肾脏不典型血管平滑肌脂肪瘤4例报道并文献复习

Atypical angiomyolipoma of the kidney:Report of four cases and review of literature

目的 :探讨肾脏不典型血管平滑肌脂肪瘤 (atypicalangiomyolipoma,AAML)的临床病理特征。 方法 :收集 4例曾误诊为肾肉瘤样癌或恶纤组的AAML行光镜、免疫组化观察 ,并对其中 1例和另 3例典型AML作电镜观察。结果 :AAML具有以下的病理特点 :①肉眼上切面呈棕褐色 ,可伴有坏死及出血 ;②光镜下表现为富细胞 ,主要由胞浆丰富嗜酸性的单核或多核多形性瘤巨细胞和梭形的肉瘤样细胞及胞浆透明成片状排列的上皮样细胞组成。缺乏成熟梭形平滑肌细胞 ,厚壁血管及脂肪细胞少或无 ;③巨核畸形核及核内胞浆包涵体较多见 ,但未见核分裂象 ;④免疫组化 :瘤细胞HMB45 (+)、CD6 8(+)、CK(- ) ,而SMA瘤巨细胞阴性 ;⑤电镜示瘤细胞胞浆内线粒体和糖原较丰富 ,并见直径约 10 0nm的密电子颗粒 ,未见明确的黑色素颗粒前体及成熟的黑色素颗粒。随访 6～ 36个月均健在。结论 :肾脏AAML可能仅在组织形态上呈肉瘤样特征 ,而实际仍属良性病变。其特征性的免疫组化表达及超微结构为其鉴别诊断提供了依据。

Purpose To study the clinicopathological characteristics of renal atypical angiomaolipoma(AML). Methods Four cases of atypical AML that had been previously diagnosed as sarcomatoid carcinoma or malignant fibrohistocytoma were investigated by histologic and immunohistochemical techniques and electron microscopy. Results Compared with AML,atypic AMLs features were as follows:①Macroscopically,it had a machogany brown cut surface with focal necrosis and hemorrhage. ②It was highly cellular and composed of various types of multinucleated or mononuclear giant cells with abundant eosinophilic cytoplasm and spindle sarcomatoid or epithelioid cells,lacking of mature smooth muscle cells,thick walled vessels and adipose tissue. ③Large and pleomorphic nuclei and pseudoinclusions were more common,but mitosis was rare. ④HMB45,CD68,SMA were positive for the tumors cells,but SMA negative in giant cells. ⑤Ultrasturcturally,rich glycogen,mitichondria and electron dense granules were observed in the cytoplasm, and melanosmes or premelanosomes were absent. All patients were alive within 6～36 months in the follow up. Conclusion Renal atypical AML may be a benign neoplasm despite of sarcomatoid appearance. Its immunophenotype is helpful for differantal diagnosis.