Review ArticlePediatric heart tumors
Introduction
Pediatric heart tumors have been the subject of several recent reviews, concerning both pediatric patients in general [1], [2], [3], [4] and neonatal and fetal tumors in particular [5], [6]. Due to their rarity, however, there are very few institutional series of heart tumors occurring in children. In one study spanning several decades, records of 27,640 children with heart disease admitted to the University of Toronto were reviewed retrospectively, revealing 56 with a clinical diagnosis of heart tumor. There was no gender predilection, and the tumors recorded comprised 44 rhabdomyomas, 6 fibromas, 1 teratoma, and 6 miscellaneous or unclassified benign lesions [4]. In series of surgically excised tumors, the proportion of tumors is different, as rhabdomyomas are often diagnosed without surgical treatment, especially in patients with tuberous sclerosis. In two reports of surgically excised pediatric heart tumors, fibromas were as common as rhabdomyoma [7], [8].
As rhabdomyomas and fibromas comprise a large majority of pediatric heart tumors, pediatric heart tumors, like heart tumors in adults, are generally benign. Whereas myxoma is the most common adult heart tumor, pediatric tumors are comprised primarily of nonneoplastic hamartomatous lesions (Table 1). These include two lesions of cardiomyocyte derivation, namely, rhabdomyoma and histiocytoid cardiomyopathy (sometimes designated Purkinje cell hamartoma), and cardiac fibroma. Fetal heart tumors are similar to those occurring in children, with a higher proportion of germ cell tumors [5] (Table 2). Mesenchymal proliferations of the myocardium, other than fibroma, are extremely rare in the pediatric age range. Most sarcomas are undifferentiated, like their adult counterparts. However, embryonal rhabdomyosarcoma primary in the heart is a tumor of children and young adults; alveolar rhabdomyosarcoma may occur in the heart as a metastatic lesion. Recently, inflammatory myofibroblastic tumors (IMFTs) have been described as originating from the endocardium. The precise nature (reactive/neoplastic) of cardiac IMFT remains undetermined.
Section snippets
Rhabdomyoma
Cardiac rhabdomyoma is the most common pediatric heart tumor. Like other heart tumors, the clinical features are highly dependent on site in the heart and includes arrhythmias, outflow tract obstruction, heart failure, and, in the case of fetal lesions, hydrops fetalis. Cardiac rhabdomyoma is highly associated with tuberous sclerosis complex (TSC) [9]; approximately 80% of children with cardiac rhabdomyoma have clinical, radiologic, or family history of TSC [4]. Conversely, more than 50% of
Fibroma
Most cardiac fibromas are discovered in children and often before 1 year of age, but the upper range of age at presentation extends into late adulthood. Approximately 3% of patients with Gorlin's syndrome have cardiac fibromas. Gorlin's syndrome results from germline mutations in the PTC gene, which maps to chromosome 9q22.3 and is homologous to the Drosophila patched (ptc) gene [15].
Fibromas are generally single lesions and often cause symptoms necessitating surgical resection [16], [17]. The
Histiocytoid cardiomyopathy
Histiocytoid cardiomyopathy is a rare, arrhythmogenic disorder caused by multifocal hamartomatous proliferation of cardiac cells with oncocytic features. Synonyms include Purkinje cell hamartoma and, in the surgical literature, simply cardiac hamartoma. The female:male ratio is 3:1 [18]. Approximately 5% of reported cases have occurred in families. Arrhythmias associated with histiocytoid cardiomyopathy include paroxysmal atrial tachycardia, atrial fibrillation, ventricular fibrillation,
Inflammatory myofibroblastic tumor
IMFTs are proliferations of uncertain histogenesis, which vary in appearance from inflammatory, reactive-appearing proliferations to low-grade sarcomas. There is probably organ-specific variation in the histologic characteristics of IMFTs. In the heart, they invariably arise from the endocardium, including valve leaflets (Fig. 4), are variably cellular, and usually have abundant myxoid matrix and surface fibrin. There is generally a background lymphocytic infiltrate (Fig. 5). Most lesions
Hemangioma
Cardiac hemangiomas are of two basic types: those that are endocardial based and have histologic features of capillary or cavernous hemangiomas and those that are intramyocardial and have histologic features similar to intramuscular hemangiomas [26]. Fewer than 25% of cardiac hemangiomas occur in the pediatric age range. In neonates, there appears to be a predilection for the right atrium [5]. A minority of children with cardiac hemangioma have extracardiac hemangiomas and rarely diffuse
Germ cell tumors
Most intrapericardial germ cell tumors occur within the pericardium and represent pericardial teratomas [27]. The rare intramyocardial teratoma is of current interest due to the potential differentiation of therapeutic stem cells into teratoma. In addition to teratomas, yolk sac tumors rarely occur in the heart and pericardial space [28].
More than 75% of cardiac teratomas occur in children under the age of 15 years, and virtually all yolk sac tumors occur in children. There is a slight female
Cardiac sarcomas
Malignant primary cardiac tumors are extremely rare in infants and children, and there are no series published to date regarding this. Many reported cases are most likely IMFTs, as noted above, especially those with purportedly benign follow-up. In an unpublished series of 16 cardiac sarcomas by the authors, most patients were male and clinical presentation was variable, including recurrent pericardial effusion, respiratory distress, pulmonary emboli, shortness of breath, arrhythmia, chest
References (30)
- et al.
Diagnosis and management of fetal cardiac tumors: a multicenter experience and review of published reports
J Am Coll Cardiol
(1995) - et al.
Primary cardiac tumors in infants and children: immediate and long-term operative results
Ann Thorac Surg
(1996) - et al.
Surgically treated primary cardiac tumors in early infancy and childhood
J Thorac Cardiovasc Surg
(2005) - et al.
Association between cardiac tumors and tuberous sclerosis in the fetus and neonate
Am J Cardiol
(2003) - et al.
Spectrum of PTCH1 mutations in French patients with Gorlin syndrome
J Invest Dermatol
(2003) - et al.
Cardiac fibroma: clinicopathologic correlates and surgical treatment
J Thorac Cardiovasc Surg
(1994) - et al.
Surgical issues in giant right ventricular fibroma
Ann Thorac Surg
(2004) - et al.
Infantile histiocytoid cardiomyopathy: three cases and literature review
Am Heart J
(1994) - et al.
Multiple myocardial hamartomas causing ventricular tachycardia in young children: combined surgical modification and medical treatment
Mayo Clin Proc
(1994) - et al.
Cryoablative techniques in the treatment of cardiac tachyarrhythmias
Ann Thorac Surg
(1987)
Undifferentiated sarcoma of the mitral valve with unique clinicopathologic presentation
J Cardiovasc Surg (Torino)
Some more about intrapericardial teratomas in perinatal period
J Pediatr Surg
Intrapericardial teratoma presenting with circulatory compromise
Ann Thorac Surg
Cardiac tumours in children
Orphanet J Rare Dis
Primary heart tumors in the pediatric age group: a review of salient pathologic features relevant for clinicians
Pediatr Cardiol
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This article was adapted from the Society for Cardiovascular Pathology 2007 Distinguished Achievement Awardee Lecture, San Diego, CA, March 2007.