肾血管平滑肌脂肪瘤的临床病理学分析

Clinicopathologic analysis of renal angiomyolipoma

目的探讨肾血管平滑肌脂肪瘤(RAML)的临床病理、诊断和鉴别诊断要点。方法回顾性分析1998-2004年62例RAML患者的临床资料,分析组织病理学及免疫组化特点。患者中男20例,女42例,年龄24～73岁,平均46岁。有临床症状42例,合并结节性硬化症6例。结果肿瘤与周围组织界限清楚,光镜下肿瘤组织由畸形血管、脂肪组织和分化程度不等的平滑肌按不同比例混合构成,未见血管浸润,其中混合型38例(61．3%),肌瘤样型14例(22．6%),脂肪瘤样型10例(16．1%)。免疫组化62例HMB45、Melan-A/MART-1和SMA均为阳性,Ki-67阴性57例、＜5%5例,p53均阴性。随访1～7年,无复发转移病例。结论RAML以混合型为主,不浸润血管可能为该瘤的组织学特征之一,HMB45、Melan-A/MART-1和SMA表达是其免疫组化特点,Ki-67和p53低表达或阴性表达间接支持该瘤为良性肿瘤。

Objective To investigate the clinicopathologic characteristics,diagnosis and differential diagnosis,and the neoplastic nature of renal angiomyolipoma （ RAML）. Methods A retrospective study was done by reviewing the clinical information of 62 cases （20 men and 42 women;age range ,24 -73 years; mean age,46 years） of RAML. HE and immunohistochemical staining were performed on paraffin-embedded tissues with a panel of antibodies including HMB45 ,Melan-A/MART-1, smooth muscle actin （SMA） , Ki-67 and P53. Results Of the 62 cases, 42 presented with clinical symptoms, and 6 had concomitantly tuberous sclerosis. Most of the tumors were sharply demarcated from the surrounding kidney parenchyma. Histologically ,the tumors were composed of 3 components in different proportions： abnormal blood vessels, variously differentiated smooth muscle cells and adipose tissues. No vascular infiltration was observed. In these cases, mixed type was in 38 cases （61.3%） ,myomatous type in 14 （22.6% ） ,lipomatous type in 10 （16.1% ） according to classification criteria. Immunohistochemically,the tumor cells were positive for HMB45,Melan- A/MART-1 and SMA, The expression of Ki-67 protein was negative in most cases, and that of P53 was negative in all. Follow-up lasted 1 -7 years,and all the cases were alive with no evidence of recurrence and metastasis. Conclusions RAML is mostly of mixed type. No vascular infiltration is one of its histologic features. Immunohistochemically, RAML is characterized by positive expression of HMB45, Melan-A/MART-1 and SMA. The low or negative expression of Ki-67 and P53 protein indirectly support that RAML is a benign tumor.