Discussion
We report our experience with a postero-inferior epicardial cyst which was successfully resected with on-pump surgery. In our patient, excision was complicated because the cyst was located in close proximity to posterior descending artery. Resection of the cyst followed by reinforcement of the thinned ventricular wall could not have been accomplished without cardiopulmonary bypass support and the risk of ventricular wall injury leading to complicated course couldnot be completely ruled out. To circumvent such situation, we decided to operate on CPB. CPB may be required when cysts compress surrounding structures or erode the ventricular wall, coronaries (2, 3, and 7). We suggest that surgeon must be aware of possible need for CPB in such situations.
Preoperative differential diagnosis between a pericardial cyst and epicardial cyst is challenging because they cannot be differentiated on CT. (6) Although MRI is useful to differentiate cysts from other mediastinal lesions, it cannot differentiate between pericardial and epicardial cyst completely. This should broaden the spectrum of the potential appearance of differentials like epicardial masses intraoperatively. Role of cardiac magnetic resonance in tissue characterization to avoid erroneous preoperative diagnosis can have diagnostic importance. (9)
Coronary CT or angiography might be considered especially with regard to the degree of adhesions and location of the coronary vessels. However, it may not always exclude the possibility of involvement of coronaries because some literature reported epicardial cysts with involvement of the coronary vessels and CPB requirement to resect those cysts despite having negative findings [1, 2].
VATS/thoracotomy might be the first option but when invasion to important structures, including the left ventricle and coronary artery is suspected, median sternotomy with CPB should be considered. Off-pump resection might be indicated for uncomplicated cysts (8).
In our case, we were concerned about adhesions and close proximity of the cyst to surrounding structures thus the less invasiveness of thoracotomy was not considered beneficial enough to outweigh the risks associated with inadmissible complication.
Surgical resection on CPB can be a safe option when cyst lies in close proximity to important structures/erosion to ventricular wall. Detailed and meticulous preoperative investigation should be considered in large cyst in order to avoid any erroneous diagnosis.