Sporadic Multicentric Right Atrial and Right Ventricular Myxoma Presenting as Acute Pulmonary Thromboembolism.

Multicentric cardiac myxoma is a rare syndrome; usually it is familial. We report a rare case of sporadic right atrium (RA) and right ventricle (RV) myxoma in a 26-year-old female presenting to our hospital for the evaluation of sudden onset of dyspnea and left precordial pain attributed to the embolization of degenerating tumor fragments to the pulmonary artery (PA). The exact incidence of sporadic multicentric RA and RV myxoma presenting as acute pulmonary embolism is unknown as multicentric RA and RV myxoma are very rare. Myxomas presenting as pulmonary embolism is <10%. Majority of cardiac myxomas present as exertional dyspnea, chest pain, positional syncope, fever, weight loss and other constitutional symptoms. Any young patient presenting with acute onset dyspnea with multiple cardiac masses may have tumor embolization to the PA diagnosis with transthoracic echocardiography and high-resolution computed tomography of thorax, fast-tracks patient transfer for urgent cardiac surgery to prevent further embolization.

INTRODUCTION

Cardiac myxoma represents approximately 50% of all benign cardiac tumors in adults, with left atrial myxomas constituting 75% of all myxomas.[1] Usually, myxoma is a solitary mass. Multicentric cardiac myxomas are very rare and usually, biatrial. The incidence is <2.5% of all cardiac myxomas.[2] Familial multicentric cardiac myxomas may present as a case of left atrial (LA) and left ventricular (LV) mass simultaneously.[3]

We report a 26-year-old female patient who presented to our emergency department with acute onset of dyspnea and was diagnosed as multicentric right atrium (RA) and right ventricle (RV) myxoma with embolization of tumor fragments to the pulmonary artery (PA) during evaluation with transthoracic echocardiogram and high-resolution computed tomography (HRCT) of the thorax.

CASE REPORT

A 26-year-old female presented to the emergency department with sudden onset of dyspnea and left precordial pain of 6 hr duration. She had no history of exertional dyspnea, fever, weight loss, prolonged immobilization, syncope, focal neurological deficits, substance abuse, endocrine disorders and dermatological ailments in the past. She had no family history of cardiac disorders, including cardiac tumors. The patient's physical examination revealed blood pressure of 94/60 mmHg, heart rate of 120 beats/min, respiratory rate of 40/min, elevated jugular venous pressure with prominent ‘v’ wave. On cardiovascular system examination, S1 was normal, S2 was narrowly split with loud P2; a pan-systolic murmur of grade III/VI intensity was present along left sternal border. Tumor plop was audible. Chest was clear on auscultation. Abdominal examination was normal. Electrocardiogram revealed sinus tachycardia, right axis deviation and QR in V1 lead. Pulse oximetry revealed a saturation of 85% at room air increasing to 90% with 100% oxygen at 6 L/min. Laboratory examination revealed hemoglobin - 12.6 g/dl, total leukocytes count - 12.600/µL and platelet count of 1,00,000/µL. Liver function tests and renal function tests were normal. Chest roentgenogram was unremarkable.

Transthoracic echocardiogram showed a large pedunculated mobile mass in RA with heterogenous echotexture attached to RA free wall and another mass attached to interatrial septum near fossa ovalis [Figure 1a]. Another mass was seen in RV measuring 11 mm × 11 mm just beneath the septal leaflet of tricuspid valve [Figure 1b]. Larger RA mass was prolapsing into RV producing severe eccentric TR jet with a gradient of 60 mmHg [Figure 1c, supplementary movie 1]. RV outflow tract and PA was dilated [Figure 1d]. Inferior vena cava was free of any mass or thrombus (supplementary movie 2). HRCT thorax revealed embolization to the lateral aspect of right PA and along the medial aspect of left PA causing subtotal obstruction with pulmonary infarct in left lung [Figure 2a and b]. Ultrasonography of abdomen and bilateral lower limb Doppler was unremarkable. Contrast-enhanced computed tomography scan of the abdomen was normal.

Figure 1

(a) Modified apical 4 chamber view TTE showing a 2.4 cm × 2.4 cm pedunculated myxoma in the right atrium (RA) attached to RA free wall extending to interatrial septum, (b) Modified apical 4 chamber view TTE showing 1.1 cm × 1.1 cm pedunculated myxoma attached to the septal leaflet of the tricuspid valve, (c) CW Doppler across the tricuspid valve showing severe high-pressure TR with 60 mmHg gradient, (d) TTE basal short axis view showing dilated RVOT, pulmonary artery and heterogenous pedunculated right atrium mass with calcium specks attached to RA free wall

Figure 2

(a) High-resolution computed tomography of the thorax showing embolic fragment in the lateral aspect of right pulmonary artery (PA) and medial aspect of left PA, (b) High-resolution computed tomography thorax showing pulmonary infarct in left lung field

Once the diagnosis of multicentric RA and RV myxoma with tumor fragment embolization to PA was made, emergency surgery was performed by standard median sternotomy and cardio-pulmonary bypass using bicaval and ascending aortic cannulation to prevent further embolic events. Systemic hypothermia was used, and cardioplegia was administered for myocardial protection. The RA was then opened and a round lobulated mass measuring 3 cm × 2.5 cm × 2.5 cm was found attached to the RA free wall by a pedicle. Another mass attached to interatrial septum near fossa ovalis was excised. Multiple degenerating tumor strands were detected in RA, which were not visualized by transthoracic echocardiography. Another solitary mass was excised from the RV originating beneath the septal leaflet of tricuspid valve [Figure 3a and b]. After the direct closure of RA, patient was weaned off the extra-corporeal circulation.

Figure 3

(a) Intra-operative findings showing 3 right atrial myxomas one of which the largest one attached to right atrial free wall, (b) Gross morphology of excised myxoma: Pedunculated lobulated mass held by forcep and degenerating myxomatous mass with hemorrhage seen on extreme left side of picture, (c) Photomicrograph (H and E, ×100) loose myxomatoid stroma with stellate and spindle cells (from right atrium mass), (d) Photomicrograph (H and E, ×45) myxoid stroma with scanty stellate cells and spindle cells amidst degenerating cells and hemorrhage (from right ventricle mass)

Gross pathological examination revealed multiple flesh-colored soft to firm lobulated mass. Gross foci of degeneration were detected. Microscopy revealed hypocellular tumor tissue with myxoid background, isolated spindle and stellate cells with no abnormal mitosis or pleomorphism [Figure 3c and d]. Gross pathology and histopathological examination were consistent with the diagnosis of cardiac myxoma.

After the surgical excision of the tumor, severity of TR decreased from severe to mild. Her breathlessness decreased. Patient was administered anticoagulation therapy postsurgery. Echocardiographic follow-up at 6 months revealed no recurrence.

DISCUSSION

We experienced a case of 26-year-old female with acute pulmonary embolism attributed to embolization of degenerating tumor fragments from multicentric RA and RV myxoma, sporadic in nature, as there was no family history of cardiac tumors in first-degree and second-degree relatives. Echocardiographic screening in relatives was normal. Usually, myxomas present with obstructive, constitutional or embolic symptoms.

Our patient had no constitutional symptoms of fever, weight loss, malaise or joint pains. She had no obstructive symptoms of exertional dyspnea or positional syncope in the past. Embolism occurs in 30–40% of patients with myxoma.[45] Since most myxomas are located in the LA, systemic embolism is particularly frequent. Pulmonary thrombo-embolism is reported to occur in approximately 3.2% of myxoma patients.[6] Pulmonary embolism is the most dreaded and devastating complication of right-sided myxoma. In cases of right atrial myxomas, clinically evident embolic events are uncommon. Nevertheless, there have been reports of embolization of thrombi or tumor fragments into the pulmonary vessels in cases of right atrial or right ventricular myxoma.[78]

Carney's syndrome consists of myxomas in other locations (breast or skin), spotty pigmentation (lentigines, pigmented nevi or both) and endocrine overactivity (pituitary adenoma, primary pigmented nodular adrenocortical disease, bilateral testicular tumors and schwannomas.[910]

Approximately 7% of cardiac mxyomas are familial or part of Carney's complex. Familial myxomas tend to occur in younger individuals, are often multiple in locations and more likely to have postoperative recurrences. In the case presented here, despite being a multicentric tumor with younger age at presentation, there was no family history unlike other multicentric cardiac myxomas and thus favoring a sporadic occurrence.

Primary benign cardiac tumors are a potentially curable form of heart disease. Early surgical excision of the cardiac myxoma is advocated to prevent embolization, sudden cardiac death and for relief of obstructive symptoms. Cardiac myxomas recur in approximately 12–22% of familial cases and in <3% of sporadic cases.[11] Recurrence is attributed to incomplete, inadequate resection of the tumor, multicentricity, younger age at diagnosis and familial myxoma syndrome. Annual follow-up examination with echocardiography is recommended in multicentric myxoma postoperatively due to recurrence risk.

CONCLUSION

In patients presenting with sudden onset of dyspnea especially young patients, tumor embolization from right sided tumors should be kept in the differential diagnosis, and timely transthoracic echocardiogram in the emergency room can help in fast-tracking the patient for urgent cardiac surgery to prevent the catastrophic complication of pulmonary embolism and sudden cardiac death.