不典型肾血管平滑肌脂肪瘤的多层CT诊断及误诊分析

摘要

目的：：探讨不典型肾血管平滑肌脂肪瘤( ARAML)的多层CT( MDCT)表现及误诊原因。方法：分析经手术病理证实的19例ARAML误诊病例的MDCT资料,观察病灶边界、密度、强化特征及其多发、伴发病灶等,分析误诊原因。结果：18例边界清楚锐利,1例合并出血、周围见渗出；所有病例肾皮质均见不同程度缺损。乏脂肪或无脂肪16例：密度均匀10例,其中延时强化7例、强化呈“快进快出”3例；密度不均匀6例,其中瘤内出现“黑斑征”5例、瘤内合并出血1例。瘤内见粗大强化血管影1例。外生富脂肪型1例,无明显强化。多房囊性1例,囊壁及分隔明显强化。4例多发,其中1例为结节性硬化症并肺内、骨骼多发高密度结节改变；1例伴发肝血管平滑肌脂肪瘤。术前误诊为肾癌17例(包括多房囊性肾癌1例),腹膜后脂肪肉瘤1例,肾转移瘤1例。结论：ARAML的MDCT表现为边界清楚锐利,增强扫描延时强化常见,伴或不伴一些特征性征象(“黑斑征”、粗大血管影、皮质缺损征等)。但少数表现极不典型者(如多房囊性、明显外生富脂性)易造成误诊。临床工作中需综合分析,仔细观察病灶及周围征象,尤其增强扫描及多平面重建有助于提高诊断正确性。%Objective:To explore atypical renal angiomyolipoma ( ARAML) multidetector CT ( MDCT) imaging features and reason of misdiagnosis. Methods:The MDCT data of 19 cases of ARAML confirmed by operation and pa-thology,including the lesion boundary, density, enhanced features and multiple or concomitant lesions. The imaging findings of the misdiagnosed lesions were analyzed. Results: In 18 cases the boundary was clear and sharp. Hemor-rhage in 1 cases,the peripheral exudation;all cases of renal cortex were seen in varying degrees of defects. The lack of fat or fat free in 16 cases:Homogeneous density in 10 cases,of which 7 cases were delayed enhancement,strengthen the "fast in fast out" in 3 cases. Uneven density in 6 cases,the tumor appeared in"black spots" sign in 5 cases,com-bined with intratumoral hemorrhage in 1 case. Intratumoral thick vessels enhancement in 1 case. Exogenous fat lesions showed no enhancement in 1 case. 1 case of multilocular cystic lesions,cystic wall and septa obvious enhancement. 4 cases of multiple,including 1 case of tuberous sclerosis which kidney,lung and skeletal had multiple high density tu-bercle;1 case with concomitant hepatic angiomyolipoma. Before operation 17 cases were misdiagnosed as renal cell carcinoma ( including 1 case of multilocular cystic renal cell carcinoma) ,1 case of retroperitoneal liposarcoma,1 case of metastatic tumor of kidney. Conclusion:ARAML showed a clear boundary of sharp,enhanced scan common delayed enhancement,with or without some characteristic signs ("black spots" sign,Intratumoral thick vessels,cortical defect syndrome) . A few ARAML performances hardly typical ( such as multilocular cystic,obvious exogenous lipid rich) are easy to be misdiagnosed. The accuracy of correctly diagnosis preoperative can be improved with comprehensive analy-sis and observing the imaging signs carefully,especially with enhanced scan and multi-planar reconstruction.