Echocardiography in benign cardiac tumors (diagnosis, approach, and follow-up)





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.



Table 8.1

WHO classification of benign cardiac tumors.



























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

Algorithm 8.2


The image depicts the diagnostic algorithm for the evaluation of benign primary cardiac tumors. CT , cardiac tomography; CMR , cardiac magnetic resonance .




Table 8.3

Advantages and limitations of cardiac imaging modalities for the diagnosis of cardiac myxomas.
























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)

TEE , transesophageal echocardiography; TTE , transthoracic echocardiography; CMR , cardiac magnetic resonance; CT , computed tomography; ECG , electrocardiography; 18 F-FDG , 18 F-fluorodeoxyglucose; PET , positron emission tomography.

Algorithm 8.4


The image depicts the proposed diagnostic imaging algorithm for suspicion of cardiac myxomas .



Fig. 8.5


(A) Transesophageal echocardiography shows a round, heterogeneous mass attached to the left atrial side of the interatrial septum, suggestive of a myxoma. (B) Cardiac catheterization demonstrates the typical appearance of tumor blush at the level of the left atrium after contrast injection in the left coronary artery, indicative of the vascular support of the tumor (arrows). (C) The excised cardiac myxoma with a gelatinous appearance is presented herein.




Table 8.6

Diagnostic triad in the presentation of atrial myxomas .






















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

Fig. 8.7


The images illustrate a left atrial myxoma. (A and B) The 4-chamber view of transthoracic echocardiography demonstrates a large semimobile heterogeneous mass, which is attached to the left atrial side of the interatrial septum and protrudes into the left ventricle in the diastole, suggestive of a large left atrial myxoma. (C) The same mass is visualized in the short-axis view at the level of the aortic valve. (D) Cardiac magnetic resonance confirms the left atrial myxoma.




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. .


Fig. 8.8


The images show a left atrial myxoma. The results of the transthoracic (B and C) and transesophageal (A) echocardiographic examinations of a patient with a left atrial myxoma are illustrated herein. Myxomas are described as nonhomogeneous, well-circumscribed echodensities that may have a globular structure. The left atrium is the most common site of myxomas (≈ 75%). Large left atrial myxomas may cause mitral inflow obstruction (i.e., functional mitral stenosis), significant mitral regurgitation (interference with mitral valve coaptation), and subsequent pulmonary hypertension .



Fig. 8.9


The images demonstrate a huge left atrial myxoma. (A, B, and D) Transthoracic echocardiography in two different patients shows huge left atrial myxomas obstructing the mitral valve flow (C) and mimicking mitral stenosis hemodynamics. The consequence is severe tricuspid valve regurgitation (E) and pulmonary hypertension (F).




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 .


Fig. 8.10


The images illustrate a left atrial myxoma and a left atrial myxosarcoma. (A and B) Transthoracic echocardiography in two different patients presenting with dyspnea on exertion shows a giant heterogeneous mass in the left atrium involving the right pulmonary veins with a similar echocardiographic appearance. (A) The image shows that the giant left atrial myxoma had entered the right pulmonary vein (Supplementary Video 8.1). (B–D) The primary myxosarcoma of the right inferior pulmonary vein presents clinically as a benign left atrial myxoma with a concurrent right lower lung tumor in the chest X-ray and the thoracic computed tomography scan. These images indicate the importance of pulmonary vein involvement in left atrial masses. Myxomas are usually attached with a stalk to the cardiac wall, most often the interatrial septum and, in descending order of frequency, the posterior atrial wall, the anterior atrial wall, and the atrial appendage. Other findings are suggestive of malignancy. Such findings include the involvement of the tumor in the pulmonary vein or the vena cava, the infiltration of the myocardium or the adjacent cardiac anatomy or organs, a broad attachment, a nonseptal origin, and the presence of pericardial effusion. In the second case, the tumor lacks any definite attachment to the interatrial septum; in addition, the chest computed tomography shows the extension of the tumor into the pulmonary vein and a concurrent right lower lung tumor. These findings are crucial in differentiating a malignant tumor from a myxoma .



Fig. 8.11


The images illustrate a right atrial myxoma. (A) Transthoracic echocardiography shows a giant right atrial villous myxoma with simultaneous pulmonary embolism considering the dilation in the right ventricle. Right atrial villous myxomas comprise a rare subtype in an unusual location with the high potential of pulmonary embolism (Supplementary Video 8.2). (B) The image demonstrates a very hypermobile right atrial myxoma protruding into the right ventricle in the diastole.




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 .


Fig. 8.13


The image depicts a right atrial myxoma with central necrosis. Transthoracic echocardiography shows a large, round mass in a dilated right atrium ( arrow ). The pathology results confirmed a myxoma with central necrosis.

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Nov 10, 2024 | Posted by in CARDIOLOGY | Comments Off on Echocardiography in benign cardiac tumors (diagnosis, approach, and follow-up)

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