Epicardial cysts are rarer benign tumors than pericardial cysts. There have been few reports on surgical management of epicardial cysts. A 17-year-old normotensive boy presented with chest pain and palpitations, which on evaluation was found to be a mediastinal mass (pericardial cyst). Surgical resection of the cyst via thoracotomy was planned. The cyst was diagnosed as an epicardial cyst intraoperatively. However, due to the epicardial origin of cyst and posterior adhesions, resection was done via midline approach. The base was formed by visceral pericardium and eroding into myocardium of left ventricle, so the resection was concluded with on-pump surgery. In case of erroneous diagnosis or undesirable finding, a safer midline approach with on-pump surgery, as an alternative to minimally invasive approach for complicated epicardial cysts (erosion into ventricle/lying in close proximity to important structures or near to coronary arteries) should be considered.