Cardiac Masses
Most suspected cardiac masses are thrombi, vegetations, normal variants, or artifacts rather than primary tumors.
Evaluation should integrate the clinical context, location, attachment, mobility, vascularity, and hemodynamic consequences.
Initial Assessment¶
Describe:
- Chamber or structure involved
- Size
- Shape and borders
- Attachment site
- Mobility
- Echogenicity
- Vascularity
- Obstruction or valve dysfunction
- Pericardial involvement
- Findings in multiple imaging planes
Before diagnosing a mass, exclude artifact and normal anatomy.
Differential by Location¶
| Location | Important considerations |
|---|---|
| LV apex | Thrombus, trabeculation, false tendon, tumor |
| LA | Myxoma, thrombus, Coumadin ridge |
| LAA | Thrombus, pectinate muscle |
| RA | Thrombus, myxoma, vegetation, crista terminalis |
| RV | Thrombus, moderator band, metastasis |
| Valve | Vegetation, Lambl excrescence, papillary fibroelastoma, thrombus |
| Myocardium | Fibroma, lipoma, metastasis |
| Pericardium | Metastatic disease, cyst, hematoma, fat |
Thrombus¶
Thrombus is favored by:
- Atrial fibrillation
- Severe atrial or ventricular dysfunction
- Regional akinesis or aneurysm
- Spontaneous echo contrast
- Intracardiac device or catheter
- Hypercoagulability
- Recent myocardial infarction
LV Thrombus¶
Usually occurs in an akinetic or dyskinetic apex. It should be distinct from the endocardium and visible in more than one view.
Use an ultrasound-enhancing agent when the apex is inadequately visualized. CMR with late gadolinium enhancement is more sensitive when suspicion remains high despite nondiagnostic echocardiography.
Right-Heart Thrombus¶
A thrombus in transit is typically highly mobile and serpiginous and may cross the tricuspid valve. This is an urgent finding, particularly when pulmonary embolism is suspected.
Vegetation¶
Vegetation is an independently mobile mass attached to the upstream side of a valve:
- Atrial surface of an atrioventricular valve
- Ventricular surface of a semilunar valve
Supporting findings include:
- New valve regurgitation
- Leaflet perforation or flail
- Abscess
- Prosthetic dehiscence
- Fistula
- Compatible bacteremia
TEE is preferred when TTE is negative but suspicion remains high, or when prosthetic valves or intracardiac devices are present.
A mass alone does not diagnose endocarditis; interpret it within the microbiologic and clinical context.
Common Tumors¶
Myxoma¶
Typical features:
- Most commonly arises from the LA
- Attached to the interatrial septum near the fossa ovalis
- Mobile, heterogeneous, and sometimes pedunculated
- May obstruct mitral inflow or embolize
Not every LA mass is a myxoma. Thrombus is more likely in the LAA, posterior LA, or areas of stasis.
Papillary Fibroelastoma¶
A small, highly mobile valvular mass with a stalk and frond-like surface. It most often involves the aortic or mitral valve and may cause systemic embolization.
Lipoma and Lipomatous Hypertrophy¶
Lipomatous hypertrophy thickens the interatrial septum while sparing the fossa ovalis, producing a characteristic dumbbell-shaped appearance.
Malignant Masses¶
Features raising concern include:
- Broad-based or infiltrative attachment
- Multiple lesions
- Rapid growth
- Pericardial effusion
- Invasion of adjacent tissue
- Right-sided involvement
- Known malignancy
Metastatic involvement is substantially more common than a primary malignant cardiac tumor.
Mimics¶
Common pseudomasses include:
- Coumadin ridge
- Crista terminalis
- Eustachian valve
- Chiari network
- Moderator band
- Papillary muscles
- Trabeculations
- False tendons
- Pectinate muscles
- Epicardial fat
- Reverberation artifact
A normal variant should have a characteristic location and attachment and remain consistent across imaging planes.
Choosing the Next Test¶
- TEE: valves, LAA, atria, prosthetic material, and small mobile masses
- CMR: tissue characterization, thrombus confirmation, vascularity, and myocardial invasion
- Cardiac CT: calcification, fat, anatomic extent, coronary relationships, and patients unable to undergo CMR
- FDG-PET/CT: selected malignant or inflammatory masses and extracardiac disease
- Biopsy: reserved for cases in which tissue diagnosis will change management and can be obtained safely
Suggested Reporting¶
A ___ × ___ cm mass is attached to the interatrial septum near the fossa ovalis. Its location and mobility favor an atrial myxoma.
A laminated echodensity is present in the akinetic LV apex, consistent with thrombus.
A small, highly mobile echodensity is attached to the aortic-valve surface. Differential considerations include papillary fibroelastoma and vegetation.
The finding is not reproduced in orthogonal views and is favored to represent artifact.
The mass is incompletely characterized by echocardiography. CMR is recommended for tissue characterization and assessment of myocardial invasion.
Key Points¶
- First exclude thrombus, vegetation, normal anatomy, and artifact.
- Location and attachment often narrow the differential more than echogenicity.
- Use contrast when the LV apex is inadequately visualized.
- TEE is best for small valvular, atrial, and LAA masses.
- CMR is generally the preferred modality for tissue characterization.