肝脏上皮样血管平滑肌脂肪瘤的影像学表现

Imaging findings of hepatic epithelioid angiomyolipoma

目的:探讨肝脏上皮样血管平滑肌脂肪瘤(epithelioid angiomyolipoma,E-AML)的影像学表现,提高诊断准确率。方法:收集并回顾性分析经手术后病理证实的20例肝脏E-AML患者的资料。20例患者中,4例同时行CT平扫及双期增强扫描、MRI平扫及动态增强扫描,1例行CT平扫及双期增强扫描,14例行MRI平扫及动态增强扫描,1例行CT血管成像(CT angiography,CTA)检查。对病灶的部位、数目、大小(最大径)、形态,病灶平扫密度或信号特点,病灶内有无脂肪成分,病灶内有无血管影及周边血管情况,有无假包膜及其强化表现,病灶动态增强特征,以及周围肝实质背景等进行记录和分析。结果:肝E-AML单发17例、多发3例;共24枚病灶,其中,尾状叶4枚、右叶9枚、左叶11枚;病灶大小1.0~25.0 cm;24枚病灶均为椭圆形或圆形;7枚病灶均为低密度,22枚病灶T1WI呈低信号、T2WI呈高信号、扩散加权成像(diffusion weighted imaging,DWI)呈高信号及表观扩散系数(apparent diffusion coefficient,ADC)均降低;动态增强10枚表现为"快进快出"型,14枚表现为"快进慢出"型;7枚含有脂肪成分;23枚病灶内及周边可见点条状血管影;14枚见"强化逐渐减退"的假包膜;1例CTA显示肝动脉供血、肝静脉引流入下腔静脉。结论:单发富血供肿块、瘤体内和周围见点条状血管影及早显引流静脉、动脉期出现强化假包膜是肝E-AML具有一定特征性的影像学表现。

Objective:To explore the imaging features of hepatic epithelioid angiomyolipoma(E-AML)so as to improve the diagnostic accuracy of the disease.Methods:A total of 20 patients with pathologically proved hepatic E-AML were retrospectively analyzed.Among them,4 patients underwent both CT and MRI dynamic contrast-enhanced(DCE)scan.One patient underwent plain and contrast-enhanced CT scan,1 patient underwent CT angiography(CTA)examination,14 patients underwent MRI DCE scan.The number,location,size,shape,density or signal intensity(SI)of plain scan of lesions,presence of fatty component,vessels within and around lesions,presence of pseudocapsule and enhancement pattern,DCE pattern of lesions and background of hepatic parenchyma were recorded and analyzed.Results:All 24 lesions(one lesion in 17 patients,multiple lesions in other 3 patients)were opal or round in shape.Four lesions were located in the caudate lobe,9 in the right lobe,11 in the left lobe.The size was 1.0-25.0 cm.Hypodensity was shown in 7 lesions with CT scan.Twenty-two lesions had hypointensity on T1WI,hyperintensity on T2WI,hyperintensity on diffusion weighted imaging(DWI)and decreased apparent diffusion coefficient(ADC).All 24 lesions were manifested as obvious enhancement on the arterial phase.Ten lesions showed“fast in and fast out”enhancement pattern and 14 showed“fast in and slow out”enhancement pattern.Only 7 lesions were presented fatty component.Twenty-three lesions were found punctiform or filiform vessels.Fourteen lesions showed pseudocapsule on arterial phase with decreased enhancement on portal venous and equilibrium phases.One lesion showed the hepatic artery as supply artery and the early hepatic venous draining into the inferior vena cava on CTA scan.Conclusion:The single hypervascular mass with opacification of punctiform or filiform vessels within and around lesion,early venous drainage,pseudocapsule presence on arterial phase are some characteristic features of hepatic E-AML.