Echocardiography is a powerful tool in the differential diagnosis of cardiac masses. Although echocardiography cannot replace pathologic examination in obtaining an exact diagnosis, characteristic features of the ultrasound images can help to differentiate these masses. Combining clinical data such as sex, age, signs of an extracardiac primary tumor, and response to therapy (anticoagulation or antibiotics) with morphologic properties, such as location, attachment site, size, mobility, texture, and number of tumors, often produces an accurate diagnosis. A correct diagnosis is crucial in therapeutic decision making, but because pathology specimens usually are obtained only during surgical resection, it is important to recognize the typical indirect and direct echocardiographic features of the various tumors. Echocardiography is the technique of choice; further, because of its close proximity to the heart, transesophageal echocardiography (TEE) in general is superior to transthoracic echocardiography (TTE).
Some normal structures may mimic cardiac masses: the eustachian (inferior caval vein) valve, the thebesian (coronary sinus) valve, a Chiari network, crista terminalis, pectinate muscles, atrial chords, a moderator band, trabeculations, ventricular noncompaction, the apical form of hypertrophic cardiomyopathy, and the ridge between the left upper pulmonary vein and left atrial appendage may all be misinterpreted as cardiac masses (see Chapter 3).1 With the development of three-dimensional real-time TEE, multislice imaging of cardiac masses is possible, allowing for better visualization of tumor morphology and location, which in turn may help to improve decision making during surgical resection.2 Real-time three-dimensional TEE may become the technique of choice for noninvasive evaluation of tumor size.3
Cardiac tumors may be primary or secondary and malignant or benign. Of all primary cardiac tumors 75% are benign and 25% are malignant. Of the benign tumors in McAllister and Fenoglio's observations of 533 primary tumors,4 24.4% were myxomas, 8.4% were lipomas, 7.9% were papillary fibroelastomas, and 6.8% were rhabdomyomas. Fibromas, hemangiomas, teratomas, atrioventricular nodal mesotheliomas, granular cell tumors, pericardial cysts, and bronchogenic cysts accounted for fewer than 5% each. In the malignant group, angiosarcoma (7.3%) and rhabdomyosarcoma (4.9%) were the most frequent, whereas mesothelioma, fibrosarcoma, malignant lymphoma, extraskeletal osteosarcoma, neurogenic sarcoma, malignant teratoma, thymoma, leiomyosarcoma, liposarcoma, and synovial sarcoma were rare conditions. Secondary tumors are more frequently carcinomas than sarcomas, but all types of tumors may be found.
Myxoma is the most frequent of the benign cardiac tumors, accounting for 30% to 50% and presenting with a female preponderance (Figure 19–1).5 They occur most often in the third through sixth decades, and more than 90% are sporadic. Left atrial localization is most frequent (75%),4,6,7 although 18% are found in the right atrium, 4% in the right ventricle, and another 4% in the left ventricle. Myxomas can present as multiple lesions in the left atrium and may be bilateral, whereas a ventricular location occurs more frequently in children. Myxomas typically are pedunculated, polypoid, friable tumors, sometimes possessing a smooth and rounded surface (Figure 19–2). They ...