Key points
- •
The most common benign cardiac tumors are myxomas. Arising from a stalk attached to the fossa ovalis membrane, myxomas are generally found in the left atrium.
- •
The most common primary cardiac tumors in children are rhabdomyomas and fibromas, both of which are benign. Rhabdomyomas usually decrease in size with age.
- •
The most common cardiac tumors involving valves are papillary fibroelastomas.
- •
Transthoracic echocardiography can evaluate the location and morphology of the mass as well as its hemodynamic effect.
- •
Transesophageal echocardiography has increased spatial and temporal resolution; hence, it is superior in depicting small, highly mobile masses.
- •
Cardiac magnetic resonance and cardiac computed tomography are complementary in that they provide tissue characterization.
| WHO classification of benign cardiac tumors |
| Cardiac myxomas |
| Rhabdomyomas |
| Papillary fibroelastomas |
| Lipomas |
| Cardiac fibromas |
| Hemangiomas |
| Histiocytoid cardiomyopathies |
| Hamartomas of mature cardiac myocytes |
| Adult cellular rhabdomyomas |
| Inflammatory myofibroblastic tumors |
| Cystic tumors of the atrioventricular nodes |
| Advantages | Limitations | |
|---|---|---|
| Echocardiography | Easily available High spatial resolution (TEE > TTE) Detection of small masses High temporal resolution Functional and hemodynamic repercussions Detection of underlying heart diseases | Patient dependent (echogenicity) Restricted field of view Poor tissue characterization |
| CMR | 3D visualization Tissue characterization (differential diagnosis) Large field of view Moderate temporal resolution | Limited availability Average spatial resolution Reduced ability to characterize small and highly mobile masses Long examination time Patient dependent (rhythm and collaboration) Contraindications (e.g., metal implants and renal failure) |
| CT | 3D visualization Fast acquisition Easy available Spatial resolution Chest wall (robotic surgery) | Radiation exposure, even more, when ECG gated Low temporal resolution Average tissue characterization, except for fat and calcification Contraindications (renal failure) |
| 18F-FDG PET/CT | Large field of view Exclusion of secondary malignant tumors | Limited availability Poor spatial and temporal resolution Limited ability to differentiate other diseases (pseudotumors, benign tumors, or infectious/inflammatory tumors) |
| Diagnostic triad in the presentation of atrial myxomas | ||
|---|---|---|
| Features | Manifestations | Frequency (%) of patients |
| Obstructive symptoms | Heart failure, dyspnea, syncope, and sudden death (rare) | 54–95 |
| Constitutional symptoms | They may mimic autoimmune disease or vasculitis (e.g., myalgia, arthralgia, weight loss, fatigue, fever, Raynaud’s phenomenon, and finger clubbing). | 34–90 |
| Embolic phenomena | Emboli may travel to any organ, but 73% reach the central nervous system, including the spinal cord | 10–45 |
Transthoracic and transesophageal echocardiographic examinations can be used in combination to assess the size, shape, morphology, and hemodynamic effects of the tumor. Cardiac myxomas are usually attached with a stalk to the atrial septum in the fossa ovalis and have lobulated margins. Their range of movement is dependent on the length, size, and morphology of the stalk. Cardiac myxomas are better visualized with the use of echocardiography contrast. On computed tomography, a myxoma appears as a well-defined, ovoid, intracavitary mass with lobulated contours, and the contrast helps to delineate the mass as a low-attenuation lesion surrounded by enhanced intracardiac blood. On cardiac magnetic resonance images, cardiac myxomas appear isointense on T1-weighted sequences and have higher signal intensity on T2-weighted sequences owing to the high extracellular water content. Regions of acute hemorrhage appear hypointense on both T1-weighted and T2-weighted images and can subsequently become hyperintense as hemoglobin in the blood is progressively oxidized. Steady-state free precession imaging can reveal the stalk-like attachment and the mobile nature of these masses, as well as prolapse across the valves. Internally, myxomas may contain cysts, regions of necrosis, fibrosis, hemorrhage, and calcification, leading to a typically heterogeneous appearance at contrast enhancement. Postcontrast delayed imaging typically shows a heterogeneous enhancement pattern, with many myxomas having a layer of surface thrombus with low signal intensity. .
Mitral valve obstruction caused by atrial myxomas represents an important hemodynamic consequence, leading to symptoms of congestive heart failure and pulmonary hypertension, as well as syncope and even sudden death. Mitral stenotic effects usually occur when the tumor diameter exceeds 5 cm. Echo Doppler studies are the most important method for the differential diagnosis with primary valve disease since they can estimate the transvalvular gradient. Chest X-rays may reveal enlargement in the left atrium and some signs of pulmonary hypertension and congestion .
A low incidence rate has been reported for right atrial myxomas. They usually originate in the fossa ovalis or the base of the interatrial septum. The signs and symptoms of right atrial myxomas are atypical and highly variable, depending on the size, position, and mobility of the tumor, and are modified according to the physical activity and body position of the patient. Right atrial myxomas may remain asymptomatic or eventually cause constitutional signs and symptoms, including fever, weight loss, arthralgia, Raynaud’s phenomenon, anemia, hypergammaglobulinemia, and an increased erythrocyte sedimentation rate due to the production of interleukin-6. These symptoms disappear after the tumor is removed. Patients may also present with atypical chest pain, syncope, lethargy, malaise, palpitation, peripheral edema, pulmonary embolism, and hemoptysis. Nevertheless, the most common manifestation is dyspnea (in 80% of patients), and right heart failure has been reported. Echocardiography remains the best diagnostic method for locating and assessing the extent of myxomas and for detecting their recurrence, with a sensitivity of up to 100%. Still, transthoracic echocardiography may fail to identify tumors smaller than 5 mm in diameter, and a transesophageal echocardiogram is required when there is suspicion of a very small tumor. The treatment of choice for myxomas is surgical removal, and the recurrence rate of sporadic tumors is very low (between 1% and 3%) ( Supplementary Videos 8.1 and 8.2 ).
A dumbbell or butterfly wing or so-called biatrial myxoma or interatrial septal myxoma with a biatrial extension usually arises from the left atrial side of the fossa ovalis and prolapses into the right atrium through the foramen ovale. Its incidence is less than 1%–5% of all intracardiac myxomas. A close differential diagnosis is a biatrial thrombus crossing a patent foramen ovale; nonetheless, either a biatrial myxoma or a straddling thrombus through the foramen ovale is a rare diagnosis. Thrombi in this situation may have identifiable causes such as deep vein thrombosis, metastasis, and mitral stenosis. Thrombi are more irregular in shape. Intracardiac thrombi are more fragile, and they usually present with evidence of pulmonary, systemic, or coronary embolism. They should be removed by wide-base resection as soon as possible because of the higher frequency of embolization. Echocardiography yields a significant number of clues such as polypoid or smooth surface myxomas, the site of origin, the satellite focus, and the diastolic blockage of the mitral or tricuspid inflow, which almost support the provisional diagnosis of a cardiac myxoma .
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
