Right coronary artery aneurysm with aneurysmal dilation and thrombosis of the sinoatrial nodal branch mimicking a right atrial mass.

Aneurysms of the branches of the coronary arteries are rare. We report a case of a right coronary artery aneurysm with aneurysmal dilation and thrombosis of the sinoatrial nodal branch presenting as a right atrial mass. The patient underwent multiple imaging evaluations before coronary CT angiography diagnosed aneurysm and thrombosis of the sinoatrial nodal branch.