Prominent crista terminalis appearing as a right atrial mass on transthoracic echocardiogram.

The crista terminalis is a fibromuscular ridge formed by the junction of the sinus venosus and primitive right atrium. In these case reports, transthoracic echocardiography suggested the presence of a right atrial mass. However, subsequent transesophageal echocardiography revealed that the "right atrial mass" was actually a prominent crista terminalis. An understanding of the anatomy and the echocardiographic appearance of a prominent crista terminalis will minimize the misdiagnosis of this structure.