肾上皮样血管平滑肌脂肪瘤CT及MRI表现

目的探讨肾上皮样血管平滑肌脂肪瘤(EAML)的CT、MRI表现。方法回顾性分析经病理证实的13例共17个肾EAML病灶的CT、MRI特征(9例仅行CT检查,2例仅行MR检查,2例同时行CT及MR检查),分析内容包括病灶数目、部位、大小、形态、边缘、密度及信号、强化模式等情况。结果单发病灶10例,多发病灶3例;其中11例病灶突出肾轮廓外,位于髓质内者1例,位于皮质与髓质多发者1例;病灶直径8～154mm,平均(63.0±47.0)mm,均呈不规则形或类圆形;14个病灶边界清楚(显示楔征6个、皮质掀起征5个),3个边界不清;7例病灶富脂肪,6例乏脂肪。CT平扫病灶实质密度均稍高于肾皮质;增强扫描示皮质期病灶实质明显强化11例,髓质期强化减退9例,髓质期持续强化2例;5例显示黑星征。MRI平扫实质部分T1WI呈等信号,T2WI脂肪抑制呈稍低信号;增强扫描皮质期明显强化,髓质期持续强化,1例显示黑星征。结论肾EAML的CT、MRI表现具有一定特征性,对术前准确诊断具有重要价值。

CT and MRI manifestations of renal epithelioid angiomyolipoma

Objective To explore the CT and MRI findings of renal epithelioid angiomyolipoma (EAML). Methods A retrospective analysis was performed to assess CT and MRI manifestations of 17 lesions in 13 patients with pathologically confirmed EAML (9 patients underwent CT, 2 underwent MR, 2 received both CT and MR). Evaluative indexes contained the lesions' number, site, size, shape, margin, density and signal and the enhancement pattern. Results Single lesion was demonstrated in 10 patients, and multiple lesions in 3 patients. Lesions destroyed renal outline in 11 patients, located in the medulla in 1 patient, and involved both cortex and medulla in 1 patient. The diameter ranged from 8 to 154 mm (average mm). All lesions were irregular or round, with clear boundary in 14 lesions (wedge sign in 6 lesions or turn up cortex sign demonstrated in 5 lesions) and obscure boundary in 3 lesions. Rich fat lesions were found in 7 patients, and lack fat lesions in 6 patients. The substantial parts of all lesions showed slightly higher density than that of normal renal cortex on plain CT images, with intense enhancement in cortical phase in all 11 patients, declining enhancement in medullary phase in 9 patients and continuous enhancement in medullary phase in 2 patients, with black star sign demonstrated in 5 patients. The substantial parts of lesions showed isointense on T1WI and slightly hypointense on T2WI, with intense enhancement in cortical phase and continuous enhancement in medullary phase, black star sign was demonstrated in only 1 patient. Conclusion CT and MRI findings of renal EAML are relatively specific, having high clinical value for preoperative diagnosis.