乳头状胶质神经元肿瘤6例临床病理分析

Papillary glioneuronal tumour: a clinicopathologic analysis of 6 cases

目的观察乳头状胶质神经元肿瘤（PGNT）的临床病理特征、影像学表现、免疫组化和电镜,探讨PGNT的诊断与鉴别诊断、治疗与预后。方法回顾性分析6例PGNT的临床资料、组织学形态、免疫组化、电镜等,结合文献对其临床特点进行分析。结果 6例PGNT中,男性4例,女性2例,平均年龄28岁。影像学上多呈颅内囊性占位。经典的病理特征是单层或假复层小立方形胶质细胞围绕在透明变性的血管轴心周围,形成假乳头样结构,乳头间区见散在的Neu-N（＋）向神经元分化的细胞。免疫组化：乳头表面的胶质细胞GFAP和S-100（＋）,Ki-67增殖指数1%-3%。电镜显示星形胶质细胞分化特征。结论乳头状胶质神经元肿瘤是一种少见的、好发于颞叶、双向分化的WHO I级肿瘤,手术完全切除肿瘤后预后良好。Ki-67指数对该肿瘤预后的提示作用仍有争议,需要大样本病例的研究。

Purpose To investigate the clinicopathologic, radiological, immunohistochemical and electronmicroscope features of papillary glioneuronal tumour （PGNT）, and to discuss the diagnosis, differential diagnosis, treatment and prognosis of the tumor. Methods Histopathological characteristics, immunohistoehemical and electron microscopic findings of 6 cases of PGNT were retrospectively studied and the relevant literatures were reviewed. Results Four patients were male and 2 were female, with a median of 28 years old. Cystic lesion was the most common radiological manifestation. The classical histopathologieal characteristics of PGNT were pseudo-papilla pattern characterized by single to multiple layers of small euboidal gliocytes lining fibrovascular cores, most of which presented a narrow lumen and markedly thickened, hyalinized walls. Neu-N labeled neurocyte-like cells were noted in between the pseudo-papillary structures. Immunohistochemically, GFAP and S100 labeled the tumor cells lining the vascular structures, which showed astrocyte differentiation under electron microscope. The Ki-67 labeling index ranged from 1 - 3%. Conclusion PGNT is a variant of mixed neuronal-glial neoplasm, usually involving the temporal lobes, and has been considered as a low grade （WHO grade I） tumor, which shows good prognosis after gross total resection. The prediction of Ki-67 on prognostication is still indefinable, and the research on large sample size of the alive cases will provide more evidence.