大脑内含有神经毡和菊形团的胚胎性肿瘤伴髓上皮瘤和间叶分化临床病理观察

Embryonal brain tumor containing neuropil and rosettes with medulloepithelioma-like and mesenchymal differentiation: report of a case and review of literature

目的探讨伴髓上皮瘤和间叶分化大脑内含有神经毡和菊形团的胚胎性肿瘤的临床病理特点、诊断与鉴别诊断。方法对1例发生在左侧颞顶叶的含有神经毡和菊形团的胚胎性肿瘤伴髓上皮瘤和间叶分化进行组织学、免疫组化观察,并结合文献复习。结果患儿男性,5岁。头颅CT示左侧颞顶叶肿瘤性病变伴钙化,左侧颞骨骨质破坏,考虑左颞顶叶占位。光镜下瘤组织由疏密相间区域构成,致密区域见原始小圆核或短梭形瘤细胞呈片状密集分布,核染色质深,异型性明显,见核分裂象伴多灶性坏死,可见横纹肌样细胞,部分区域见柱状上皮构成的原始神经管样结构或Homer-Wright菊形团形成伴结缔组织增生;稀疏区见分化良好的胶质神经毡样基质内有小型神经元样瘤细胞或节细胞样瘤细胞散在分布。免疫组化:原始神经管样结构基底部vimentin(+),原始瘤细胞和横纹肌样细胞nestin、INI-1和p53(+),横纹肌样细胞NF、Syn、MAP2和Cg A(+),Ki-67为局灶20%,原始神经管样结构CK和EMA(-),横纹肌样细胞SMA(-),横纹肌样细胞GFAP和NSE灶(+),小型神经元样瘤细胞S-100和Neu N(+),Olig2(-/+),β-catenin和desmin(-)。结论大脑内含有多量神经毡和真性菊形团的胚胎性肿瘤伴髓上皮瘤和间叶分化确诊依赖于影像、组织学和免疫组化,需要与髓母细胞瘤、非典型畸胎样/横纹肌样瘤、室管膜母细胞瘤和脉络丛乳头状癌鉴别。

Purpose To explore the clinical and pathological features,diagnosis and differential diagnosis of embryonal brain tumor containing neuropil and rosettes with medullary epithelial tumor and mesenchymal differentiation. Methods A case of rare brain tumor with medulloepithelioma and mesenchymal differentiation occurred in left tempoparietal area was observed by histopathological analysis and immunohistochemical staining,and relevant literatures were reviewed. Results The CT of the head showed the left temporoparietal lesions with calcification and bone destruction,and thus the left temporoparietal tumor was considered. Microscopically,tumor tissue consisted of dense and sparse area. In dense region,there were primitive small nuclei or short spindle tumor cells with flaky distribution. The nuclus was atypia with coarse chromatin. The mitosis was easily observed with multiple focal necrosis. Rhabdoid cells were visible. In some area,there were Homer-Wright rosettes with hyperplasia of connective tissue and primitive neural tube like structure consisting of columnar epithelium. In sparse area,small neuronal tumor cells or ganglion cells-like tumor cells scattered in well differentiated neuropil like matrix. The basal part of the primitive neural tube like structure was positive for vimentin. Both rhabdoid cells and the primitive tumor cells were positive for nestin,INI- 1 and P53. Rhabdoid cells were positive for NF,GFAP,SYN,NSE,MAP2,Cg A and vimentin. Small neuron like cells were positive for S100 and Neu N. Ki-67 index was20% in focal area. The tumor cells were negative for CK,EMA,SMA,Olig2,β- catenin and desmin. Conclusions Definite diagnosis of embryonal brain tumor containing large amounts of neuropil and true rosettes with medullary epithelial tumors and mesenchymal differentiation depends on the imaging,histological features and immunohistochemical results.The tumour also must be distinguished from medulloblastoma,atypical teratoid / rhabdoid tumor,ependymoblastoma and choroid plexus carcinoma.