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

Objective: To explore the relationship between computed tomography (CT) manifestations of thymoma andits WHO pathological classification.
Methods: One hundred and five histopathologically confirmed cases werecollected for their pathological and CT characteristics and results were statistically compared between differentpathological types of thymoma.
Results: Tumor size, shape, necrosis or cystic change, capsule integrity, invasionto the adjacent tissue, lymphadenopathy, and the presence of pleural effusion were significantly different betweendifferent pathological types of thymomas (P <0.05). Type B2, B3 tumors and thymic carcinomas were greater insize than other types. More than 50% of type B3 tumors and thymic carcinomas had a tumor size greater than10 cm. The shape of types A, AB, and B1 tumors were mostly round or oval, whereas 75% of type B3 tumorsand 85% of thymic carcinomas were irregular in shape. Necrosis or cystic change occurred in 67% of type B3thymomas and 57% of thymic carcinomas, respectively. The respective figures for capsule destruction were 83%and 100% . Increases in the degree of malignancy were associated with increases in the incidence of surroundingtissue invasion: 33%, 75%, and 81% in type B2, type B3, and thymic carcinomas, respectively. Pleural effusionoccurred in 48% of thymic carcinomas, while calcification was observed mostly in type B thymomas.
Conclusions:Different pathological types of thymic epithelial tumors have different CT manifestations. Distinctive CT featuresof thymomas may reflect their pathological types.