INTRODUCTION
Hepatocellular carcinoma has a tendency to spread into the venous system. Several reports have described malignant cardiac metastasis with hepatoma. The reported incidence of metastatic involvement of the heart is about 10%1,2). The most common site of cardiac metastasis is the pericardium3). However, metastases occur rarely in the cardiac cavities.
These patients usually have a short life span because of pulmonary embolism, heart failure, or cancer progression. And the tumor thrombus can hinder the blood flow into the right atrium and ventricle4). Therefore, early detection of intracavitary tumor thrombus and effective surgical resection are important factors of survival prolongation.
Herein we report an echocardiographic detection of the right atrial mass in two cases of hepatocellular carcinoma.
CASE REPORT
Case 1
A 61-year-old man, with a history of NIDDM ten years previously, was admitted due to epigastric pain, indigestion, and malaise. On admission, he had a regular pulse rate, was normotensive and relatively well-looking. There was no icterus, spider angioma, palmar erythema or cardiac murmur. Liver and spleen were not palpable.
Laboratory examinations showed serum trans aminase(SGOT:89 IU/L. SGPT:33 IU/L, and GGT 105 IU/L). Blood count was normal. Abdominal ultrasonogram favored a hepatoma of the right lobe with a right hepatic vein thrombus(Fig. 1). Liver biopsy showed a poorly differentiated hepatocellular carcinoma(Fig. 2). The electrocardiogram was normal. Two-dimensional echocardiographic examination and transesophageal echocardiogram were performed, showing a large right atrial mass(Fig. 3). The IVC had a tumor, which appeared to be continuous with the right atrial mass.
Hence, chemotherapy with 5-fluorouracil, adriamycin and mitomycin was started. The serial echocardiogram showed no significant change in the right atrial mass.
The patient expired 6 months later due to hepatic failure.
Case 2
The patient was a 34-year-old woman. One year prior to admission, she had began suffer-ing from an abdominal fullness and weakness. Physical findings revealed a hard non-tender mass in the right upper quadrant.
Laboratory examinations manifested serum ALT of 391IU/L, serum AST of 341IU/L, alkaline phosphatase of 279IU/L, gamma glutamyl transferase of 298IU/L, alpha-fetoprotein of more than 7000ng/ml and alpha 1-antitypsin of 410mg/dl. Blood count was normal.
Abdominal computed tomography revealed an ill-definded large inhomogeneous mass filling the entire right lobe of the liver with underlying liver cirrhosis and tumor thrombus in the upper portion of the IVC and the right atrium (Fig. 4). The electrocardiogram was normal. Two-dimensional echocardiogram manifested thrombus in the right atrium(Fig. 5). She expired 4 months later.
DISCUSSION
There are several reports about secondary cardiac malignancy. Hepatoma, testicular teratoma and smooth muscle sarcoma may cause the right atrial tumor growth through the inferior vena cava1,5–7). Especially, hepatocellular carcinoma is known for its tendency to grow in the venous system. Frequently, hepatoma extends into the portal vein or inferior vena cava. But, the most common sites of metastasis are the regional lymph nodes and the lungs8).
The incidence of metastatic involvement of the heart in hepatoma ranges from 1.5 to 18.3%2). However, such cardiac metastasis occur through the lymphatic system or by infiltrating from neighboring organs, such as the lung and breast. Therefore, cardiac metastases occur mainly in the pericardium and myocardium. Intracavitary cardiac metastasis or tumor invasion is an uncommon form of secondary cardiac malignancy, and metastasis to the right atrium is even less common (0.67–4.8%)9,10). A report by Hanfling showed that intracardiac tumor thrombus occur from above the pulmonary vein to the left cardiac cavities, and from below the superior and inferior vena cava to the right cavities2). Tumor implantation to the right ventricle without right atrial involvement and extensive myocardial invasion is unusual in hepatoma. The left atrial involvement is probably related to tumor growth from the pulmonary veins following massive metastasis to the lung, direct invasion of the atrial septum or tumor implantation via subclinical right-to-left shunt through the patent foramen ovale. Lei et al. reported unusual patterns of cardiac metastasis in three cases of hepatocellular carcinoma:one patient was noted to have a large right ventricular tumor mass with intracavitary growth and myocardial invasion:the second had massive pulmonary and left atrial metastasis; and the third patient had a right atrial tumor mass with concomitant right ventricular and left atrial involvement11).
In the past, antemortem diagnosis of right atrial tumor thrombi in patients with primary hepatoma was difficult, and such cases were reported by angiography12). Okuda described the angiographic findings of the right atrial tumor thrombi from the liver;thread and streak sign13). Recently, EKG-gated magnetic resonance imaging(MRI), computerized tomography(CT), transthoracic echocardiogrphy and transesophageal echocardiography are available to detect the right atrial tumor thrombus from hepatoma. Transthoracic echocardiography can be considered the first step in case of suspected cardiac masses, but it in sometimes limited by the thoracic conformation and not always discriminant. The resolutive diagnosis in possible thanks to MRI. Therefore, MRI can be considered the second step in the imaging of cardiac masses. CT is limited by the only axial or para-axial scans with low quality reconstructions, worsened in these cases by respiratory and cardiac movements. Transesophageal echocardiography is semi-invasive, so esophageal varices were relative contraindication to transesophageal echocardiography. Chua and colleagues reported two cases of right atrial tumor associated with hepatoma diagnosed by two-dimensional echocardiography14). Molinari et al. reported that MRI compared to CT in the intracardiac spread of hepatocellular carcinoma15).
Tumor thrombus in the right atrium hinders the blood flow. Therefore, abnormal cardiac sounds and murmurs subsequantly develop. When the tumor thrombus is mobile, this symptom is termed the ball-valve thrombus syndrome.
According to Kato, 3 percent(5 of 156) of hepatocellular carcinoma cases had right atrial metastasis, and these patients had edema in the legs, venous dilatation in abdominal wall, ascites, and dyspnea;secondary Budd-Chiari syndrome10,16).
Because of the high risk of sudden death from tricuspid valve obstruction in patients with mobile right atrial mass, prompt diagnosis and surgical intervention may prolong the patient’s life. Despite progress in liver surgery, hepatocellular carcinoma with a tumor thrombus extending into the right atrium has been considered beyond the reach of resection. Although sporadic reports of successful diagnosis have been published, surgical removal has rarely been reported. Fujisak et al. reported the removal of a tumor thrombus in the right atrium using cardiopulmonary bypass17). Similar procedures have been carried out by Ehrlich12), Hill and Hetzer18), and Miller19). The survival periods have ranged from 4 weeks to 1 year.
These patients who have hepatoma and intracardiac extending mass usually die within a short period because of pulmonay embolism, heart failure or cancer progression. There is ittle doubt that prompt diagnosis and surgical intervention relieved suffering and prolonged life.