Although diagnosed infrequently, cardiac tumors often are included in the differential diagnosis of cardiac problems because of their protean clinical manifestations. Cardiac tumors may be intracavitary or intramural, and the location determines their echocardiographic appearance. Intracavitary tumors appear as sessile or mobile echo densities attached to the mural endocardium while intramural tumors appear as localized thickening of the LV wall. The pericardium also may be involved with cardiac tumors, with or without the presence of concomitant effusion (Chap. 85). Myxomas Myxomas are the most common primary cardiac tumors, accounting for about 25 percent of all such lesions (Chap. 95).317 Myxomas can occur in any cardiac chamber, but 75 percent are found in the LA.317 On 2D imaging, myxomas usually appear as gelatinous, speckled, sometimes globular masses with frond-like projections (Figs. 15–132A and B). Tissue heterogeneity is common, but calcification is rare. Although they may be sessile, myxomas are usually attached to the endocardial surface by a pedicle. Typically, they are attached to the interatrial septum, but they can originate from the posterior or anterior atrial wall, the appendage, or even the cardiac valves. Large tumors are almost always mobile to some degree, and a sizable left atrial mass that appears fixed in position is therefore less likely to be a myxoma. Large left atrial myxomas may move back and forth into the MV annulus during the cardiac cycle, entering the orifice in diastole and the LA in systole. Accordingly, Doppler interrogation may demonstrate either obstruction of flow, valvular regurgitation, or both.318 Most myxomas are visible on TTE, but TEE is superior for the delineation of tumor attachments and detection of small myxomas. Since approximately 5 percent of myxomas are biatrial, careful evaluation of the RA is mandatory.317 | | Figure 15–132. A. Apical four-chamber image of a left atrial myxoma which is attached to the interatrial septum and prolapses through the mitral valve. LA = left atrium; RA = right atrium; RV = right ventricle; LV = left ventricle. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders, 1996:452–480. With permission.) B. Apical four-chamber image of a large left atrial myxoma (arrows), which is attached to the lateral wall of the atrium. LA = left atrium; RA = right atrium; RV = right ventricle; LV = left ventricle; PE = pericardial effusion; PL = pleural. |
Additional Primary Tumors Benign Rhabdomyomas are rare cardiac tumors associated with tuberous sclerosis (Chap. 80). There is a strong tendency for multiple tumors to occur within an affected heart (90 percent of cases). Fibromas are found most often in children and affect the left ventricle most frequently. The tumor may grow within the myocardium rather than expanding into a cardiac chamber. Papillary fibroelastomas are usually quite small in size (less than 1 cm in diameter) and often grow on cardiac valves or chordae (Fig. 15–133A). These rare tumors typically have multiple small fronds that tend to embolize.299,319 Echocardiographic differentiation from vegetations can be difficult (Chap. 85). | | Figure 15–133. A. Transesophageal images of a surgically proven papillary fibroelastoma on the right coronary cusp of the aortic valve (arrow). The upper and lower panels show transverse and longitudinal planes through the aortic valve, respectively. B. Primary cardiac angiosarcoma (subcostal imaging plane). The tumor mass (M) is present in the right atrium (RA), and has extended through the atrial wall into the pericardial space. LA = left atrium; LV = left ventricle; E = pericardial effusion. |
Malignant Primary malignant cardiac tumors are quite rare and confer a very poor prognosis. Angiosarcoma is the most common and occurs most often in the right atrium (Fig. 15–133B). Rhabdomyosarcoma is an additional primary cardiac malignancy.320 Echocardiography can be useful in monitoring response to therapy, but its diagnostic utility is limited as most findings are nonspecific. Metastatic and Secondary Tumors of the Heart and Pericardium Metastatic tumors to the pericardium and heart occur 20 to 40 times more often than primary cardiac tumors (Fig. 15–134A).321 Tumors that commonly involve the heart and pericardium include breast and lung carcinoma, melanoma, and lymphoma (Fig. 15–134B). Involvement may be secondary to hematogenous, lymphatic, or contiguous spread. Tumors such as hepatoma and renal carcinoma can also extend to the heart via the venae cavae. In these cases, tumor is often visible in the inferior vena cava and RA. Metastatic disease affects the pericardium more frequently than the heart itself, and pericardial effusion is the most common echocardiographic manifestation in patients with cardiac metastases.321 Intracavitary and pericardial masses are easily visualized with 2D imaging, although intramural tumors are sometimes difficult to image. Echocardiographic findings are nonspecific, and metastatic tumors may be mistaken for primary cardiac neoplasms, vegetations, thrombi, or even prominent muscular trabeculations (Chap. 85). | | Figure 15–134. A. Modified subcostal image showing a metastatic tumor on the epicardium (arrows) and a malignant pericardial effusion. RV = right ventricle; LV = left ventricle. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452–480. With permission.) B. Transesophageal images from a case of metastatic lung carcinoma. The tumor (arrows) has entered the left atrium via contiguous spread through the left upper pulmonary vein. |
Additional Cardiac Masses The heart is rarely involved in echinococcal disease (<2 percent of cases), but intracardiac or intrapericardial rupture of a cyst can lead to anaphylaxis and cardiac tamponade, respectively.322 Echocardiographic detection of a multiseptated cyst in the left ventricle or interventricular septum suggests cardiac echinococcal disease. Simple pericardial cysts usually occur in the right costophrenic angle (posterior to the right atrium) and have a benign prognosis. The structures are nonseptated and fluid-filled; they do not compress the cardiac chambers.323 |
