Right Ventricular Myxoma Obstructing the Outflow Tract

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Abstract

Cardiac myxomas are benign tumors of endocardial origin. Symptoms might mimic heart disease as well as infectious disease, immunodeficiency, and malignant processes. We present the case of a 59-year-old female patient with a large right ventricular myxoma that was connected to the basal interventricular septum. Movement in systole provoked the obstruction of the right ventricular outflow tract. She presented clinically with syncope, systolic murmur, and signs of right heart failure. The diagnosis of the right ventricular tumor was based on 2D echocardiography, magnetic resonance, and multislice computed tomography findings. Emergency surgical excision of the myxoma was necessary to prevent embolism and sudden death.

Correspondence
Branislava Ivanovic, MD, PhD, Associate Professor, Clinic for Cardiology, Clinical Centre of Serbia, Koste Todorovica 8, 11000 Belgrade, Serbia. E: lole@scnet.rs
DOI
https://doi.org/10.15420/ahhj.2010.8.2.118

Primary tumors of the heart are rare, with an incidence of 0.0017–0.19% in unselected autopsy series.1 Three-quarters of primary heart tumors are benign. Approximately half of all cardiac tumors are myxomas, which occur in 0.5 in a million people each year.2 Although these tumors are histologically benign, they are potentially fatal because of the associated risk of embolization and intracardiac obstruction.

We report a case of a 59-year-old female with a large myxoma of the right ventricle that caused obstruction of the right ventricular outflow tract.

Case Report

A 59-year-old Caucasian female was hospitalized because of syncope on exertion. Dyspnea on exertion had appeared four months before and became more intensive about 10 days prior to admission. A month before hospitalization, pretibial edema had appeared.

The patient had no personal or familial medical history of cardiac disease or Carney syndrome. On examination her blood pressure was 110/70mmHg, her heart rate was 92 beats per minute, and her temperature was normal. The patient was cyanotic with a plethoric face and jugular vein distension. Auscultation revealed a regular heart beat, but a diminished second sound with 3/6 holosystolic ejection murmur on the left upper sternal border. There was no change in the murmur with respiration and position. The lungs were clear, the liver was 3cm palpated in the midclavicular line, and peripheral edema was evident. The patient had no neuroendocrine clinical signs or skin problems.

Results of routine blood tests were normal apart from an erythrocyte sedimentation rate of 41mm/h and raised C-reactive protein (CRP) levels (24mg/l). Blood gases were within normal ranges as were tumor marker levels and levels of interleukin 6 (IL-6).

Chest X-rays in the prone position showed an enlarged heart and bilateral reduction in transparency of the lung parenchyma in the lower third of the lungs.

An electrocardiogram showed sinus rhythm with right bundle branch block. 2D transthoracic echocardiography (TTE) revealed an abnormally large, peduncular, solid mass with an irregular surface in the right ventricle, which originated from the basal interventricular septum progressed through the right ventricle outflow tract and prolapsed into the pulmonary artery during systole, almost completely blocking the outflow tract at the maximum gradient 70mmHg (see Figure 1). The right ventricle was markedly dilatated and larger than the left ventricle. Moderate tricuspid regurgitation was also found. The calculated pulmonary artery systolic pressure was 40mmHg.

Magnetic resonance imaging (MRI) revealed that the left ventricle was compressed by the large right ventricle (maximum diameter was 53mm), which contained a huge nonhomogenic mass measuring 30x60x70mm rising from the basal interventricular septum and growing throughout the right ventricular outflow tract to the truncus pulmonalis (see Figure 2).

Multislice computed tomography (MSCT) confirmed the dilatation of the right ventricle and indicated a lobular, sharply delimited, relatively homogenous polypoid soft tissue structure within, which protruded into the infundibulum and almost blocked it. However, there were no significant changes in the coronary arteries (see Figure 3).

The patient immediately underwent surgery. Cardiopulmonary bypass was established using aortic and bicaval cannulas with moderate hypothermia. The right atrial approach did not allow sufficient space to excise the whole mass. Instead, right ventriculoctomy was performed and a large mass, weighing 57g and measuring 80x60x30mm was excised with the surrounding septal wall to prevent relapse (see Figure 4). The right ventricular septal wall was repaired with an autologous glutaraldehyde-treated pericardial patch. Histopathologic findings confirmed the diagnosis of myxoma (see Figure 5). Post-operative recovery was uneventful and there was no recurrence in the following six months.

Discussion

Cardiac myxomas are often found in the atria. About 75% of myxomas arise from the left atrium and 15–20% from the right atrium. Only 3–4% of all myxomas are detected in the left ventricle and the same proportion in the right. Symptoms depend on tumor size, mobility, and localization.1,3 In the majority of patients with myxoma clinical presentation relates to obstruction of blood flow and embolic phenomena. Patients with right ventricular myxomas may present with symptoms and signs of inflow or outflow obstruction, syncope, embolism, and arrhythmia.3 In this patient, the large myxoma obstructed the right ventricle outflow tract. She presented with exertional syncope, signs and symptoms of right heart failure, and auscultatory findings of pulmonary stenosis. Certain constitutional symptoms can occur irrespective of tumor localization, and dimension. These include: malaise, fever, erythematous rash, arthralgia, myalgia, weight loss, Raynould’s phenomena, anemia, and elevated CRP levels. The tumor may secrete IL-6, resulting in inflammatory and autoimmune manifestations.4 Myxomas localized in the right ventricle can be associated with tumors in the left and right atria or the left ventricle and may be familial. The condition in which multiple myxomas located in different parts of the heart occur with skin problems (skin and mucous membrane lentigines, schwanomas, and skin myxomas) and endocrine tumors is defined as Carney syndrome. This diagnosis is given if two or more of previously mentioned criteria are present.5 Routine blood tests, electrocardiograms, and chest X-rays are often non-specific, as in this case.

Before 1952, myxomas could only be diagnosed during autopsy or accidentally during angiography. Transthoracic echocardiography has facilitated detection of these tumors. TTE can identify a tumor, its localization, dimensions, shape, attachment, and mobility. Transesophageal echocardiography can help accurately to detect the place of insertion and morphologic characteristics of the myxoma.6 Ha et al. identified two distinct types of myxoma by echocardiography: a round type characterized by a solid, round shape with a non-mobile surface, and a polypoid type characterized by a soft, irregular shape with a mobile surface.7 The polypoid type of tumor is the only independent predictor of systemic embolism.

Computed tomography can be used to reveal intracardiac tumor masses, which, in the case of myxoma, are characterized by a lobular shape and heterogeneous attenuation. Tumor visualization is enabled by using contrast enhancement to reveal defects in contrast filling. However, the determination of tumor attachment using this method is difficult.4

MRI has an important role in the evaluation of cardiac masses, especially when echocardiograpic findings are equivocal or suboptimal, or when localization is atypical. Besides shape, it also provides data about signal intensity. Heterogeneity of signal intensity is correlated with hemorrhage, calcification, fibrosis, and cystic changes.4,8 MSCT reveals similar information to that obtained from MRI. In this case, this method gave unequivocal confirmation of a large mobile tumor prolapsing in the truncus pulmonalis.

The treatment of choice for a large and mobile myxoma is urgent surgical resection to eliminate the risks of distal emolization, cardiovascular complications, and sudden death. The presence of a polypoid multylobular tumor with a rough surface in this patient indicated a need for urgent surgical intervention. The choice of longitudinal right ventriculectomy was based primarily on tumor size. In addition to complete excision of the tumor, special attention was paid to the adequate removal of myxoma margins in order to avoid recurrence.

Histopathologic data are always required for a definitive diagnosis. Intracavitary tumors that obstruct the right ventricular outflow tract are rare and benign tumors are 40–140 times more frequent than malignant tumors.9 Right ventricle myxomas, particularly those which block the outflow tract are unusual.10–14 Sporadic case reports of right ventricular myxoma stress the importance of surgical removal of the tumor not only to unblock the infundibulum but also to prevent embolism and sudden death.

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