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BackgroundIn patients operated for malignant glioma, 5-aminolevulinic acid (5-ALA)-induced fluorescence guidance is useful. However, we occasionally experience instances of non-visible fluorescence despite a histopathological diagnosis of high-grade glioma. We sought to identify factors that influence the intraoperative visualization of gliomas by their 5-ALA-induced fluorescence.Patients and methodsWe reviewed data from 60 patients with astrocytic or oligodendroglial tumors who underwent tumor removal under 5-ALA-induced fluorescence guidance between January 2014 and December 2015. Their characteristics, preoperative magnetic resonance imaging (MRI) findings, histological diagnosis, and genetic profile were analyzed and univariate and multivariate statistical analyses were performed.ResultsIn 42 patients (70%) we intraoperatively observed tumor 5-ALA fluorescence. They were 2 of 8 (25%) patients with World Health Organization (WHO) grade II, 9 of 17 (53%) with grade III, and 31 of 35 (89%) patients with grade IV gliomas. Univariate analysis revealed a statistically significant association between 5-ALA fluorescence and the isocitrate dehydrogenase 1 (IDH1) status, 1p19q loss of heterozygosity (LOH), the MIB-1 labeling index, and the tumor margin, -heterogeneity, and -contrast enhancement on MRI scans (p < 0.001, p = 0.003, p = 0.007, p = 0.046, p = 0.021, and p = 0.002, respectively). Multivariate analysis showed that the IDH1 status was the only independent, statistically significant factor related to 5-ALA fluorescence (p = 0.009).ConclusionsThis study identified the IDH1 status as the factor with the most influence on the 5-ALA fluorescence of diffuse gliomas.

OBJECTIVE The methylation status of the O6-methylguanine-DNA methyltransferase ( MGMT) gene promoter is a prognostic factor in adults with glioblastoma (GBM); it also yields information that is useful for clinical decision-making in elderly GBM patients. While pyrosequencing is the gold standard for the evaluation of the methylation status of MGMT, methylation-sensitive polymerase chain reaction (MS-PCR) assay continues to be used widely. Although MS-PCR results exhibited a good correlation with the prognosis of patients with GBM treated under the Stupp protocol, interpretation of the bands is based on subjective judgment, and the assay cannot be used to analyze heterogeneously methylated samples. We assessed whether methylation-sensitive high-resolution melting (MS-HRM) is an alternative to MS-PCR. METHODS The authors prepared 3 primer sets that covered CpG 72-89 for MS-HRM analysis to determine the methylation levels of 6 human glioma cell lines. The results were validated by bisulfite sequencing of cloned alleles. The authors also subjected surgical samples from 75 GBM patients treated with temozolomide (TMZ) to MS-HRM to assess the MGMT methylation status and compared the findings with MS-PCR results using receiver operating characteristic (ROC), univariate, and multivariate analyses. RESULTS There was a strong correlation between the methylation levels of the 6 glioma cell lines evaluated by MS-HRM and by bisulfite sequencing; with primers 1 and 2, the correlation was significant (r = 0.959 and r = 0.960, respectively, p < 0.01). Based on log-rank analysis, MS-HRM was significantly better than MS-PCR for predicting progression-free survival (PFS) and overall survival (OS) based on the methylation status of the MGMT promoter (PFS predicted by MS-HRM and MS-PCR = 0.00023 and 0.0035, respectively; OS = 0.00019 and 0.00028, respectively). ROC analysis showed that the area under the curve was larger with MS-HRM than with MS-PCR (PFS: 0.723 vs 0.635; OS: 0.716 vs 0.695). Based on multivariate Cox regression analysis, MS-HRM was significantly better than MS-PCR for predicting the treatment outcome (MS-HRM vs MS-PCR: PFS, p = 0.001 vs 0.207; OS, p = 0.013 vs 0.135). CONCLUSIONS The authors' findings show that MS-HRM is superior to MS-PCR for the detection of MGMT promoter methylation. They suggest MS-HRM as an alternative to MS-PCR for assessing the prognosis of patients with GBM.

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Although carmustine (Gliadel) wafers improve local tumor control and extend the overall survival in patients with malignant glioma, adverse effects have been documented. The authors report the first case of eosinophilic meningitis triggered by the placement of Gliadel wafers. A 61-year-old man with a history of alimentary allergy and glioblastoma in the right frontal lobe underwent resection followed by the implantation of Gliadel wafers. Three weeks later he suffered the sudden onset of headache, vomiting, and progressive consciousness disturbance. Computed tomography revealed enlargement of the ventricular system and subdural space on the side of the tumor. His CSF leukocyte count increased up to 3990 cells/mm; 95% of the cells were eosinophilic granulocytes (EGs), suggesting eosinophilic meningitis. Laboratory examination showed the patient to have various elevated allergy indicators. The administration of corticosteroids failed to improve his condition. Despite the insertion of a lumbar drain his symptoms failed to improve. He underwent a second surgical intervention to remove the Gliadel wafers. Histologically, EGs had assembled around the wafers. Eosinophilic infiltrate was present in the brain parenchyma around small vessels. After ventriculoperitoneal shunting his course was favorable. A drug lymphocyte stimulation test against the Gliadel wafers failed to demonstrate a positive reaction; polifeprosan, the wafer matrix without 1,3-bis(2-chloroethyl)-1-nitrosourea, yielded a positive reaction. These findings strongly suggest that although extremely rare, polifeprosan (the wafer matrix) can elicit an allergic reaction. When eosinophilic meningitis is suspected after the implantation of Gliadel wafers, their immediate removal should be considered.