Coronary artery aneurysm is an uncommon condition defined as abnormal dilatation of the coronary artery. We report the case of a man admitted in Emergency Department for suspected intestinal obstruction. At abdominal/thoracic computed tomography (CT) it was reported a suspected pericardial cyst. Contrast echocardiography showed a clear pattern of blood flow inside the mass with a probable origin at a very limited region where it was also possible to sample an ECG-synchronized systo-diastolic pulse-wave (PW)-Doppler pattern, typical for a coronary artery flow. Our suspicion of giant coronary artery aneurysm was then confirmed by coronary CT and by coronary angiography. The patient was transferred to a Cardiac Surgery center where he underwent surgical treatment of the aneurysm. Most coronary aneurysms are clinically silent and are often incidentally detected. Coronary angiography is the ‘‘gold standard’’ for diagnosis and evaluation of coronary artery aneurysms. Among non-invasive diagnostic techniques, Computed Tomography Coronary Angiography is the best method for coronary artery anatomy and coronary abnormalities. However echocardiography with use of contrast agent, a cost-effective with non-radiation nature and widespread use method, may be a reliable method to detect and to characterize the masses, allowing a differential diagnosis.