Key points
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Fetal cardiac tumors are extremely rare and most are benign.
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They tend to appear between 20 and 30 weeks of pregnancy.
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The most common types of fetal cardiac tumors are rhabdomyomas, teratomas, and fibromas respectively.
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Fetal cardiac tumors may cause important complications, including arrhythmias, ventricular outflow or inflow obstruction, atrioventricular valve insufficiency, heart failure, and hydrops fetalis.
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Cardiac tumors are generally easy to diagnose prenatally by fetal echocardiography.
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Due to possible life-threatening complications, all cases should be referred to the perinatal center.
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Pregnancy should be continued as long as possible if there are no significant cardiovascular complications.
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The outcome of affected fetuses depends on the type of tumor and also on its location, size, number, cardiovascular complications, and associated extracardiac disorders.
Introduction
Fetal cardiac tumors are relatively rare, representing 0.02% to 0.13% of cases in fetal cardiac series. They tend to appear between 20 and 30 weeks of pregnancy . Most fetal cardiac tumors are benign, but they may cause important complications, including arrhythmias, ventricular outflow or inflow obstruction, atrioventricular valve insufficiency, heart failure, and hydrops fetalis . Rarely, interference with the coronary arterial circulation may cause sudden fetal death .
Heart tumors are generally easy to diagnose prenatally by fetal echocardiography. Due to possible life-threatening complications, all cases should be referred to the perinatal center .
Fetal primary cardiac tumors
Among the various histological types, the three most common types of fetal cardiac tumors are rhabdomyomas, teratomas, and fibromas, respectively . Most fetal primary cardiac tumors (FPCTs) are benign and fetal malignant and metastatic cardiac tumors are very rare .
Cardiac rhabdomyoma
Cardiac rhabdomyomas are the most common fetal cardiac tumors accounting for 70%–80% of cases in fetal cardiac series . Cardiac rhabdomyomas are benign tumors of striated muscle cells. Echocardiography shows a homogeneous, well-circumscribed mass that is significantly more echogenic relative to the myocardium .
Cardiac rhabdomyoma may be intracavitary or intramural, found within the ventricular free wall or septum, the apex, the outflow tract, the conus papillary muscles, or rarely, within the atria. They are multiple tumors in 90% of cases, with variable sizes, usually sessile but can occasionally be mobile .
Cardiac rhabdomyoma may grow in size prior to 32 weeks and regress thereafter. Therefore serial assessment of an affected fetus is important particularly prior to 32 weeks . Symptoms depend on the size, number, and location of the rhabdomyomas. An intervention is only necessary when serious complications occur .
Despite the large size of tumors and flow obstruction or valve insufficiency, fetal hemodynamic compromise is rare in rhabdomyomas .
Fetal outcome depends on the tumor size, impairment of flow, and rhythm disturbances. Early delivery at a viable age may be necessary for fetal hydrops with plans for neonatal intervention .
Rhabdomyomas are benign lesions and grow in utero due to the transmission of maternal estrogens to the fetus . In general, they tend to shrink after birth and an operation is rarely necessary .
It should be noted that small tumors, when located in the septum or ventricular cavity, often mimic an echogenic focus, thus leading to difficulty in recognizing them through early ultrasonographic screening ( Supplementary Videos 31.1–31.7 ).
Fetal pericardial teratomas
Pericardial teratomas account for 10%–15% of cardiac tumors in fetal life and are usually benign. Teratomas are derived from two or three germinal cell layers and are typically extracardiac masses .
Teratomas are typically extracardiac masses found within the pericardial reflection at the junction of the SVC, right atrium, and near the aorta and pulmonary artery. They are large encapsulated, irregularly shaped mass of heterogeneous echo texture, with calcified and cystic elements and usually single. Teratomas can also be found in other locations, including the mediastinum and rarely within the heart. Fetal teratomas can be multifocal .
