Advances in Thymoma Imaging

Abstract

Thymoma is the most common primary neoplasm of the anterior mediastinum, but it accounts for <1% of all adult malignancies. It is the most common of the thymic epithelial neoplasms, which, in addition to thymoma, include thymic carcinoma and thymic carcinoid. Because of the rarity of thymoma, it has not been studied thoroughly. Over the last half decade, there has been increased interest in this disease, with greater international collaboration and dedicated thymic malignancy work groups; this has culminated in the formation of the International Thymic Malignancy Interest Group, instituted to provide a scientific infrastructure for the study of these lesions and foster collaborative research. Imaging plays a major role in the identification and staging of thymoma, as well as in the follow-up monitoring for its recurrence. Currently, imaging is predominantly carried out with computed tomography (CT). In selected cases, there is a role for magnetic resonance imaging and ¹⁸F-fluorodeoxyglucose positron emission tomography in the investigation of an anterior mediastinal mass suspected to be thymoma. Because patients with advanced thymoma receive neoadjuvant chemotherapy, radiologists should be familiar with the staging system of thymoma and the imaging features of advanced-stage thymoma to identify such patients before surgery. This review serves as an update of the recent imaging studies on thymoma, which may help in tailoring the approach to the patient with a biopsy-proven or suspected thymoma.