To Explore The Diagnosis Value Of Spiral CT To Thymic Epithelial Tumors

SectionⅠTo Explore the Diagnosis Value of Spiral CT to Identify the Invasion of Thymic Epithelial TumorsObjective:Thymic epithelial tumors are the most common tumors of the anterior mediastinum.They show variable histologic features and heterogeneous oncologic behavior,the invasion of which is the most important factor for predicting prognosis. As the routine imaging method of thoracopathy,whether CT differentiate invasive from noninvasive thymic epithelial tumors before surgery has most important implications for treatment planning and prognosis.This study is to analyze retrospectively surgical records and pathologic examination records in order to explore the diagnosis value of spiral CT to identify the invasion of thymic epithelial tumors.Materials and Metbods:Seventy-seven patients with thymic epithelial tumors confirmed by surgery and pathology were retrospectively analyzed.All of them underwent computed tomography before surgery.Their CT findings including mass margins and invasion of pleural,pericardium,vessels and lung were compared with surgical records and pathologic examination.Results:Encapsulated tumors were more likely to have smooth margins than tumors with no encapsulation(P＜0.01).To the encapulated tumors,there were no statistically difference between tumors with encapsulation invasion and no encapsulation invasion(P＞0.05).The sensitivity,specificity,and accuracy of CT to diagnosis encapsulated tumors with smooth margins in CT images were 69.2%,84.0%and 74.0%.The sensitivity,specificity,and accuracy of CT in identifying pleural invasion, pericardium invasion,vessels invasion,and lung invasion were 76.6%,78.7%,77.9 %,52.6%,84.5%,76.6%,100%,82.1%,84.4%,and 57.1%,96.8%,89.6% respectively.Conclusion:Invasion of pleural,pericardium,vessels,and lung diagnosed by CT are credible;The possibility of pericardium and lung invasion can't be excluded while no obvious invasive CT findings,because of low sensitivity of CT in identifying invasion of pericardium and lung.Although encapsulated tumors were more likely to have smooth margins than tumors with no encapsulation,it's difficult to identify invasion or not for tumors with only encapsulation invasion by CT.SectionⅡCorrelations of the WHO Histological Classification of Thymic Epithelial Tumors to Their CT FindingsObjective:Thymic epithelial tumors that have been traditionally classified into thymoma and thymic carcinoma are the most common tumors of the anterior mediastinum.They show variable histologic features and heterogeneous oncologic behavior.The most recent version of the WHO classification of thymic epithelial tumors(2004) divided them based on their relative propotion of epithelial cells to lymphocytes and on the shape of the epithelial ceils into type A,type AB,type B1, type B2,type B3 and thymic carcinoma(including neuroendocrine epithelial tumors of the thymus),which has most important implications for treatment planning and prognosis because they not only reflect their clinical feature,but also their oncological behavior.The objective of this study is to explore the correlations of the new WHO histological classification of thymic epithelial tumors to their CT findings.Materials and Methods:Sixty-three patients with thymic epithelial tumors confirmed by surgery and pathology were retrospectively reviewed.All of them underwent CT scan before surgery.All histopathologic specimens were reviewed and divided according to the latest WHO classification(2004) by an experienced pathologist.The CT findings were compared with the simplifid subgroups of WHO histologic classification(low-risk thymomas,high-risk thymomas,thymic carcinomas)eventually.Results:The study found 35 low-risk thymomas,16 high-risk thymomas,12 thymic carcinomas.On CT imaging,thymic carcinomas were more likely to have irregular contours,rough margin or no clear boundary,mediastinal fat invasion,lymph node enlargement,pleural invasion,other tissue invasion,extrathymic metastasis;smooth margin,lobulated and round/oval shape,clear mediastinal fat plane are more commonly seen in low-risk thymomas and high-risk thymomas(P＜0.05).Conclusion:The presence of irregular contours,rough margin or no clear boundary, mediastinal fat invasion,lymph node enlargement,pleural invasion,other tissue invasion,extrathymic metastasis are suggestive of thymic thymic carcinomas;smooth margin,lobulated and round/oval shape,clear mediastinal fat plane are suggestive of low-risk thymomas or high-risk thymomas.It's difficult for CT to identify low-risk thymomas and high-risk thymomas.Novel ideas in the present study:①There were too few research relevant to the diagnosis value of spiral CT to identify the invasion of thymic epithelial tumors at home and abroad,though CT is the routine imaging method of thoracopathy.②To explore the diagnostic criteria of CT to identify invasion of encapsulation or surrounding tissue for thymic epithelial tumors.③To explore the correlations of the new WHO histological classification of thymic epithelial tumors to their CT findings.