Fig. 1

Transthoracic echocardiogram in the parasternal long-axis view. A An image captured by the physician in the primary clinic two hours before admission to our hospital. An oval tumor (arrows) measuring about 25 × 35 mm in the left atrium was revealed. There was a 12-mm round hypoechoic area within the tumor. B An image taken upon admission to our hospital. A tumor (arrows) approximately 40 × 50 mm in size included a 20 × 30-mm-sized cystic lesion within it. The tumor and its internal cystic lesion were obviously expanded compared to those in the image captured in the primary clinic two hours earlier