Thrombi migration to atrium diagnosed by transesophageal echocardiography.

Two days before surgery in a 70-year-old man with renal cell carcinoma, transthoracic echocardiography showed a dense mass in the inferior vena cava, lying proximally, but no mass was observed in the right atrium. Intraoperative transesophageal echocardiography revealed unexpected tumor thrombi in the right atrium, and the surgical plan was changed. This case highlights the importance of intraoperative transesophageal echocardiography in patients with renal cell carcinoma.