Giant coronary artery aneurysm in the atrial septum.

A man in his 60s with paroxysmal atrial fibrillation was scheduled for a catheter ablation but was admitted to our department after contrast-enhanced CT showed a large homogeneous right atrial mass (52×52 mm) as well as a dilated right coronary artery (RCA). Coronary artery angiography showed a large fistula from the RCA to the mass in the right atrium. A giant coronary artery aneurysm was suspected and a surgical resection was performed. The mass was attached to the atrial septal wall and was palpated in the right atrium with a feeding artery from the RCA. The final diagnosis was an extremely rare case of giant coronary artery aneurysm originating from the RCA. The surgery was successful, and the patient was discharged 30 days later.