Abstract: Objective To report a case of special morphological papillary glioneuronal tumor of central nervous system with its cytology, histopathology, ultrastructure and molecular genetics changes. Methods Retrospective study was performed to analyse the clinical manifestations, imaging characteristics, cytologic and histopathologic and ultrastructure findings. Immunohistochemical staining and fluorescence in situ hybridzation (FISH) detecting were done to the tumor tissue. Results The main clinical manifestations were headache, dizziness accompanied by nausea, vomiting in short course. MRI revealed a huge cystic and solid space-occupying with enhanced solid part in brain parenchyma of right frontotemporal lobe. The fresh tumor tissue imprint showed papillary structure with blood vessel core and ganglion-like tumor cells. Histopathologic examination revealed clear boundary between tumor tissue and the normal white matter. The local ganglion?like tumor cells were arranged in sheet with scattered ganglion cells and eosinophilic granular bodies, and some pseudopapillary tumor cells were arranged around the vessel wall thickened with hyalinization. Ultrastructure showed that the tumor cells with cytoplasm-rich and prominent nucleoli contained many rough endoplasmic reticulums and ribosomes. Tumor cells showed diffuse strong positive expression of vimentin (Vim), CD34 and nestin (Nes). Papillary tumor cells were positive for AE1/AE3 and epithelial membrance antigen (EMA), focal sheet cells expressed neurofilament (NF), CD56, synaptophysin (Syn) and glial fibrillary acidic protein (GFAP). Only few cells were P53-positive and mean Ki-67 index of tumor cells was about 3% . FISH test showed that there were some polyploid tumor cells, but without amplification of epidermal growth factor receptor (EGFR), EGFR-1 and human epidermal growth factor receptor-2/topoisomerase Ⅱ (HER-2/Topo Ⅱ). Due to a small amount of residual tumor, the patient received radiotherapy and no recurrence signs were detected after follow-up of 20 months. Conclusion This tumor shows features of papillary glioneuronal tumor, but with some solid sheet area and special immunohistochemical expression, so we recommend that using a new subtype of papillary glioneuronal tumor—solid?pseudopapillary subtype names this tumor. This kind of tumor should be further followed up.

Key words: Glioma, Central nervous system neoplasms, Immunohistochemistry, Microscopy, electron

摘要： 目的   报告一例中枢神经系统特殊形态的乳头状胶质神经元肿瘤患者的细胞学、组织病理学特点，以及超微结构和分子遗传学改变。方法   回顾分析患者临床表现、影像学特点。印片、常规HE 染色和电子显微镜观察肿瘤细胞形态、组织学特点和超微结构，荧光原位杂交试验检测分子遗传学改变。结果   临床主要表现为头痛、头晕伴恶心、呕吐，病程短。头部MRI 检查显示右侧额颞叶脑实质内巨大囊实性占位性病变伴强化。组织病理学观察可见血管乳头中央和神经节细胞样细胞；肿瘤组织与脑白质分界较清楚，局部神经节细胞样细胞呈实片状排列，神经节细胞样细胞和嗜酸性颗粒小体呈散在分布，部分肿瘤细胞呈假乳头状排列，血管壁增厚伴透明变性；超微结构观察肿瘤细胞胞质丰富，内含较多粗面内质网和核糖体，核仁明显；免疫组织化学检测肿瘤细胞呈弥漫强阳性表达波形蛋白、CD34 和巢蛋白，局灶表达AE1/AE3 和上皮膜抗原，部分肿瘤细胞表达神经丝蛋白、CD56、突触素和胶质纤维酸性蛋白，个别细胞P53 表达阳性，Ki-67 抗原标记指数约为3%。荧光原位杂交试验可见散在多倍体细胞，但无表皮生长因子受体、表皮生长因子受体-1和人类表皮生长因子受体-2/拓扑异构酶Ⅱ的扩增。手术后局部放射治疗1 个月，随访20 个月未见复发征象。结论   该例患者肿瘤细胞虽具备乳头状胶质神经元肿瘤的特点，但部分呈实片状分布，具有特殊的免疫组织化学表达，建议采用乳头状胶质神经元肿瘤中亚型——实性假乳头亚型命名。患者预后尚有待进一步随访观察。

关键词: 神经胶质瘤, 中枢神经系统肿瘤, 免疫组织化学, 显微镜检查, 电子