Comparative study of CT appearances in clear cell renal cell cracinoma, renal cell carcinoma associated with Xp11.2 translocation/TFE gene fusion, collecting duct carcinoma and chromophobe renal cell carcinoma

Abstract

Objective To investigate the differential diagnostic features of subtpes of renal cell carcinoma (RCC) using CT scan.Methods The CT appearances of 53 RCCs,including 28 clear cell RCCs (CCRCC),6 Xp11.2 /TFE RCCs (Xp11.2 /TFE RCC),7 collecting ducts RCCs (CDC),12 chromophobe RCCs (CRCC),were retrospectively analyzed and compared with finding of pathology.Dynamic contrast-enhanced CT (DCE-CT) was conducted in each case after intravenous administration of contrast agent,and the data was analyzed by AVONA and LSD text.Results On unenhanced and enhanced CT,most CCRCCs and CDCs showed heterogeneous density (23/28,6/7),with necrosis (21/28,6/7),and most Xp11.2/TFE RCCs,CRCCs showed homogeneous density(5/6,8/12).Most CCRCCs,Xp11.2/TFE RCCs and CRCCs had clearly boundaries with well demonstrated at enhanced CT delayed phase (25/28,6/6,10/12),CDCs had unclearly boundaries (6/7),and most CCRCCs had lymph node or other metastasis (19/28).A phenomenon of quick staining and quick fainting was observed in CCRCCs.Xp11.2/TFE RCCs,CDCs,CRCCs showed delayed enhancement.On unenhanced CT,the Xp11.2/TFE RCC attenuation was greater than CCRCC,CDC,CRCC and normal renal cortex (53.7±4.1 vs 45.8±3.6 vs 41.4±2.4 vs 47.7±3.6 vs 41.5±5.1,F=5.458,P＜0.01,respectively).The enhancement degree was highest for CCRCCs,lowest for CDCs,and intermediate for Xp1 1.2/TFE RCCs and CRCCs.The enhancement degree of Xp1 1.2/TFE RCC was higher than that of the CDC and CRCC (P＜ 0.01).The enhancement degree of Xp11.2/TFE RCC and CRCC were higher than that of the normal renal medulla at cortical and medullary phases (P＜0.01),but lower than that of the renal medulla on delayed phase (P＜0.01).The enhancement degree of CDC were lower than that of the normal renal cortex and medulla on cortical,medullary and delayed phases (P＜0.05).Conclusions CT could distinctly show imaging features of CCRCC,Xp1 1.2/TFE RCC,CDC and CRCC,which were related to their pathological characteristics,and these features were helpful in predicting a specific subtype of RCC. Key words: Renal cell carcinoma; Differential diagnosis; Subtpe; Computed tomography