Abstract: Objective  To study clinicopathological features, diagnosis, differential diagnosis and prognosis of central nervous system (CNS) liponeurocytoma outside the cerebellum.  Methods  One case of the third ventricle liponeurocytoma was reported focusing on the following aspects: clinical manifestations, histopathological features and immunophenotypes, and the relevant literatures were reviewed.  Results  A 52-year-old female presented headache, and her head CT scan showed that there was a low-density lesion area at the former of the brain midline. The tumor was detected in the third ventricle during surgery. The size of tumor was 5.80 cm × 4.00 cm × 3.80 cm. Under optical microscopy, the tumor was biphasic in appearance, which consisted isomorphic small neuronal cells and mature adipose cells and adipose-like cells. Mature osseous tissue and intensive areas of calcification could also be seen. There was no necrosis or mitosis. By using immunohistochemical staining, the tumor cells were diffusely positive for S-100 protein (S-100) and β-catenin. A part of tumor cells were positive for neuronal nuclear antigen (NeuN), synaptophysin (Syn), murine double minute 2 (MDM2) and P53. Besides, the tumor cells were negative for glial fibrillary acidic protein (GFAP), oligodendrocyte transcription factor-2 (Oligo-2), isocitrate dehydrogenase 1 (IDH1), desmin (Des), CD68 and myelin basic protein (MBP). Ki-67 labeling index was about 1%.  Conclusions  Central nervous system liponeurocytoma is a rare tumor, which is predominantly located in the cerebellar hemispheres, and those located out of cerebellum are much more seldom. Definite diagnosis could be made by typical histopathological characteristics and immunohistochemical expressions. Central nervous system liponeurocytoma has a very well prognosis. Most patients can survive over 5 years, and the longest sugvival is more than 18 years.

Key words: Neurocytoma, Third ventricle, Immunohistochemistry, Pathology

摘要： 目的 探讨中枢神经系统小脑外脂肪神经细胞瘤的临床病理特征、诊断与鉴别诊断要点，以及影响预后的因素。方法与结果 女性患者，52 岁。临床仅表现为头痛，CT 显示中线前区域低密度病灶。术中可见肿瘤位于第三脑室前，大小约5.80 cm × 4.00 cm × 3.80 cm。组织学特征呈明显双相性，由大小一致的小圆形细胞和成熟脂肪细胞及其脂肪样细胞构成，有成熟骨组织、部分区域密集钙化灶形成，无坏死和核分裂象；肿瘤细胞弥漫表达S-100 蛋白、β-连接素，少数表达神经元核抗原、突触素、鼠双微体2、P53，不表达胶质纤维酸性蛋白、少突胶质细胞转录因子-2、异柠檬酸脱氢酶1、结蛋白、CD68、髓鞘碱性蛋白，Ki-67 抗原标记指数约为1%。结论 中枢神经系统脂肪神经细胞瘤临床罕见，主要发生于小脑，小脑以外脑组织极为罕见，明确诊断依赖其独特的组织形态学特征和免疫组织化学表型。患者预后良好，生存期超过5年，最长可超过18年。

关键词: 神经细胞瘤, 第三脑室, 免疫组织化学, 病理学