A 69-year-old healthy woman was hospitalized twice within a few weeks for management of acute inferior myocardial infarction with thrombolysis and stenting of the right coronary artery (RCA) ostium. After the second myocardial infarction, follow-up angiography showed subocclusion of the proximal RCA, and transesophageal echocardiography and chest computed tomography revealed the presence of a mobile, 2-cm diameter spherical mass partially adherent to the RCA ostium and penetrating the stent. A benign papillary fibroelastoma was surgically excised, the stent was removed, and vein bypass grafting of the RCA was performed. The literature relevant to this case report is reviewed.