The diagnostic and therapeutic approaches to mediastinal tumors and cysts have changed over the past three decades. This report summarizes our forty-two years of experience with these tumors.

This study retrospectively reviewed 479 patients with primary mediastinal tumors and cysts that were diagnosed and managed over the past 17-year period (1985~2002) and compared them to the report of the previous 25-year result (1960~1985) in Yonsei University College of Medicine, Severance Hospital in Seoul, Korea.

During the 17 years, there were 479 cases of pathologically proven mediastinal tumors and cysts. Thymoma (38.2%) was the most common mediastinal tumor and has increased noticeably during recent years. The gender ratio showed a male predominance (1.3:1) and the age distributions were even over all the age groups. The most common sites of the tumor and the proportion(28.6%) of malignant tumors were the same as that previously reported. A diagnosis of a tumor in asymptomatic patients was possible in 174 cases (36.3%), which was higher that reported previously. The diagnostic yield of a fine needle aspiration biopsy was 68.6% in the total tumors and 80.9% in the malignant tumors. A surgical resection was the most frequently chosen treatment modality and was performed in 405 cases (84.6%). The complete resection rate was 91.1%, which is higher than the previous result of 78.8%.

These results showed that the prevalence of mediastinal tumors and cysts, particularly thymoma, increased. A fine needle aspiration biopsy was a valuable preoperative differential diagnostic method for malignant tumors. The surgical and complete resection rate increased remarkably possibly due to the better applicable chest CT scans, the more frequent health check-up provided by the regular health promotion program for all people as a health insurance policy, and the improved diagnostic techniques in the pathologic, radiological, and clinical fields.