A 22-year-old woman, previously having no cardiac symptoms, during pre-anesthetic check up for right ureteric calculi was found to have cardiomegaly on chest x-ray film (A). She was advised to undergo transthoracic echocardiography, which revealed a large cystic lesion with dense echocardiographic contrast and thrombus, compressing the entire right ventricle (B, Online Video 1). Bubble study revealed a large communication to the right atrium, and similar findings were revealed on transesophageal echocardiography (C, Online Videos 2 and 3). Contrast computed tomography revealed a large aneurysm (11 × 9 cm) arising from the right atrial appendage, compressing the right ventricle and lifting the entire heart upward (D, Online Video 4). Magnetic resonance imaging of the heart and vessels confirmed the connection of the aneurysm to the right atrial appendage and also showed slight compression of the descending thoracic aorta by aneurysm (E, Online Video 5). The patient underwent successful resection of the aneurysm (F) and closure of the right atrial appendage, under cardiopulmonary bypass. Her post-operative period was uneventful. Histology of the section revealed fibroconnective tissue lined by endocardial cells (G).