[A clinicopathologic study of thymomas: a review of 52 cases, with particular reference to results of treatment].

Clinicopathologic aspects of 52 thymomas were reviewed. Masaoka staging revealed stage I in 32, stage II in 2, stage III in 12, stage IV a in 3, and stage IV b in 3. Eleven patients (21%) had associated myasthenia gravis (MG), and three (6%) had pure red cell aplasia (PRCA). Operation was complete resection in 39 patients (stage I 32, stage II 2, stage III 2, and stage IV b 3), subtotal resection in 4 patients (stage III 2, stage IV a 2), partial resection or simple biopsy in 7 patients (stage III 6, stage IV a 1). Survival rates at 5 years and 10 years were 88%, 88% in noninvasive thymomas, and 65%, 45% in invasive thymomas, respectively. Statistical analysis indicated that patients with noninvasive thymomas had significantly longer survival than those with invasive thymomas. Significant difference was not found in survival on the basis of tumor cell type according to lymphocyte/epithelial cell ratio. Associated MG had no influence on the survival of thymoma patients, however, the presence of PRCA was an adverse factor in survival. In cases of invasive thymomas, there was statistically significant difference in the survival rates between the group of patients undergoing complete or subtotal resection and the group undergoing partial resection or only biopsy. Irradiation was of value in local control of thymoma, but lymphogeneous or hematogeneous recurrence occurred in 21% of patients with invasive thymomas from 3 months to 12 years postoperatively. Lifelong follow-up should be necessary in thymoma patients since late recurrence is not so rare.