Anaplastic ganglioglioma with epithelioid cell components

A 40‐year‐old man was admitted to our hospital because of disorientation and mild left‐sided weakness. Radiological examination revealed a solid and cystic tumor in the right temporal lobe, and total resection was performed. Histologically, the tumor was composed mainly of low‐grade gangiloglioma and had some high‐grade glial components with focal necrosis and microvascular proliferations. In the high‐grade component, there were epithelioid cells with round cytoplasm and eccentric nuclei. The high‐grade area with epithelioid cells was intermingled within the low‐grade area, which suggests that epithelioid cells were an anaplastic transformation of ganglioglioma. The epithelioid cells were histologically similar to neoplastic cells of epithelioid glioblastoma (E‐GBM), a rare aggressive variant of isocitric dehydrogenase wild‐type glioblastoma. A BRAF V600E mutation, frequently observed in E‐GBM, was detected in both the ganglioglioma and epithelioid cell components. The epithelioid cells were mitotically active, which suggests that if the surgery was delayed, the histological appearance might have eventually evolved into E‐GBM. Indeed, a case of pleomorphic xanthoastrocytoma which transformed into E‐GBM after a long latency was reported elsewhere. This is the first report to describe focal epithelioid cells in anaplastic ganglioglioma.     

Response to combined BRAF/MEK inhibition in adult BRAF V600E mutant spinal pilocytic astrocytoma

Pilocytic astrocytomas are World Health Organisation (WHO) grade I tumors, occurring predominantly supratentorially and in the pediatric population. Although the mainstay of treatment is local therapies such as surgery, targeted systemic therapies may be necessary for recurrent or unresectable disease. The majority of sporadic pilocytic astrocytomas are associated with the BRAF-KIAA fusion gene, which results in constitutive activation of the MAP Kinase pathway. Less frequently, the BRAF V600E point mutation has been described, occurring in less than 10% of supratentorial pilocytic astrocytomas. Tumours with this mutation may respond to targeted therapy against the BRAF/MAP Kinase pathway. We report the first described case of a spinal pilocytic astrocytoma in an adult patient with a BRAF V600E mutation responding to targeted therapy using BRAF and MEK tyrosine kinase inhibitors, and share our experiences with the management of toxicity in this patient population.     

BRAF alterations are frequent in cerebellar low-grade astrocytomas with diffuse growth pattern

Cerebellar low-grade astrocytomas with a diffuse pattern of growth are uncommon, comprising World Health Organization (WHO) grade II diffuse astrocytomas (DA) and a minority of WHO grade I pilocytic astrocytomas (PA), so-called PA, "diffuse variant." Among 106 cerebellar low-grade astrocytomas (WHO grade I and II) operated on at the Mayo Clinic (1984-2010), we identified 19 such cases: 8 PA, "diffuse variant," 5 DA, and 6 that we were unable to classify further (low-grade astrocytomas, subtype indeterminate). We characterized these tumors using immunohistochemistry and currently available molecular markers (IDH1/2 mutations and BRAF mutation/fusion gene status) and investigated whether the markers could be used to aid the diagnostic process in combination with the clinical and pathologic features. KIAA1549-BRAF fusion was detected in 4 PA, "diffuse variant," 2 DA, and 2 low-grade astrocytomas, subtype indeterminate, indicating that these tumors were molecularly consistent with PA, the most common subtype of the series. A BRAF V600E mutation was detected in 1 PA, "diffuse variant" case; an IDH1 R132G mutation was found in 1 DA case. These results suggest that KIAA1549-BRAF fusion status and IDH1/2 and BRAF V600E mutational analyses may assist in the histologic classification of this diagnostically challenging group of tumors and result in a more accurate and objective combined molecular and histologic classification.     

Clinical neuropathology practice news 2-2012: BRAF V600E testing

Activating mutations of the serine threonine kinase v-RAF murine sarcoma viral oncogene homologue B1 (BRAF), most commonly of the V600E type, are found in a wide range of human neoplasms including primary and secondary brain tumors. Therapeutic BRAF inhibitors have shown clinically meaningful activity, particularly in metastatic BRAF V600E mutated melanoma including patients with brain metastases. Therefore, in current neuropathological practice BRAF testing is of clinical importance in tissue samples of melanoma brain metastases in order to identify cases amenable to therapy with BRAF inhibitors. BRAF mutation testing may also add additional information for differential diagnosis of primary brain tumors in selected situations, e.g., for differentiation of anaplastic pleomorphic xanthoastrocytoma (BRAF V600E mutation in 65%) from glioblastoma (BRAF V600E mutation in < 5%). The BRAF mutation status can be tested with DNA-based methods and immunohistochemistry using a V600E mutation-specific antibody. In summary, at this point BRAF V600E testing is clinically indicated in relatively few cases of the daily clinical neuropathology practice, but has important predictive implications for patients with melanoma brain metastases. Depending on the results of additional clinical studies, determination of BRAF mutation status may become clinically relevant also for primary brain tumors such as glioblastoma in the future.     

A comprehensive analysis identifies BRAF hotspot mutations associated with gliomas with peculiar epithelial morphology

Brain tumors harbor various BRAF alterations, the vast majority of which are the BRAF kinase‐activating V600E mutation. BRAF mutations are most frequently detected in certain subtypes of low‐grade glioma, such as pilocytic astrocytoma (PA), pleomorphic xanthoastrocytoma (PXA), ganglioglioma (GG) and dysembryoplastic neuroepithelial tumor (DNT). However, it is unclear whether gliomas harboring BRAF mutations can be invariably regarded as these glioma subtypes or their derivatives. To address this question, we analyzed 274 gliomas in our institutional case series. We performed high‐resolution melting analyses and subsequent direct Sanger sequencing on DNA isolated from snap‐frozen tumor tissues. As expected, BRAF mutations were detected in the aforementioned low‐grade gliomas: in 4/27 PAs, 2/3 PXAs, 4/8 GGs, and 1/6 DNTs. In addition to these gliomas, 1/2 astroblastomas (ABs) and 2/122 glioblastomas (GBs) harbored BRAF mutations. Pathological investigation of the two GBs revealed that one was a GB displaying epithelial features that presumably arose from a precedent GG, whereas the other GB, which harbored a rare G596 A mutation, showed marked epithelial features, including astroblastic rosettes. Our results indicate that in addition to being present in established BRAF‐associated gliomas, BRAF mutations might be associated with epithelial features in high‐grade gliomas, including sheet‐like arrangement of polygonal tumor cells with a plump cytoplasm and astroblastic rosettes, and thus could potentially serve as a genetic marker for these features.     

A case of high‐grade astrocytoma with BRAF and ATRX mutations following a long‐standing course over two decades

Pediatric high‐grade gliomas are rare and occasionally hard to classify. These tumors often feature a well‐demarcated histology and are expected to have a better outcome than ordinary diffuse high‐grade gliomas in adults. We herein report a case of circumscribed high‐grade glioma that showed a distinct molecular profile and followed an excellent course for 26 years. The patient, a 3‐year‐old boy at onset, presented with a contrast‐enhancing mass in the right temporal lobe and underwent resection. Histologically, the tumor mainly consisted of compact bundles of GFAP‐positive spindle cells. With its malignant features including brisk mitotic activity and pseudopallisading necrosis, a diagnosis of high‐grade astrocytoma was made and adjuvant chemoradiotherapy was administered. After a disease‐free period of two decades, the tumor recurred locally. The resected tumor was histologically identical to the primary tumor and additionally contained pleomorphic cells, but lacked eosinophilic granular bodies and reticulin networks. The primary and recurrent tumors both harbored the BRAF V600E mutation, and the recurrent tumor was immunonegative for ATRX. Combined BRAF and ATRX mutations are rare in gliomas, with only a pediatric case of glioblastoma being reported in the literature. However, our case cannot be regarded as glioblastoma because of its well‐demarcated histology and excellent course. The distinction of either a diffuse or localized nature in gliomas is important, particularly in children, for predicting prognoses and selecting adjuvant therapies that consequently affect life‐long health care. The present case provides novel insights into pediatric high‐grade astrocytomas.     

Analysis of BRAF V600E mutation in 1,320 nervous system tumors reveals high mutation frequencies in pleomorphic xanthoastrocytoma, ganglioglioma and extra-cerebellar pilocytic astrocytoma

Missense mutations of the V600E type constitute the vast majority of tumor-associated somatic alterations in the v-RAF murine sarcoma viral oncogene homolog B1 (BRAF) gene. Initially described in melanoma, colon and papillary thyroid carcinoma, these alterations have also been observed in primary nervous system tumors albeit at a low frequency. We analyzed exon 15 of BRAF spanning the V600 locus by direct sequencing in 1,320 adult and pediatric tumors of the nervous system including various types of glial, embryonal, neuronal and glioneuronal, meningeal, adenohypophyseal/sellar, and peripheral nervous system tumors. A total of 96 BRAF mutations were detected; 93 of the V600E type and 3 cases with a three base pair insertion between codons 599 and 600. The highest frequencies of BRAF (V600E) mutations were found in WHO grade II pleomorphic xanthoastrocytomas (42/64; 66%) and pleomorphic xanthoastrocytomas with anaplasia (15/23; 65%), as well as WHO grade I gangliogliomas (14/77; 18%), WHO grade III anaplastic gangliogliomas (3/6) and pilocytic astrocytomas (9/97; 9%). In pilocytic astrocytomas BRAF (V600E) mutation was strongly associated with extra-cerebellar location (p?=?0.009) and was most frequent in diencephalic tumors (4/12; 33%). Glioblastomas and other gliomas were characterized by a low frequency or absence of mutations. No mutations were detected in non-glial tumors, including embryonal tumors, meningiomas, nerve sheath tumors and pituitary adenomas. The high mutation frequencies in pleomorphic xanthoastrocytomas, gangliogliomas and extra-cerebellar pilocytic astrocytomas implicate BRAF (V600E) mutation as a valuable diagnostic marker for these rare tumor entities. Future clinical trials should address whether BRAF (V600E) mutant brain tumor patients will benefit from BRAF (V600E)-directed targeted therapies.     

Correlation between magnetic resonance imaging characteristics and BRAF alteration status in individuals with optic pathway/hypothalamic pilocytic astrocytomas

Background and purposeMost individuals with optic pathway/hypothalamic pilocytic astrocytoma (OPHPA) harbor either the BRAF V600E mutation or KIAA1549-BRAF fusion (K-B). This study aimed to investigate the imaging characteristics of OPHPA in relation to BRAF alteration status.Materials and methodsSeven cases of OPHPA harboring either the BRAF V600E mutation or K-B fusion were included in the study. Preoperative magnetic resonance imaging (MRI) was assessed for degree of T2 hyperintensity on T2-weighted images (T2WI) and the ratio of nonenhancing T2 or fluid-attenuated inversion recovery (FLAIR) hyperintense area to the contrast enhanced area (CE) on gadolinium-enhanced-T1 weighted images (T2/FLAIR-CE mismatch). The T2 signal intensity was normalized to cerebrospinal fluid (T2/CSF) for both the V600E and K-B group and compared. T2/FLAIR-CE mismatch was assessed by calculating the proportion of the tumor volume of nonenhancing high T2 signal intensity to the whole lesion (nonenhancing and enhancing components).ResultsFour and three cases of OPHPA harboring the BRAF V600E mutation and K-B, respectively, were analyzed. The T2/CSF value was higher in the K-B group than in the V600E group. Moreover, the V600E group had a larger T2/FLAIR-CE mismatch than the K-B group.ConclusionsThe BRAF alteration status in individuals with OPHPA was associated with preoperative MRI by focusing on T2 signal intensity and T2/FLAIR-CE mismatch. The BRAF V600E mutation was associated with a lower T2/CSF value and larger T2/FLAIR-CE mismatch, whereas K-B fusion was associated with a higher T2/CSF value and smaller T2/FLAIR-CE mismatch.     

Adult diffuse leptomeningeal glioneuronal tumour with limited leptomeningeal involvement,lack of 1p deletion and BRAF V600E mutation

Diffuse leptomeningeal glioneuronal tumours (DLGNT) are rare primary CNS tumours, traditionally characterised by leptomeningeal growth and usually affecting children. A recent large study defined DLGNT on a molecular basis, of which all demonstrated 1p deletions. The vast majority also demonstrated MAPK/ERK pathway activations, however BRAF V600E mutation has not been previously documented in adult cases. In this case report, we describe an unusual cerebral DLGNT, with limited leptomeningeal spread, intact 1p status and a BRAF V600E mutation.     

Immunohistochemical testing of BRAF V600E status in 1,120 tumor tissue samples of patients with brain metastases

Brain metastases (BM) are frequent and carry a dismal prognosis. BRAF V600E mutations are found in a broad range of tumor types and specific inhibitors targeting BRAF V600E protein exist. We analyzed tumoral BRAF V600E-mutant protein expression using the novel mutation-specific antibody VE1 in a series of 1,120 tumor specimens (885 BM, 157 primary tumors, 78 extra-cranial metastases) of 874 BM patients. In 85 cases, we performed validation of immunohistochemical results by BRAF exon 15 gene sequencing. BRAF V600E protein was expressed in BM of 42/76 (55.3%) melanomas, 1/15 (6.7%) ovarian cancers, 4/72 (5.5%) colorectal cancers, 1/355 (0.3%) lung cancers, 2/6 thyroid cancers and 1/2 choriocarcinomas. BRAF V600E expression showed high intra-tumoral homogeneity and was similar in different tumor manifestations of individual patients. VE1 immunohistochemistry and BRAF exon 15 sequencing were congruent in 68/70 (97.1%) cases, but VE1 immunostaining identified small BRAF V600E expressing tumor cell aggregates in 10 cases with inconclusive genetic results. Melanoma patients with BRAF V600E mutant protein expressing tumors were significantly younger at diagnosis of the primary tumor and at operation of BM than patients with non-mutated tumors. In conclusion, expression of BRAF V600E mutant protein occurs in approximately 6% of BM and is consistent in different tumor manifestations of the same patient. Thus, BRAF V600E inhibiting therapies seem feasible in selected BM patients. Immunohistochemical visualization of V600E-mutant BRAF protein is a promising tool for patient stratification. An integrated approach combining both, VE1 immunohistochemistry and genetic analysis may increase the diagnostic accuracy of BRAF mutation analysis.     

BRAF V600E mutation is a significant prognosticator of the tumour regrowth rate in brainstem gangliogliomas

BRAF V600E mutations are progression factors in paediatric low-grade gliomas. Furthermore, a high percentage of paediatric brainstem gangliogliomas have BRAF V600E mutations. However, their clinical significance, including possible connections between the biomarkers and ganglioglioma’s clinical features, especially a brainstem counterpart, is unclear. To identify potential molecular features predictive of brainstem ganglioglioma’s clinical outcomes, a retrospective cohort of 28 World Health Organization (WHO) grade I brainstem gangliogliomas was analysed for BRAF V600E, IDH1 R132H, and IDH2 R172K mutations, TERT C228T/C250T promoter mutation, H3F3A K27M mutation and MGMT methylation. The volume of tumours was calculated accurately by using 3D Slicer software. The clinical data of these patients were retrospectively analysed. In tumours with BRAF V600E mutations, the tumour regrowth rate was significantly faster than that of the wild type group (p = 0.001). Moreover, the BRAF V600E mutant group had shorter progression-free survival (PFS) compared with wild type (p = 0.012). On multivariate analysis, no factor was found to be an independent prognostic factor; however, tumours with faster regrowth rates had a strong trend towards an increased risk for shorter PFS (HR = 1.027, p = 0.056). No statistical analysis could be performed to evaluate factors affecting overall survival (OS). These data suggest that BRAF V600E can predict the regrowth rate of brainstem gangliogliomas after microsurgery, and a BRAF V600E-targeted therapeutic may be a promising early intervention measure for patients who harbour BRAF V600E mutation after microsurgery.     

Mutant BRAF V600E protein in ganglioglioma is predominantly expressed by neuronal tumor cells

Ganglioglioma is a rare CNS tumor with a benign biological behavior. Recently, the BRAF V600E mutation was identified in approximately 20 % of gangliogliomas. Here, we analyzed a total of 71 gangliogliomas for BRAF V600E mutational status by VE1 immunohistochemistry and direct DNA sequencing. The BRAF V600E mutation was detected in 41/71 (58 %) gangliogliomas by immunohistochemistry. DNA sequencing was concordant in 60 of 62 analyzed cases. BRAF status was compared with clinical, histological and immunohistochemical data. Presence of the BRAF V600E mutation was associated with expression of synaptophysin in the tumor (p = 0.0008), presence of dysplastic neurons (p = 0.011) and lymphocytic cuffs (p = 0.018), and with younger age (p = 0.0054). Extensive hemosiderin deposition within the tumor was significantly associated with BRAF wild-type status (p = 0.042). No significant association was found with proliferation (p = 0.053), presence of phospho ERK (p = 0.1) or senescence marker p16^INK4a (p = 0.22). Using VE1, we localized the BRAF V600E-mutated protein predominantly to the neuronal compartment, indicating that BRAF mutations occur in cells that have the capacity to differentiate into ganglionic cells. In many cases mutant BRAF is additionally expressed by the glial compartment, indicating that in these cases the cell targeted by BRAF mutation was likely capable of differentiating along both the ganglionic and glial lineages. No cases with an exclusive expression of BRAF V600E in the glial compartment were observed. Thus, using VE1 we identified the neuronal compartment as an essential part of this mixed glioneuronal tumor.     

J1‐31 protein expression in astrocytes and astrocytomas

J1‐31 is one of the astrocytic proteins, the expression of which has not been evaluated in astrocytomas. In the present study, we studied the expression of J1‐31 protein in astrocytes and astrocytomas in comparison with GFAP, p53 and Ki‐67. Materials consisted of formalin‐fixed paraffin‐embedded tissue specimens that included five cases of normal brain, 17 of gliosis, 15 of pilocytic astrocytoma (WHO grade I), 26 of low‐grade diffuse astrocytoma (WHO grade II), four of anaplastic astrocytoma (WHO grade III), and eight of glioblastoma (WHO grade IV). GFAP was highly expressed in all specimens examined. The anti‐J1‐31 antibody exhibited strong cytoplasmic staining of reactive gliosis in 17/17 (100%) cases with a higher intensity of staining than that observed in the adjacent normal astrocytes. The antibody showed reactivity with tumor cells in 12/15 (80%) cases of pilocytic astrocytoma, although intensity of staining was generally weaker and more focal than observed in reactive gliosis. J1‐31‐positive tumor cells were detected in only 9/26 (35%) cases of the low‐grade diffuse astrocytoma and none of the cases of anaplastic astrocytoma and glioblastoma. Increasing Ki‐67 indices paralleled advancing tumor grades. p53 protein was expressed more commonly in infiltrating astrocytomas compared to pilocytic astrocytoma. In conclusion, down‐regulation of J1‐31 expression correlates with advancing grade of astrocytomas. The result suggests this protein plays some role in astrocytes that is progressively lost in malignant progression. The anti‐J1‐31 antibody may help further our understanding of astrocytes in disease and may be useful as an aid in the pathologic diagnosis of astrocytic lesions.     

存在BRAF V600E突变的混合性多形性黄色星形细胞瘤和节细胞胶质瘤

目的回顾分析1例存在BRAF V600E突变的混合性多形性黄色星形细胞瘤和节细胞胶质瘤患儿的临床病理学和分子遗传学特征。方法与结果男性患儿,14岁,临床表现为发作性意识丧失伴四肢抽搐6年,头部MRI显示左侧颞叶海马类圆形异常信号,考虑占位性病变。手术全切除肿瘤,术中可见颞叶深部局部脑回粉红色,肿瘤组织呈灰红、灰白色,质地较韧,内有钙化,伴囊性变,血供较丰富,无包膜,与周围脑组织界限清晰。组织学形态表现为肿瘤细胞弥漫性生长,肿瘤具有异质性:部分区域呈节细胞胶质瘤结构,部分区域呈多形性黄色星形细胞瘤结构。免疫组织化学染色和特殊染色,节细胞胶质瘤区域胶质纤维酸性蛋白(GFAP)和神经微丝蛋白(NF)散在阳性,神经节细胞样细胞微管相关蛋白-2和神经元核抗原阳性,Ki-67抗原标记指数约2%;多形性黄色星形细胞瘤区域梭形肿瘤细胞GFAP和NF散在阳性,黄瘤样细胞CD163和CD68阳性,Ki-67抗原标记指数3%~5%,网织纤维丰富。基因检测显示两部分区域均存在BRAF V600E突变。术后未予放射治疗和药物化疗,口服抗癫药物(丙戊酸钠1.20 g/次、2次/d和左乙拉西坦0.50 g/次、2次/d)1年,临床症状明显改善。随访18个月未见肿瘤复发。结论混合性多形性黄色星形细胞瘤和节细胞胶质瘤是临床少见的中枢神经系统肿瘤,具有多形性黄色星形细胞瘤和节细胞胶质瘤的组织学形态特征,但具有BRAF V600E突变的相同分子遗传学特征。该病例对混合性胶质瘤和混合性神经元-胶质肿瘤的组织学形态、组织来源和分子遗传学研究具有很好的提示意义。     

Patients with IDH1 wild type anaplastic astrocytomas exhibit worse prognosis than IDH1-mutated glioblastomas, and IDH1 mutation status accounts for the unfavorable prognostic effect of higher age: implications for classification of gliomas

WHO grading of human brain tumors extends beyond a strictly histological grading system by providing a basis predictive for the clinical behavior of the respective neoplasm. For example, patients with glioblastoma WHO grade IV usually show a less favorable clinical course and receive more aggressive first-line treatment than patients with anaplastic astrocytoma WHO grade III. Here we provide evidence that the IDH1 status is more prognostic for overall survival than standard histological criteria that differentiate high-grade astrocytomas. We sequenced the isocitrate dehydrogenase 1 gene (IDH1) at codon 132 in 382 patients with anaplastic astrocytoma and glioblastoma from the NOA-04 trial and from a prospective translational cohort study of the German Glioma Network. Patients with anaplastic astrocytomas carried IDH1 mutations in 60%, and patients with glioblastomas in 7.2%. IDH1 was the most prominent single prognostic factor (RR 2.7; 95% CI 1.6-4.5) followed by age, diagnosis and MGMT. The sequence from more favorable to poorer outcome was (1) anaplastic astrocytoma with IDH1 mutation, (2) glioblastoma with IDH1 mutation, (3) anaplastic astrocytoma without IDH1 mutation and (4) glioblastoma without IDH1 mutation (p < 0.0001). In this combined set of anaplastic astrocytomas and glioblastomas both, IDH1 mutation and IDH1 expression status were of greater prognostic relevance than histological diagnosis according to the current WHO classification system. Our data indicate that much of the prognostic significance of patient age is due to the predominant occurrence of IDH1 mutations in younger patients. Immunohistochemistry using a mutation-specific antibody recognizing the R132H mutation yielded similar results. We propose to complement the current WHO classification and grading of high-grade astrocytic gliomas by the IDH1 mutation status and to use this combined histological and molecular classification in future clinical trials.     

Analysis of Isocitrate Dehydrogenase 1 Mutation in 97 Patients with Glioma

The objective of this study is to investigate the expression and significance of isocitrate dehydrogenase 1 (IDH1) mutation in different subtypes of human gliomas. Direct DNA sequencing, western blot, and immunohistochemistry were used to detect IDH1 mutation and IDH1 gene expression levels in 97 cases of glioma and 9 cases of other CNS tumors. IDH1 mutation was heterozygous, with wild-type arginine 132 replaced by histidine (R132H). Expression in different glioma subtypes was (1) 0 out if 5 in pilocytic astrocytoma; (2) 15 out of 22 in diffuse astrocytoma, 6 out of 9 in oligodendroglioma, 4 out of 6 in oligoastrocytoma, and 0 out of 4 in ependymoma; (3) 11 out of 19 in anaplastic astrocytoma, 4 out of 7 in anaplastic oligodendroglioma, 3 out of 4 in anaplastic oligoastrocytoma, and 0 out of 3 in anaplastic ependymoma; and (4) 1 out of 6 in primary glioblastoma, 8 out of 10 in secondary glioblastoma, and 0 out of 2 in medulloblastoma. IDH1 mutation is a somatic mutation that is found only in some glioma subtypes. It can be used as a molecular marker for glioma subtypes. For example, it can be used to distinguish primary glioblastoma from secondary glioblastoma, combining TP53 mutation and loss of heterozygosity involving 1p/19q. It can also be used as a marker for some gliomas. For example, it can be used to distinguish pilocytic astrocytoma from diffuse astrocytoma, combining detected BRAF proto-oncogene mutations.     

Spinal cord anaplastic astrocytoma with BRAF V600E mutation: A case report and review of literature

A 17-year-old female complained of lower extremity pain that progressed to low back pain accompanied by paraparesis. Magnetic resonance imaging revealed a mass in the conus medullaris of the spinal cord at the thoracic spine 11–12 level. The patient underwent resection of the mass. The pathological diagnosis was anaplastic astrocytoma based on the densely proliferating astrocytic tumor cells without necrosis or microvascular proliferation. The patient received chemoradiotherapy with oral temozolomide and a total of 54 Gy of local irradiation, followed by 24 courses of temozolomide as maintenance chemotherapy. The patient survived for 8 years without tumor recurrence following the initial treatment. Genetic analysis of the tumor revealed a BRAF V600E mutation that has not yet been reported in spinal cord high-grade gliomas (HGGs). In recent years, the molecular therapy targeting the BRAF V600E mutation has been applied in clinical practice for several cancer types. Although the frequency in spinal cord HGGs is uncertain, it is necessary to investigate BRAF V600E mutation as a potential therapeutic target in the future.     

间变型多形性黄色瘤型星形细胞瘤

目的报道1例男性间变型多形性黄色瘤型星形细胞瘤患儿的临床资料,探讨其临床病理学、免疫表型、基因突变特征,以及诊断与鉴别诊断要点。方法与结果男性患儿,11岁,头痛伴左上肢无力15 d。头部CT和MRI显示右侧颞叶和基底节区巨大占位性病变,提示胶质瘤。遂行右侧颞叶和基底节区占位性病变切除术,术中可见肿瘤呈囊实性,实性部分呈灰黄色,质地柔软,血供丰富,无包膜,与周围组织界限清晰。术中冰冻病理学提示低级别胶质瘤,遂分块全切除肿瘤。组织学形态观察,肿瘤细胞呈多形性,由梭形和圆形星形胶质细胞以及单核细胞和多核瘤巨细胞组成,核分裂象罕见;局部可见较成熟的神经元或节细胞分化成分,伴淋巴细胞浸润;部分区域肿瘤细胞呈间变特征,细胞密度增加,异型性明显,以圆形和梭形细胞为主,核分裂象5个/10高倍视野,血管内皮细胞增生,伴血管周围假"菊形团"样结构,局灶性坏死。免疫组织化学染色,低级别肿瘤细胞胞质表达胶质纤维酸性蛋白(GFAP)和BRAF V600E、胞质和胞核表达S-100蛋白、胞膜表达CD34,少数肿瘤细胞胞质表达突触素和非磷酸化神经丝重链SMI-32,Ki-67抗原标记指数为3%;低级别和高级别肿瘤细胞胞核均表达P53;高级别肿瘤细胞胞质表达GFAP和BRAF V600E,Ki-67抗原标记指数为30%。网织纤维染色可见肿瘤细胞周围包绕基底膜样物质。基因检测显示,低级别和高级别肿瘤均存在BRAF V600E杂合突变。结论2016年世界卫生组织中枢神经系统肿瘤分类将间变型多形性黄色瘤型星形细胞瘤定义为核分裂象5个/10高倍视野,属WHOⅢ级,预后较WHOⅡ级多形性黄色瘤型星形细胞瘤差。鉴别诊断主要包括胶质母细胞瘤、毛细胞型星形细胞瘤和节细胞胶质瘤,尽管上述肿瘤临床表现、组织学形态、免疫表型和基因突变有重叠,但生物学行为、治疗及预后各异。