|Year : 2004 | Volume
| Issue : 2 | Page : 66-69
Right atrial thrombus mimicking right atrial tumor
Sayed M Abdou1, Rachel Hajar2
1 Department of Cardiology and Cardiovascular Surgery, Hamad Medical Corporation, Doha, Qatar
2 Department of Cardiology and Cardiovascular Surgery, Hamad Medical Corporation, Doha; Director, Non-invasive Cardiac Laboratory, Department of Cardiology and Cardiovascular Surgery, Hamad MedicalCorporation, Doha, Qatar
|Date of Web Publication||22-Jun-2010|
Sayed M Abdou
Department of Cardiology and Cardiovascular Surgery, Hamad Medical Corporation, P.O. Box 3050, Doha
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Abdou SM, Hajar R. Right atrial thrombus mimicking right atrial tumor. Heart Views 2004;5:66-9
| Introduction|| |
Lesions most commonly presenting as cardiac mural masses include myxomas, sarcomas, metastatic lesions, and mural thrombus  . Primary tumors of the heart are rare. They have been found in less than 0.02% of unselected patients at autopsy  . Seventy-five percent of these tumors are benign and 50% are myxomas. Prior to the development of cardiac catheterization in 1951, intracardiac tumors were diagnosed only at autopsy. With the introduction of two-dimensional echocardiography, it has replaced cardiac catheterization as the diagnostic procedure of choice. The use of transesophageal echocardiography has remarkably improved its diagnostic accuracy. Misinterpretation of a cardiac mass may result in an incorrect management strategy and therefore accurate diagnosis is crucial. The clinical presentation combined with information as to the size, shape, location, mobility, and attachment site of a cardiac mass usually can differentiate these masses. We report a case where definite diagnosis of the nature of an intracardiac mass was difficult by echocardiography due to the patient's unique clinical setting and echocardiographic characteristics of the mass.
| Case presentation|| |
A 54-year old hypertensive female was admitted to the medical ward with a two-month history of shortness of breath, palpitations, dizziness and recurrent fainting attacks lasting a few seconds. The patient was on amiodarone due to episodes of Holter documented ventricular tachycardia 5 years prior to admission. She was also diagnosed to have poorly differentiated ductal carcinoma of the breast, grade III with lymph node metastasis. She underwent radiotherapy and chemotherapy. Two years prior to admission, a Life port catheter was inserted through the right jugular vein for IV delivery of chemotherapeutic agents. A modified radical left mastectomy and axillary clearance was performed one year prior to admission. One year after carcinoma of the breast was diagnosed, she was found to have a benign renal tumor in the form of angiomyolipoma.
On physical examination, the patient was fully conscious, well-oriented, and not in distress. Vital signs were: PR 80/min, T 36.8, RR 16/min, and BP 110/80. Heart and chest examination were normal. The rest of the physical examination was unremarkable.
Electrocardiography showed normal sinus rhythm. Laboratory work up revealed WBC 10,100/ul, Hb 13.3 g/dl, platelet 242,000/ul, ESR 39 mm/1h (N=0-30), BUN=4.6 (N=3-9), serum creatinine 56 umol/L (N=53-124) and normal liver function tests.
The transthoracic echocardiogram [Figure 1] revealed normal left ventricular systolic function (EF 60%) with grade I diastolic dysfunction. A large mass measuring 4cm x 2.4cm was noted in the right atrium (RA). The tip of the Life port catheter was also visualized in the RA and the mass seemed to be attached to the catheter. The mass was moderately mobile but did not prolapse through the tricuspid valve during diastole. There was no tricuspid inflow obstruction by Doppler.
A transesophageal echocardiogram [Figure 2] showed a large mass, measuring 4cm x 1.8cm attached to the inferolateral wall of the right atrium near the orifice of the IVC with limited mobility. The mass was well demarcated with slight irregularity of its borders. The tip of the Life port catheter was clearly visualized and was free of thrombus. The mass was not attached to the catheter. However, the mass and the catheter appeared to "touch" in systole.
The patient underwent surgery. A shinny glistening mass attached to the inferolateral wall of the RA was found and resected [Figure 3]. The mass measured 5.1cm x 2cm [Figure 4]. The mass consisted of multiple irregular grey white and brownish soft tissue masses. Cut sections showed white grey appearance with creamy white areas. Histology revealed eosinophilic cells with fibrin consistent with thrombus and subendocardial fibrosis. There was no evidence of myxoma or malignancy [Figure 5].
| Discussion|| |
This case demonstrates a number of unusual features that are important and challenging from clinical, diagnostic, and pathophysiologic perspectives. The preoperative differential diagnoses were right atrial myxoma, metastatic tumor, and right atrial thrombus.
In view of the age of the patient, history of breast cancer, and benign renal tumor, the possibility of intracardiac tumor either primary or secondary was raised. Although the mass was clearly not attached to the catheter, RA thrombus could not be definitely excluded.
Tumors of the right atrium are unusual, and tend to become large before the onset of symptoms. The most common primary benign cardiac neoplasm is myxoma, about 15 to 20% of which arise in the right atrium. The majority of myxomas are attached to the interatrial septum, at the border of the fossa ovalis  . Atypical locations are the left ventricle, the right ventricle, atrioventricular valve or from multiple sites. Myxomas occur most often between the 3rd and 6th decades of life  .
Atypical myxoma is usually associated with a familial pattern called Carney complex and usually occurs in younger patients along with lentiginosis and endocrine abnormalities  . Myxomas are typically pedunculated, gelatinous and friable. The diagnosis is usually established by echocardiography, and if the attachment site can be established, the diagnosis is almost assured. In our patient, echocardiography clearly showed that the mass was not attached to the atrial septum.
A far more common cause of right atrial tumors are metastatic tumors that arise in the abdomen and pelvis, especially hepatoma and renal cell carcinoma, which directly invade the inferior vena cava and extend into the right heart , . Secondary infiltrative tumors of the heart usually extend into the right atrium from the IVC (and less commonly from the right atrial free wall). Tumor extension along the IVC and into the right atrium is the mechanism of intracardiac tumor spread, most frequently described in renal cell carcinoma, Wilm's tumor, hepatoma and uterine leiomyoma  . Although our patient had a history of breast carcinoma with lymph node metastasis, there was no evidence suggesting metastatic involvement of the liver or kidneys.
She had a history of renal tumor (angiomyolipoma), which was benign. Renal angiomyolipoma is a benign tumor with a propensity for extrarenal extension via the left renal vein and inferior vena cava, into the right atrium  . Macroscopic renal vein and vena caval tumor thrombi in patients with angiomyolipoma may be diagnosed preoperatively with CT scan by the demonstration of abundant fat within the tumor components  . In our patient the transesophageal echocardiographic study showed a clean IVC and histopathological examination of the mass showed no evidence of angiomyolipoma.
Various normal and abnormal structures may appear as a mass in the right atrium on two-dimensional echocardiography such as the Eustachian valve, pacemaker wire, balloon or central-line catheter, vegetation, and thrombus. Each structure has characteristic features and careful examination can differentiate one from the others. The diagnosis of thrombus is based on the detection of an echogenic mass with well-defined margins, clearly identifiable throughout the cardiac cycle, adjacent to asynergic myocardium or regions where there is stasis of blood. Thrombus formation is less common in the right compared to the left atrium. It occurs in association with in-dwelling catheters, especially at the junction of the superior vena cava and right atrium.
Our patient had a chronic in-dwelling Life port catheter, which commonly predisposes to thrombus formation. Catheter-induced thrombosis is usually attached to the catheter. In our patient, the mass was not attached to the catheter but its point of attachment was at the inferolateral right atrial wall, adjacent to the orifice of IVC. Right atrial mural thrombus was confirmed in our patient by histopathological examination [Figure 5] with no evidence of malignancy or myxoma.
Intracavitary right atrial thrombosis is currently and most often considered to result from line-tip thrombosis extension. However, there are other mechanisms of thrombus formation in the setting of an in-dwelling catheter. The to and fro motion of the catheter within the right atrial cavity may produce endocardial injury, and thus predispose to thrombus formation  . Another hypothesis is that the delivery of chemotherapeutic agent may cause "jet lesion" injury, thus setting the stage for thrombogenesis. Other factors that have been mentioned in the literature include the type of material used for the construction of central venous catheters. Certain materials such as Teflon or polyurethane have been reported to be particularly thrombogenic, whereas silicone catheters are biologically inert and more resistant to thrombosis. Polyurethane, a commonly used material for catheter construction, includes a broad class of thermoplastic polymers that have an intermediate level of thrombogenicity  . Patients with cancer may have a higher incidence of catheter-related thrombosis since patients with certain types of solid tumors (eg, pancreatic, renal cell) are predisposed to vascular thrombosis.
In our case, right atrial thrombus formation could be explained by the to and fro movement of the catheter within the right atrial cavity, producing endocardial damage. In addition, the delivery of chemotherapeutic agent may have been a possible cause of endothelial irritation with consequent injury to the right atrial wall.
Our case illustrates that even with advanced and sophisticated diagnostic techniques, differentiating intracardiac masses is still challenging in a unique clinical setting such as our patient. Accurate diagnosis of an intracardiac mass is of prime importance in choosing the appropriate management. In-dwelling catheter thrombus is most commonly attached to the catheter but thrombus could occur away from the catheter as in our patient.
The use of in-dwelling central venous catheters is common in medical practice; however, thromboembolism is a major complication, which could be fatal  . Therefore, more scientific information regarding the thrombogenicity of catheter materials are needed and clinical studies to gain better insights into the factors and variables involved in catheter-related thrombosis are essential.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]