脑室内伸长细胞型室管膜瘤的临床病理学特征:病例报告并文献综述

Clinicopathological features of intraventricular tanycytic ependymoma: case report and review of the literature

目的探讨脑室内伸长细胞型室管膜瘤的临床病理学特征。方法对1例右侧侧脑室内伸长细胞型室管膜瘤患者的临床、影像学、病理学和免疫组织化学特征进行回顾性分析,并复习相关文献。结果患者临床表现为无明显诱因的头痛,呈进行性加重;MRI检查提示右侧侧脑室内囊实性病灶。经手术完全切除,大体组织呈鱼肉样,约2cm×3cm×1cm大小,部分区域脑组织呈沙砾感。组织病理学检查长梭形肿瘤细胞呈单极或双极伸长,由簇状梭形细胞形成的细胞核密集区及细胞突起呈束状排列的纤维样无核区构成,未见核分裂象及坏死灶,围绕血管分布形成血管周围假菊形团;部分区域可见血管壁玻璃样变和钙化小体。免疫组织化学染色肿瘤细胞胶质纤维酸性蛋白、S-100蛋白、波形蛋白、巢蛋白和神经微丝表达阳性;上皮膜抗原呈局灶性核旁点状阳性反应;突触素和神经元核抗原表达阴性;MIB-1标记指数约为0.50%。文献报道国外29例伸长细胞型室管膜瘤,其中发生于脑室内6例,组织病理学和免疫组织化学特征与本文病例基本一致。电子显微镜观察肿瘤细胞呈室管膜细胞的典型特征,包括细胞突起内可见大量的中间纤维丝、明显的细胞间连接、大量位于细胞表面的纤细的微绒毛以及微绒毛构成的小管状结构。结论伸长细胞型室管膜瘤是一种较少见的起源于室管膜伸长细胞的室管膜瘤亚型,组织病理学上应与其他由梭形细胞组成的神经系统肿瘤相鉴别,如毛细胞型星形细胞瘤、纤维型星形细胞瘤、神经鞘瘤和孤立性纤维性肿瘤等,免疫组织化学染色及电子显微镜下的特征性改变有助于诊断与鉴别诊断。

Objective To investigate clinicopathological characteristics of intraventricular tanycytic ependymoma. Methods The clinical, imaging, pathological and immunohistochemical characteristics of one patient with tanycytic ependymoma in the right lateral ventricle were retrospectively analysed and related literatures were reviewed. Results The patient had a progressive exacerbating headache without obvious causes. MRI showed a cysticsolid mass in the right lateral ventricle. The mass was completely dissected. The tumor showed as fish meat with 2 cm × 3 cm × 1 cm in size and presented as grit in some areas. Histopathological examination showed the tumor cells as fusiform with prolonged, monopolar or bipolar processes, and presented areatus fusiform tumor cells which formed dense nuclear areas and some arranging in tract-form fibroid cellular processes areas without nuclei. No mitosis and necrotic foci were seen. Vascular pseudo-chrysanthemum-like ball were found surrounding the vessels. In some areas, there were hyaline vessels and calcified bodies. Immunohistochemical assay indicated that the expression was positive for glial fibrillary acidic protein （GFAP）, S-100 protein, vimentin, nestin and neurofilament （NF）, and negative for synapsin （Syn） and neuronal nuclear antigen （Neu-N）. The epithelial membrane antigen （EMA） presented positive focal paranuclear dotlike reaction. MIB-I labeling index was about 0.50%. Twenty-nine foreign cases of tanycytic ependymoma, including 6 intraventricular cases, were reported in literatures. Their histopatbological and immunohistochemical features were similar to those in this case. In the electronic microscopic observation, the tumor cell presented typical ependymal cell features including many intracytoplamic intermediate filaments, prominent intercellular junctions, numerous tenuous surface microvilli, and microvilli-lined lumina.Conclusion Tanycytic ependymoma is an uncommon subtype of ependymoma originating from tanycyte of ependyma.Histopathologically,tanycytic ependymoma need to be differentiated from other nervous system tumors composed of spindle cells,such as pilocytic astrocytoma,fibrillary astrocytoma,schwannoma and solitary fibrous tumor.Immunohistochemistry and electronic microscope findings can be helpful for the diagnosis and differentiation of tanycytic ependymoma from other tumors.