黏液乳头型室管膜瘤临床病理及超微结构分析

Clinicopathological and ultrastructural analysis of myxopapillary ependymoma

目的:探讨黏液乳头型室管膜瘤(MPE)的临床病理特点、诊断及鉴别诊断。方法:对12例MPE患者的病理标本进行光镜、免疫组化、电镜观察,并结合其临床资料和国内外文献进行分析。结果:12例MPE患者中,女性6例,男性6例,年龄14～50岁,平均31岁。本研究中6例患者随访10～80个月,其中2例术后复发;6例患者失访。12例MPE患者的肿瘤均位于脊髓内,多局限于脊髓圆锥、马尾节段。肉眼观察肿瘤均为灰白色、半透明状;组织学上肿瘤主要由立方形或长梭形细胞构成,呈单层或多层围绕纤维血管间质成乳头状排列,细胞分化好,核呈卵圆形,核分裂象罕见,未见坏死;免疫组化标记瘤细胞胶质原纤维酸性蛋白(GFAP)、S-100蛋白(S-100)、波形蛋白(vimentin)阳性,细胞角蛋白(CK)和癌胚抗原(CEA)阴性。超微结构观察,见瘤细胞胞质内数量较多呈束状排列的中间细丝、微囊及囊内纤毛。结论:MPE是室管膜瘤的一个独特亚型,易与其他乳头状肿瘤混淆,其诊断依赖于组织学及免疫组化和电镜观察辅助。

Objective To appraise the clinical pathological characteristics, diagnosis and differential diagnosis of myxopapillary ependymoma （MPE）. Methods Twelve cases of MPE were studied by light and electron microscopy and immunohistochemistry, and were analyzed in coordination with clinical data and published literature. Results Six patients were female and six were male, aged 14-50 years （mean 31 years）, 6 cases were followed for 10-80 months, 2 cases relapsed after resection and 6 cases were lost of follow-up. All tumors were located in the spine cord and most in the caudal-sacral segment. Microscopically, the tumor consisted of cubic or long spindle cells arranged in mono- or multi-layer surround a fibrovascular core in a papillary pattern. The cells were well-differentiated and the nuclei were oval in shape, mitotic activity was rarely seen and no necrosis was found. Immunohistochemical study showed positive GFAP, S-100 and vimentin, and negative cytokeratin （CK） and carcino-embryonic antigen （CEA）. Ultrastructural study showed abundent intermediate filaments arranged in spindle pattern, microvesicles and intravesicle filaments located in the cytoplasm of tumor cells. Conclusions MPE is an unique subtype of ependymoma, which may be confused with other tumors with papillary structure. Diagnosis is based on histological characteristics supplemented with immunohistochemical and uhrastructural findings.