Background/Purpose: Few studies have examined the surgical outcomes of mediastinal mature teratoma in Taiwan. In the present study, the clinicopathological characteristics of mature teratoma and their impact on surgical outcome were analyzed. Methods: From 1988 to 2005, 57 cases of mediastinal mature teratoma were reviewed. We collected and analyzed data about patient age, sex, symptoms, blood sugar, pulmonary function, diagnosis, tumor size, histopathological features, operative methods, operative time, tumor adhesion, blood loss, ventilator requirement, intensive care unit stay, chest tube requirement, and postoperative hospital stay. Results: There were 18 male and 39 female patients with a median age of 27 years. Forty- three patients received conventional open surgery, whereas 14 received video-assisted thoracoscopic surgery. The patients in the thoracoscopic group had a decreased operative time (106.4 +/- 35.7 min vs. 205.4 +/- 75.7 min, p = 0.038), fewer ventilator days (0. 2 +/- 0.4 vs. 0.5 +/- 0. 8, p = 0.034), and a shorter stay in the intensive care unit (0.6 +/- 0.8 days vs. 1.5 +/- 1.4 days, p = 0.030). Pancreatic tissue was identified in 21 of 57 tumors (36.8%). The patients with tumors that contained pancreatic tissue had more presenting symptoms and complicated surgery than those whose tumors were without pancreatic tissue (76.2% vs. 33.3%, p = 0.002, and 42.9% vs. 11.1%, p = 0.008). The patients with symptoms had a higher incidence of complicated surgery than those without (39.3% vs. 6.9%, p = 0.004). Conclusion: Mediastinal mature teratoma commonly occurs in young women. Thoracoscopic surgery is a feasible technique for mediastinal mature teratoma resection if no dense adhesions are found during preoperative assessment. The presence of symptoms might be a relative contraindication for thoracoscopic teratoma resection because of its association with surgical complications. ; 附設醫院創傷醫學部 ; 醫學院附設醫院 ; 期刊論文