胸腺上皮源性肿瘤的WHO组织学分型和CT征象的相关性

Correlation of World Health Organization Classification of Thymic Epithelial Tumors to Their CT Features

背景与目的:胸腺上皮肿瘤的生物学和大体形态学的特征多样化,本文旨在探讨根据1999年WHO组织学分型的各亚型胸腺上皮源性肿瘤的CT征象。方法:对经病理检查证实的94例胸腺上皮源性肿瘤患者螺旋CT征象进行回顾性分析,其中包括A型7例,AB型24例,B1型16例,B2型13例,B3型16例,C型18例。结果:在本组94例患者病灶中,A、AB型的长短径明显小于C型(P<0.05);所有A型肿瘤均表现为轮廓光滑,A→C型出现率逐渐下降,A、AB、B1型更常呈轮廓光滑(P<0.05),B3、C型更常呈轮廓不规则(P<0.05);A型瘤内的坏死灶较其他亚型少见(P<0.001);B2、B3、C型肿瘤较A、AB、B1型的瘤灶内更常见多发钙化灶(P<0.05);瘤灶均匀强化更常见于A、AB、B1、B2型(P<0.001);B3、C型瘤灶浸润纵隔脂肪的发生率明显高于其他亚型(P<0.05)。结论:尽管各亚型肿瘤的CT征象存在一定的重叠,小肿瘤、轮廓光滑、类圆形、密度均匀(无钙化、坏死灶)、均匀强化高度提示A型肿瘤,大肿瘤、轮廓不规则、瘤内出现坏死灶、多发钙化、不均匀强化、浸润纵隔脂肪、浸润大血管等高度提示B3、C型肿瘤。

BACKGROUND ＆ OBJECTIVE： Thymic epithelial tumors have a broad spectrum of biologic and morphologic features. This study was to assess the CT features of various subtypes of thymic epithelial tumors on the basis of the 1999 World Health Organization （WHO） classification. METHODS： CT features of thymic epithelial tumors in 94 patients were retrospectively analyzed. All cases were confirmed histologically according to the 1999 WHO classification, including 7 cases of type A, 24 cases of type AB, 16 cases of type B1, 13 cases of type B2, 16 cases of type B3, and 18 cases of type C. RESULTS： In the 94 cases, the long- and short-axis diameters of type A and type AB tumors were significantly shorter than those of type C tumors （P〈0.05）. All type A tumors had smooth contours, type A, AB, and B1 tumors were likely to have smooth contours （P〈0.05）, while type B3 and C tumors were likely to have irregular contours （P〈0.05）. Type A tumors had less necrotic areas than any other types （P〈0.05）. Multiple calcifications were more frequently seen in type B2, B3, and C tumors than in type A, AB, and B1 tumors （P〈0.05）. Homogeneous enhancement was more frequently seen in type A, AB, B1, and B2 tumors than in type B3 and C tumors （P〈0.001）. Type B3 and C tumors significantly preferred to infiltrate into mediastinal fat than any other types （P〈0.05）. CONCLUSION： Though CT features of different subtypes of thymic epithelial tumors according to WHO classification are overlapped, short diameter, smooth contour, round shape, homogeneous density, and homogeneous enhancement are most suggestive for type A tumor; large diameter, irregular contour, necrosis and multiple calcifications in the lesion, heterogeneous enhancement, mediastinal fat infiltration, and great vessel infiltration are most suggestive for type B3 and C tumors.