肾上腺皮质嗜酸性腺瘤病理分析:附7例报道

Pathologic analysis of adrenocortical oncocytic adenomas with report of 7 cases

目的:病理分析肾上腺皮质嗜酸性腺瘤(AOA)的诊断标准、Weiss评估系统的意义以及AOA的鉴别诊断。方法:根据7例AOA光镜﹑免疫组化、2例电镜观察和随访结果并结合文献,提出AOA良恶性评估标准。结果:光镜下观察到肿瘤主要由嗜酸性上皮细胞组成,呈弥漫排列,仅局灶区域可见腺泡状﹑管状或梁状结构。免疫组化波形蛋白(vimentin)﹑神经元特异性烯醇化酶(NSE)﹑S-100蛋白阳性率高,嗜铬素A(CgA)﹑突触素(Syn)部分弱阳性,其余标记广谱细胞角蛋白(AE1/3)﹑黑素细胞相关蛋白A(melan-A)﹑抑制素-α(inhibin-α)﹑CD10﹑P53以阴性为主,MIB-1阳性率均<5%。电镜下嗜酸性腺瘤细胞胞质内含丰富的线粒体。结论:AOA良恶性评估标准对判断AOA良恶性具简明实用特点。根据AOA良恶性评估标准,嗜酸性腺瘤显示以下3条主要标准中任何一条(核分裂象>5个/50HPF、有不典型核分裂象或静脉侵犯),即为恶性;如肿瘤显示1条或几条其他次要标准(体积>10cm3、质量>200g和有坏死、包膜或血窦侵犯),即为恶性潜能不明(交界性);如缺乏所有主要及次要标准即诊断为良性。本组7例肿瘤均符合AOA的诊断标准,随访至今患者均无复发或转移。组织学上,AOA应与肾上腺嗜酸性嗜铬细胞瘤、肾上腺皮质癌伴灶性嗜酸性变、肾细胞癌伴嗜酸细胞特征或嗜酸细胞变异的嫌色细胞癌累及肾上腺及肝细胞肝癌等鉴别。

Objective To analyze the diagnosis criteria, the significance of Weiss system and the differential diagnosis of adrenocortical oncocytic adenomas. Methods The morphologic, immunohistochemieal and electron microscopic examinations were carried out in 7 cases of adrenocortical oncocytic adenomas, and the associated literatures were reviewed. Results All the tumors of the 7 cases were predominantly composed of the oncocytic epithelial cells, which arranged mainly in a diffuse architectural pattern and some in alveolar, tubular and trabecular patterns. The immunohistochemical examination showed that the expressions of vimentin and neuron-specific enolase were strongly positive, and the S-100 protein expression was slightly positive in almost all the cases. The expressions of chromogranin-A and synaptophysin were slightly positive in partial cases. And the expressions of AE1/3, melan-α,inhibin-α, C D10 and P53 were negative in nearly all the cases. The positive rate of MIB-1 was less than 5%. The electron microscopic studies showed that the cytoplasm of the oncocytes was packed with abundant mitochondria. Conclusions The criteria modified from the traditional Weiss system are proposed as following, if an oncocytic tumor exhibits a mitotic rate of more than 5 mitoses per 50 high power fields or any atypical mitoses or venous invasion （defined as major criteria）, it is considered as malignant; if the tumor exhibits 1 or several other worrisome features （ the size 〉10 cm and/or the weight 〉200 g, with necrosis, capsular invasion, or sinusoidal invasion）（defined as minor criteria）, the tumor is considered as uncertain malignant potential （borderline）; if none of the above features is present, the tumor is benign. Depending on the modified Weiss system, the diagnosis of all these 7 cases with AOA was unambiguous and none of these patients recurred or had any metastasis. The differential diagnosis of AOA includes the following entities： oncocytic pheochromocytoma, adrenocortical carcinoma exclusively composed of compact cells, adrenocortical carcinoma with focal oncocytic changes, renal carcinoma with oncocytic features, and eosinophilic variant of chromophobe renal carcinoma involving the adrenal and hepatocellular carcinoma.