Right atrial blood cyst with total occlusion of the right coronary artery.

Cardiac blood cysts are rarely seen in adult patients and in the right atrium. The origin of cardiac blood cysts is not understood, and several hypotheses have been proposed. We present a rare case of right atrial blood cyst with total occlusion of the right coronary artery (RCA). Inflammatory processes may have played an important role in the development of the cyst, because infiltration of inflammatory cells was observed in the cystic wall. Additionally, total obstruction of the proximal RCA indicated that ischemia and/or infarction in the right atrium might be related to formation of the cyst.