A new type of epileptogenic tumor, the polymorphous low-grade neuroepithelial tumor of the young (PLNTY) was firstly reported by Jason T. Huse et al. at 2016. After that, only 1 case of PLNTY was reported by article. The radiological characteristics of PLNTY have not been concluded. The objective of our study was to report 3 cases of PLNTYs in details and to analyze the image characteristics and genetic alterations of PLNTYs by reviewing our cases and articles. There were 3 cases diagnosed as PLNTY by pathology in our hospital during the last 10 years, with the average age of 15. They were all suffered from different degrees of epilepsy. All of them underwent magnetic resonance (MR) imaging and 2 of them underwent computer tomography (CT) imaging. The PLNTYs are all appearing as a solid or solid-cystic cortical mass with little mass effect and unclear boundary with normal brain tissue. They are all shown as hyperintensity in T2WI and iso−/hypointensity in T1WI with slight or no enhancement after contract enhanced in MR imaging. The “salt and pepper sign” in T2WI and grit calcification in CT images might be specific characteristics of PLNTY. All of them recovered after excision of the tumors. The gene tests revealed fibroblast growth factor receptors 3 (FGFR3)-TACC3 fusion and FGFR3 amplification in one case, and the B-Raf proto-oncogene (BRAF) V600E mutation in another case. In the image, the partial ill-marginated cortical mass with “salt and pepper sign” in T2WI or grit calcification in CT imaging might be the typical imaging characteristics of PLNTY. We also prove that the BRAF V600E mutation as well as the FGFR2 and FGFR3 have a close relationship with PLNTY.

中文翻译：

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年轻人的多形性低度神经上皮性肿瘤：病例报告和综述集中于放射学特征和遗传改变

Jason T. Huse等人首先报道了一种新型的癫痫源性肿瘤，即多形性低级年轻神经上皮肿瘤。在2016年。此后，仅报道了1例PLNTY病例。PLNTY的放射学特征尚未得出结论。我们的研究目的是详细报告3例PLNTY病例，并通过回顾我们的病例和文章来分析PLNTY的图像特征和遗传变异。近10年来，我院经病理诊断为PLNTY的3例，平均年龄15岁。均患有不同程度的癫痫病。他们都接受了磁共振（MR）成像，其中两人接受了计算机断层扫描（CT）成像。PLNTYs均表现为实心或实性囊性皮层肿块，几乎没有肿块效应，并且与正常脑组织的边界不清楚。它们均表现为T2WI中的高强度和T1WI中的等-/低点，在MR成像中增强了收缩后没有或几乎没有增强。T2WI中的“盐和胡椒征”和CT图像中的砂砾钙化可能是PLNTY的特定特征。切除肿瘤后所有患者均康复。基因测试显示，在一种情况下，成纤维细胞生长因子受体3（FGFR3）-TACC3融合和FGFR3扩增，在另一种情况下，B-Raf原癌基因（BRAF）V600E突变。在图像中，T2WI中带有“盐和胡椒征”的部分边缘不清的皮质块或CT成像中的砂砾钙化可能是PLNTY的典型成像特征。