Remarkable giant right atrial diverticulum in asymptomatic patient

We describe the case of a 31-year-old man who had a giant right atrial diverticulum. Although he was asymptomatic, preoperative echocardiography and three-dimensional computed tomography scan found a large mass on the right atrium. He was diagnosed with a right atrial diverticulum and underwent surgical resection of the diverticulum because of the risk of thromboembolism, arrhythmia and rupture of the diverticulum. Intra-operative finding was compatible with the feature of a diverticulum which includes thin wall and large space inside the diverticulum. Postoperative pathological examination showed a thin diverticulum wall consisting of only fibrous tissue and intima without muscular tissue. We concluded that a large diverticulum should be treated surgically because of the critical complications.