Thrombus, tumor or vegetation?

Thrombus, tumor or vegetation?

This question is often faced by the echocardiographer while evaluating a mass detected on the heart valves or cardiac chambers. Usual method is to take it in the clinical context. There could also be non-infective vegetations of marantic endocarditis which are almost impossible to differentiate from infective vegetations. Marantic vegetations can be suspected in the presence of small and multiple vegetations changing from one examination to another, without associated abscess or valve destruction [1]. It may be noted that echocardiography is neither 100% specific nor 100% sensitive for the diagnosis of infective endocarditis.

Vegetations in general are irregular in shape, mobile and attached to a valve. But there could be vegetations attached to the myocardium in locations of jet lesions. Tumors of the heart are considered more likely in certain locations like a left atrial myxoma or a ventricular rhabdomyoma in an infant. But left atrium is also the commonest site for a large thrombus, especially in the presence of mitral stenosis.

Thrombus will not have a stalk unlike a left atrial myxoma which often has a stalk, though sessile myxomas are also there. Thrombus responds to thrombolytic therapy, with a significant risk of major embolism in the process! But a giant organized thrombus responds poorly to thrombolysis. In case of left ventricular mass, associated regional or global hypokinesia may favor the diagnosis of thrombus. Associated systemic lupus erythematosus or antiphospholipid syndrome may also favor the diagnosis of thrombus [2].

Sometimes computed tomography and magnetic resonance imaging may be useful when echocardiography does not clearly distinguish whether the mass is a tumor or thrombus. MRI with gadolinium contrast is likely to be more useful [3], though not feasible in those with renal dysfunction. MRI is considered to be superior to CT in giving anatomic details and does not involve ionizing radiation.

References

1. Habib G, Badano L, Tribouilloy C, Vilacosta I, Zamorano JL, Galderisi M, Voigt JU, Sicari R, Cosyns B, Fox K, Aakhus S; European Association of Echocardiography. Recommendations for the practice of echocardiography in infective endocarditis. Eur J Echocardiogr. 2010 Mar;11(2):202-19. doi: 10.1093/ejechocard/jeq004. PMID: 20223755.
2. Patnaik S, Shah M, Sharma S, Ram P, Rammohan HS, Rubin A. A large mass in the right ventricle: Tumor or thrombus? Cleve Clin J Med. 2017 Jul;84(7):517-519. doi: 10.3949/ccjm.84a.16115. PMID: 28696199.
3. El Ouazzani J, Jandou I, Christophe Thuaire I. Thrombus or vegetation?Importance of cardiac MRI as a diagnostic tool based on case report and literature review. Ann Med Surg (Lond). 2020 Dec 5;60:690-694. doi: 10.1016/j.amsu.2020.12.007. PMID: 33318794; PMCID: PMC7726452.