Primary cardiac tumors are rare and constitute only a small fraction of all tumors that involve the heart or pericardium. The most common primary tumor is atrial myxoma; it comprises about 50% of all tumors in adult case series. It is generally attached to the atrial septum and is more likely grow on the LA side of the septum rather than the RA. Patients with myxoma can rarely present with the characteristics of a systemic illness, with obstruction of blood flow at the mitral valve level or with signs of peripheral embolization. The syndrome includes fever, malaise, weight loss, leukocytosis, elevated sedimentation rate, and emboli (peripheral or pulmonary, depending on the location of the tumor). This is sometimes confused with infective endocarditis, lymphoma, other cancers, or autoimmune diseases. In other cases, the tumor may grow to considerable size and produce symptoms by simply obstructing mitral inflow. Episodic pulmonary edema (classically occurring when an upright posture is assumed) and signs of low output may result. Physical examination may reveal a diastolic sound related to motion of the tumor (“tumor plop”) or a diastolic murmur similar to that of mitral stenosis (AUDIO 10–25). Right-sided myxomas may cause symptoms of right-sided failure. Familial myxomas occur as part of the Carney complex, which consists of myxomas, pigmented skin lesions, and endocrine neoplasia.
Audio 10–25. Left atrial myxoma.
Note the presystolic murmur, S1 followed by S2 and a tumor plop, and a soft diastolic murmur. (Reproduced, with permission, from T. Anthony Don Michael, MD. Mastering Auscultation [CD-ROM], 2000.)
The diagnosis of atrial myxoma is established by echocardiography (VIDEO 10–26) or by pathologic study of embolic material. Cardiac MRI is useful as an adjunct. Contrast angiography is frequently unnecessary, although it may demonstrate a “tumor blush” when the mass is vascular. Surgical excision is usually curative, though recurrences do occur and serial echocardiographic follow-up is recommended.
Video 10–26: Left atrial myxoma on echocardiogram.
(Used, with permission, from B Macrum and E Foster.)
The second most common primary cardiac tumors are valvular papillary fibroelastomas and atrial septal lipomas. These tend to be benign and usually require no therapy, although large papillary fibroelastomas may embolize or cause valvular dysfunction and should be removed if large and mobile. Other primary cardiac tumors include rhabdomyomas (that often appear multiple in both the RV and LV), fibrous histiocytomas, hemangiomas, and a variety of unusual sarcomas. Some sarcomas may be of considerable size before discovery. Primary pericardial tumors, such as mesotheliomas related to asbestos exposure, may also occur. The diagnosis may be supported by an abnormal cardiac contour on radiograph. Echocardiography is usually helpful but may miss tumors infiltrating the ventricular wall. Cardiac MRI is the diagnostic procedure of choice along with gated CT imaging for all cardiac tumors.