Current therapy for thymoma.

Abstract

Thymomas are the most frequently encountered neoplasm of the anterior mediastinum. Thymic neoplasms can be divided into 3 broad categories based on histologic appearance and behavior. Thymomas are tumors with benign-appearing cellular features. If there is no gross or microscopic invasion beyond the capsule, the tumor is considered benign. Any tumor with gross or microscopic invasion through the capsule is considered malignant. In a third category, thymic tumors which have histologically malignant epithelial features, are considered thymic carcinomas and generally have an adverse prognosis. Microscopically, thymomas consist of a variable component of lymphocytic, epithelial, and fusiform (spindle) cell elements. The tumors may be classified according to the predominant cell type or are considered mixed if no cell type predominates. Prognosis is most strongly linked to clinical stage. The role of adjuvant radiotherapy or chemotherapy in the treatment of such tumors is controversial, but malignant thymomas are generally responsive to radiotherapy. Associated myasthenia gravis does not adversely affect the prognosis of thymoma, and medical attention to the myasthenia may contribute to earlier diagnosis of the thymoma. Cisplatin-based chemotherapy may be used to treat advanced disease with a modest response rate.