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Pilocytic astrocytomas (PA) typically exhibit distinct clinical, radiological, histopathological, and genetic features. DNA-methylation profiling distinguishes PA according to their location (infratentorial, midline, hemispheric, or spinal). In the hemispheric location, distinguishing PA from glioneuronal tumors remains a common diagnostic challenge for neuropathologists. Furthermore, the current version of the DKFZ classifier seems to have difficulty separating them from gangliogliomas. In this study, after central radiological review, we identified a histopathologically defined set of PA (histPA, n = 11) and a cohort of DNA-methylation defined PA (mcPA, n = 11). Nine out of the 11 histPA matched the methylation class of hemispheric PA, whereas 2 cases were classified at the end of the study as dysembryoplastic neuroepithelial tumors. Similarly, the mcPA cohort contained tumors mainly classified as PA (7/11), but 4 cases were classified as glioneuronal. The analysis of the 16 tumors with an integrated diagnosis of PA revealed that they affect mainly children with a wide spectrum of radiological, histopathological (i.e. a predominantly diffuse growth pattern), and genetic characteristics (large range of mitogen-activated protein kinase alterations). Based on these results, we consider hemispheric PA to be different from their counterparts in other locations and to overlap with other glioneuronal tumors, reinforcing the necessity of interpreting all data to obtain an accurate diagnosis.

ObjectiveThe aim of this study was to better characterise clinical presentation, management and outcome in infants and children with brain abscess.MethodsThe authors conducted a retrospective, multicentre study in two national reference centres over a 25-year period (1992–2017). During this period, 116 children and 28 infants (age <1 year) with brain abscess were treated.ResultsThe median age at diagnosis was 101.5 (range: 13–213) months in children and 1 (0–11) month in infants. Significant differences were observed between children and infants. The most common predisposing factor was meningitis in infants (64% of cases vs 3% in children), while it was otolaryngology-related infection in children (31% of cases vs 3.6% in infants). Infants presented more frequently with fever and meningism compared with children. 115 patients were treated with aspiration and 11 with excision. Reoperation was required in 29 children vs 1 infant. The overall mortality rate was 4% (3.4% for children, 7.1% for infants). At 3-month follow-up, the outcome was favourable in 86% of children vs in 68% of infants.ConclusionThere is a clear difference between children and infants with brain abscess in terms of predisposing factors, causative organisms and outcome. Despite surgical drainage and directed antibiotic therapy, 25% of patients with brain abscess require reoperation. Mortality is improved compared with historical series; however, long-term morbidity is significant particularly in the infant population.

Pediatric chordomas are rare malignant neoplasms, and few data are available for optimizing therapeutic strategies and outcome. This study aimed at evaluating how best to manage them and to identify prognostic factors. This multicentric retrospective study included 40 children diagnosed with chordomas between 1966 and 2012. Clinical, radiological, and histopathological data, treatment modalities, and outcomes were reviewed. The median age was 12 years old. Most chordomas were histologically classical forms (45.5%) and were mostly located at the skull base (72.5%). The overall survival (OS) was 66.6% and 58.6%, and progression-free survival (PFS) was 55.7% and 52% at 5 and 10 years, respectively. Total resection was correlated with a better outcome (p = 0.04 for OS and PFS, log-rank). A histopathological/immunohistochemical grading system recently crafted for adults was applied. In a multivariate analysis, it significantly correlated with outcome (PFS and OS, p = 0.004), and the loss of BAF47 immunoexpression appeared to be a significant independent prognostic factor (PFS, p = 0.033). We also identified clinical and histopathological parameters that correlated with prognosis. A new grading system combined with the quality of surgical resection could help classify patients to postpone radiotherapy in case of low risk. Targeted therapy and reirradiation at recurrence may be considered as potential therapeutic strategies.