[An unusual left retroatrial mass].

We describe the case of a 75-year-old hypertensive patient who comes to the emergency room for an infero-postero-lateral myocardial infarction. The entry echocardiogram showed a rounded formation with mixed echogenicity (maximum transverse diameter 4.5 cm), attached to the free wall of the left atrium and without any hemodynamic impact. Coronary angiography revealed a giant aneurysm of the circumflex artery, followed by an occlusion of the distal tract. After Heart Team evaluation, angioplasty with implantation of a drug-eluting stent was performed in the occluded coronary tract. This is one of the very rare cases in the literature of a giant coronary aneurysm diagnosed within the clinical picture of acute coronary syndrome. There is a lack of guidelines and consensus documents regarding management of this condition. In our case report, we discuss the resulting therapeutic challenges.