Cardiac masses and the role of imaging in their diagnostic

Cardiac masses often pose challenges both in terms of diagnosis and therapeutic management. They include thrombi, vegetations and, much less frequently, tumors. Often discovered incidentally, without any characteristic signs or symptoms, primary cardiac tumors are rare clinical-pathological entities and, in most cases, benign.^[1,2]

Thus, within this histopathologically heterogeneous group, the first five tumors in terms of frequency do not exhibit malignant potential and account for approximately 80%–90% of all cases. They are represented by myxoma, fibroma, lipoma, papillary fibroelastoma, and rhabdomyoma. As for primary malignant tumors of the heart, angiosarcoma represents the most common histopathological type.^{[3, 4]}

Myxomas are the most common primary tumors of the adult heart, with the vast majority originating in the left atrium. Macroscopically, they are generally pedunculated, with a gelatinous consistency and variable dimensions. Approximately 35% are villous and friable, leading to embolisms being the main form of presentation. Larger tumors often have a smooth surface and are associated with cardiovascular signs and symptoms.^[1,5]

We present the case of a 64-year-old female patient with a personal history of grade 2 obesity and grade 3 essential hypertension.

She presents to an outpatient clinic, experiencing symptoms of fatigue and dyspnea during moderate exertion, where an echocardiogram revealed a mass highly suggestive of a left atrial myxoma. Consequently, the patient was referred to our clinic for further investigations and specialized treatment.

It is important to note that the patient was on chronic medication for her hypertension, which included Bisoprolol and Candesartan.

Upon admission, the patient had a blood pressure of 150/80 mmHg and a heart rate of 65 bpm, while basic laboratory exams showed dyslipidemia with no other significant modifications. The ECG presented a normal sinus rhythm 80/min with two premature ventricular contractions and a premature atrial contraction (Figure 1).

Figure 1

Transthoracic echocardiography (TTE) revealed a normal-sized left ventricle (LV) with preserved global systolic function, corresponding to a volumetric ejection fraction (EFvol) of 59%. There were no global or regional kinetic abnormalities observed. However, biatrial dilation was noted (Figure 2A). During the examination the presence of a pedunculated mass in the left atrial cavity, attached to the interatrial septum, measuring 25/17 mm was able to be confirmed. The mass did not interfere with the movement of the mitral valve, and it was strongly suggestive of myxoma (Figure 2B).

Figure 2

Given the great diversity of intracardiac masses, there are currently no guidelines or consensus regarding the optimal approach to diagnosis and treatment. In the case of this patient, the decision was made to perform a transesophageal echocardiogram (TEE), which can provide a detailed anatomical description of the intracardiac mass and the surrounding tissues. TEE is superior to TTE, as it captures the relationship between the tumor and adjacent structures, especially in cases of atrial localization. It is also superior to magnetic resonance imaging (MRI) when it comes to tracking small and highly mobile masses such as vegetations or papillary fibroelastomas.^[6]

In our case, transesophageal echocardiography described a tumor-like mass in the left atrium, resembling a myxoma, with maximum dimensions of 26/27 mm. It was attached to the posteroinferior region of the interatrial septum, without affecting the hemodynamics of the mitral valve (Figure 3A). Additionally, an aneurysmal interatrial septum was observed, bulging towards the right atrium, with a fenestrated appearance in the area of the foramen ovale. There were two small atrial septal defects measuring 6 mm and 7 mm, respectively, with a left-to-right shunt (Figure 3B).

Figure 3

Furthermore, for a more detailed description of the cardiac mass and the surrounding tissues, as part of the preoperative assessment, the patient underwent cardiac CT angiography, which revealed the following: Agatston calcium score of 0, patent epicardial coronary arteries without stenoses and within the left atrium, attached to the lower portion of the interatrial septum, a hypodense tumor-like mass, relatively round, with a slightly polygonal contour, measuring 28/20/32 mm (a-p/t/cc), with an implantation base of approximately 10 mm and without contrast enhancement (Figure 4).

Figure 4

In the differential diagnosis of the left atrial myxoma we have taken into consideration intracavitary thrombi, vegetations, and other histological types of benign and malignant tumors.

The possibility of a vegetation was excluded based on the position and attachment site of the mass, its well-defined contour and increased dimensions, the absence of clinical or biological signs of inflammation, the absence of predisposing factors and of any history of recent infection.

Most intracavitary thrombi are located in the left atrial appendage and are associated with certain predisposing conditions, particularly atrial fibrillation, mitral stenosis, and dilated or restrictive cardiomyopathies.^[7] The patient had a predisposing factor (biatrial dilation), but the position of the mass and the presence of a pedicle attachment to the interatrial septum made this diagnosis less likely.

When it comes to benign and malignant tumors, the definitive diagnosis is made through histopathological examination of the surgical resection specimen or, in some cases, by biopsy of the tumor. Although the echocardiographic characteristics can be highly suggestive of a myxoma, as in the case of this patient (pedunculated tumor located in the left atrium with attachment to the interatrial septum), there are rare situations where thrombi or other histopathological types of tumors, including malignant ones, are identified postoperatively.^{[7, 8]}

Therefore, the diagnosis of left atrial myxoma and fenestrated foramen ovale was established, and, after completing the preoperative assessment, the patient was referred to the cardiovascular surgery department.

The patient underwent surgery in the cardiovascular surgery department and the histopathological examination of the resected specimen confirmed the diagnosis of myxoma. The postoperative course was favorable, without complications (Figure 5AB).

Figure 5

Intracardiac masses comprise a histopathologically heterogeneous spectrum, which includes vegetations, thrombi, and tumors. The location of these masses is of major importance in the differential diagnosis and should be carefully correlated with the patient’s age, comorbidities, clinical context, and morphological characteristics of the tumor.^[1]

Fibromas and lipomas are more commonly found in children. Atrial fibrillation should raise suspicion for a probable diagnosis of atrial thrombus, while ventricular dysfunction may suggest the presence of a ventricular thrombus. In the case of valvular masses, risk factors for infective endocarditis (such as valve prostheses and immunodeficiency) and thrombotic risk factors, including antiphospholipid antibody syndrome, should be taken into consideration.^[9]

The clinical presentation of patients with intracavitary masses is diverse and influenced by various factors, including the location of the tumor, its size, and its malignant or benign nature. However, it is important to note that a significant proportion of cases are asymptomatic and are incidentally discovered during an echocardiographic examination.^[10]

Many tumors, especially myxomas, are accompanied by constitutional signs and symptoms, including fever, chills, and weight loss. Additionally, laboratory tests may show signs of inflammation such as leukocytosis, increased levels of C-reactive protein and elevated erythrocyte sedimentation rate, likely as a result of the tumor secreting inflammatory cytokines. On cardiovascular examination, specific changes are usually not observed, except for a protodiastolic murmur (“tumor plop”) in the case of atrial tumors associated with valvular prolapse.^[11]

Some patients may present with an embolic clinical picture, which varies depending on the tumor location and the presence or absence of intracardiac shunts: –

tumors of the right heart and those of the left heart associated with a left-to-right shunt can lead to pulmonary embolism, which is typically completely unilateral and does not respond to anticoagulant treatment;

The electrocardiogram can be normal or may show nonspecific changes, such as various rhythm or conduction disorders, predominantly in the case of infiltrative tumors.^{[5, 12]}

Imaging investigations prove to be the most useful in evaluating these patients. Transthoracic echocardiography provides the possibility of dynamic monitoring and has the advantage of capturing both the anatomical appearance and the extension of the tumor, as well as its physiopathological consequences. This can be complemented with contrast administration to differentiate between highly vascularized malignant tumors, benign tumors, and thrombi.^{[13, 14]}

Transesophageal echocardiography is particularly important for describing left-sided cardiac masses, especially those involving the atria or the mitral valve. It has the advantage of being used intraoperatively for real-time monitoring during tumor resection.

Cardiac computed tomography (CT) allows for the assessment of myocardial infiltration and provides optimal spatial resolution for evaluating the lungs, pleura, and mediastinum. It is particularly preferred in cases of malignant tumors.^[5]

Cardiac magnetic resonance imaging (CMR) is particularly useful when the echocardiographic result is uncertain or in patients with difficult echocardiographic windows. It can provide detailed information about the size, shape, margins, and extent of the cardiac mass and can accurately differentiate between thrombi and tumors. Although it has the advantage of being non-ionizing, it is not cost-effective and is not suitable for patients with implanted cardiac devices.^{[11, 13]}

The gold standard for confirming the diagnosis of intracardiac masses remains the histopathological examination of the resected tissue, which is performed postoperatively. Immunohistochemical tests using various antibody panels are employed to provide further characterization of the tissue and to aid in the definitive diagnosis. ^[5]

The choice of treatment for intracardiac masses varies depending on the underlying etiology. In our case, as well as in most primary cardiac tumors, surgical resection becomes the clear choice. ^[3]

The particularity of the case lies in the diagnosis of a left atrial myxoma along with the presence of a fenestrated foramen ovale. This combination of findings is relatively rare and requires careful evaluation and management. The patient underwent transesophageal echocardiography, cardiac CT, and surgical resection of the myxoma, which confirmed the diagnosis and resulted in a favorable postoperative outcome without complications or recurrence. The treatment plan also included medication adjustment with Bisoprolol and Olmesartan/Amlodipine. The comprehensive approach to diagnosis, preoperative assessment, and successful surgical intervention contributed to the positive outcome in this particular case.

When dealing with a patient presenting with an intracardiac mass, a thorough transthoracic echocardiographic evaluation is essential. This evaluation should describe the location, dimensions, appearance, and hemodynamic impact of the mass.

A more detailed assessment, especially for masses involving the left atrium and mitral valve, can be obtained through transesophageal echocardiography, which provides a better anatomical description of both the mass and adjacent structures.

It is crucial to correlate all these findings with the patient’s age, comorbidities, and clinical context in order to differentiate between a possible tumor, thrombus, or vegetation. The treatment approach will vary depending on the specific diagnosis.

Multidisciplinary collaboration among cardiologists, cardiac surgeons and pathologists is essential in the management of patients with intracardiac masses to ensure accurate diagnosis and appropriate treatment.