Cardiac and Pericardial Tumors

S. Bruce Greenberg and Cathy Macdonald

Primary cardiac tumors are rare in infants and children, with a reported prevalence of up to 0.32%.¹ Use of echocardiography has resulted in more frequent detection of cardiac tumors in the fetus and neonate.² More than 90% of cardiac tumors in infants and children are benign.¹ Symptoms are variable and usually depend on tumor location and size. Intracavitary cardiac tumors can cause cardiac valve obstruction or result in spread of tumor emboli into either the pulmonary or systemic vascular beds. Children with intracavitary cardiac tumors present with heart failure, dyspnea, or neurologic symptoms. Myocardial tumors compress the cardiac lumen, leading to obstruction or heart failure, and can be associated with arrhythmias. Pericardial tumors are associated with pericardial effusions. Conventional radiographs may show cardiomegaly, an abnormal cardiac shape, or pulmonary edema from congestive heart failure (e-Fig. 81-1). Cardiac tumors in children can be associated with several syndromes, as shown in Table 81-1. Computed tomography (CT) and magnetic resonance imaging (MRI) findings can help differentiate tumor types (Table 81-2).

Table 81-1

Cardiac Tumors Associated with Syndromes

Tumor	Association
Rhabdomyoma	Tuberous sclerosis
Fibroma	Gorlin (basal cell nevus) syndrome
Myxoma	Carney syndrome

Table 81-2

Cardiac Tumors: Computed Tomographic and Magnetic Resonance Imaging Findings

CT, computed tomography; MRI, magnetic resonance imaging.

^*Relative to myocardium.

^†Multiple and recurrent tumors associated with familial forms.

e-Figure 81-1 Cardiomegaly in a child with a cardiac fibroma.

Rhabdomyoma

Pathophysiology and Clinical Presentation: Rhabdomyoma is the most common primary cardiac tumor of childhood and accounts for 60% to 79% of all cardiac tumors during the first year of life.1,3 Rhabdomyomas are hamartomas that regress and have no potential for malignancy. More than half of fetuses with rhabdomyomas are asymptomatic. Patients with rhabdomyomas can present with nonimmune fetal hydrops, outflow tract obstruction, or arrhythmia. At least 50% of patients with rhabdomyomas have tuberous sclerosis, and rhabdomyomas can be the first detectable manifestation of tuberous sclerosis.³

Imaging: Rhabdomyomas are round, hyperechoic, solid masses on echocardiography (e-Fig. 81-2). They usually are multiple and occur most commonly in the ventricular tissue but also can arise from atrial walls.^4,5 The rhabdomyoma signal characteristics on T1- and T2-weighted MRI are similar to those of myocardium, making MRI less sensitive than echocardiography.⁶ Signal is increased on contrast-enhanced T1-weighted and proton-weighted imaging.⁷ Rhabdomyomas are easier to detect when they extend into the cardiac lumen (Fig. 81-3). They have increased attenuation compared with myocardium on noncontrast-enhanced CT scans, and they have mild delayed enhancement with contrast (e-Fig. 81-4).⁸ Small fat globules may be detected in rhabdomyomas.

Figure 81-3 Rhabdomyomatosis in an infant shows multiple bulging tumors with isointense signal to the left ventricular myocardium on axial T1-weighted imaging.

e-Figure 81-2 Echocardiography of multiple rhabdomyomas shows hyperechoic foci in the left ventricle. (Courtesy Renee Bornemeier, MD, Little Rock, AR.)

e-Figure 81-4 Rhabdomyoma in an infant with neurostigmata of tuberous sclerosis.
A broad-based ovoid mass (arrow) isointense to myocardium extends from the interventricular septum on axial (A) and short-axis steady-state free-precession (B) images.

Fibroma

Pathophysiology and Clinical Presentation: Cardiac fibroma is the second most common and the most commonly resected primary cardiac tumor of childhood.9,10 The tumors frequently are detected in the first year of life but can present throughout childhood. Fibromas are solitary tumors located in the myocardium. They are composed of fibroblasts and collagen. Calcifications are frequent and a differentiating finding compared with rhabdomyomas.^1,10 The tumor can be associated with Gorlin (basal cell nevus) syndrome.^7,9,10 Children can present with heart failure and arrhythmia.

Imaging: Echocardiography reveals a heterogeneous, echogenic, solitary mass.¹⁰ Cardiac fibroma signal intensity is isointense to slightly hypointense on T1-weighted imaging and low on T2-weighted imaging.^9,11 Classically, contrast-enhanced MRI of fibromas initially shows rim enhancement but decreased central enhancement compared with myocardium.¹² Enhancement on delayed imaging is characteristic (Video 81-1 and Fig. 81-5 and e-Figs. 81-6 and 81-7).^7,13 Calcifications may be detected by CT (e-Fig. 81-8).¹⁴