A rare case of cardiac myxoma from the left atrial appendage presenting with acute myocardial infarction

Excerpt

A 35-year-old man presented to the emergency department with acute-onset chest pain and cold sweating. His electrocardiogram was suggestive of anterior wall ST segment elevation myocardial infarction (STEMI). Clinical examination and cardiac auscultation did not show any abnormality. He was thrombolysed successfully with streptokinase. He had no known risk factors for coronary artery disease (CAD). Transthoracic echocardiogram was suggestive of mild hypokinesia of the left anterior descending artery (LAD) territory with preserved left ventricular (LV) systolic function. Strikingly, a thin, highly mobile echogenic mass mimicking vegetation was found near mitral leaflets (Fig. 1) and the left atrial appendage appeared hazy in transthoracic echocardiography. The origin and type of the mass cannot be specified in transthoracic echocardiography. Transesophageal echocardiogram was performed, which showed clearly the same mass arising from the left atrial appendage attached with a stalk, measuring 5.5 cm × 0.6 cm (Fig. 2). It was attached at the left atrial appendage and the rest of the mass is thin, long and highly mobile, and was prolapsing in the LV cavity in diastole through mitral inflow. The commonest mass in the left atrium is a thrombus. But this is unlikely in our case. We suspected this mass as myxoma or fibroelastoma. Coronary angiogram was performed on the third day and showed clean coronaries, probably because of thrombolysis of embolus, which are most often thrombus forming over the surface of myxoma than tumour embolus. The patient was advised surgical excision of that mass. The macroscopic and histopathology examination confirmed the nature of the mass as myxoma. Systemic embolisation including coronary arteries is reported from the left atrial myxoma [1]. The presence of any mass other than thrombus is extremely rare in the left atrial appendage. There are very few case reports describing myxoma causing coronary embolism and myocardial infarction [1‐3] or arising from the left atrial appendage [4, 5]. We have reported the first case of left atrial appendage myxoma causing coronary embolism and myocardial infarction. In our case, the shape of the myxoma is very atypical, along with its site of origin and presentation. This case also showed the importance of transesophageal echocardiography over transthoracic echocardiography to delineate the left atrial appendage pathology.

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