[Thoracoscopic treatment of mediastinal thymic cyst].

A mediastinal thymic cyst was excised under thoracoscope in a 66 year-old man. Mass lesion was noted in the left anterior mediastinum on chest X-p during a screening examination. Based on the findings of the chest CT and MRI, the mass was diagnosed as a cyst containing low fat and low protein fluid without solid tissue. This lesion was diagnosed as a mediastinal thymic cyst. Under general anesthesia, the thoracoscopy was inserted to the left thoracic cavity. Then, the cyst was resected sharply and bluntly with pair of scissors, while electric coagulation was performed as needed. In cases of mediastinal thymic cyst, it is possible to completely resect the cyst by thoracoscopic treatment, causing minimal surgical invasiveness. Considering that a few thymic cysts are combined with malignant tumor, complete resection of the lesion is required in the treatment of thymic cyst.