A 58-year-old male patient was admitted to the emergency service with dyspnoea.The patient underwent several laboratory and imaging tests including echocardiography and a diagnosis of descending aortic aneurysm was suspected.After computerised tomography scanning, a normal-size descending aorta was found so that echocardiography was done once more. Intravenous contrast examination revealed a giant coronary sinus in this patient.