青少年多形性低级别神经上皮肿瘤1例病例报告并文献复习

Polymorphous Low-Grade Neuroepithelial Tumor of the Young: A Case Report and Literature Review

摘要: 目的：探讨青少年多形性低级别神经上皮肿瘤(PLNTY)的临床、影像学、病理及分子特征，为临床诊疗提供参考。方法：回顾性分析1例经病理证实的PLNTY患者的临床资料，包括病史、临床症状、影像学表现、病理形态学特征、免疫组化结果及分子检测数据，并结合相关文献进行复习。结果：患者男性，30岁，以6年药物难治性癫痫为核心症状，从局灶性面部肌肉抽搐进展为混合性发作。头颅MRI提示左侧颞极类圆形异常信号影，T1WI等信号、T2WI及FLAIR低信号，增强扫描无强化，初步诊断为海绵状血管瘤。24小时视频脑电监测提示左侧前颞区异常放电。行左颞叶病损切除术后，病理诊断为PLNTY (CNS WHO 1级)；镜下可见薄壁血管团、玻璃样变性、钙化及胶质细胞增生，免疫组化示CD34弥漫阳性、GFAP (+)、Olig-2 (+)，Ki-67增殖指数1%；分子检测提示BRAF突变型阳性、BRAF V600E (VE1)弱+，无恶性相关突变。术后患者癫痫完全控制，随访至今恢复良好。结论：PLNTY以长期药物难治性癫痫为典型表现，好发于颞叶，影像学可存在不典型表现(如本例T2WI低信号)，确诊需结合病理形态学、免疫组化及分子检测；BRAF V600E突变型PLNTY生物学行为惰性，手术完整切除为核心治疗手段，预后良好；分子分型可指导个体化随访策略，对于存在长期颞叶癫痫发作表现且具有不典型影像学特征的患者，临床医师应保持对PLNTY的高度怀疑。

Abstract: Objective: To investigate the clinical, radiological, pathological and molecular characteristics of polymorphous low-grade neuroepithelial tumor of the young (PLNTY), and to provide evidence for optimized clinical diagnosis and treatment strategies. Methods: We retrospectively analyzed the complete clinical data of a patient with pathologically confirmed PLNTY, including medical history, clinical manifestations, neuroimaging findings, histopathological features, immunohistochemical profiles and molecular testing results. A comprehensive literature review was conducted to contextualize our findings. Results: A 30-year-old male patient presented with 6-year history of drug-resistant epilepsy, which progressed from focal facial muscle twitching to mixed seizures. Cranial magnetic resonance imaging (MRI) revealed a well-circumscribed round lesion in the left temporal pole, showing isointensity on T1-weighted imaging (T1WI), hypointensity on both T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) sequences, with no enhancement after contrast administration. The initial clinical diagnosis was cavernous angioma. Twenty-four-hour video electroencephalography (vEEG) demonstrated abnormal epileptiform discharges localized to the left anterior temporal region. The patient underwent left temporal lesion resection, and the final pathological diagnosis was PLNTY (CNS WHO Grade 1). Histopathological examination showed thin-walled vascular clusters, hyaline degeneration, calcification and glial cell proliferation. Immunohistochemical staining revealed diffuse positivity for CD34, as well as positivity for GFAP and Olig-2, with a Ki-67 proliferation index of 1%. Molecular testing confirmed BRAF mutation positivity with weak expression of BRAF V600E (VE1), and no malignancy-associated mutations were detected. Postoperatively, the patient achieved complete seizure control and remained in excellent clinical condition during follow-up to date. Conclusion: PLNTY typically manifests as long-standing drug-resistant epilepsy and has a predilection for the temporal lobe. Atypical imaging presentations, such as T2WI hypointensity observed in this case, may lead to initial misdiagnosis. Definitive diagnosis requires integrated evaluation of histopathological morphology, immunohistochemistry and molecular profiling. PLNTY harboring BRAF V600E mutation exhibits indolent biological behavior, and gross total resection is the cornerstone of treatment with favorable prognosis. Molecular subtyping can guide individualized follow-up strategies, and clinicians should maintain a high index of suspicion for PLNTY in patients with long-standing temporal lobe epilepsy and atypical imaging features.