摘要目的:探讨年轻人多形性低级别神经上皮肿瘤（PLNTY）的临床病理学特征、诊断及预后。方法:收集浙江省宁波市临床病理诊断中心2016年1月至2019年12月确诊的2例PLNTY，观察其临床特征、组织学形态、免疫表型和分子遗传学特征，并结合文献进行复习和总结。结果:2例患者均为女性，年龄分别为14岁和25岁，临床上均以癫痫发作为主要表现。影像学检查显示大脑皮层混杂性信号，分别位于枕叶和颞叶。镜下观察肿瘤组织均有特征性的少突胶质细胞瘤样的形态结构，常伴有钙化。免疫组织化学标记显示瘤细胞CD34弥漫强阳性，周围皮层神经元CD34阳性表达呈毛刺状；胶质纤维酸性蛋白（GFAP）、Olig2和ATRX阳性，IDH1阴性，其他标志物包括Neu N、巢蛋白和上皮细胞膜抗原（EMA）等均阴性，Ki-67阳性指数均<2%。分子检测例2显示BRAF V600E突变，例1显示无BRAF V600E突变和1p/19q共缺失。术后随访2和24个月，患者情况良好，未见癫痫发作。结论:PLNTY是一种少见的低级别神经上皮肿瘤，确诊依赖病理学诊断，并需与少突胶质细胞瘤进行鉴别。PLNTY相当于WHOⅠ级肿瘤，手术完全切除肿块后，预后良好。

abstractsObjective:To investigate the clinicopathological features, diagnosis and prognosis of polymorphous low-grade neuroepithelial tumor of the young (PLNTY).Methods:Two cases of PLNTY diagnosed during January 2016 to December 2019 were collected from Ningbo Diagnostic Pathology Center, Zhejiang, China. The clinical features, histopathological characteristics, immunohistochemical and molecular genetic findings were analyzed and the relevant literature was reviewed.Results:The two patients were both female, at the ages of 14 and 25 years, respectively. Both patients presented with seizure attacks. The imaging study showed a mixed signal in the cerebral cortex, located in the occipital and temporal lobes, respectively. Microscopically, the tumors were characterized by the invariable presence of oligodendroglioma-like appearance, often with calcification. Immunohistochemically, the tumors were diffusely and intensely CD34 positive with ramified, CD34-expressing neural elements in regional cortex. The tumors were positive for GFAP, Olig2 and ATRX, and negative for IDH1, Neu N, nestin and EMA. The Ki-67 labeling index was less than 2%. The case number 2 harbored the BRAF V600E mutation, while the case number 1 was negative for both the BRAF V600E mutation and 1p/19q codeletion. Both patients recovered very well and were free of seizures after the following-up of 2 and 24 months, respectively.Conclusions:PLNTY is an uncommon neuroepithelial tumor. Histopathologic and immunohistochemical examinations are necessary for establishing the diagnosis and for excluding oligodendroglioma. PLNTY should be considered as a benign tumor corresponding to WHO Grade I. The prognosis is overall good after complete tumor-resection.