Right atrial aneurysm with downward displacement of the anterior leaflet that resembled Ebstein's anomaly.

A 13-year-old boy presented with right atrial aneurysm and downward displacement of the anterior leaflet in the tricuspid valve into the right ventricle, without tricuspid valve regurgitation. Paroxysmal atrial flutter was caused by an abnormal electrical re-entry circuit, which could not be treated using catheter radiofrequency ablation. Therefore, the patient underwent surgical ablation and resection of the enlarged right atrial wall. The anterior leaflet of the tricuspid valve was plastered and displaced downward into the right ventricle, which resembled Ebstein's anomaly. Pathological evaluation revealed a thin wall that contained fibrous tissue with lipomatous degeneration and few muscular elements. No postoperative arrhythmia was observed.