Thymoma in a 12-year-old boy.

A case of thymoma in a 12-year-old boy is presented. The patient had a history of thymic irradiation in infancy, and a family history of leukemia. The mass was readily resected and the patient is well 10 years later. The tumor contained an unusual admixture of normal thymic tissue with the neoplastic epithelial elements. This peculiar histologic pattern is discussed in relationship to the patient's age and history.