Relationship Between CT Manifestations of Thymic Epithelial Tumors and the WHO Pathological Classification

Thymic epithelial tumors account for 15-21.7% of mediastinal tumors and 47% of anterior mediastinal tumors (Chen et al., 2002; Engels and Pfeiffer, 2003). Until 2004, there was a wide range of pathological classifications for thymic tumors (Travis et al., 2004; Okumura et al., 2008). The World Health Organization (WHO) updated the pathological classification in 2004, and thymic tumors are now classified as one of 5 types of thymomas (types A, AB, B1, B2, and B3) or as thymic carcinoma (including neuroendocrine carcinoma) (Travis et al., 2004). Studies have suggested that this WHO classification reflects well the clinical and prognostic features of thymic tumors (Chen et al., 2002; Okumura et al., 2002; Kondo et al., 2004). There have been reports about the CT manifestations of thymic tumors with different WHO pathological classifications, but the number of cases in these reports was limited (Tomiyama et al., 2002; Han et al., 2003; Sadohara et al., 2006). To explore further the relationship between the CT manifestations and the WHO pathological classification, we conducted a retrospective analysis of 105 cases of thymic tumors.