儿童小脑脑室外神经细胞瘤临床病理观察

Extraventricular neurocytoma of cerebellum in child:a clinicopathologic analysis

目的探讨儿童小脑脑室外神经细胞瘤的临床病理和生物学特点。方法对1例儿童小脑脑室外神经细胞瘤进行组织形态学、影像学和免疫组化研究,并复习相关文献。结果患儿男性,6岁。突发眩晕反复发作3个月。头颅MRI示右侧小脑半球囊性占位,T1等低信号,T2高信号,囊内附壁结节不规则强化。组织学表现为弥漫一致的小圆细胞构成特征性的无核原纤维岛及围绕血管形成菊形团结构,另一特点是瘤细胞具有少突胶质细胞样特征,可见散在的节细胞分化。免疫表型示神经毡基质Syn强(+),肿瘤细胞Syn、NSE、Oligo2、NeuN和NF(+),少数细胞GFAP(+);CD99,S-100,vimentin和EMA均(-);血管CD34(+),Ki-67<2%。结论脑室外神经细胞瘤是一种较为少见的肿瘤,发生于儿童且位于小脑者更为罕见,组织学特点多数为典型性,一般无复发或转移,完整切除预后较好。

Purpose To investigate the clinicopathological and biological characteristics of neurocytoma of the cerebellum in children.Methods The clinical presentation,histological observation,radiological examination and immunohistochemical staining were analyzed in one case of neurocytoma of the cerebellum in a child and related literatures were reviewed.Results A 6-year-old boy presented with abrupt vertigo in three months.Brain MRI scanning showed a cystic mass of iso-hypointense in the right cerebellum on T1-weighted images and hyperintense on T2-weighted images.It showed anirregular enhancing mural nodule after administration of gadolinium.Microscopically,the tumor was composed of uniform round cells with characteristic fibrillary areas and rosettes.Another feature was the oligodendroglial-like cell（OLC） with ganglionic differentiation.A typical feature of neurocytomas was strongly diffuse immunoreactivity to synaptophysin both within the cytoplasm and in the neuropil.The cells were also positive for NSE,Oligo2,NeuN,NF,GFAP（a few） and negative for CD99,S100,VIM,and EMA.The cell proliferation index（Ki-67） was lower than 2%.Conclusion Extraventricular neurocytoma is uncommon and the cerebellum is a rare location,whose histological examination is usually typical,lack of recurrence or metastasis,and the prognosis is good after total resection.