肾细胞癌假包膜的MRI表现及在肿瘤剜除术中的意义

MRI appearance of pseudocapsule of renal cell carcinoma and its significance in tumor enucleation

目的：探讨磁共振各序列显示肾细胞癌（RCC）假包膜的差异及假包膜在肿瘤剜除手术中的意义。方法：收集我院2012年10月-2014年1月46例肾脏非囊性肿瘤患者临床资料,男27例,女19例,年龄25-76岁,平均47岁。肿瘤位于左侧22例,右侧24例。所有患者术前均行MRI检查,观察假包膜的MRI各序列表现,并与病理对照,评价磁共振成像各序列显示RCC假包膜的敏感性和特异性,并分析RCC组织学类型、分级及临床分期对假包膜完整性的影响,数据分析采用卡方检验。结果：T1WI、T2WI、T2抑脂、T1增强显示RCC假包膜的敏感性分别为43.8%、87.5%、50.0%、43.8%,差异具有统计学意义（χ2=8.635,P=0.035）;特异性分别为53.8%、80.8%、38.5%、46.2%,差异有统计学意义（χ2=10.676,P=0.014）。病理显示肾透明细胞癌的假包膜完整率40.6%,乳头状腺癌假包膜完整率30.0%,两者比较差异无统计学意义（χ2=0.53,P=0.817）;高分化RCC包膜完整率达56.5%,中、低分化RCC假包膜完整率仅15.8%,差异有统计学意义（χ2=7.32,P=0.007）;Ⅰ期、Ⅱ期、Ⅲ＋Ⅳ期RCC的包膜完整率分别为61.1%、30.8%、9.0%,差异有统计学意义（χ2=9.013,P=0.011）。结论：RCC假包膜在MRI的常规T2加权像上显示最为敏感,若术前MRI显示肿瘤周围存在完整假包膜,预示着肿瘤分化较好,临床分期较低,已经发生癌细胞局部扩散及远处转移的可能性较小,提示肿瘤剜除术的可行性。

Objective：To investigate the role of different MRI sequences in detection of the pseudocapsule of renal cell carcinoma,and its significance in selecting patients for tumor enucleation.Method：From October 2012 to January 2014,data were collected prospectively from 46 consecutive patients who had non-cystic renal neoplasms.There were 27 men and 19 women,aged from 25 to 76（mean,47）years old.They presented with a total of 46 lesions,22in left kidney and 24 in right kidney.All patients were preoperatively evaluated by MRI.The appearances of pseudocapsule on MRI sequences were analyzed and correlated with pathologic findings to assess the sensitivity and specificity of MRI sequences in determining the pseudocapsule.Then tumor histological types,grading and the effect of clinical staging on the integrity of pseudocapsule were analyzed.The data were tested by chi-square.Result：The sensitivity of T1-weighted images,T2-weighted images,fat-suppressed T2-weighted images and postcontrast T1-weighted images in showing the pseudocapsule were 43.8%,87.5%,50.0%,43.8%respectively,and the difference was statistically significant（χ2=8.635,P =0.035）.The specificity were 53.8%,80.8%,38.5%,46.2% respectively,and the difference was also statistically significant（χ2=10.676,P =0.014）.The intact rate of clear cell carcinoma and papillary RCC were 40.6%,30.0% respectively,and the difference between two groups had no statistical significance（χ2=0.53,P=0.817）.The intact rate of highly differentiated RCC was 56.5%,while only 15.8%in mid and low differentiated RCC,which were statistically significant（χ2=7.32,P=0.007）.The integrity rate of pseudocapsule with stagingⅠ,Ⅱ,Ⅲ＋Ⅳ RCC were 61.1%,30.8%and 9.0%,and the difference was statistically significant（χ2=9.013,P=0.011）.Conclusion：A routine T2-weighted sequence is the most useful sequence for showing the pseudocapsule of RCC.The presence of an intact pseudocapsule implicates a low clinical staging and well differentiated neoplasm,which is less likely to infiltrate into surrounding tissues or metastasize.Thus,the tumor can be removed by enucleation.