黏液乳头型室管膜瘤WHO组织学分级重新评估及其HOTAIR表达的诊断价值

Reassessment of WHO histological grade of myxopapillary ependymoma and the diagnostic value of HOTAIR expression

目的重新评估黏液乳头型室管膜瘤(myxopapillary ependymoma,MPE)的WHO组织学分级及探索HOTAIR表达的诊断价值。方法收集2002~2021年南京大学医学院附属鼓楼医院诊治的19例MPE,分析其临床病理学特征及影像学表现,同时行RNA scope检测其长链非编码RNA HOTAIR的表达。结果19例MPE中男性12例,女性7例。年龄15~52岁,平均年龄31岁。MRI检查均显示长T1长T2信号,增强后稍均匀强化。镜下经典的组织学表现为形态较一致的肿瘤细胞围绕血管黏液样间质呈假乳头状排列,细胞下方缺乏基膜,可见细胞外黏液。部分病例核分裂象增多,所有病例均未见明显坏死及微血管增生。免疫表型:肿瘤细胞弥漫表达GFAP(15/16)及S-100(14/16),部分病例核旁点状表达(2/16)或弱表达(3/16)EMA。Ki-67增殖指数低,个别病例高达20%。5例行RNA原位杂交(in situ hybridization,ISH)检测,均表达长链非编码RNA HOTAIR。13例获得随访,1例于术后1年因子宫颈癌去世;1例于术后4年复发;其余11例均无复发或转移。结论MPE的组织学特征及生物学行为符合WHO(2021)中枢神经系统肿瘤分类Ⅱ级的诊断标准。HOTAIR的表达对MPE有一定的诊断价值,必要时可行ISH检测以辅助诊断。

Purpose To re-evaluate the WHO grade of myxopapillary ependymoma and to explore the diagnostic value of HOTAIR expression.Methods Ninteen MPEs diagnosed in Nanjing Drum Tower Hospital,from 2002 to 2021 were collected,to analyze the clinical and pathological features and to detect the expression of long non-coding RNA(lncRNA)HOTAIR.Results There were 12 male and 7 female patients,with age range 15-52 years(median=31 years).MRI indicated tumors with uniform long T1,T2 signals,which increased significantly after enhancement.Histologically,the tumor cells showed a pseudopapillary arrangement around the vessels with myxoid stroma.The basement membrane below the cells was lost.It also showed extracellular mucus.Some cases showed more mitoses,but none obvious spontaneous necrosis or microvascular proliferation.By immunohistochemistry(IHC),GFAP(15/16)and S-100(14/16)were positive.Epithelial membrane antigen(EMA)was para-nuclear dot positive(2/16)or weakly positive(3/16).Ki-67 proliferation index was low,but up to 20%in one case.lncRNA HOTAIR was positive in all the 5 cases by RNA in situ hybridization(ISH).Follow-up data were obtained from 13 cases:one died of cervical cancer in one year,and one relapsed in 4 years,but no recurrence or metastasis in the remaining 11 cases.Conclusion The pathological features and biological behavior of MPE meet the diagnostic standard of the latest WHO grade 2.They rarely recur due to their benign biological behavior,but clinical follow-up is needed for cases with increased cytological atypia,mitoses and Ki-67 proliferation index.The expression of HOTAIR has certain diagnostic value for MPE,and ISH detection can be used to assist the diagnosis if necessary.