The Left Atrial “Medusa Myxoma” Elbert E. Williams, BS, Jerry W. Pratt, MD, and David E. Martin, MD Michigan State University College of Human Medicine – Kalamazoo Campus, and Borgess Heart Institute, Borgess Medical Center, Kalamazoo, Michigan

Although myxomas are the most commonly seen primary cardiac tumors, encompassing 30% to 50% of all primary tumors of the heart, they remain a rare finding with an annual reported incidence of 0.5 per million. The presenting symptoms of an atrial myxoma are widely varied as are the clinical consequences. Regardless of presentation, once a diagnosis is made prompt surgical excision is recommended to minimize the potential complications of obstruction or embolization. We present the “Medusa myxoma,” an arborizing 4-fingered left atrial myxoma extending from the fossa ovalis across the left atrium. (Ann Thorac Surg 2014;97:e49–51) Ó 2014 by The Society of Thoracic Surgeons

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ardiac myxomas are a relatively rare phenomena in clinical practice with an incidence of 0.5 per million people annually [1]. However, in several longitudinal studies, typical characteristics of these tumors have been established. They are classically pedunculated masses that stem off of the fossa ovalis of the left atrium that present with a mix of obstructive cardiac, embolic, or constitutional symptoms [2, 3]. A 47-year-old man initially presented with complaints of sudden fever of 40 C, chills, shortness of breath, and cellulitis of the left lower extremity. His past medical history was significant for hypertension, obesity, and presumed chronic obstructed pulmonary disease secondary to a 30-pack year smoking history. He recently experienced a toothache 3 to 4 weeks previously, which resolved with conservative measures. He was given broad-spectrum intravenous antibiotics to treat the presumed lower extremity cellulitis. Blood cultures at 24 and 48 hours were reported as negative. A workup for potential endocarditis was initiated. Cardiac examination revealed no murmurs, rubs, or gallops. A transthoracic echocardiogram revealed a left-sided heart mass that appeared to originate from the ventricular surface of the anterior leaflet of the mitral valve. Suspicious for intracardiac vegetation, transesophageal echocardiography was performed and mitral valve vegetation was ruled out. However, a large mass originating from the interatrial septum with several projections extending across the atrium penetrating into the mitral annulus was visualized (Fig 1). Extensions of the mass prolapsed into the left

ventricle during diastole. The patient’s left ventricular ejection fraction was 0.60 to 0.65 with no evidence of interatrial shunting or cardiomegaly. Only trace amounts of mitral regurgitation were appreciated. The patient was taken to the operating room for planned excision of the left atrial mass. A median sternotomy was performed and the patient was placed on cardiopulmonary bypass. A left transverse atriotomy through the Waterston groove was performed and a 4-fingered myxomatous tumor mass was immediately evident (Fig 2). The mass and the interatrial septum were excised en bloc. The atrial septal defect was repaired with an autologous pericardial patch closure. The postoperative course was uneventful and he was discharged on postoperative day 8. Pathologic analysis revealed a 5.8  2.2  0.7 cm benign arborizing atrial myxoma with 4 frond-like projections (Fig 3). The patient was followed in the wound clinic for his lower extremity cellulitis, which resolved. He was seen multiple times in the cardiothoracic surgery office and was without signs of cardiac disease. Transthoracic echocardiograph 6 months postoperatively revealed no signs of atrial septal defect, cardiac or valvular dysfunction, or residual myxoma (Fig 4).

Comment This tumor, which we named the “Medusa myxoma,” is unique in that our literature search revealed no other cases involving an arborizing atrial myxoma. Myxomas are typically pedunculated with a short stalk in 85% of cases while the remaining 15% are sessile [2]. Most left atrial myxomas arise from the atrial septum in close proximity to the fossa ovalis [2, 3]. Our myxoma originated from the fossa ovalis but this led to several tumor projections rather than a solid mass off of a short stalk. The presenting symptoms for myxomas are quite variable and often nonspecific, with a broad range of clinical findings. Some patients remain asymptomatic. However, most patients will present with at least 1 of the following classic triad of symptoms: obstructive cardiac signs;

Accepted for publication Sept 5, 2013. Address correspondence to Dr Martin, Borgess Heart Institute, 1722 Shaffer St, Ste 2, Kalamazoo, MI 49048; e-mail: david.martin@ borgess.com.

Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc

Fig 1. Transesophageal echocardiograph demonstrating several arms of the left atrial myxoma prolapsing into the left ventricle. 0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2013.09.067

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CASE REPORT WILLIAMS ET AL LEFT ATRIAL MEDUSA MYXOMA

Ann Thorac Surg 2014;97:e49–51

Fig 4. Transthoracic echocardiograph showing no signs of residual myxoma or cardiac dysfunction 6 months postoperatively.

Fig 2. Medusa myxoma seen through transverse atriotomy incision.

embolic signs; and constitutional or systemic signs [2, 4, 5]. Symptoms of cardiac obstruction are present in approximately 68% of patients, whereas signs of systemic embolization are seen in 29% to 40% of cases of cardiac myxomas [2, 3]. Constitutional symptoms, such as fever and fatigue, are seen in approximately 34% of patients [2]. Our patient was free from signs of cardiac obstruction or failure but presented with constitutional signs of fever and chills. These nonspecific constitutional signs mimicked symptoms of systemic infection and resulted in the workup for endocarditis and sepsis. In retrospect, it is possible that the erythema and swelling of his left lower extremity may have actually represented tumor

microembolization rather than cellulitis. Given the atypical structure of the Medusa myxoma, it is likely that this patient was at a higher risk of embolic sequelae due to the multiple tumor arms, each with greater range of motion than seen in the classical large pedunculated mass. Giving additional support to tumor embolization as the cause of his lower extremity pathology was the protracted healing course of his lower extremity in the wound clinic. However, venous and arterial duplex ultrasounds of the extremity showed no signs of macroscopic emboli. Unfortunately, these ultrasound studies were not done immediately upon his entering the hospital but rather 5 days after initial presentation, allowing time for additional fragmentation and reabsorption. Regardless of presentation, prompt excision is warranted due to the concern of embolization and cardiac impairment. In a series of 98 intracardiac myxoma excisions at a single center, 97% survived the operation with an 89% 5-year survival [3]. Our patient presented with an atypical arborizing Medusa myxoma of his left atrium. In retrospect, he presented with both embolic and constitutional signs resulting in a workup for endocarditis and sepsis. En bloc resection of his tumor resulted in resolution of his symptoms and he was without signs of cardiac disease postoperatively. The unique morphology of the Medusa myxoma is, to our knowledge, unreported in the literature previously.

The authors would like to thank Leandra Burke and Sherry Keith for their help with this manuscript.

References

Fig 3. Resected Medusa myxoma.

1. McManus B. Primary tumors of the heart. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald’s heart disease – a textbook of cardiovascular medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2012:1640–4.

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2. Pinede L, Duhaut P, Loire R. Clinical presentation of left atrial cardiac myxoma. A series of 112 consecutive cases. Medicine (Baltimore) 2001;80:159–72. 3. Garatti A, Nano G, Canziani A, et al. Surgical excision of cardiac myxomas: twenty years experience at a single institution. Ann Thorac Surg 2012;93:825–31.

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4. Strecker T, Agaimy A. Giant left atrial myxoma causing drop attacks by prolapsing into the mitral valve. Int J Clin Exp Pathol 2012;5:996–9. 5. Yuce M, Dagdelen S, Ergelen M, Eren N, Caglar N. A huge obstructive myxoma located in the right heart without causing any symptom. Int J Cardiol 2007;114:405–6.

The left atrial "Medusa myxoma".

Although myxomas are the most commonly seen primary cardiac tumors, encompassing 30% to 50% of all primary tumors of the heart, they remain a rare fin...
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