16例小脑毛细胞型星形细胞瘤MRI及病理分析

目的 探讨小脑毛细胞型星形细胞瘤的磁共振成像(MRI)影像特点和病理学特征.方法 回顾性分析16例小脑毛细胞型星形细胞瘤的术后病理、术前MRI资料.结果 16例小脑毛细胞型星形细胞瘤中,发生于小脑蚓部11例,小脑半球5例.小脑毛细胞型星形细胞瘤可呈单纯囊肿型、囊肿附壁结节型或瘤囊型.MRI平扫肿瘤境界清楚,无明显瘤周水肿;增强扫描囊壁瘤结节或瘤体部分明显强化,囊壁光滑、强化或不明显强化.显微镜下瘤组织内致密、疏松区双相交替,瘤细胞呈细长梭形,致密区见数量不等Rosenthal纤维,疏松区有微囊样结构、嗜酸性小体形成;肿瘤免疫组化GFAP强阳性.结论 小脑毛细胞型星形细胞瘤MRI影像表现和病理组织学具有特征性,把握其病理特点有助于术前影像诊断.     

CT、MRI检查对儿童毛细胞型星形细胞瘤的诊断价值

目的 探讨CT、MRI检查对儿童毛细胞型星形细胞瘤（PA）的诊断价值。方法 选取107例疑似PA患儿,均接受CT、MRI检查,以病理检查结果为金标准,评估CT、MRI检查对PA的诊断价值。结果 病理检查结果显示,107例患者中阳性85例,阴性22例。CT检查诊断PA的灵敏度、特异度、准确度分别为67.06%、40.91%、61.68%,与病理检查结果的一致性一般（Kappa=0.541,P﹤0.01）;MRI检查诊断PA的灵敏度、特异度、准确度分别为78.82%、77.27%、78.50%,与病理检查结果的一致性一般（Kappa=0.608,P﹤0.01）。CT检查诊断PA的特异度和准确度均低于MRI检查,差异均有统计学意义（P﹤0.05）。结论 MRI检查诊断PA的价值较高,诊断特异度和准确度均高于CT检查。     

毛细胞型星形细胞瘤的临床特点和外科治疗

背景和目的：毛细胞型星形细胞瘤是一特殊病理类型的星形细胞瘤，本文结合我们的临床病例，探讨毛细胞型星形细胞瘤的临床特点、病理学和影像学特点以及治疗方法。方法：回顾性分析我院近7年来18例经手术病理证实的毛细胞型星形细胞瘤临床资料。结果：18例患者平均发病年龄20岁，大多位于小脑，临床表现主要为颅内压增高症和共济失调，CT和MRI可分为囊性伴囊壁结节、假囊性伴囊壁结节、实质性3种影像学表现。病理以镜下见到大量Rosenthal氏纤维为特征性改变。预后与手术切除程度有关，全切组(11例)无肿瘤复发；部分残留组(6例)肿瘤易复发(2例)和恶性变(1例)，未放疗组1例肿瘤复发，为次全切除组。结论：毛细胞型星形细胞瘤好发于年轻人和小脑，有较典型的影像学和病理学特点，应争取外科全切除。对未全切病例术后应行放疗，化疗可作为预防肿瘤复发的一种辅助治疗方法。     

31例小脑毛细胞型星形细胞瘤形态学观察

小脑毛细胞型星形细胞瘤是少见的肿瘤，国内文献报告极少。主要表现：头痛、恶心、呕吐、视物不清、走路不稳等颅内压增高症状。肿瘤多位于小脑蚓部、半球及四脑室，大体有囊性变．     

血管畸形合并毛细胞星形细胞瘤1例报告

1病例报告患者女性,11岁,因反复头晕、头痛1个月入院。CT示:右侧颞枕叶可见高密度影,范围约3.5 cm×2.5 cm,边界清晰,CT值45～57 HU,周边呈低密度影,周围脑室受压变窄,局灶脑沟消失,中线结构向左侧移位。临床诊断:右侧颞枕叶血管畸形。遂行右侧颞枕叶病灶切除术,术中见:右侧颞枕叶一灰红色结     

脑多形性黄色瘤型星形细胞瘤的病理特征分析

目的:探讨脑多形性黄色瘤型星形细胞瘤（pleomorphic xanthoastrocytoma,PXA）的病理特征。方法:对1例左侧海马脑PXA进行头颅MRI检查、病理检查及免疫组织化学检查,并对其结果进行分析。结果:头颅MRI在左侧海马发现直径约0.8mm的斑片状异常信号影,T1W1稍低信号,T2W1 稍高信号,部分囊影呈现高信号,边界不清楚,未见明显占位效应。其余脑组织的信号均匀,异常信号影未见。光镜检查结果显示肿瘤组织含较多砂粒体、似黄色瘤样,与正常脑实质的界限欠清,细胞形态多样,由梭形、单核样及椭圆形等形态细胞组成,多核瘤巨细胞也散在可见,瘤细胞胞浆有的含脂滴,瘤细胞间质可见嗜酸性颗粒小体,灶区附近可见散在淋巴粒细胞浸润。对PXA患者进行免疫组织化学及组织化学特染发现,肿瘤细胞表达中GFAP、CD34、S-100、Vimenin为阳性,EMA、CD163、NF、NeuN染色为阴性,Ki-67增殖指数小于2%;对其进行网状纤维染色,可发现网状纤维网将瘤细胞分割包绕于其中。结论:脑PXA的临床影像学及病理特征具有一定的特征性,正确认识其特征对其临床诊断和治疗具有指导作用。     

儿童颅内毛细胞黏液样星形细胞瘤8例影像学表现

摘 要：［目的］ 探讨儿童毛细胞黏液样星形细胞瘤（PMA）的影像学表现。［方法］ 回顾性分析8例颅内PMA患儿信息,总结分析其影像学特点。［结果］ 肿瘤均边界清楚,位于下丘脑-视交叉-第三脑室区5例;MRI检查,实性病灶4例,囊实性1例;T1WI,4例病灶实性成分表现为低信号,1例信号略高,呈等低信号;T2WI,4例表现为高或略高信号,1例实性部分呈等信号;T2FLAIR上3例呈稍高信号,2例呈等信号;DWI病灶均呈低信号。5例增强后实性成分均明显强化。2例侵犯视交叉、视束、丘脑及基底节区。2例出现脑脊液播散。病灶均无明显瘤周水肿。位于小脑蚓部3例;MRI检查,2例以实性成分为主,其内可见囊变,1例为囊实性;T1WI实性成分均表现为等低信号;T2WI均表现为高或略高信号;2例增强后实性成分明显强化,1例病灶无明显强化;DWI呈低信号;病灶均无明显瘤周水肿;1例行SWI检查,可见病灶内点状出血。平扫CT检查,7例表现为等低密度,1例表现为稍高密度。［结论］ PMA好发于儿童和青少年,下丘脑-视交叉-第三脑室区常见,年龄偏小（平均2.4岁）,发生在小脑区者年龄较大（平均5.5岁）;肿瘤多以实性为主,强化方式多样,肿瘤内出血和周围水肿少见,脑脊液播散较常见。     

星形细胞瘤临床病理研究

目的对星形细胞瘤进行分级，探讨组织类型、分级与复发、预后的关系。方法依据WHO神经系统肿瘤新分类对79例颅内星形细胞瘤的临床和病理资料进行回顾性研究。结果组织类型、分级与预后生存率差异有显著性，Ⅲ级间变性星形细胞瘤和Ⅳ级胶质母细胞瘤术后2年、5年的生存率偏低。结论星形细胞瘤患者的预后与病理组织学类型、分级明显相关。     

髓内星形细胞瘤与室管膜瘤的MRI诊断与鉴别诊断

目的:探讨髓内星形细胞瘤与室管膜瘤的MRI表现及鉴别诊断要点。方法:回顾性分析12例髓内星形细胞瘤与室管膜瘤患者的临床资料和MRI资料,并总结其MRI特征。结果:12例患者中,星形细胞瘤7例,室管膜瘤5例。7例星形细胞瘤中,4例位于颈段脊髓,3例位于胸段脊髓,MRI表现为浸润性生长,范围广泛,增强扫描呈不均匀强化,边界不清,趋向于散在强化。5例室管膜瘤中,3例位于颈段脊髓,2例位于圆锥和终丝段,多呈膨胀性生长,可占据整个脊髓断面,增强扫描呈较均匀性强化,边界可相对清楚,多伴有脊髓空洞和囊变,出血常见。结论:髓内室管膜瘤手术可完全切除,预后较好;星形细胞瘤较难完全切除,预后相对较差,MRI可提供对于二者的鉴别依据,具有一定的临床意义。     

脑星形细胞瘤形态计量病理分级诊断的研究

目的:探讨星形细胞瘤形态定量病理分级诊断方法。方法:应用图像分析定量技术,对136例人星形细胞瘤和3例正常对照的细胞核的面积等8项形态参数、肿瘤4项分布密度参数和细胞核分维值进行量化。结果:经图像分析定量,说明细胞核的面积、周长、直径、短轴和长轴、细胞核数、巨细胞面数密度、血管交点面数密度和细胞核面数密度等9项指标能够较好地反映星形细胞瘤4级间的差异,具有较好的鉴别诊断价值。结论:应用形态计量方法进行星形细胞瘤的病理分级诊断更加客观可靠。     

Adult pilocytic astrocytomas: clinical features and molecular analysis

Background

Adult pilocytic astrocytomas (PAs) are rare and have an aggressive clinical course compared with pediatric patients. Constitutive Ras/RAF/MAPK signaling appears to be an important oncogenic event in sporadic PA. We evaluated clinical data and molecular profiles of adult PAs at our institution.

Methods

We identified 127 adult PAs in our institutional database. Cases with available tissue were tested for BRAF-KIAA1549 fusion/duplication (B-K fusion) by fluorescence in situ hybridization and submitted for mutation profiling using the Sequenom mutation profiling panel. Subgroup analyses were performed based on clinical and molecular data.

Results

The majority of adult PAs are supratentorial. Twenty-two percent of cases had an initial pathologic diagnosis discordant with the diagnosis made at our institution. Recurrence was seen in 42% of cases, and 13% of patients died during follow-up. Adjuvant radiotherapy following surgical resection was associated with a statistically significant decrease in progression-free survival (P = .004). B-K fusion was identified in 20% (9 of 45) of patients but was not associated with outcome. No BRAF V600E mutations (0 of 40 tested) were found.

Conclusion

This was the largest single institution series of adult PA. A significant proportion of adult PAs follow an aggressive clinical course. Our results support a period of observation following biopsy or surgical resection. B-K fusion in adult PA does not influence outcome, and BRAF V600E mutation appears to be a very rare event. Further study of tumor biology and optimal treatment is needed, given a more aggressive clinical behavior.     

Analysis of pilocytic astrocytoma by comparative genomic hybridization

Very little is known about genetic abnormalities involved in the development of pilocytic astrocytoma, the most frequently occurring brain tumour of childhood. We have analysed 48 pilocytic astrocytoma specimens using comparative genomic hybridization. Only five of 41 tumours from children showed abnormalities detectable by comparative genomic hybridization, and in each case this represented gain of a single chromosome. Interestingly, two of seven tumours from adults showed abnormalities, which were multiple and relatively complex. Six of the seven tumours showing abnormalities were from female patients (two adults and four children). The most frequently detectable abnormality was gain of 9q34.1-qter, which was present in three cases (two adult and one paediatric).     

Upfront observation versus radiation for adult pilocytic astrocytoma

BACKGROUND:

Although pilocytic astrocytoma accounts for up to 40% of all childhood brain tumors, it is a rare disease in adults. Consequently, there are few mature data on the impact of up‐front treatment options after surgery that include observation or adjuvant radiotherapy.

METHODS:

Ten women and 20 men were identified who were diagnosed with pilocytic astrocytoma from 1971 to 2007 and were retrospectively reviewed. The median patient age was 30 years (range, 18‐64 years), and the median follow‐up was 87 months (range, 16‐420 months). Initial surgery included biopsy (10% of patients), subtotal resection (57% of patients), or gross‐total resection (33% of patients). Nineteen patients were observed postoperatively, whereas 11 patients received up‐front postoperative adjuvant radiotherapy (50 grays in 25 fractions). No patient received adjuvant or concurrent chemotherapy. Progression‐free survival (PFS) and overall survival (OS) were calculated using the Kaplan‐Meier method. Differences between survival curves were analyzed with the log‐rank test.

RESULTS:

For the entire cohort, the 5‐year and 10‐year OS rates were 95% and 85%, respectively, and the 5‐year and 10‐year PFS rates were 63% and 35%, respectively. The median PFS was 8.4 years. Initial radiation, compared with observation, did not have an impact on OS but significantly improved PFS. The 5‐year PFS rate for patients who were observed versus those who received radiation was 42% versus 91%, respectively; and, at 10 years, the PFS rate was 17% versus 60%, respectively (P = .005). Patients who progressed after observation (11 of 19 patients) received various salvage therapies, resulting in a 2‐year PFS rate of 68% compared with 33% for patients who progressed after initial radiation (3 of 11 patients) and were salvaged with either chemotherapy or surgery (P = .1).

CONCLUSIONS:

Adjuvant radiotherapy for pilocytic astrocytoma significantly prolonged PFS at both 5 years and 10 years compared with observation. However, equivalent OS was observed, which reflected the efficacy of salvage therapies. Cancer 2011;. © 2011 American Cancer Society.     

Frequent recurrence and progression in pilocytic astrocytoma in adults

BACKGROUND: Most pilocytic astrocytomas (piloA) are benign growths (World Health Organization [WHO] grade 1) of the deep midline structures, the brainstem, and the cerebellum. To the authors' knowledge, the literature contains only scarce data regarding piloA in adults. METHODS: Between 1995 and 2005, 44 patients (26 women and 18 men) underwent surgery for a primary or recurrent piloA at the authors' institution. All patients were aged > 16 years (mean +/- standard deviation: 31 +/- 14 years) at the time of their first surgery. The histopathologic diagnoses were reviewed, and relevant clinical information was obtained through a chart review and telephone interviews. The mean follow-up was 76 +/- 59 months (range, 1-227 months). RESULTS: There were 20 patients (45%) with supratentorial lobar piloA (including 10 temporal/temporomesial tumors, 5 parietal tumors, 3 insular tumors, 1 frontal tumor, and 1 occipital tumors), 12 patients with cerebellar piloA, 7 patients with brainstem piloA, 2 patients with opticochiasmatic PiloA, 1 patient with intramedullary piloA, and 2 patients with piloA of the basal ganglia. All but 1 patient with a lobar tumor presented with epilepsy. In 6 of 44 patients (14%), increased proliferative activity was revealed. WHO grade 3 primary anaplastic piloA was diagnosed in 2 patients (5%), and WHO grade 3 secondary anaplastic piloA was diagnosed in 4 patients (9%). Tumor recurrence or disease progression was observed in 13 of 44 patients (30%). Eight of 44 patients (18%) died from their disease. Histologic grading and extent of surgical resection proved to be important predictors of survival. CONCLUSIONS: PiloA in adult patients, surprisingly, often was not a benign disease. The degree of surgical resection was found to be of major importance for the patient's further clinical course; therefore, an aggressive surgical resection should be attempted whenever possible.     

Unusual early recurrence of a cerebellar pilocytic astrocytoma following complete surgical resection

Summary Pilocytic cerebellar astrocytomas are usually benign tumors with generally an excellent prognosis following complete surgical resection. The goal of surgery is total resection to minimize the risk of recurrence. In this case report, a 5-year old boy who had undergone total resection of a posterior fossa pilocytic cerebellar astrocytoma (as documented by a contrast-enhanced computed tomography (CT) scan within 24 hours following surgery), developed a massive recurrence of the tumor within four months. Both the initial histology and the sections examined after the second resection revealed features typical for a pilocytic astrocytoma with no suspicion of malignancy. This case is unusual in that it is contrary to other reports suggesting that CT-documented complete surgical resection of pilocytic astrocytomas is without recurrence, and suggests the need for vigilant radiographic and clinical follow-up of these patients even if apparent complete resection of the tumor has been achieved.     

Hemorrhagic onset of pilocytic astrocytoma and pilomyxoid astrocytoma

The incidence of hemorrhagic onset in pilocytic astrocytoma and pilomyxoid astrocytoma, and the clinical and histological characteristics, were compared to other types of neuroepithelial tumors or nonhemorrhagic pilocytic astrocytoma by retrospective review of 445 consecutive neuroepithelial tumors treated at our institute. Hemorrhagic onset was observed in 4 of 35 (11.4%) patients with pilocytic astrocytoma and pilomyxoid astrocytoma, with higher incidence than in glioblastoma (3.9%), anaplastic oligodendroglioma (7.7%), and anaplastic ependymoma (7.1%). The hemorrhagic onset occurred in 2 patients with sporadic pilocytic astrocytoma, 1 with pilocytic astrocytoma associated with neurofibromatosis type 1, and 1 with pilomyxoid astrocytoma. There was no correlation between hemorrhagic onset and clinical features, including age, sex, tumor location, proliferative activity, or microvascular proliferation. Hemorrhagic onset of pilocytic astrocytoma and pilomyxoid astrocytoma is not as uncommon as was previously thought, so pilocytic astrocytoma or pilomyxoid astrocytoma should be considered in the differential diagnosis of patients with brain tumors manifesting as hemorrhagic onset.     

Functional characterization of a BRAF insertion mutant associated with pilocytic astrocytoma

Pilocytic astrocytoma (PA) is emerging as a tumor entity with dysregulated Ras/Raf/MEK/ERK signaling. Common genetic lesions observed in PA, which are linked to aberrant ERK pathway activity, include either NF1 inactivation, KRAS or BRAF gain-of-function mutations. To investigate the mutation spectrum within the proto-oncogene encoding the Ser/Thr-kinase B-Raf in more detail, we analyzed 64 primary tumor samples from children with PA including two patients with neurofibromatosis type 1 (NF1). The well-known BRAF(V600E) mutation was found in 6/64 (9.38%) of our samples. For the first time, we report concomitant presence of a somatic BRAF(V600E) mutation in an NF1 patient indicating that more than one Ras/ERK pathway component can be affected in PA. Furthermore, 2/64 (3.13%) of our samples carried a 3-bp insertion in BRAF resulting in the duplication of threonine 599. This conserved residue is located within the activation segment and, if phosphorylated in a Ras-dependent manner, plays a key role in Raf activation. Here, we demonstrate that this mutant (B-Raf(insT) ) and another B-Raf mutant, which carries two additional threonine residues at this position, display an in vitro kinase activity and cellular MEK/ERK activation potential comparable to those of B-Raf(V600E) . Notably, replacement of threonines by valine residues had similar effects on B-Raf activity, suggesting that the distortion of the peptide backbone by additional amino acids rather than the insertion of additional, potential phosphorylation sites destabilizes the inactive conformation of the kinase domain. We also demonstrate that B-Raf(insT) and B-Raf(V600E) , but not B-Raf(wt) , provoke drastic morphological alterations in human astrocytes.     

毛黏液星形细胞瘤的临床病理观察(英文)

Objective:The aim of this study was to study the clinicopathological and immunohistochemical features of pilomyxoid astrocytoma(PMA).Methods:The clinical and pathologic features in six cases of PMA were analyzed.Immunohistochemical staining for glial fibrillary acidic protein(GFAP),synaptophysin(Syn),Chromogranin A(CgA),cytokeratin(AE1/AE3),epithelial membrane antigen(EMA)and Ki67 was performed on paraffin-embedded sections.Results:Among the six cases,five occurred in female patients,one was male,the age at diagnosis ranged from 2 to 15 years.Four cases were located in the hypothalamic area and optic pathway,one case in the third ventricle,and one case in left parietal lobe.On imaging,PMAs often appears as well-circumscribed mass.Microscopically,the tumor was composed of monomorphous bipolar(piloid)cells setting in a prominent myxoid background with an angiocentric radiating growth pattern in some areas.PMA lacked biphasic pattern,Rosenthal fibers and eosinophilic granular bodies which were usually typical in a classic pilocytic astrocytoma(PA).Immunohistochemcal study showed that the tumor cells were diffusely positive for GFAP.Syn positive staining was observed in one case.The Ki67 labeling index measured less than 5%.Conclusion:PMA is a distinct aggressive variant of pilocytic astrocytoma with special histological and immunohistochemical features.It is typically a rare tumor of early childhood.Immunohistochemical staining for GFAP and Syn is helpful in differential diagnosis.     

MicroRNA profiling in pediatric pilocytic astrocytoma reveals biologically relevant targets,including PBX3, NFIB,and METAP2

Pilocytic astrocytoma (PA) is a World Health Organization grade I glioma that occurs most commonly in children and young adults. Specific genetic alterations have been described in PA, but the pathogenesis remains poorly understood. We studied microRNA (miRNA) alterations in a large cohort of patients with PA. A total of 43 PA, including 35 sporadic grade I PA, 4 neurofibromatosis-1 (NF1)–associated PA, and 4 PA with pilomyxoid features, as well as 5 nonneoplastic brain controls were examined. BRAF fusion status was assessed in most cases. RNA was examined using the Agilent Human miRNA Microarray V3 platform. Expression of miRNA subsets was validated using quantitative real-time PCR (qRT-PCR) with Taqman probes. Validation of predicted protein targets was performed on tissue microarrays with the use of immunohistochemistry. We identified a subset of miRNAs that were differentially expressed in pediatric PAs versus normal brain tissue: 13 miRNAs were underexpressed, and 20 miRNAs were overexpressed in tumors. Differences were validated by qRT-PCR in a subset, with mean fold change in tumor versus brain of -17 (miR-124), -15 (miR-129), and 19.8 (miR-21). Searching for predicted protein targets in Targetscan, we identified a number of known and putative oncogenes that were predicted targets of miRNA sets relatively underexpressed in PA. Predicted targets with increased expression at the mRNA and/or protein level in PA included PBX3, METAP2, and NFIB. A unique miRNA profile exists in PA, compared with brain tissue. These miRNAs and their targets may play a role in the pathogenesis of PA.