Implications of new understandings of gliomas in children and adults with NF1: report of a consensus conference

Gliomas are the most common primary central nervous system tumors occurring in children and adults with neurofibromatosis type 1 (NF1). Over the past decade, discoveries of the molecular basis of low-grade gliomas (LGGs) have led to new approaches for diagnosis and treatments. However, these new understandings have not been fully applied to the management of NF1-associated gliomas. A consensus panel consisting of experts in NF1 and gliomas was convened to review the current molecular knowledge of NF1-associated low-grade “transformed” and high-grade gliomas; insights gained from mouse models of NF1-LGGs; challenges in diagnosing and treating older patients with NF1-associated gliomas; and advances in molecularly targeted treatment and potential immunologic treatment of these tumors. Next steps are recommended to advance the management and outcomes for NF1-associated gliomas.

Paediatric posterior fossa tumour resection rates in a small volume centre: the past decade's experience

BACKGROUND

Paediatric brain tumour resection rates have been shown to correlate with outcome and, it is argued, are linked to operator volume and caseload. The British paediatric neurosurgery community has previously debated centralisation of paediatric neuro-oncology. At the 2018 British Paediatric Neurosurgery Group (BPNG) meeting, a commitment was made to prospectively collect tumour resection data at each Neurosurgical Unit (NSU). Here we review our prospectively-collected 10-year database of the three commonest paediatric posterior fossa tumours - astrocytomas, medulloblastomas and ependymomas.

MATERIALS AND METHODS

Our primary outcome was extent of resection (EOR) on post-operative MRI scans reviewed by neuro-radiologists. Secondary outcomes comprised neurosurgical morbidity including infection, need for cerebrospinal fluid (CSF) diversion and the occurrence of posterior fossa syndrome (PFS).

RESULTS

55 children had 62 operations, where our complete resection rates for pilocytic astrocytomas, medulloblastomas and ependymomas were 77%, 79% and 63%, respectively. Both our primary and secondary outcomes were in keeping with the published literature and we discuss here some of the factors which may contribute towards favourable outcomes in a small volume centre.

CONCLUSION

Our results suggest that small volume centres can expect equivalent results to larger volume NSUs with regards to paediatric brain tumour surgery. Continuing efforts nationally for data collection on resection rates and operative outcomes is a key step towards optimising management in these children.

Cerebellar pilocytic astrocytomas with spontaneous intratumoral hemorrhage in the elderly: A case report and review of the literature

RATIONALE

Pilocytic astrocytoma (PA) is the most common pediatric central nervous system glial tumor. Adult occurrence is rare, especially in elderly adults. How to manage the pilocytic astrocytoma with spontaneous intratumoral hemorrhage in the elderly is still unfamiliar with clinician.

PATIENT CONCERNS

Reports of tumors with intratumoral hemorrhage in elderly adults are extremely rare. We report a case of a 62-year-old male diagnosed with cerebellar pilocytic astrocytomas with spontaneous intratumoral hemorrhage. Informed consent was obtained from the patient.

DIAGNOSES

Histological examination of the specimens revealed pilocytic astrocytomas, including a hemorrhagic portion.

INTERVENTIONS

The patient underwent the radical resections of tumour and was given the regular follow-up.

OUTCOMES

12 months later, he recovered without evidence of disease.

LESSONS

Cerebellar pilocytic astrocytomas associated with hemorrhages occur over the age of 60 is extremely rare. Removing the tumor and hematoma completely is the best treatment options. Long term follow-up is very necessary for this tumor.

Integrated DNA methylation analysis identifies topographical and tumoral biomarkers in pilocytic astrocytomas

Pilocytic astrocytoma (PA) is the most common glioma in pediatric patients and occurs in different locations. Chromosomal alterations are mostly located at chromosome 7q34 comprising the BRAF oncogene with consequent activation of the mitogen-activated protein kinase pathway. Although genetic and epigenetic alterations characterizing PA from different localizations have been reported, the role of epigenetic alterations in PA development is still not clear. The aim of this study was to investigate whether distinctive methylation patterns may define biologically relevant groups of PAs. Integrated DNA methylation analysis was performed on 20 PAs and 4 normal brain samples by Illumina Infinium HumanMethylation27 BeadChips.

We identified distinct methylation profiles characterizing PAs from different locations (infratentorial vs supratentorial) and tumors with onset before and after 3 years of age. These results suggest that PA may be related to the specific brain site where the tumor arises from region-specific cells of origin. We identified and validated in silico the methylation alterations of some CpG islands. Furthermore, we evaluated the expression levels of selected differentially methylated genes and identified two biomarkers, one, IRX2, related to the tumor localization and the other, TOX2, as tumoral biomarker.

Clinical review of pediatric pilocytic astrocytomas treated at a tertiary care hospital in Pakistan

Background:

Pilocytic Astrocytoma (PA) is a common type of brain tumor in the pediatric population. They have a fairly good prognosis. This study describes PAs in detail, with a focus on the demographic factors, presenting features, management and prognosis, and aims, to identify the negative outcome predictors in our population, which can affect the course of the disease. This article will add to the understanding of PAs from a third world perspective.

Methods:

The Aga Khan University medical records (1995 – 2007) were reviewed, to study the clinical features, management, and outcome of patients (0 – 15 years) with Pilocytic Astrocytomas (PAs) in our population. After a thorough review of the medical records, all the PAs diagnosed on the basis of histopathology at our Pathology Laboratory, during this period, were included in the study.

Results:

Twenty-two patients were included with a mean age of 9.25 years. Male-to-female ratio was 1 : 1. The most common presenting feature was a sign of increased intracranial pressure. The most common location was the cerebellum followed by the cerebrum. Fifteen patients underwent maximum surgical resection. Three had recurrence, despite no residual tumor. There were 10 Intensive Care Unit (ICU) admissions and one inpatient mortality. Fifteen patients followed up in the clinic: Eight had recurrence and four underwent repeat surgery (three showed clinical improvement). Hydrocephalus was a predictor of ICU admission. Solid consistency was found to be a marker of recurrence.

Conclusion:

Pilocytic Astrocytomas are the most common pediatric brain tumors in our population, commonly located in the cerebellum. Complete resection is the best treatment option, but some tumors are aggressive and recurrence is not uncommon. The possible negative outcome predictors are age, source of admission, extent of resection, hydrocephalus, and solid consistency.

Findings on preoperative brain MRI predict histopathology in children with cerebellar neoplasms

BACKGROUND/AIMS

The majority of pediatric patients with cerebellar neoplasms harbor pilocytic astrocytomas (PAs), medulloblastomas, or ependymomas. Knowledge of a preoperative likelihood of histopathology in this group of patients has the potential to influence many aspects of care. Previous studies have demonstrated hyperintensity on diffusion-weighted imaging to correlate with medulloblastomas. Recently, measurement of T(2)-weighted signal intensity (T2SI) was shown to be useful in identification of low-grade cerebellar neoplasms. The goal of this study was to assess whether objective findings on these MRI sequences reliably correlated with the underlying histopathology.

METHODS

We reviewed the radiologic findings of 50 pediatric patients who underwent resection of a cerebellar neoplasm since 2003 at our institution. Region of interest placement was used to calculate the relative diffusion-weighted signal intensity (rDWSI) and relative T2SI (rT2SI) of each neoplasm.

RESULTS

Tukey's multiple comparison test demonstrated medulloblastomas to have significantly higher rDWSIs than PAs/ependymomas, and PAs to have significantly higher rT2SIs than medulloblastomas/ependymomas. A simple method consisting of sequential measurement of rDWSI and rT2SI to predict histopathology was then constructed. Using this method, 39 of 50 (78%) tumors were accurately predicted.

CONCLUSION

Measurement of rDWSI and rT2SI using standard MRI of the brain can be used to predict histopathology with favorable accuracy in pediatric patients with cerebellar tumors.