Clinical study and differential diagnosis of intracranial hemangiopericytomas

Objective Intracranial hemangiopericytomas (HPCs) were rare neoplasms with relatively high rates of recurrence and extracranial metastasis.The differential diagnoses from angiomatous meningiomas and solitary fibrous tumors(SFTs) are very important. This study aimes to reveal differences in the specific immunohistochemical features of HPCs,angiomatous meningiomas and SFTs by newly

Extracellular vesicles in the diagnosis and treatment of central nervous system diseases

Extracellular vesicles,including exosomes and microvesicles,play a fundamental role in the activity of the nervous system,participating in signal transmission between neurons and providing the interaction of central nervous system with all body systems.In many neurodegenerative diseases,neurons pack toxic substances into vesicles and release them into the extracellular space,which leads to the spread of misfolded neurotoxic proteins.The contents of neuron-derived extracellular vesicles may indicate pathological changes in the central nervous system,and the analysis of extracellular vesicle molecular content contributes to the development of non-invasive methods for the diagnosis of many central nervous system diseases.Extracellular vesicles of neuronal origin can be isolated from various biological fluids due to their ability to cross the blood-brain barrier.Today,the diagnostic potential of almost all toxic proteins involved in nervous system disease pathogenesis,specificallyα-synuclein,tau protein,superoxide dismutase 1,FUS,leucine-rich repeat kinase 2,as well as some synaptic proteins,has been well evidenced.Special attention is paid to extracellular RNAs mostly associated with extracellular vesicles,which are important in the onset and development of many neurodegenerative diseases.Depending on parental cell type,extracellular vesicles may have different therapeutic properties,including neuroprotective,regenerative,and anti-inflammatory.Due to nano size,biosafety,ability to cross the blood-brain barrier,possibility of targeted delivery and the lack of an immune response,extracellular vesicles are a promising vehicle for the delivery of therapeutic substances for the treatment of neurodegenerative diseases and drug delivery to the brain.This review describes modern approaches of diagnosis and treatment of central nervous system diseases using extracellular vesicles.

Accuracy of ultrasonography in diagnosis of fetal central nervous system malformation

BACKGROUND Prenatal examination is an important measure for the screening and diagnosis of fetal malformations.AIM To investigate the accuracy of ultrasonography in the diagnosis of fetal central nervous system(CNS)malformations.METHODS One hundred and thirteen pregnant women suspected of having fetal CNS malformations were examined at our hospital from December 2018 to October 2020 using two-dimensional ultrasonography and three-dimensional ultrasonography,respectively.RESULTS According to the pathological results,there were 79 cases of CNS malformations and 34 cases of non-CNS malformations among the 113 pregnant women suspected of having fetal CNS malformation.Fifty-one cases of CNS malformation and 26 cases of non-CNS malformation were detected by two-dimensional ultrasonography,and 73 cases of CNS malformation and 30 cases of non-CNS malformation were detected by three-dimensional ultrasonography.The diagnostic sensitivity(92.41%)and accuracy(91.15%)of three-dimensional ultrasonography were higher than those of two-dimensional ultrasonography(64.56% and 68.14%,respectively)(P=0.000).The specificity of three-dimensional ultrasonography(88.24%)was higher than that of two-dimensional ultrasonography(76.47%);however,the difference was not significant(P=0.203).CONCLUSION Three-dimensional ultrasonography has high application value in the diagnosis of fetal CNS malformations.In addition,the image quality is clear,and the diagnostic sensitivity and accuracy are high.

Noninvasive tools based on immune biomarkers for the diagnosis of central nervous system graft-vs-host disease:Two case reports and a review of the literature

BACKGROUND Central nervous system graft-vs-host disease(CNS-GVHD)is a rare cause of CNS disorders after allogeneic hematopoietic stem cell transplantation.Currently,establishing a diagnosis of CNS-GVHD is challenging because the diagnostic criteria and diagnostic methods are not well defined and many confounding factors need to be ruled out.CASE SUMMARY Here,we present two patients with CNS-GVHD.Both patients with a history of acute GVHD or chronic GVHD developed neurological symptoms that could not be explained by other causes,and had abnormal cerebrospinal fluid(CSF)studies as determined by CSF and blood immune biomarker examinations,suggestive of suspected CNS-GVHD.Due to the lack of specific magnetic resonance imaging abnormalities and the rapid clinical deterioration of the patients,we did not attempt to perform a brain biopsy,but prompted the initiation of empirical immunosuppressive therapy.In view of the rapid and favorable response to local and systematic immunosuppressive treatment and the aforementioned neurologic manifestations together with CSF abnormalities and other negative findings,a final diagnosis of CNS-GVHD was made.CONCLUSION CSF and blood immune biomarker examinations facilitated the diagnosis of CNSGVHD,which are particularly suitable for patients who are critically ill and require urgent treatment and for those who are unsuitable for invasive diagnostic procedures.

Primary central nervous system lymphoma:status and advances in diagnosis,molecular pathogenesis,and treatment

Primary central nervous system lymphoma(PCNSL)is a rare group of extra-nodal non-Hodgkin lymphoma which is confined to the central nervous system or eyes.This article aims to present a brief profile of PCNSL diagnosis and treatment in immunocompetent patients.The authors retrieved information from the PubMed database up to September 2019.The annual incidence of PCNSL increased over the last four decades.The prognosis of PCNSL has improved mainly due to the introduction and wide-spread use of high-dose methotrexate,which is now the backbone of all first-line treatment polychemotherapy regimens.Gene expression profiling and next-generation sequencing analyses have revealed mutations that induce activation of nuclear factor-kB,B cell antigen receptor,and Janus kinases/signal transducer and activator of transcription proteins signal pathways.Some novel agents are investigated in the treatment of relapsed PCNSL including immunotherapy and targeted therapy.In particular,lenalidomide and ibrutinib have demonstrated durable efficiency.Treatment of PCNSL has evolved in the last 40 years and survival outcomes have improved in most patient groups,but there is still room to improve outcome by optimizing current chemotherapy and novel agents.

Diagnosis, treatment, and misdiagnosis analysis of 28 cases of central nervous system echinococcosis

Background:To explore central nervous system(CNS)involvement in this disease,from the perspectives of diagnosis,treatment,and misdiagnosis Methods:Twenty-eight patients with CNS echinococcosis were included in this retrospective study,including 18 males(64.3%)and 10(35.7%)females.The average age of all the patients were 23.5 years(ranged 4–60 years).Twenty-three(23)patients(82.1%)received the first surgical resection in our hospital.Five(5)patients(17.9%)gave up surgical treatment for multiple-organ hydatidosis and previous surgery history at other hospitals,and albendazole was applied for a long-term(3–6 months)adjunct therapy for the 5 patients.The average follow-up time was 8 years.Results:For the 28 patients,23 cases received surgical treatments,and the diagnosis was confirmed by pathological examinations.The diagnosis of 4 cases of brain echinococcosis and 2 cases of spinal cord echinococcosis could not be confirmed,resulting in a misdiagnosis rate of 21.4%(6/28).For the pathological examination,a total of 17 cases were infected with Echinococcus granulosus(including 2 cases of spinal cord echinococcosis),and 6 cases were infected with Echinococcus alveolaris.Conclusion:The diagnosis should be specifically considered in endemic regions.The clinical features of CNS hydatidosis were intracranial space-occupying lesions.For the treatment,the surgical removal of cysts should be necessary.In addition,the adjuvant therapy with drug and intraoperative prophylaxis is also suggested.The misdiagnosis may have resulted from atypical clinical features and radiographic manifestations,as well as the accuracy of hydatid immunologic test.

Inflammatory myofibroblastic tumor of the central nervous system:A case report

BACKGROUND An inflammatory myofibroblastic tumor(IMT)occurring in the central nervous system is very rare,and thus its pathogenesis is unknown.This case report and literature review aimed to explore the pathogenesis,clinical features,imaging findings,pathological characteristics,immunohistochemical characteristics,diagnoses,treatments,and risks of postoperative recurrence of IMT in the central nervous system.CASE SUMMARY A 67-year-old woman was admitted to the hospital with an exophthalmic protrusion and double vision in the left eye that had persisted for 3 mo.Magnetic resonance imaging(MRI)showed a 2.4 cm×1.3 cm heterogeneous large mass in the bottom of the left anterior cranial fossa,which was closely related to the dura mater.Before surgery,we suspected the mass to be meningioma.The entire mass was successfully removed under neuronavigation and electrophysiological monitoring,and postoperative pathology indicated an IMT with extensive infiltration of chronic inflammatory cells and scattered multinucleated giant cells.Head MRI at the 3-mo follow-up showed that the tumor at the bottom of left anterior cranial fossa had been completely resected without recurrence.CONCLUSION From the histological,immunohistochemical,and genetic analyses,the present case suggests that the pathogenesis of IMT-CNS is related to autoimmunity.

Primary isolated central nervous system acute lymphoblastic leukemia with BCR-ABL1 rearrangement:A case report

BACKGROUND BCR-ABL1 fusion gene is associated with a poor prognosis and a high incidence in central nervous system(CNS)leukemia.CNS invasion which detected at the initial diagnosis is commonly with bone marrow infiltration.It is uncommon for the leukemia cells to be located primarily in the CNS without bone marrow involvement.CASE SUMMARY We here report the rare initial presentation of CNS-restricted BCR-ABL-positive acute lymphoblastic leukemia in a 30-year-old female patient who clinically manifested with leukemic meningitis,with no involvement in peripheral blood or bone marrow.Identification of abnormal phenotypes of blast cells,and BCR-ABL1 rearrangement in the cerebrospinal fluid alone established the diagnosis of primary CNS-isolated acute lymphocytic leukemia.The patient received a combination of intrathecal therapy and high-dose chemotherapy.But the benefits of the treatments were short-lived and she experienced recurrence.CONCLUSION Flow cytometry in combination with molecular genetic analysis improved diagnostic accuracy.New approaches that may enhance the efficacy of the existing therapies and cure CNS leukemia are required.

脑胶质瘤误诊误治分析

目的探讨脑胶质瘤临床误诊的原因及防范措施。方法回顾性分析2020年5月—2023年10月收治的曾误诊的脑胶质瘤2例临床资料。结果1例因头晕、左侧肢体无力等就诊,行头颅MRI提示多发异常信号,误诊为脑梗死、中枢神经系统淋巴瘤,最终经活组织病理检查确诊为脑胶质瘤,患者拒绝手术治疗,出院后死亡。1例因发作性左上肢抽搐伴意识不清等就诊,行头颅MRI提示右侧额叶皮层异常信号,磁共振波谱示病灶区胆碱/N-乙酰天门冬氨酸升高,误诊为髓鞘少突胶质细胞糖蛋白抗体阳性单侧皮质脑炎,最终经组织病理检查确诊为脑胶质瘤,患者术后尚可,未再癫痫发作。结论脑胶质瘤临床表现复杂多样,缺乏特异性,因此对于此类疾病,临床医生需反复追问病史,结合临床特征及其他医技检查,必要时行病理活检,从而做出正确诊断,以免误诊。

胚胎发育不良性神经上皮肿瘤33例临床病理分析

目的探讨胚胎发育不良性神经上皮肿瘤(dysembryoplastic neuroepithelial tumor,DNT)的临床病理特征及预后。方法收集33例DNT患者的临床资料,采用免疫组化EnVision两步法检测Olig2、NeuN、Syn、GFAP、IDH1、CD34、BRAF V600E、H3K27M和Ki67的表达,观察其病理组织学形态及免疫组化特征进行回顾性分析,并复习相关文献。结果33例中可随访28例,其中女性10例,男性18例;发病年龄4~57岁,平均24.97岁;临床以难治性癫痫为常见症状。DNT主要发生在幕上区域,以皮层为主。肿瘤大多界限清楚,呈分叶状、囊性或囊实性结构。镜检:DNT主要由少突胶质样细胞、漂浮在黏液基质中的神经元和增生星形胶质细胞组成,偶见钙化,未见坏死或微血管增生。免疫表型:神经元表达NeuN、Syn,少突胶质样细胞表达Olig2,增生的星形胶质细胞表达GFAP,p53多为野生型,Ki67增殖指数较低(多数<4%)。结论DNT是一种良性混合性胶质神经元肿瘤,病理诊断需结合影像学特点、镜下形态、免疫组化结果及必要的分子检测,手术完整切除后患者预后良好。

血行播散性肺结核合并颅内结核的临床特点

目的分析血行播散性肺结核合并颅内结核的临床特点,以提高临床医生的诊断意识。方法选取341例血行播散性肺结核患者,其中83例合并颅内结核。收集并分析患者的性别、年龄、既往史、临床表现;痰抗酸杆菌涂片、痰结核分枝杆菌培养、痰结核分枝杆菌/利福平耐药实时荧光定量核酸扩增技术(X-pert);颅内压,脑脊液常规、生化,脑脊液抗酸杆菌涂片、结核分枝杆菌培养、X-pert;血常规、丙氨酸转氨酶、天冬氨酸转氨酶、碱性磷酸酶、白蛋白、C反应蛋白、红细胞沉降率、结核抗体、结核感染T细胞检测(T-SPOT);胸部CT平扫、头颅CT平扫及增强扫描、头颅MRI平扫及增强扫描检查结果。结果83例合并颅内结核患者的症状以发热(74例)、头痛(53例)为主,11例合并糖尿病,9例使用激素/免疫抑制剂,4例合并妊娠/分娩/流产,6例合并腹腔结核,6例合并骨关节结核,2例生殖系统结核,1例淋巴结结核,1例泌尿系统结核,1例口腔黏膜结核。49例血钠降低(<135 mmol/L),平均131.0(126.2,135.8)mmol/L。44例患者的脑脊液蛋白质≥1 g/L,37例患者的脑脊液葡萄糖水平<2.2 mmol/L,25例患者的脑脊液腺苷脱氨酶(ADA)≥6 U/L。83例患者均行胸CT检查,64例显示粟粒性结节,33例表现为单纯急性血行播散性肺结核,21例表现为单纯亚急性和慢性血行播散性肺结核,29例合并继发性肺结核。34例患者行头颅CT检查,其中梗死灶10例,结核瘤4例,脑积水1例。51例行头颅MRI检查,其中脑基底部脑膜强化10例,脑梗死灶7例,结核瘤4例。结论充分评估血行播散性肺结核患者的年龄、症状、头胸部影像学、脑脊液、血钠等有助于诊断颅内结核。

张风梅基于辨病-辨证-辨体诊疗模式治疗慢性CSC

中心性浆液性脉络膜视网膜病变(CSC)是眼科一种常见多发病,具自限性、易复发的特点,多次复发后严重影响患者视功能。王琦院士提出的“辨病-辨证-辨体”三辨诊疗模式,为中医眼科诊疗CSC提供了新的思路与方法。本文整理总结了张风梅运用三辨诊疗模式诊断及治疗慢性CSC的经验,主张临证时先辨病确定病名,再辨证确定证型,结合辨体判定体质与疾病内在联系。治疗上在症候明显的阶段以辨证治疗为主,结合调理体质,临床症状消失后或发病时无全身症状、缺乏明显的证候特点的个体,以辨体论治为主以调体质的偏颇,从而达到改善症状、调理体质而治愈慢性CSC、减少复发的目的。

A new paradigm for diagnosis of neurodegenerative diseases: peripheral exosomes of brain origin

Neurodegenerative diseases are a heterogeneous group of maladies, characterized by progressive loss of neurons. These diseases involve an intricate pattern of cross-talk between different types of cells to maintain specific signaling pathways. A component of such intercellular cross-talk is the exchange of various types of extracellular vesicles (EVs). Exosomes are a subset of EVs, which are increasingly being known for the role they play in the pathogenesis and progression of neurodegenerative diseases, e.g., synucleinopathies and tauopathies. The ability of the central nervous system exosomes to cross the blood-brain barrier into blood has generated enthusiasm in their study as potential biomarkers. However, the lack of standardized, efficient, and ultra-sensitive methods for the isolation and detection of brain-derived exosomes has hampered the development of effective biomarkers. Exosomes mirror heterogeneous biological changes that occur during the progression of these incurable illnesses, potentially offering a more comprehensive outlook of neurodegenerative disease diagnosis, progression and treatment. In this review, we aim to discuss the challenges and opportunities of peripheral biofluid-based brain-exosomes in the diagnosis and biomarker discovery of Alzheimer’s and Parkinson’s diseases. In the later part, we discuss the traditional and emerging methods used for the isolation of exosomes and compare their advantages and disadvantages in clinical settings.

视频眼震电图和视频头脉冲检查在急性前庭综合征患者快速定位诊断中的应用效果

目的探讨视频眼震电图和视频头脉冲检查(vHIT)在急性前庭综合征(AVS)患者快速定位诊断中的应用效果。方法选取中枢血管性AVS与前庭外周性AVS患者各149例,分别设为中枢组、外周组。所有患者入院后均进行视频眼震电图检查、vHIT,观察两组患者检测结果差异。结果中枢组的病理性自发眼震、病理性凝视眼震的检出率均高于外周组,位置性眼震的检出率低于外周组(均P<0.05)。中枢组患者的平稳跟踪试验结果、扫视试验结果、静态平衡姿势试验结果的异常率均高于外周组,转椅旋转-急停试验结果异常率低于外周组(均P<0.05);中枢组患者的Ⅲ型曲线、Ⅳ型曲线、扫视欠冲、慢扫视、本体觉异常、反向或垂直眼震的检出率均高于外周组,眼震增益单侧减弱的检出率低于外周组(均P<0.05)。中枢组患者的vHIT异常率、代偿性扫视阳性率均低于外周组,低频前庭眼动反射增益值、视跟踪异常率均高于外周组(均P<0.05)。结论中枢血管性AVS患者具有明显的视眼动系统功能异常,可伴不同程度的前庭脊髓反射功能与前庭眼动系统异常,前庭周围性AVS患者主要为体位相关性自发前庭反应和单侧前庭眼动系统功能异常。视频眼震电图与vHIT可为AVS患者的病变定位诊断提供可靠依据。

易误诊为海绵状血管瘤的大脑后动脉夹层动脉瘤介入栓塞一例

大脑后动脉远端夹层动脉瘤相对少见,其鉴别诊断仍需更多认识。作者报道1例易误诊为海绵状血管瘤的大脑后动脉远端夹层动脉瘤病例,复习了国内外相关文献,探讨了颅内海绵状血管瘤与大脑后动脉远端夹层动脉瘤的影像学表现、鉴别诊断和治疗方法,以提高临床医师对这两种疾病的认识。

能谱CT定量对肝脓肿和伴有中心液化坏死的肝转移瘤的鉴别诊断价值分析

目的:分析能谱CT定量对肝脓肿和伴有中心液化坏死的肝转移瘤的鉴别诊断价值。方法:选择我院2019年9月至2021年9月收治的126例经穿刺活检或病理结果证实为肝脓肿或肝转移瘤患者作为研究对象,其中肝脓肿(肝脓肿组)52例,肝转移瘤(肝转移瘤组)74例。所有患者均行能谱CT检查,比较两组患者病灶囊腔长径,分析病灶中心液性成分不同单能量(40~140 kev)的平扫CT值、能谱曲线类型、碘浓度比、病灶与正常肝组织碘浓度比,并通过受试者工作特征曲线(ROC)分析能谱CT参数对两种疾病的鉴别诊断价值。结果:两组患者病灶囊腔长径比较差异无统计学意义(P>0.05);肝脓肿组以平坦型能谱曲线为主(占50.9%),肝转移瘤组以下降型能谱曲线为主(占48.0%);肝脓肿组40~110 kev单能量CT值(17.6±6.2)~(21.2±7.8)HU,肝转移瘤组为(20.1±6.3)~(30.2±9.9)HU,在此范围的CT值比较差异有统计学意义(P<0.05);肝脓肿组能谱CT下碘浓度比、病灶与正常肝组织碘浓度比均明显低于肝转移瘤组(均P<0.05);ROC曲线分析结果显示以能谱CT 40 keV下CT值21.4 HU为截断值,诊断鉴别两种疾病的敏感性为74.2%、特异性为80.0%、AUC 0.872,明显优于碘浓度比、病灶与正常肝组织碘浓度比对两种疾病的鉴别诊断。结论:能谱CT参数在肝脓肿、伴有中央坏死的肝转移瘤的囊腔有所差异,其中40 keV CT值在鉴别诊断两者的效能最佳。

视频脑电图监测对小儿中枢神经系统感染性疾病鉴别诊断价值及对患儿预后预测价值

目的探讨视频脑电图(VEEG)监测对小儿中枢神经系统感染性疾病鉴别诊断价值及对患儿预后的预测价值。方法选取2020年5月至2021年5月新疆医科大学第一附属医院收治的92例疑似中枢神经系统感染患儿为研究对象,患儿入院后均接受临床病理学诊断、24 h VEEG监测。以临床病理学诊断结果为金标准,采用Kappa分析法评估VEEG监测结果与临床病理学诊断结果的一致性。根据临床病理诊断结果将患儿分为感染组、未感染组,比较两组患儿VEEG差异。对感染组VEEG异常患儿进行6个月的跟踪随访,根据认知功能评价、后遗症发生情况将患儿分为预后良好组、预后不良组,绘制受试者工作特征(ROC)曲线评估VEEG监测对小儿中枢神经系统感染性疾病的诊断价值,采用线性趋势检验法评估VEEG异常程度对患儿预后的预测价值。结果在92例疑似中枢神经系统感染患儿中,经临床病理学诊断,62例确诊中枢神经系统感染性疾病,其中病毒脑膜炎15例、化脓性脑膜炎24例、脑微循环障碍23例;经VEEG监测,60例确诊中枢神经系统感染性疾病,VEEG监测结果与临床病理学诊断结果的一致性良好(Kappa=0.951,P<0.001)。感染组患儿VEEG监测结果均显示异常,其中轻度异常占43.55%(27/62),中度异常占35.48%(22/62),重度异常占20.97%(13/62),未感染组患儿仅2例出现脑电图轻度异常,占6.67%(2/30),感染组VEEG监测结果异常占比明显高于未感染组(χ^(2)=83.183,P<0.001)。根据临床脑电图进行诊断,结果显示,以δ波广泛持续增多为主的VEEG重度异常患儿均表现为病毒性脑炎,以背景波形变慢为主的VEEG轻度异常、以广泛持续δ波为主的VEEG重度异常患者表现为病毒性脑炎、化脓性脑膜炎或脑微循环障碍,上述三种疾病VEEG改变缺乏特异性。随访6个月,感染组VEEG轻度异常、中度异常、重度异常患儿预后不良发生率分别为22.22%(6/27)、59.09%(13/22)、76.92%(10/13),线性趋势检验结果显示,感染组VEEG异常程度越严重,患儿预后越差(χ^(2)=-12.624,P=0.002)。ROC曲线结果显示,VEEG监测预测小儿中枢神经系统感染性疾病的灵敏度为90.77%,特异度为69.15%,阳性预测值为100.00%,阴性预测值为93.75%,ROC曲线下面积为0.801。结论VEEG监测诊断小儿中枢神经系统感染性疾病的阳性率较高,可为小儿中枢神经系统感染性疾病鉴别、预后评估提供可靠的依据。

Circular RNAs:Diagnostic and Therapeutic Perspectives in CNS Diseases

Circular RNAs(circRNAs)are a class of regulatory non-coding RNAs characterized by the presence of covalently closed ends.A growing body of evidence suggests that circRNAs play important roles in physiology and pathology.In particular,accumulating data on circRNA functions in various central nervous system(CNS)diseases and their correlations indicate that circRNAs are critical contributors to the onset and development of brain disorders.In this review,we focus on the regulatory and functional roles of circRNAs in CNS diseases,highlighting their diagnostic and therapeutic potential,with the aim of providing new insights into CNS diseases.

血清标志物在儿童中枢神经系统感染鉴别诊断中的研究进展

儿童中枢神经系统感染(ICNS)是新生儿科常见疾病,由于儿童的血脑屏障发育暂不完善,极易受到细菌、病毒等各类病原体侵犯,导致脑实质、脑膜等部位发生炎性、非炎性疾病。若未能及时诊治,可引发脑积水、脓肿等,严重者可危及患儿生命。现阶段,临床鉴别诊断ICNS的常用方法为血清学、脑脊液检查,但儿童依从性普遍较差,脑脊液检查危险性高;而血清标志物检测操作简便、对儿童造成的痛苦较小且安全性高,是临床鉴别诊断各类疾病的常用检测方式。因此,寻找有效、准确鉴别诊断儿童ICNS的血清学指标十分重要。

幕下原发性中枢神经系统淋巴瘤的MRI多模态分析

目的分析幕下原发性中枢神经系统淋巴瘤(PCNSL)的MRI表现,以提高鉴别诊断能力。方法回顾性分析经病理证实为幕下PCNSL的11例患者的临床、病理及MRI资料。结果男8例,女3例;年龄19~68岁。11例均为单发病灶,其中右侧桥小脑角区及四脑室各1例,位于小脑9例。大部分病灶T2WI呈等信号,DWI呈高信号,增强10例明显均匀强化,1例环状强化,可见“脐凹征”9例、“裂隙征”3例、“尖角征”8例、“内环征”2例、“梳齿征”5例。4例瘤周中度水肿,7例瘤周重度水肿。MRS出现高耸的LIP峰。9例ASL检查8例呈低灌注,1例呈高灌注。结论幕下PCNSL临床缺乏特异性,除了典型征象,认识“内环征”及“梳齿征”,可提高术前诊断率。