Cardiac Tumors

63 Cardiac Tumors



Hanna K. Sanoff, Mark A. Socinski


Until the second half of the twentieth century, cardiac tumors were diagnosed almost exclusively at autopsy, and no treatment options existed for those rare instances of antemortem discovery. Advances in cardiac imaging—principally echocardiography—and the advent of cardiopulmonary bypass made cardiac tumors treatable. Primary tumors of the heart are rare and typically benign. Because of their critical location, however, they are almost never clinically benign. Secondary tumors are more common, particularly in the setting of metastatic disease.


Data from autopsy series place the incidence of primary heart tumors around 0.02%, of which 75% are benign. Myxomas represent half of all benign primary tumors. Of primary malignant neoplasms, approximately 95% are sarcomas.


Secondary malignant neoplasms have an autopsy incidence of 1% and occur most commonly in the setting of widely disseminated metastatic disease. Of patients who die of metastatic cancer, 20% have some degree of cardiac involvement, frequently asymptomatic. The cancers most likely to involve the heart are lung cancer, breast cancer, lymphoma, and myeloid leukemia. Melanoma has a predilection for the heart; cardiac involvement is present in 50% of patients with advanced disease.



Clinical Presentation


The clinical presentation of a cardiac tumor depends on its location. Tumors located on the endocardial surface, such as myxomas, usually present with various embolic phenomena or symptoms of valvular obstruction. Tumors that arise within the myocardium are more likely to produce arrhythmias and disruption of the conduction system. Diffuse myocardial infiltration can result in heart failure from systolic or diastolic dysfunction. Epicardial and pericardial involvement may manifest as pain, effusion, or heart failure in the form of constriction or tamponade. Myxomas also present with systemic illness—principally constitutional symptoms and hematologic abnormalities.



Differential Diagnosis


Primary tumors of the heart should be considered in the differential diagnosis of embolic phenomena, valvular disease, heart failure, and arrhythmia. Infectious endocarditis may present in a manner virtually indistinguishable from that of a cardiac tumor—particularly myxomas that present with constitutional symptoms—and is a key component of the differential diagnosis. Other diagnostic considerations include atrial or ventricular thrombosis, endocrine derangements (particularly thyroid disease), and rheumatologic diseases such as lupus and systemic vasculitis.



Embolization


Emboli from cardiac tumors result from dislodgement of adherent thrombus or tumor fragments. The clinical picture from embolization of multiple small fragments may resemble small-vessel vasculitis or endocarditis. Larger emboli can cause stroke, infarction of visceral organs, and peripheral ischemia from arterial emboli. Tumor emboli should always be included in the differential diagnosis of embolic phenomena. Hence, a pathologist should review all resected emboli.



Obstruction


Valvular obstruction by a tumor produces symptoms similar to valvular heart disease. Because atrial tumors are more common, obstruction of the atrioventricular valves mimicking mitral and tricuspid stenosis is typical. Classic symptoms caused by tumor obstruction can be distinguished from valvular disease by the paroxysmal and positional nature of obstruction by a mobile tumor.



Arrhythmia


Infiltration of the myocardium and irritation by an endocardial tumor can cause supraventricular and ventricular arrhythmias. Disruption of the conduction system may cause all degrees of atrioventricular nodal block. Sudden cardiac death is a risk; however, this presentation is unusual in patients with cardiac tumors.



Diagnostic Approach


Transthoracic echocardiography is the standard means by which many cardiac tumors are diagnosed. Echocardiography is most sensitive in the diagnosis of endocardial tumors and least well suited for diagnosing tumors originating from the pericardium. Transesophageal echocardiography allows further evaluation of right-sided tumors and better characterization of questionable masses seen on transthoracic cardiac imaging. MRI can further assess pericardial disease and the extent of cardiac involvement of a tumor. Both MRI and CT scans may help further characterize the tumor, allowing for a presumptive diagnosis in the absence of biopsy. Biopsy of cardiac tumors is typically not warranted if operative intervention is planned, since the risk of complication—particularly embolization—often outweighs the need for a preoperative diagnosis.



Primary Benign Cardiac Tumors


The majority of benign cardiac tumors are myxomas; however, a wide variety of tumors arise within the heart (Table 63-1).


Table 63-1 Histologic Distribution of Primary Benign Cardiac Neoplasms










































  Percentage of Tumors
Benign Tumor Adults Children
Myxoma 45 15
Lipoma 21 0
Papillary fibroelastoma 16 0
Rhabdomyoma 2 45
Fibroma 3 15
Hemangioma 5 5
Teratoma 1 13
Other 6 6

With permission from Allard MF, Taylor GP, Wilson JE, et al. Primary cardiac tumors. In: Goldhaber S, Braunwald E, eds. Atlas of Heart Diseases. Philadelphia: Current Medicine; 1995:15.1–15.22.



Myxoma


Myxomas are the most common primary cardiac neoplasm, accounting for 50% of all benign cardiac tumors (Fig. 63-1). There is a female predominance of 2 : 1 to 3 : 1, and the median age of presentation is 50 years, although myxomas can occur at any age. Myxomas arise in the left atrium 75% of the time, usually on the interatrial septum near the fossa ovalis. Right atrial myxomas account for 20% of tumors (Fig. 63-2). The balance of myxomas occur in either ventricle and, in rare cases, on the cardiac valves. The majority of myxomas (>90%) are solitary.


image

Figure 63-1 Heart tumors.


LA, left atrium; RV, right ventricular.


image

Figure 63-2 Echocardiographic image of a right atrial tumor.


At the time of resection, the tumor was found to be a myxoma. LA, left atrium; LV, left ventricle; MYX, myxoma; RA, right atrium; RV, right ventricle.


An autosomal-dominant, familial myxoma syndrome, the Carney’s complex, has been described. Affected individuals demonstrate variable phenotypic expression but have in some form at least two of the main features: heavy facial freckling, endocrine hyperactivity (i.e., Cushing’s syndrome), both myxomatous and nonmyxomatous endocrine neoplasia, noncardiac myxomas (typically breast and skin), and cardiac myxomas. Cardiac myxomas associated with the Carney’s complex have an equal male-to-female ratio, occur at a younger age (mean age of diagnosis, 25 years), and are more likely to be multiple or ventricular and to recur after resection. Linkage analysis has mapped gene loci to 17q12–q13, 17q22–q24, and 2p16. Mutations in the PRKAR1A gene, encoding a protein kinase A regulatory subunit, seem to be responsible for as many as 70% of cases of the Carney’s complex.


Myxomas originate from multipotent mesenchymal cells. Grossly, they are gelatinous, pedunculated tumors with an average size of 4 to 8 cm. The tumor surface may be friable or smooth. A smooth surface is associated with systemic signs and symptoms. Friable tumors are more likely to present with embolization.



Clinical Presentation

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  2. Left and Right Heart Catheterization
  3. Interventional Approaches for Peripheral Arterial Disease
  4. Aortic Regurgitation

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Jun 12, 2016 | Posted by in CARDIOLOGY | Comments Off on Cardiac Tumors

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