Xp11.2易位/TFE3基因融合相关性肾癌的MRI表现

MRI imaging findings of renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusions

目的探讨Xp11.2易位/TFE3基因融合相关性肾癌(简称Xp11.2易位性肾癌)的MRI表现特征。方法回顾性分析中国人民解放军总医院2008年12月至2015年8月经病理证实的14例Xp11.2易位性肾癌患者资料。14例行肾脏MRI平扫及多期多时相扫描。观察分析Xp11.2易位性肾癌瘤体的部位、大小、形态、信号特征及强化方式。结果 14例14个病灶均位于髓质,实性13个,囊实性1个。病灶大小平均(4.5±2.1)cm;圆形/类圆形病灶9个,不规则形/分叶状病灶5个。T2WI像13个病灶信号混杂(含囊实性病灶),1个病灶信号均匀,瘤体内均见不同范围短T2信号,主要表现为两种类型:15个病灶以短T2信号为背景,内见结节状或条状稍长T2信号;29个病灶以等和稍长T2信号为背景,内见斑片状短T2信号随机分布。T1WI像7个病灶表现为等和稍长T1信号,7个病灶表现为等和短T1信号。动态增强扫描表现为瘤体内等或稍长T2信号区域皮质期中度强化,髓质期持续强化,延迟期廓清。结论 Xp11.2易位性肾癌MRI表现有一定的特征,当MRI平扫发现位于髓质内信号混杂伴有不同范围短T2信号,皮质期中度强化,髓质期持续强化,延迟期廓清时,结合临床可作出诊断。

Objective To investigate the characteristics of MRI in renal cell carcinoma associated with Xp11.2translocation/TFE3 gene fusions（abbreviated as Xp11.2 translocation renal cell carcinoma）. Methods The clinical data of 14 patients with Xp11.2 translocation renal cell carcinoma who confirmed by pathology in General Hospital of PLA from December 2008 to August 2015 were retrospectively analyzed. Renal MRI plain and multiphase contrast-enhanced scan were performed in 14 cases. The tumor＇s location, size, shape, signal features and the enhancement mode were investigated. Results All the tumors of 14 cases were located in the kidney medulla, with solid lesions in 13 cases and cystic lesion in 1 case. The average tumor size was（4.5±2.1） cm, including circular or oval lesions in 9 cases and irregularly shaped/lobulated lesions in 5 cases. Thirteen cases who undergoing T2 WI showed mixed signal（include cystic lesion）, and 1 lesion was unifrom. Fourteen cases accepting MRI exhibited imaging features with signals in range of short T2 signal, which were two main types： 1 5 lesions had short T2 signal as the background, in which we could see nodular or strip slightly long T2 signal. 2 9 lesions had equal and slightly longer T2 signal as the background, in which we could see patchy short T2 signal random distribution. Seven cases of T1 WI showed equal and slightly longer T1 signal,with other 7 cases showed equal and slightly short T1 signal. Dynamic enhanced scan showed moderate enhancement in equal or slightly longer T2 signal region in cortical phase, continued enhancement in medullary phase, and clearance in lag phase. Conclusion MRI performance of Xp11.2 translocation renal cell carcinoma have certain characteristics,such as mixed signals with different range of short T2 signal in medulla, moderate enhancement in cortical phase, continued enhancement in medullary phase, and clearance in lag phase. All the above features combined with clinical practice can contribute to the diagnosis.