Surgical resection for a huge right ventricular hemangioma

Abstract

Cardiac hemangiomas are particularly rare entities, are often asymptomatic, and are often merely observed because of its slow growth and benign nature. We report a 52-year-old male patient who presented with exercise intolerance and chest discomfort due to the mass effect of a large 14 × 10 × 6-cm epicardial hemangioma. The tumor arose from the recess between the aorta and main pulmonary artery and featured a prominent feeding artery from the right coronary artery. The tumor was successfully resected, and pathology confirmed the diagnosis of cavernous hemangioma. We review the clinical features, imaging characteristics, pathological findings, and prognosis of cardiac hemangiomas.

1. Introduction

Hemangiomas are a class of tumors that arise from vascular endothelial hyperplasia and usually are benign in nature. They may develop in any part of the body, including the heart. Cardiac hemangiomas are a very rare type of cardiac tumors, accounting for only 2.5% of all primary cardiac tumors. Clinical presentation may vary widely depending on the size and location of the lesion, so imaging studies are paramount to establish the correct diagnosis, to rule out other concomitant cardiac illnesses, and to determine treatment plan. Treatment is usually surgical excision if the tumor is well circumscribed and usually carries a favorable prognosis in experienced heart centers. We present such a case of an adult male with a large epicardial hemangioma that was treated surgically.

2. Case History

A 52-year-old male patient with a history of hypertension presented to our hospital with intermittent chest tightness on exertion. A mediastinal tumor was detected by a transthoracic echocardiogram on a routine health checkup at another medical institution. His original physician recommended a VATS biopsy under general anesthesia, but he sought a second opinion. Physical examination showed a blood pressure of 150/82 mm Hg and a heart rate of 55 beats per minute. Heart auscultation revealed regular heart beats and no murmurs. No other signs of heart failure or right-sided elevated filling pressures such as engorged jugular veins were noted. Electrocardiography showed a heart rate of 55 beats per minute and sinus rhythm. Echocardiography demonstrated a huge solid tumor 10 ×10 cm located in front of the right atrium and aorta. No chamber enlargement, systolic dysfunction, diastolic dysfunction, or thrombosis was noted, and only mild aortic and tricuspid valve regurgitation were found. A fluorodeoxyglucose (FDG) positron emission tomography scan was used to rule out extracardiac primary malignancies, which may manifest as metastatic cardiac lesions, but no evidence of extracardiac malignancy was found. The cardiac lesion was mildly FDG avid, and no abnormal focal increased FDG uptake was found in the myocardium or pericardium. A cardiac magnetic resonance imaging (CMR) disclosed a well-defined lesion measuring 10 × 9.8 × 8.8 cm attached to the periaortic recess and the anterior superior wall of the ascending aorta, with extensions along the right atrioventricular groove, with mass effect to the right atrium. The lesion exhibited high signals at T2WI with gradual peripheral enhancement. A coronary angiography clearly demonstrated multiple large feeding vessels to the tumor arising from the proximal right coronary artery (RCA). All these findings were consistent with the diagnosis of cardiac hemangioma. On day 7 of admission, the patient underwent open surgery for tumor resection. A median sternotomy was made, and a large tumor was found overlying the right atrium and ventricle upon opening the pericardium. Upon closer inspection, the tumor lay over and compressed the right atrium because of its massive size but was entirely separate from the right atrium; rather, the tumor was encapsulated in the same epicardium overlying the right ventricle and had mild adhesions to the surface of the right ventricle, thus confirming its location as a right ventricular tumor. The tumor was heart shaped, well circumscribed, soft, and devoid of visible ulcerations, palpable calcifications, or infiltrations into the underlying myocardium. Cannulation of the ascending aorta, superior vena cava, and inferior vena cava were done, and cardiopulmonary bypass was initiated. The epicardium was delicately opened, and the tumor was meticulously dissected from the cardiac surface. Mild adhesions were removed by sharp dissection. Three feeding arteries from the RCA were indeed found on the inferior aspect of the tumor, the largest of which was 0.5 cm in diameter; all were ligated with 4-0 Silk ties. The dissection was carried further along the plane to the confluence of the aorta and main pulmonary artery, where there was no extension of the tumor into the cardiac chambers or the lumens of the great vessels, so the tumor was resected en bloc. No damage was done to any major cardiac structures or coronary arteries. Postoperatively, the patient made an expedient and uneventful recovery. His intensive care unit length of stay was 2 days, and his admission length of stay was 14 days. His chest tightness improved significantly after the operation, resulting in improved exercise tolerance. The patient reported no new complaints on subsequent office visits. On pathology, gross inspection revealed a dark red soft tissue mass, measuring 14 × 10 × 6 cm. Histopathology examination of the mass showed a picture of aggregates of large irregular spaces lined by thin endothelial cells, separated by variable amounts of connective tissue, which was compatible with the cavernous subtype of cardiac hemangiomas. The lumina were filled with blood cells, and immunostaining for SOX-10 was negative.

3. Discussion

Because most cardiac tumors are metastatic lesions, primary cardiac neoplasms are rare. Of all primary cardiac tumors, 75% are benign, of which the most common type are myxomas, whereas hemangiomas only constitute approximately 5% of benign cardiac tumors, therefore constituting only 2.5% of all primary cardiac neoplasms. Hemangiomas are benign vascular malformations composed of channels lined by endothelial cells that may present in any part of the body. Presentation is usually determined by the tumor size and location. Although patients may be asymptomatic and present only with abnormal imaging studies, symptomatic patients may present with angina, arrhythmias, pericardial effusion, ventricular outflow tract obstruction, congestive heart failure, peripheral embolism, or sudden death.^[1] Cardiac hemangiomas typically appear as a hyperechoic lesion on echocardiography, but its usefulness is limited by operator dependability and technical limitations. A chest computed tomography (CT) or CMR can better assess the tumor itself based on attenuation values or patterns of enhancement, as well as its relationship to the other thoracic structures, such as invasions to adjacent tissue or multiple lesions. On chest CT, hemangiomas are typically seen as a heterogeneous mass lesion with intense enhancement upon contrast infusion due to its high vascularity. On CMR, they are present with isotense or intermediate signal intensity on T1-weighted images comparable with myocardium and as hyperintense lesions on T2-weighted images.^[2] We believe that a CMR is preferrable to a CT, because it more clearly demonstrates if there is a clear surgical plane for resection. We also believe that a coronary angiography is indispensable to the evaluation of cardiac tumors, because it may demonstrate the feeding arteries to the tumor with a characteristic tumor blush, thus clarifying the surgical plan. It is also of critical importance to these patients that a VATS biopsy is avoided; because of the high vascularity of the tumor, any intervention that disrupts the tumor’s integrity may result in life-threatening hemorrhage. Instead, surgical candidacy should be evaluated, and surgery should be undertaken expediently to rule out malignancy and for symptomatic relief. Key to successful surgery is locating and ligating the feeding arteries to avoid inadvertent damage to the underlying coronary arteries, which may necessitate ligation of the native coronary artery for hemostasis and subsequent bypass grafting. Although they are usually well demarcated, some hemangiomas may have infiltrative borders, rendering complete surgical resection difficult (Fig. 1). In cases of hazardous surgery with a high potential of residual unresectable tumor, conservative management may be considered in asymptomatic patients, although these patients are predisposed to malignant arrhythmias, rupture, embolism, or sudden cardiac death. Grossly, cardiac hemangiomas may present as intracavitary, intramural, epicardial, or pericardial lesions, the rarest of which are epicardial lesions. Intracavitary lesions may arise from any cardiac chamber, although it is most commonly seen in the right ventricle (35.7%), followed by the left ventricle (33.9%), right atrium (23.2%), interatrial septum (10.7%), interventricular septum (10.7%), and left atrium (7.1%).^[3] Multiple tumors may occur in approximately 30.4% of cases. Hemangiomas are differentiated from malignant angiosarcomas by a distinct lack of necrosis, nuclear atypia, and mitotic activity (Fig. 2). Hemangiomas can be further categorized by histology into cavernous, capillary, and arteriovenous subtypes. The cavernous subtype is characterized by multiple thin or thick-walled dilated vessels; the capillary subtype consists of lobules of endothelial cells forming small, capillary-like vessels; the arteriovenous subtype is composed of dysplastic thick-walled arterioles, venous-like vessels, and capillaries.^[4] The postoperative prognosis is usually excellent in patients with resectable tumors, but periodic echocardiography is nevertheless recommended to survey for recurrence of tumor growth.

Figure 1: A, Chest x-ray showing a distinctive bulge at the right cardiac border, which should raise suspicion of a cardiac tumor (B) TTE PLAX view and (C) chest CTA showing a huge extracardiac, hyperechoic lesion over the anterior wall with obvious compression of the right atrial chamber. D, Intraoperative TEE confirmed a no flow within or immediately adjacent to the tumor, confirming its position in the epicardium rather than the more commonly seen intracardiac chambers. E, T1-weighted MRI showing early heterogeneous enhancement (F) T2-weighted MRI showed rapid enhancement of the lesion. G, A coronary angiogram showing a characteristic tumor blush (black arrow) originating from a large feeding vessel (white arrow) arising from the RCA.

Figure 2: A, Gross examination of the tumor upon initial surgical exposure, showing a large, maroon-colored lesion overlying the right ventricle without infiltrative borders. B, Manual manipulation showed freely movable borders without adhesions. C, The largest of three feeding artery was 0.5 cm in diameter. It was found on the inferior aspect of the tumor and originated from the RCA. D, The ligated stump of the resected feeding vessel. E, Gross examination of the specimen, which was removed en bloc, and its cut surface. F, Pathology slides revealed that the tumor consisted predominately of large, dilated, thin-walled vessels; hence, the patient’s tumor was of the cavernous subtype.

In summary, cardiac hemangiomas are rare and benign tumors comprising of endothelial cells that most commonly arise from the right side of the heart. These tumors often have unpredictable natural histories, with a wide range of clinical manifestations. Current improvements in imaging modalities such as CT angiogram and CMR have led to improved diagnosis and evaluation of surgical resectability of the hemangiomas. Surgical resection is the recommended treatment modality for most cases, and patients with complete resection without residual tumor generally enjoy a favorable prognosis without recurrence.