Abstract：Objective: To assess the CT imaging findings of each type of thymic epithelial tumors and to determine useful findings in differentiating the main subtypes of low-risk thymomas, high-risk thymomas, and thymic carcinomas. Methods: CT features of 62 low-risk thymoma, high-risk thymoma, and thymic carcinoma cases confirmed by operation and pathology were reviewed retrospectively. The imaging characteristics of each group were compared and the main different characteristics among the three groups were analyzed. Results: On CT imaging, lobulation and irregularity of contour, necrotic or cystic component within tumor, great vessel invasion, presence of mediastinal lymphadenopathy and extrathymic metastasis are more common in thymic carcinomas than thymomas. High-risk thymomas usually have pleural metastasis. Clusters calcification are usually seen in thymic carcinomas, nodosity and punctiform and eggshell calcification are more common in thymomas. Conclusion: The presence of irregular contour, necrotic or cystic formation, mediastinal lymphadenopathy and extrathymic metastasis, great vessel invasion are suggestive of thymic carcinomas. The fiber diremption in tumor and eggshell calcification only seen in thymomas. Pleural metastasis are suggestive of high-risk thymomas.
2011, Vol. 22 
