[Crista terminalis bridge mimicking right atrial mass; report of a case].

A 67-year-old female was operated upon because of transthoracic echocardiograms revealing a 13 x 8 mm mass in right atrium. However, there was no mass and was prominent crista terminalis (CT) instead. CT is the largest and strongest fibromuscular bundle in the right atrium, which separates primitive right atrium from the venous sinus. Prominent CT can mimic right atrial mass on transthoracic echocardiography. It was difficult to make a differential diagnosis because prominent CT formed a bridge-like shape in this case. To obtain certain diagnosis, transesophageal echocardiography (TEE) is necessary, and prevalence of three-dimensional (3D)-TEE is expected to improve the accuracy of diagnosis. We report this case as a pitfall of the diagnosis for the right atrial mass.