Epidemiology of Thymic Neoplasms

Thymic malignancies represent a wide range of anatomical, clinical, histological, and molecular entities that may be aggressive and difficult to treat. The World Health Organization histopathologic classification distinguishes thymomas from thymic carcinomas; thymomas are further subdivided into different types (so-called A, AB, B1, B2, and B3) based upon the morphology of epithelial tumor cells (with an increasing degree of atypia from type A to B3), the relative proportion of the non-tumoral lymphocytic component (decreasing from type B1 to B3), and resemblance to normal thymic architecture. Thymic carcinomas are similar to their extrathymic counterpart, the most frequent subtype being squamous cell carcinoma.