Imaging of thymic epithelial tumors-a clinical practice review.

Abstract

This review article comprehensively examines the diagnostic approach to thymic epithelial tumors (TETs) and other mediastinal masses, focusing on imaging modalities and differential diagnosis. Beginning with a discussion on traditional and contemporary classification systems for mediastinal tumors, including the Japanese Association for Research on the Thymus (JART) and International Thymic Interest Group (ITMIG) classifications, it highlights the shift towards computed tomography (CT)-based categorizations. Emphasis is placed on the importance of distinguishing between solid and cystic lesions in the anterior mediastinum, with detailed insights into imaging characteristics and histological features of various TET subtypes such as thymomas, thymic carcinomas, and thymic neuroendocrine tumors (NETs). The review also elucidates common differential diagnoses, including lymphomas and germ cell tumors, providing guidance on key imaging findings and considerations for accurate diagnosis. Furthermore, it underscores the significance of patient background and blood tests in differential diagnosis, discussing age-related prevalence patterns and tumor marker assessment. After addressing the diagnostic challenges posed by thymic cysts offering insights into their radiological features, management considerations, and potential complications, this review extends to other rare mediastinal lesions highlighting the need for a comprehensive evaluation for accurate identification and management of these tumors. Finally, as illustrative examples, we present six cases highlighting various aspects of anterior mediastinal tumors, including TET. These cases provide valuable insights into the diagnostic challenges, imaging characteristics, and management considerations encountered in clinical practice. The cases presented herein do not all illustrate typical images, courses, and diagnoses. However, they each contain significant implications. Thus, we present them with the belief that they will aid in understanding the intricate nuances of image diagnosis in actual clinical practice.