中枢神经系统非典型畸胎样／横纹肌样瘤临床病理及免疫表型特征

Clinicopathologic and immunohistochemical study of atypical teratoid/rhabdoid tumor of central nervous system

目的探讨中枢神经系统非典型畸胎样／横纹肌样瘤的临床病理特征、诊断及鉴别诊断。方法对2例非典型畸胎样／横纹肌样瘤应用光镜行HE、网状纤维染色及免疫组织化学染色观察,并结合文献复习。结果非典型畸胎样／横纹肌样瘤具有特征性的横纹肌样细胞,伴有不同程度的原始神经外胚叶、上皮和间质分化。肿瘤组织富于网状纤维,免疫组织化学标记示波形蛋白、CD99、上皮细胞膜抗原、细胞角蛋白、胶质纤维酸性蛋白、S-100蛋白、神经微丝蛋白、结蛋白、平滑肌肌动蛋白阳性,突触素、肌调节蛋白、胎盘碱性磷酸酶和HMB45阴性。结论非典型畸胎样／横纹肌样瘤是中枢神经系统一种罕见的高度恶性肿瘤,好发于儿童,偶见于成人,呈异源性组织学和免疫组织化学表型。其诊断需与脑内其他多形性肿瘤鉴别。

Objective To study the clinicopathologic features and differential diagnosis of atypical teratoid/rhabdoid tumor （AT/RT） occurring in the central nervous system. Methods Two cases of AT/RT were studied by hematoxylin-eosin, reticulin and immunohistochemical staining. The clinical and pathologic features were analyzed and the literatures reviewed. Results Histologically, AT/RT was characterized by the presence of rhabdoid cells associated with various degrees of primitive neuroectodermal, epithelial or mesenchymal differentiation. Abundant reticulin fibers and a complex immunophenotype were observed. The tumor cells were positive for vimentin, CD99, epithelial membrane antigen, cytokeratin, glial fibrillary acidic protein, S-100 protein, neurofilament, desmin and smooth muscle actin. They were negative for synaptophysin, MyoD1, placental alkaline phosphatase and HMB45. Conclusions AT/RT is a highly malignant tumor occurring in the central nervous system. It manifests mainly in children and occasionally in adults. The tumor is characterized by a heterogeneous histologic and immunohistochemical phenotype. It needs to be distinguished from a number of central nervous system tumors, including medulloblastoma, primitive neuroectodermal tumor, germ cell neoplasm and rhabdoid meningioma.