Thymus and Mediastinum

Abstract

The thymus is a lymphoepithelial organ in the anterior mediastinum and is the site of maturation for T cells, serving a similar function as lymph nodes for B cells. Unlike lymph nodes, however, the thymus has a prominent epithelial component. It is these epithelial cells that give rise to the tumors called thymomas and thymic carcinomas. Lymphomas can also arise within the thymus, as can tumors of other cellular elements that are found in smaller numbers in the thymus, such as nerves, fat, smooth muscle, and even germ cells. This chapter will cover the neoplasms of the thymus as well as other tumors of the mediastinum.