Summary: A 74-year-old female with acute cholecystitis on computed tomography (CT) also has an incidental finding of a cardiac mass. Cardiac magnetic resonance imaging (MRI) was requested for
Axial T2 HASTE, 4-chamber SSFP, and 4 chamber late gadolinium enhancement (LGE) images are provided. A pedunculated mass within the right atrium
arises from the interatrial septum and is mildly hyperintense on T2-weighted
imaging, iso to hyperintense on steady state free precession (SSFP) imaging, and demonstrates heterogeneous late gadolinium enhancement with a small cap of nonenhancement, which represents
adherent thrombus on the enhancing mass.
Myxomas are the most common primary intracavitary cardiac neoplasm, most
commonly occurring in the left atrium (75% of the time) or right atrium (20% of
the time). Myxomas are gelatinous neoplasms, which are almost invariably round
or ovoid with lobulated margins. They usually arise from the atrial septum via
a small stalk, but may occasionally arise from the septal leaflets. Myxomas may
be mobile depending on the degree of attachment to the atrial wall, and can
obstruct the mitral and tricuspid valves. Patients are often asymptomatic and
the lesions are detected incidentally. However, patients may present with
constitutional symptoms, such as fever, malaise, and weight loss, or with
symptoms of valvular obstruction or tumor embolization.
Radiographically, myxomas are best evaluated with cardiac MRI or
echocardiography. Typically myxomas are hyperintense on T2 weighted images
relative to normal myocardium, iso or hypointense on SSFP sequences, and
demonstrate heterogeneous enhancement. Cine gradient-echo images may demonstrate
low-signal intensity due to calcifications or adherent thrombus. Cine images
are also useful for evaluation of mobility and possible prolapse through the
mitral or tricuspid valves. The most important imaging feature is the
demonstration of a stalk connecting the mass to the interatrial septum, which
helps discriminate the mass from thrombus. Additional pertinent negatives to
help exclude malignant lesions are the lack of invasion of the cardiac wall,
lack of lymphadenopathy, and lack of a pericardial effusion.
Treatment consists of complete surgical resection to prevent obstruction
or tumor embolization.
- Grebenc ML, Rosado-de-Christenson ML, Green CE, et al. Cardiac myxoma: Imaging features in
83 patients. Radiographics. 2002;22:673-689.
- Sparrow PJ, Kurian JB, Jones TR, Sivananthan MU. MR Imaging of cardiac tumors.