Ultrasound Learning Center EFSUMB, Klinik Hirslanden, Zürich, Switzerland.
Institut für Pathologie, Universitätsspital, Zürich, Switzerland.
BMC Nephrol. 2018 May 30;19(1):123. doi: 10.1186/s12882-018-0919-0.
Epithelioid angiomyolipoma is defined as potentially malignant mesenchymal neoplasm, characterized by proliferating epithelioid cells, whereas classic angiomyolipoma, composed of fat, smooth muscle cells and dysmorphic vessels, is defined as a potentially benign. The usual or classic angiomyolipoma is often found incidentally on imaging studies, relatively easily identified due to the presence of fat, in contrast to the epithelioid angiomyolipoma that can pose diagnostic challenges.
We report a 51-year-old female patient in which an ultrasonography examination showed a solid mass close to the right renal pelvis with hypoechoic and hyperechoic areas. A differential diagnosis of atypical sinus lipomatosis, lipoma and a transitional cell carcinoma was postulated whereas in a subsequent computed tomography a classic angiomyolipoma was postulated. A re-examination by contrast enhanced ultrasound revealed a striking perfusion difference of the hypoechoic and hyperechoic areas. The hypoechoic area showed homogenous and prolonged enhancement whereas the hypoechoic area displayed a marked slower contrast material flooding and a relatively rapid wash out. The histological analysis from the biopsy of the hyperechoic area showed a classic angiomyolipoma, whereas the sample of the hypoechoic central portion revealed an epithelioid angiomyolipoma. A nephrectomy was performed because of the malignant potential of the epithelioid variant of the angiomyolipoma.
A solid kidney mass with two sharply defined parts, one-part compatible with a classical angiomyolipoma and the other being suspected of carcinoma, is rare, but also illustrative and instructive. The combination of different imaging modalities in the work up of a solid renal mass facilitated to discriminate benign from malignant areas.
上皮样血管平滑肌脂肪瘤被定义为具有潜在恶性的间叶性肿瘤，其特征是增殖的上皮样细胞，而由脂肪、平滑肌细胞和发育不良的血管组成的经典血管平滑肌脂肪瘤被定义为潜在良性肿瘤。通常或经典的血管平滑肌脂肪瘤在影像学研究中经常偶然发现，由于存在脂肪，相对容易识别，而上皮样血管平滑肌脂肪瘤则可能带来诊断挑战。
我们报告了一名 51 岁女性患者，超声检查显示右肾盂附近有一个实性肿块，存在低回声和高回声区域。推测存在非典型性窦脂肪瘤、脂肪瘤和移行细胞癌的鉴别诊断，而随后的计算机断层扫描提示为经典血管平滑肌脂肪瘤。对比增强超声的再次检查显示低回声和高回声区域的灌注差异明显。低回声区域表现为均匀和持续增强，而低回声区域显示出明显较慢的对比剂填充和相对较快的洗脱。高回声区域的活检组织学分析显示为经典血管平滑肌脂肪瘤，而低回声中央部分的样本显示为上皮样血管平滑肌脂肪瘤。由于上皮样血管平滑肌脂肪瘤的恶性潜能，进行了肾切除术。
具有两个截然分明部分的实性肾脏肿块，一部分与经典血管平滑肌脂肪瘤相容，另一部分疑似为癌，这种情况较为罕见，但也具有说明性和启发性。在实性肾脏肿块的评估中结合不同的成像方式有助于区分良性和恶性区域。
