[Appropriate surgical approach to cystic thymic lesions]

We retrospectively analyzed surgical approach to cystic thymic lesions based on 25 cases. We classified to 4 groups as follows, 12 thin-wall solitary cysts with low uniform density, 7 solitary cysts with ununiform density, 5 cysts with tumor lesions and 1 multiple cysts. Preoperative image diagnoses were 10 thymic cysts, 7 cystic thymomas, 4 mature teratomas, and 1 each of multilocular thymic cyst and thymic lymphoma. Twenty cases were indicated to video-assisted thoracic surgery( VATS), the other 5 cases were operated by sternotomy. The reasons for thoracotomy were adherence with left brachiocephalic vein(LBCV)3, huge cyst compressing superior vena cava (SVC) 1, diffuse multiple cysts and tumors in hypertrophic thymus 1. Three cases were converted to open thracotomy from VATS because of dense adhesions around LBCV and malignant diagnosis. Final diagnosis are 16 congenital cysts, 3 thymomas, and one each multilocular thymic cyst, mature teratoma, thymic cancer, thymolipoma, venous hemangioma and mucosal associated lymphoid tissue( MALT) lymphoma. Thin-wall solitary cysts with low uniform density are able to diagnosed congenital thymic cysts by computed tomography( CT)/magnetic resonance imaging (MRI) appearances. On the contrary un-uniform density cysts or cysts with tumor lesions are difficult to achieve correct diagnoses by images. These lesions may contain thymoma or thymic cancer, so that rapid pathological examination should be prepared during surgical operation. Cysts adhering to LBCV should be operated by thoracotomy to avoid accidents of massive bleeding.