Abstract:

Objective To explore the clinicopathological features and molecular genetics of diffuse leptomeningeal glioneuronal tumor (DLGNT). Methods and Results A 5 - year- old boy presented with severe hydrocephalus and two times of convulsions. Head MRI showed obvious broadening of bilateral lateral ventricles, suggesting hydrocephalus, and abnormal patchy mildly high-intensity signals scattered in bilateral cerebellar superior sulci; spinal MRI revealed thickened spinal cord at the level of T_5-7 and mildly high-intensity signals within the spinal cord; enhanced MRI showed thickening and enhancement of the surface of brainstem, meninges on the surface of bilateral cerebellar hemispheres, whole spinal meninges and partial spinal dura mater, and cauda equina. The patient underwent exploratory resection of thoracic lesions and spinal canal reconstruction. Intraoperative findings showed semi - transparent gelatinoid hyperplasia between subarachnoid and soft meningeal, which blocked the subarachnoid cavity. Histological findings showed low-to moderate-density monomorphic oligdendroglial-like tumor cells with diffusely growth or in small nests in the leptomeninges. Mitotic activity and necrosis were not found. Immunohistochemical staining showed oligdendroglial-like tumor cells expressed oligodendrocytes transcription factor-2 (Olig-2) in nuclei, synaptophysin (Syn), microtubule - associated protein - 2 (MAP - 2) and S - 100 protein (S -100) in cytoplasm. Ki-67 labeling index was 4%-10%. Fluorescence in situ hybridization (FISH) analysis revealed deletion of 1p, whereas 19q was intact. The final diagnosis was DLGNT. The patient was hospitalized for 22 d and died 3 months after discharge. Conclusions DLGNT is a group of primary brain neoplasm of recent acquisition in the 2016 World Health Organization (WHO) classification of central nervous system tumors and does not yet assign a distinct WHO grade to the entity. At present, DLGNT has not been reported in China. DLGNT is very rare and always confused with other central nervous system tumors and inflammatory lesions. Therefore, histological morphology, immunohistochemistry and characteristics of molecular genetics are very important for diagnosis.

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摘要：

目的 探讨弥漫性软脑膜胶质神经元肿瘤的临床病理学和分子遗传学特征。方法与结果 男性患儿，5 岁9 个月，临床表现为严重脑积水伴抽搐发作2 次；头部MRI 显示，双侧侧脑室明显增宽，提示脑积水，并出现双侧小脑上沟散在斑片样异常略高信号影；脊椎MRI显示，T_{5 ~ 7}水平脊髓增粗，可见髓内异常略高信号影；增强扫描可见脑干表面、双侧小脑半球表面脑膜、全脊膜和部分硬脊膜、马尾神经增厚并强化征象。遂行胸髓病变探查切除术+ 椎管重建术，术中可见蛛网膜与软脊膜之间半透明胶冻样异常组织增生，堵塞蛛网膜下隙。组织学形态，低或中等密度的形态单一的少突胶质细胞样肿瘤细胞，在软脑膜内呈弥漫性或巢团样生长，未见坏死和核分裂象。免疫组织化学染色，肿瘤细胞胞核表达少突胶质细胞转录因子2，胞质表达突触素、微管相关蛋白-2 和S-100 蛋白，Ki-67 抗原标记指数为4% ~10%。荧光原位杂交显示单独1p杂合性缺失。最终诊断为弥漫性软脑膜胶质神经元肿瘤。患者共住院22 d，出院后3 个月死亡。结论 2016 年世界卫生组织中枢神经系统肿瘤分类第4 版修订版新增弥漫性软脑膜胶质神经元肿瘤的诊断，但未予明确分级，目前国内尚无报道。由于该病较为少见且极易与其他中枢神经系统肿瘤和炎症性病变相混淆，因此组织学形态、免疫组织化学染色和分子遗传学特征显得尤为重要。

关键词: 脑肿瘤, 神经胶质, 神经元, 软脑脊膜, 免疫组织化学, 病理学