Interact CardioVasc Thorac Surg 2009;9:1029-1031. doi:10.1510/icvts.2009.215855
© 2009 European Association of Cardio-Thoracic Surgery
Case report - Cardiac general |
Hamartoma of mature cardiac myocytes of the pulmonary infundibulum
Antonella Galeonea,*,
Pierre Validireb,
Jean-Brice Gayetc and
François Labordea
a Department of Cardiac Surgery, Institut Mutualiste Montsouris, 42 Bd Jourdan, 75014 Paris, France
b Department of Pathology, Institut Mutualiste Montsouris 42 Bd Jourdan, 75014 Paris, France
c Department of Imaging, Institut Mutualiste Montsouris 42 Bd Jourdan, 75014 Paris, France
Received 7 July 2009;
received in revised form 12 August 2009;
accepted 17 August 2009
*Corresponding author. Tel.: +33 1 56 61 65 07; fax: +33 1 56 61 65 23.
E-mail address: a.galeone{at}email.it (A. Galeone).
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Abstract
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We describe the incidental finding and treatment of a very rare and voluminous cardiac tumour located near to the pulmonary infundibulum. The mass was surgically resected and final diagnosis was hamartoma of mature cardiac myocytes. Postoperative course was uneventful and the patient is asymptomatic after six months of follow-up.
Key Words: Cardiac tumour; Right ventricle
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1. Case report
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A 56-year-old woman with a previous hysterectomy was hospitalised for right hydrosalpinx. Preoperative assessment revealed a pericardial effusion. Echocardiography showed a mass located near to the pulmonary infundibulum and associated to early signs of compression, but excluded any other cardiac anomaly. Thoracic computed tomography (CT) showed a voluminous vascularised mass of about 9 cm in diameter (Fig. 1a). A coronary angiogram found the mass to be vascularised by both right coronary and left anterior descending arteries branches. ECG and physical examination were normal.
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Fig. 1. (a) Three-dimensional CT reconstruction showing a voluminous vascularised mass located near to the pulmonary infundibulum. (b) Histology showing disordered hypertrophied myocytes, abundant malformed blood vessels and adipose tissue (hematoxylin-eosin; x10). (c) Intra-operative appearance of the mass after pericardial incision. (d) Displacement of the mass showing left ventricle below. (e) Vertical dissection of the mass.
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Surgery was performed through median sternotomy. Following pericardium incision, a gross vascularised mass belonging to pulmonary infundibulum was visualised (Fig. 1c, d); nutritive branches from right coronary and left anterior descending arteries were localised. Cardiopulmonary bypass was established with aortic and atrio-caval cannulation and cardioplegic arrest was achieved with cold crystalline solution. Pulmonary artery root was dissected allowing right ventriculotomy while respecting pulmonary artery annulus. The mass was vertically dissected and the limit between sane myocardium and tumour was detected (Fig. 1e). The two half-sections were totally excised and nutritive arteries tied up. A dacron patch (HemapatchTM) was used to reconstruct the pulmonary infundibulum. Postoperative course was uneventful. Six months later the patient is asymptomatic and follow-up CT and echocardiography confirm that the tumour has been fully excised and that the right ventricular cavity is not altered.
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2. Histopathology
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Pathologic examination of the tumour revealed a whitish and well circumscribed mass developed inside the right ventricle (RV) wall without any necrotic area. The mass weighed 210 g and measured 9x9x4 cm; histologically it was composed of mature cardiac myocytes within an interstitial stroma rich for differently sized and at times dilated blood vessels and mature adipose tissue (Fig. 1b). Inflammatory mononuclear cells were rare. Moderate myocyte hypertrophy, haphazard pattern of disarray and mild vacuolisation were detectable. Endothelial cells were normal. A panel of immunohistochemical markers comprising antibodies to desmin, alpha-smooth actine, CD34 and CD31 was performed and staining resulted strongly positive. Positive staining confirms the presence of cardiac myocytes, detected by antibodies to desmin and alpha-smooth actine, and endothelial cells detected by antibodies to CD34 and CD31. Immunohistochemical staining for antigens associated with cellular proliferation was negative (Ki-67 <2%), thus excluding any malignancy. Final diagnosis was hamartoma of mature cardiac myocytes.
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3. Discussion
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Primary cardiac tumours are rare and usually benign. Hamartoma of mature cardiac myocytes is extremely rare and only a handful of such tumour has been reported in the literature [1–10] (Table 1). It was firstly described by Tanimura et al. in 1988 [1]. The tumour was incidentally found at autopsy in a 68-year-old male with retroperitoneal leiomyosarcoma; it was located at the apex of the heart and microscopically it was composed of dense collagenous tissue, mature adipose tissue and proliferated blood vessels, intermingled with cardiac muscle cells, the latter being hypertrophic and disarrayed.
A hamartoma is a focal benign overgrowth of differentiated mature cells that are typically native to the affected organ. However these cells are disorganized, the mass resulting from the anomalous development of embryonic cells. Several distinct types of cardiac hamartomas have been described: rhabdomyoma, fibroma, histiocytoid cardiomyopathy. Rhabdomyoma typically occurs in infancy, it is strongly associated with tuberosis sclerosis and it may be multiple; pathologically, it is composed of immature cardiac myocytes with diffused vacuolated myocytes, and extensive glycogen deposits. In contrast, cells composing the hamartoma of mature cardiac myocytes display only focal areas of vacuolisation and lack extensive glycogen. Cardiac fibroma is a mass of fibrous and elastic tissue that is primarily found in children; it is predominantly (>90%) composed of collagen and fibroblasts and may contain entrapped myocytes only at the periphery of the lesion. Fibromas are poorly vascularised and focally calcified, whereas hamartomas of mature cardiac myocytes are non-calcific and may be highly vascularised with dilated venous channels [7]. Histiocytoid (oncocytic) cardiomyopathy is characterised by subendocardial nodules composed of myocytes with granular eosinophilic cytoplasm due to increased mitochondria and loss of myofibres; it usually affects females and presents in infancy as tachyarrhytmia or sudden death.
Hypertrophic cardiomyopathy may share some histological findings with a hamartoma of mature cardiac myocytes as it is characterised by diffuse myocyte hypertrophy with focal fibromuscular disarray. However, these two disorders can be distinguished by lack of increased vascularity, more diffuse myocardial involvement, characteristic septal localisation and familiar background of hypertrophic cardiomyopathy [6].
Hamartomas of mature cardiac myocytes show no predilection for age or location in the heart. They preferentially develop in the ventricle free wall [1, 3, 4, 7, 8, 10], but they have been described in the interventricular septum [2, 6, 8] and in the right atrium (RA) too [3, 5, 9]. They can be single or multiple [3] and primarily affect males.
Clinical presentations vary according to size and location of the mass in the heart and range from asymptomatic cases [1, 8, 9] to non-specific ECG findings [3, 8], palpitations [1, 7], respiratory distress [8], ventricular [4] or supraventricular tachycardia [6], syncope [3] and sudden death [3, 8].
Imaging techniques as CT, magnetic resonance and coronary angiography provide size, location and vascular supply of the mass, thus indicating the surgical technique to follow; they may be helpful to distinguish hamartoma of mature cardiac myocytes from other entities such as cardiac fibroma that typically shows low vascularity and areas of calcification.
Benign masses generally have good prognosis when surgically excised. Surgery allows to remove hamartomas and to achieve symptoms remission if present [2–9]. We presented the most voluminous hamartoma of mature cardiac myocytes ever reported; surgery was effective in removing the hamartoma in its entirety and the use of a patch allowed to reconstruct the RV outflow tract with excellent short-term results.
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References
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- Chu PH, Yeh HI, Jung SM, Chien LY, Cheng NF, Wu HH, Chu JJ, Hsueh C, Lee YS. Irregular connexin43 expressed in a rare cardiac hamartoma containing adipose tissue in the crista terminalis. Virchows Arch 2004 Apr;444:383–386.[CrossRef][Medline]
- Gilman G, Wright RS, Glockner JF, Starret RS, Hansen WH, Sinak LJ, Tazelaar HD, Tajik AJ, Dearani JA. Ventricular septal hamartoma mimicking hypertrophic cardiomyopathy in a 41-year-old woman presenting with paroxysmal supraventricular tachycardia. Echocardiogr 2005;18:272–274.[CrossRef]
- Martinez Quesada M, Trujillo Berraguero F, Almedro Delia M, Hidalgo Urbano R, Cruz Fernandex J. Cardiac hamartoma. Case report and literature review. Rev Esp Cardiol 2005;58:450–452.[CrossRef][Medline]
- Fealey ME, Edwards WD, Miller DV, Menon SC, Dearani JA. Hamartomas of mature cardiac myocytes: report of seven new cases and review of literature. Hum Pathol 2008;39:1064–1071.[CrossRef][Medline]
- Movahedi N, Boroumand MA, Sotoudeh Anvari M, Yazdanifard P. Mature cardiac myocyte hamartoma in the right atrium. Asian Cardiovasc Thorac Ann 2008 Oct;16:e47–e48.[Abstract/Free Full Text]
- Menon SC, Miller DV, Cabalka AK, Hagler DJ. Hamartomas of mature cardiac myocytes. Eur J Echocardiogr 2008 Nov;9:835–839.[Abstract/Free Full Text]
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Abstract
1. Case report