Thymoma: Computed tomography

Thymoma is an epithelial tumor generally considered to have an indolent growth pattern but malignant nonetheless because of potential for local invasion, pleural dissemination, and even systemic metastases. The diagnosis of thymoma is usually made clinically. A thymoma is an incidental finding on a chest radiograph or on chest computed tomography (CT), which appears as a well-defined lobulated mass in the antero-superior mediastinum. CT plays an important role in the management of patients with thymoma. It is often used when thymoma is suspected clinically but not detected on radiography. It provides information on differential diagnosis and on the precise anatomic location of the lesion and its relationship to surrounding structures. Moreover, CT can be used in the presurgical planning providing information on the presence and degree of invasion. It can be used to monitor tumor behavior during chemo- and/or radiation therapy and to detect recurrent or metastatic neoplasm after the treatment has been completed. Thymoma can be staged at the time of surgery on the presence or absence of intact tumor capsule. Computed tomography can be used to differentiate normal thymus and thymoma or other thymic neoplasms. Complete surgical resection is the mainstay of therapy for thymomas and is the most important predictor of long-term survival. © 2008 Elsevier Inc.