肾上皮样血管平滑肌脂肪瘤的CT与MR特征

CT and MR Appearances of Renal Epithelioid Angiomyolipoma

目的探讨肾上皮样血管平滑肌脂肪瘤(EAML)的CT与MR特征,提高对该病的诊断准确性。方法回顾性分析18例经手术病理证实为肾EAML的CT与MRI资料。结果肾EAML瘤体通常较大,最大径平均(8.5±5.0)cm,15例>4 cm,8例>8 cm;肿瘤多呈类圆形,边缘光整,无明显分叶,瘤体突出于肾轮廓外,与肾实质分界清晰;CT平扫呈相对稍高密度、T2WI呈相对低信号;常乏脂肪,瘤内可出现粗大血管影,出血坏死多见而钙化少见;强化方式有"快进快出"及"快进慢出"两种;4例伴发肾内经典型血管平滑肌脂肪瘤,1例侵犯肾静脉,1例侵犯肾静脉及下腔静脉并出现肝转移。结论肾EAML平扫呈相对稍高密度、T2WI呈相对低信号、乏脂肪及瘤内显现畸形血管影为其相对特征性表现,有助于术前正确诊断。

Objective To analyze the CT and MRI characteristics of renal epithelioid angiomyolipoma（EAML） and to improve the diagnosis. Methods The CT and MRI appearances of 18 patients with pathologically confirmed EAMLs were retrospectively analyzed. Results Renal EAML showed a big size with an average diameter of （8.5 ± 5.0） cm , 15 cases were bigger than 4 cm , 8 cases were bigger than 8 cm in diameter. Masses were well defined and had regular round shape without obvious lobular sign. They were bulging from kidney and showed clear boundary from renal parenchyma. High atten- uation on unenhanced CT images and hypointense on T2WI than kidney were frequently seen in EAML. No visible fat were found in most cases; Malformation vessels were identified in some cases and EAMLs were prone to hemorrhage and necro- sis, but calcification was rare. Enhancement patterns were quick wash-in and quick wash-out or quick wash-in and slow wash-out. 1 case was accompanied with conventional angiomyolipoma （AML） ;1 case presented with invasion into renal vein;1 case presented with invasion into renal vein and inferior vena cava with postoperative hepatic metastasis. Conclu- sion Some features, including high density on unenhanced CT images, hypointense on T2 WI, absence of fat and identifica- tion of malformation vessels were the most specific image findings of renal EAML and they were helpful for preoperative di- agnosis.