Giant Right Ventricular Mass Protruding into the Pulmonary Artery during Systole.

Myxomas are the most common primary cardiac tumors in adults and mainly originate in the left atrium with a slight female predominance. Only 3%-4% of myxomas are detected in the right ventricle. Although these tumors are histologically benign, they can lead to several catastrophic complications such as embolization or obstruction of blood flow at the mitral or tricuspid valve orifices. We report a rare case of right ventricular myxoma presented with near-syncope attacks and worsening dyspnea.

INTRODUCTION

Primary cardiac tumors are rarely encountered in clinical practice. Myxoma is the most common benign cardiac tumor with an incidence of 0.002%–0.3% at autopsy.[1] The clinical presentation depends on its size and anatomic location. Approximately 75% of these tumors are seen in the left atrium where they are commonly localized at the atrial septum in or adjacent to the fossa ovalis, and 7%–18% are seen in the right atrium. The remaining (2.5%–4%) are found either biatrially or in the left or right ventricle (RV).[23] In this report, we present a rare case of a right ventricular myxoma protruding into the pulmonary artery.

CASE REPORT

A 26-year-old male with the complaints of near-syncope attacks and worsening dyspnea on exertion for 2 years was admitted to our hospital. His past medical history was unremarkable. Physical examination was normal except for a harsh systolic murmur best audible at the lower left sternal border. Transthoracic echocardiogram (TTE) revealed a large mass with lobular contours in the RV that occupied almost the whole RV [Figure 1 and Video 1]. The mass was protruding into the pulmonary artery and produced right ventricular outflow obstruction with a maximal peak gradient of 30 mmHg [Figure 2 and Video 2]. A few days after the diagnosis, surgical intervention was made using median sternotomy and cardiopulmonary bypass. After a longitudinal right atriotomy, the mass with the base deeply embedded within the trabeculae carneae was resected as much as possible through the tricuspid valve. On gross examination, the mass had a gelatinous consistency with hemorrhagic areas [Figure 3]. The De Vega annuloplasty technique was used to repair tricuspid valve regurgitation before closure of the right atriotomy. Microscopically, the mass consisted of areas of stellate cells scattered in a myxoid stroma [Figure 4]. A definitive diagnosis of right ventricular myxoma was made. Control TTE before discharge revealed normal functioning tricuspid valves with a minimal degree of tricuspid regurgitation. The postoperative course was uneventful, and the patient was discharged on day 17.

Figure 1

Right ventricle inflow transthoracic echocardiogram showing the mass. RA = Right atrium, RV = Right ventricle

Figure 2

Parasternal short-axis transthoracic echocardiogram showing the mass protruding into the pulmonary artery

Figure 3

Gross specimen of the right ventricular mass with hemorrhagic areas

Figure 4

Spindle-shaped cells in a loose myxoid stroma (H and E, ×20)

DISCUSSION

A high percentage of cardiac myxomas are sporadic, but familial cases have been reported with an incidence of 7%.[4] They less commonly occur in the right atrium or, very rarely, in the ventricles.[5] Although benign, myxomas may lead to several complications such as heart valve obstruction, pulmonary or systemic embolism, and arrhythmia.[1] Embolism is the most feared complication of the tumor, which has been reported in 30%–40% of patients.[1]

In clinic practice, myxomas are often detected in asymptomatic patients, which can be easily overlooked and lead to delayed diagnosis. Myxomas arising from the RV may often cause obstruction of the RV outflow tract.[4] Patients may present symptoms related to low hypoperfusion or to increased pulmonary arterial pressure with RV failure findings. However, the clinical presentation may vary with the localization of the tumor. Our patient presented with manifestations of right ventricular outflow tract obstruction. Multiple pulmonary embolisms can be seen in the cases of friable polypoid myxomas, which may lead to severe pulmonary arterial hypertension and occasionally also to aneurysms of the pulmonary arteries.[67] Although they were not demonstrated in our patient, a syndromic relationship (e.g., Carney's complex) and family history should be sought in young adult patients with an uncommon location.[4]

For a long time, cardiac myxomas were thought to have originated from mural thrombi. However, the body of evidence has clearly demonstrated that they are not of thrombotic origin and are, actually, neoplastic. As myxomas are vascular tumors, they may be neovascularized by the coronary arteries and/or their branches.[124]

In the present case, the differential diagnosis included myxoma and thrombus. However, it was difficult to diagnose it as a myxoma or thrombus due to morphology and mobility of the mass. Furthermore, we could not find the localization of the stalk, and the location of the mass for a myxoma was atypical. Sometimes, thrombi may have stalk and can be misdiagnosed as a myxoma.[89] Although we did not use, due to considering the fact that it could not affect the diagnostic or therapeutic plan, cardiac magnetic resonance imaging (MRI) may be useful for the further tissue characterization of the cardiac masses before planning a surgical intervention. In cases of doubt, attempting cardiac mass biopsy before surgical resection may result in devastating complications. In our case, TTE findings provided valuable information about the interaction of the mass with the heart valves, hemodynamic compromise, its size, and location. Indeed, neither computerized tomography nor MRI findings may be sufficient to confirm this diagnosis. Surgical excision and histopathologic examination are mandatory for a definitive diagnosis, as in the present case.[10] Because of the proximity of the tumor with the cardiac structures, a total resection is mostly not possible. Attempting to make a total resection can lead to injury of the cardiac muscle, papillary muscles, chordae tendineae, valves, or conductive bundles.

On the other hand, emergency surgery has been questioned on the basis of a series of 40 patients with cardiac myxoma.[8] In our case, we decided to perform surgery due to the risk of recurrent pulmonary embolism, right ventricular outflow obstruction symptoms, and the bigger size of the mass.

Although good long-term outcomes have been reported following the complete resection of the tumor, recurrences may rarely occur, especially in cases of familial types and incomplete tumor removal.[2458] We planned regular follow-up echocardiogram controls for our patient to monitor any signs of future recurrence.

CONCLUSION

In cardiac myxomas, the major determinants of mortality are the time of diagnosis and the surgical intervention. Left ventricular myxomas are associated with a higher potential for complications and should be scheduled for surgery at the earliest possible time. Approximately, 8% of myxoma cases die during the waiting period for surgery due to embolic complications or total obstruction of intracardiac blood flow.[12] Therefore, after the diagnosis has been made, surgery should be performed without delay for the prevention of possible embolic complications or sudden death.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.