Differentiation Of Renal Angiomyolipoma(AML)with Minimal Fat From Renal Cell Carcinoma(RCC)using 3 Phase Contrast-enhanced Computed Tomography(CT)scan

Objectives.The purpose of this study was to retrospectively assess whether there are computed tomography(CT)imaging features that can be used to differentiate fat poor angiomyolipomas(AMLs)from renal cell carcinomas(RCCs)using a 3 phase CT scan examination.Materials and Methods.Institutional review board approval and a waiver of informed consent were obtained for this study from ZHONGDA hospital.CT images from 179 pathologically proved renal masses(163RCCs and 16 minimal fat AMLs from 110 men and 69 women)at our academic institution were evaluated.Computerized tomography and enhancement characteristics were assessed.Two radiologists who were blinded to the pathologic results independently assessed the imaging findings and compared the values of each parameters between fat poor angiomyolipoma and renal cell carcinoma as a group.Results were analyzed by using the independent t-test,chisquare test,and multivariate logistic regression analysis for all renal masses when applicable.A P value of less than.05 was considered to indicate a statistically significant difference.Statistical analysis used.PASW software version 20.0(SPSS/IBM,Inc.,Chicago,IL).Results.The sample in our study consisted of 179 pathologically proved renal tumors,including 110 men(age range,24–83 years;mean age,58 years)and 69 women(age range,28–82 years;mean age,60 years).These tumors included 16 lipid-poor angiomyolipomas and 163 renal cell carcinomas.Homogeneous enhancement in the cortico-medullary phase(CMP)was observed in 75% of fat poor AML vs 23.9% of RCC p < 0.001;Homogeneous enhancement in the nephrogenic phase(NP)was observed in 75% of fat poor AML vs 31.9% of RCC p = 0.002;hyperenhancement was observed in 68.8% of fat poor AML vs 42.3% RCC p = 0.045;round margin was observed in81.2% of fat poor AML vs 55.8% of RCC p = 0.049 and female patients were observed in 68.8%of fat poor AML vs 35.6% of RCC p= 0.009.Conclusion.The diagnostic accuracy of CT for differentiating minimal fat poor AML from RCC is poor.However,Specific CT features can potentially be used to differentiate lipid-poor renal angiomyolipoma from renal cell carcinoma.