the heart. Am J Cardiovasc Pathol 1992;4:85–90 4. Li J, Ho SY, Becker AE, Jones H. Multiple cardiac lipomas and sud-
Cardiovasc Pathol Vol. 9, No. 1 January/February 2000:55–57
VAL-BERNAL ET AL. PEDUNCULATED EPICARDIAL LIPOMA
57
Figure 1. (Continued)
5.
6. 7.
8.
den death: A case report and literature review. Cardiovasc Pathol 1998;7:51–55. Graham TR, Chalmers JAC, Aldren C. A large epicardial lipoma. An insight into the surgical anatomy of the interatrial septum. Int J Cardiol 1989;25:119–121. Eng J, Ruiz K, Kay PH. Giant epicardial lipoma. Int J Cardiol 1992;37:115–117. Cooper MJ, deLorimier AA, Higgings CB, Van Hare GF, Enderlein MA. Atrial flutter-fibrillation resulting from left atrial compression by an intrapericardial lipoma. Am Heart J 1994;127:950–951. Lang-Lazdunski L, Oroudji M, Pansard Y, Vissuzaine C, Hvass U. Successful resection of giant intrapericardial lipoma. Ann Thorac Surg 1994;58:238–241.
9. Elliot GB, Freigang B. Aseptic necrosis, calcification and separation of appendices epiploicae. Ann Surg 1962;155:501–505. 10. Vuong PN, Guyot H, Moulin G, Houissa-Vuong S, Berrod JL. Pseudotumoral organization of a twisted epiploic fringe or “hardboiled egg” in the peritoneal cavity. Arch Pathol Lab Med 1990;114:531–533. 11. Veinot JP, Tazelaar HD, Edwards WD, Colby TV. Mesothelial/monocytic incidental cardiac excrescences: cardiac MICE. Mod Pathol 1994;7:9–16. 12. Luthringer DJ, Virmani R, Weiss SW, Rosai J. A distinctive cardiovascular lesion resembling histiocytoid (epithelioid) hemangioma. Evidence suggesting mesothelial participation. Am J Surg Pathol 1990;14:993–1000.