非典型畸胎样/横纹肌样瘤5例临床病理学分析

Atypical teratoid/rhabdomyoid tumor:a clinicopathologic analysis of five cases

目的探讨非典型畸胎样/横纹肌样瘤(AT/RT)的临床病理特征、免疫表型分析、诊断及鉴别诊断及其生物学行为及预后。方法收集2015-12—2022-12北京大学国际医院诊断的AT/RT病例5例,观察其临床及影像学表现,分析其组织学、免疫组化、分子遗传学特点,收集随访结果,并复习相关文献。结果5例病例均可见多少不等的横纹肌样分化区域和小细胞胚胎成分,呈巢片状及条索样分布,核分裂象多见。还可见不同程度的上皮样分化、间充质分化以及梭形细胞间质分化,甚至呈腺样乳头样排列,部分病例可见血管内皮细胞增生、片状坏死。5例SMARCB1(INI1)均表达缺失,而SMARCA4(BRG1)均阳性表达;肿瘤不同程度地表达GFAP、EMA、Vimentin、CD34、S-100和CK,Ki-67增殖指数高,可高达80%。4例术后3个月内死亡,1例目前存活15个月。结论AT/RT是一种好发于幼儿的胚胎性恶性肿瘤,其侵袭性强,预后差,伴有横纹肌样分化及多少不等的原始神经外胚层、间充质和上皮细胞分化。大部分伴有SMARCB1(INI1)表达缺失,少部分伴有SMARCA4(BRG1)表达缺失,需与其他中枢神经系统肿瘤进行鉴别。

Objective To investigate the atypical teratoid/rhabdomyoid tumor(AT/RT)of the clinical pathological features,immune phenotype analysis,diagnosis and differential diagnosis and its biological behavior and prognosis.Methods Five AT/RT5 cases diagnosed in Peking University International Hospital from December 2015 to December 2019 were collected,their clinical and imaging manifestations were observed,their histological,immunohistochemical and molecular genetic characteristics were analyzed,follow-up result were collected,and relevant literature was reviewed.Results In all the 5 cases,different striated muscle-like differentiation regions and small-cell embryonic components were observed.Different degrees of epithelioid differentiation,mesenchymal differentiation and spindle cell interstitial differentiation were seen,and even adenoid papillary arrangement was noted.In some cases,vascular endothelial cell hyperplasia and lamellar necrosis were also observed.The expression of SMARCB1(INI1)was absent in all 5 cases,while the expression of SMARCA4(BRG1)was positive.GFAP,EMA,Vimentin,CD34,S100 and CK were expressed to different degrees in the tumor,and the Ki-67 proliferation index was high,up to 80%.Four patients died within 3 months after surgery,and one survived for 15 months.Conclusion AT/RT is a kind of embryonal malignant tumor that tends to occur in young children.It is highly invasive and has a poor prognosis,accompanied by rhabdomyoid differentiation and differentiation of primitive neuroectoderm,mesenchymal and epithelial cells.Most of them are accompanied by SMARCB1(INI1)expression loss,and a few are accompanied by SMARCA4(BRG1)expression loss,and differentiation from other central nervous system tumors is required.