11例SMARCA4(BRG1)缺失性癌的临床病理分析

Clinicopathological Analysis of 11 Cases of SMARCA4(BRG1)-deficient Carcinoma

目的探讨SMARCA4(BRG1)缺失性癌患者的临床病理特征、免疫表型及诊治要点。方法回顾性分析11例SMARCA4(BRG1)缺失性癌患者的临床资料,总结其HE染色后的形态及免疫组织化学特征,并结合文献进行分析。结果11例患者中男性8例,女性3例;中位年龄60岁。8例行根治性手术切除,3例行传统化疗联合靶向及免疫治疗。镜下肿瘤细胞胞质丰富、红染,呈上皮样、横纹肌样或梭形,具明显的嗜酸性核仁,核分裂象易见(>5/10 HPF),肿瘤组织内见多灶状坏死,脉管内见大量癌栓,可伴间质黏液样变性。11例肿瘤细胞SMARCA4(BRG1)表达缺失,同时表达上皮源性CK和间叶源性Vim标记,SMARCB1(INI1)表达保留,p53突变型,肿瘤细胞呈高增殖活性(Ki-67>60%),突触素Syn呈中等强度阳性。3例为错配修复蛋白缺陷,分别表现为MLH1/PMS2、PMS2、MSH6表达缺失,其中1例经Sanger测序法检测证实为高度微卫星不稳定型。结论SMARCA4(BRG1)缺失性癌发病率低,易与其他肿瘤混淆,术前诊断困难,需依靠免疫组织化学明确诊断。

Objective To investigate the clinicopathological features,immunophenotype,diagnosis and treatment of SMARCA4(BRG1)-deficient carcinoma.Methods Clinical data of 11 patients with SMARCA4(BRG1)-deficient cancer were collected.The morphologic and immunohistochemical features of this tumour were summarized,and the relevant literature was reviewed.Results Among the 11 cases of SMARCA4(BRG1)-deficient carcinoma,eight were male and three were female,with median age of 60.Seven patients underwent radical resection,and four underwent traditional joint targeted chemotherapy and immunotherapy.Microscopically,the tumor cells were epithelioid,rhabdoid or spindle-shaped,with prominent eosinophilic nucleoli and frequent mitoses(>5/10 HPF).Multiple foci of necrosis were found in the tumor tissue,a large number of tumor emboli in the blood vessels and myxoid stromal degeneration.Among these cases,11 cases showed loss of SMARCA4(BRG1)expression,whereas the CK and Vim markers were expressed,SMARCB1(INI1)expression was retained,and p53 mutation was detected.The tumor cells showed high proliferation activity(Ki-67>60%),and synaptophsin was moderately positive.Three cases were mismatch repair deficient and respectively showed the loss of MLH1/PMS2,PMS2 and MSH6 expression.Conclusion The incidence of SMARCA4(BRG1)-dificient carcinoma is low.It can be easily confused with other tumors and is difficult to be diagnosed before operation,which requires confirmation by immunohistochemistry.