Giant myxoma in left atrium

A 72- year old patient with a history of arterial hypertension and diabetes presented with a progression of dyspnea to a local hospital.

Figure 1 ECG on admission - Atrial fibrillation with rapid ventricular response 120/min.

She was referred to our centre after initiation of anticoagulation and rate control therapy for a suspected left atrial myxoma found on a transthoracic echocardiography (TTE).

‍Video 1 TTE with suspected myxoma in the left atrium 

Figure 2 Mitral stenosis caused by myxoma documented on TTE

Figure 3 Size of myxoma documented on TTE (60x49mm)

A transesophageal echo (TEE) was performed.

Video 2 Myxoma in the left atrium documented on TEE

Video 3 Myxoma in the left atrium causing severe mitral stenosis combined with moderate mitral regurgitation

A CT scan showed a previously unknown subacute ischemic lesion probably due to myxoma embolism. 

Figure 4 CT head

A decision was made to pursue myxoma extraction, surgery was performed without complications.

Figure 5 Myxoma before sending for histology.

Postoperative histological examination confirmed the suspected diagnosis of myxoma.

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Clinical context

Primary tumors of the heart are rare, with an estimated incidence between 0.0017% and 1.9% of unselected patients in autopsy studies. Among malignant tumors, sarcoma is the most common type, followed by angiosarcoma.

Myxoma is a benign tumor with unknown exact origin composed from multiple types of cells such as smooth muscle cells, endothelial cells and myxoma stroma which consists of spindle- and stellate-shaped cells. 

From an epidemiologic perspective, cardiac myxomas are best divided into the following 2 categories: those that arise in isolation and those that arise in the setting of a syndrome (so-called Carney complex).

The most common localization of myxoma is the left atrium (in about 80% of cases). It occurs more frequently in women, typically in 40-60 years of age. 

Myxoma itself is asymptomatic unless it causes obstruction of valves or it begins to embolize - such as in our case. 

In most cases they are usually surgically removed after diagnosis.  

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Learning points‍

1) Myxoma of the left atrium may cause a mitral valve stenosis
- In such cases, it presents as dyspnea, pulmonary edema or syncope or other nonspecific symptoms

2) What are the most common manifestations of cardiac myxoma?
- According to studies, 80% of patients with a cardiac myxoma presented with dyspnea. Other presenting symptoms included palpitations, syncope, pedal edema, chest pain, and constitutional symptoms. Around 30% of the patients presented with signs and symptoms associated with secondary embolization.

3) Myxoma poses a risk of embolisation.
- In our case, the embolisation was asymptomatic, however an ischemic stroke or embolisation to a different localization may occur and lead to serious and potentially fatal complications. 

What are the risk factors for myxoma embolism?
- A recent meta analysis found that (NYHA) class I/II, hypertension, irregular tumor surface, tumor in atypical location, narrow base of tumor and increased fibrinogen are significant risk factors of embolism in patients with cardiac myxoma. However, sex, age, body mass index, smoking, left ventricular ejection fraction, diabetes, hyperlipidemia, atrial fibrillation, valvular heart disease, coronary heart disease, tumor size, platelet count, white blood cells, and hemoglobin were not associated with embolism.
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4) Diagnosis is usually based on echo appearance which demonstrates a mass in the left atrium with a stalk that is usually attached to the interatrial septum. TEE offers better resolution and delineation of the tumor including dimensions.

5) Only curative option is surgical removal of the tumor. Multiple procedures can be performed in one surgery such as in our case. This eliminates the need for re-operations. 


References

1. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 11th ed, Zipes DP, Libby P, Bonow RO, et al, W.B. Saunders Company, Philadelphia 2018.
2. Liu, Yanna, Jiwei Wang, Liangyun Guo, and Luyi Ping. 2020. “Risk Factors Of Embolism For The Cardiac Myxoma Patients: A Systematic Review And Metanalysis”. Bmc Cardiovascular Disorders 20 (1). https://doi.org/10.1186/s12872-020-01631-w.
3. Thyagarajan, Braghadheeswar, Monisha Priyadarshini Kumar, Shil Patel, and Abhinav Agrawal. 2017. Extracardiac Manifestations Of Atrial Myxomas. Journal Of The Saudi Heart Association 29 (1): 37-43. https://doi.org/10.1016/j.jsha.2016.07.003.
4. Domínguez-Pérez L, Fernández-Elías E, Arias MA, Akerström F, Orradre JL, Palacios-Castañeda D. Fatal presentation of a cardiac myxoma. Rev Esp Cardiol (Engl Ed). 2012 Jun;65(6):578-80. doi: 10.1016/j.recesp.2011.09.007. Epub 2011 Nov 29. PMID: 22129586.
5. Lee KS, Kim GS, Jung Y, Jeong IS, Na KJ, Oh BS, Ahn BH, Oh SG. Surgical resection of cardiac myxoma-a 30-year single institutional experience. J Cardiothorac Surg. 2017 Mar 27;12(1):18. doi: 10.1186/s13019-017-0583-7. PMID: 28347356; PMCID: PMC5368917.
   

Authors: Michal Pazderník, Michael Jenšovský