中文摘要：

目的探讨低回声为主型肾血管平滑肌脂肪瘤常规超声与超声造影（CEUS）特征。方法经手术病理证实的11例低回声为主型肾血管平滑肌脂肪瘤患者,均接受常规超声及CEUS,并分析其影像学特征。结果 11例均经手术病理证实为少脂肪或乏脂肪肾血管平滑肌脂肪瘤,其中9例为经典型肾血管平滑肌脂肪瘤,2例为潜在恶性的上皮样血管平滑肌脂肪瘤。常规超声示11例肿块均以低回声为主,肿块内部或周边可见散在点状及小片状高回声;彩色多普勒示2例为富血供肿块,2例为少血供肿块,7例为乏血供肿块。CEUS示3例为＂快进快出＂型（3/11,27.27%）,8例为＂快进慢出＂型（8/11,72.73%）;7例为边缘型增强（7/11,63.64%）,1例为中央型增强（1/11,9.09%）,3例为同步增强（3/11,27.27%）。结论低回声为主型肾血管平滑肌脂肪瘤为少见型肾肿瘤,常规超声结合CEUS有助于诊断和鉴别诊断。

英文摘要：

Objective To explore the features of hypoechoic renal angiomyolipoma（RAML） with conventional ultrasound and contrast-enhanced ultrasound（CEUS）.Methods Eleven patients confirmed sequentially with operation and pathology underwent conventional ultrasonography and CEUS,and the imaging characteristics were analyzed.Results Totally 11 patients were demonstrated as RAML with no or a minimal amount of fat tissue,including 9 classical RAML and 2 epithelioid RAML with potentially aggressive.All 11 patients showed hypoechoic primarily,with less hyperecho in periphery and interior of the tumors in conventional ultrasound,2 were hypervascular,2 were hypovascular and 7 were avascularity in color Doppler ultrasound.During CEUS,fast wash-in and fast wash-out（3/11,27.27%） was detected in 3 tumors,and fast wash-in and slowly wash-out in 8（8/11,72.73%）,with enhancement first happened on peripheral,then in the center area in 7（7/11,63.64%）,first happened in the center,then on peripheral area in 1 tumor（1/11,9.09%）,simultaneously on peripheral and center area in 3 tumors（3/11,27.27%）.Conclusion The hypoechoic RAML is a rare kind of renal tumor.Conventional ultrasound combining with CEUS are significant in diagnosis and differential diagnosis of this tumor.