肾上皮样血管平滑肌脂肪瘤的诊治

Epithelioid angiomyolipoma of the kidney

背景与目的：肾上皮样血管平滑肌脂肪瘤自2004年起被WHO单独分类在肾脏肿瘤中，但其真正的生物学行为仍不清楚。本研究探讨。肾上皮样血管平滑肌脂肪瘤的临床病理特征、诊断治疗及预后。方法：选择本院诊治的肾上皮样血管平滑肌脂肪瘤患者7例。男性3例，女性4例。中位年龄28（23-55）岁。有首发症状4例，体检发现3例。4例肿物局限于肾内，1例侵犯肾盂并侵犯肾静脉形成静脉瘤栓，1例同时发现腹膜后淋巴结转移，1例侵犯肾盂并同期发现肝多发转移和肺多发转移。术前诊断肾癌5例，诊断少脂肪血管平滑肌脂肪瘤2例。行根治性肾切除术5例，行肾部分切除术2例。结果：肿瘤假包膜均不明显，大体标本测量最大径2．5-14cm，中位最大径5cm。肿物切面质硬，多结节状，灰白至灰黄红色，有向肾周脂肪浸润性生长倾向，2例浸润腰大肌，2例浸润肾盂，1例形成肾静脉瘤栓，1例肾周淋巴结转移。7例镜下均见到特征增生的上皮样细胞；病理免疫组化染色后均表现黑色素细胞标志物HMB45、Melan-A强阳性，平滑肌细胞标志物SMA弱阳性，上皮细胞标志物cK阴性。病理诊断为上皮样血管平滑肌脂肪瘤。术后患者随访3-36个月，中位随访12个月，7例患者目前均存活。4例复诊未发现复发及转移征象。2例术后出现远处转移并行手术切除。1例术前发现肝、肺多发转移患者接受舒尼替尼靶向治疗3个月后，疗效评价部分缓解（PR），继续治疗3个月后肿瘤进展，疗效评价为疾病进展（PD）。结论：肾上皮样血管平滑肌脂肪瘤临床和影像学表现不典型，需要和肾癌及少脂肪血管平滑肌脂肪瘤鉴别。病理免疫组化黑色素细胞标志强阳性为特征表现。手术为主要治疗方法，术后有复发和转移可能。手术和靶向治疗可能成为转移灶的有效治疗手段。

Background and purpose： The epithelioid angiomyolipoma has been recognized in the 2004 WHO classification of renal tumors, but there is still limited understanding of the true biologic nature of this tumor. This study was to investigate the clinicopathologic features, diagnosis, and treatment of epithelioid angiomyolipoma of the kidney. Methods： Seven cases of epithelioid angiomyolipoma of the kidney were analyzed retrospectively. There were 3 males and 4 females with median age of 28 years （ranging from 23-55 years）. Four patients had chief complain and the other 3 cases were found renal masses in routine physical examination. Four tumors localized in the kidney; I tumor invaded pelvis and renal vein; 1 tumor accompanied with retroperitoneal lymph node metastases; 1 tumor accompanied with liver and lung metastases. Five cases were diagnosed as renal cell carcinoma and the other 2 cases were diagnosed as minimal fat renal angiomyolipoma. Five cases were received radical nephrectomy and 2 cases were received partial nephrectomy. Results： Tumors were lacking pseudocapsule with renal tissue. The median mass diameter was 5cm （ranging from 2.5-14 cm）. Tumors were hard, multinodular, grey to grey yellow or grey red, 2 tumors invaded psoas major; 2 tumors invaded pelvis; 1 tumor invaded renal vein; 1 tumor had local lymph nodes metastases. Tumors were composed of typical epithelioid cells, HMB45 and Melan-A positive, SMA weak positive, and CK negative by immunohistochemcial staining. Pathological diagnosis was epithelioid angiomyolipoma. All cases were followed up for 3 to 36 months. Median follow up was 12 months. All 7 cases were surviving, 4 cases did not recurrence or metastases; 2 cases were suffered metastases and were received surgery; 1 case with liver and lung metastases was receivedsunitinib treatment 6 months. Conclusion： Renal epithelioid angiomyolipoma was atypical in clinical and imaging findings, need differential with renal cell carcinoma and minimal fat renal angiomyolipoma. HMB45 was positive in immunohistochemcial staining. Operation was major method but recurrence or metastases were possible. Surgery and target therapy may be effective treatment for metastases.