Pilocytic astrocytoma: pathology, molecular mechanisms and markers

Abstract Pilocytic astrocytomas (PAs) were recognized as a discrete clinical entity over 70 years ago. They are relatively benign (WHO grade I) and have, as a group, a 10-year survival of over 90 %. Many require merely surgical removal and only very infrequently do they progress to more malignant gliomas. While most show classical morphology, they may present a spectrum of morphological patterns, and there are difficult cases that show similarities to other gliomas, some of which are malignant and require aggressive treatment. Until recently, almost nothing was known about the molecular mechanisms involved in their development. The use of high-throughput sequencing techniques interrogating the whole genome has shown that single abnormalities of the mitogen-activating protein kinase (MAPK) pathway are exclusively found in almost all cases, indicating that PA represents a one-pathway disease. The most common mechanism is a tandem duplication of a ≈2 Mb-fragment of #7q, giving rise to a fusion between two genes, resulting in a transforming fusion protein, consisting of the N-terminus of KIAA1549 and the kinase domain of BRAF. Additional infrequent fusion partners have been identified, along with other abnormalities of the MAP-K pathway, affecting tyrosine kinase growth factor receptors at the cell surface (e.g., FGFR1) as well as BRAF V600E, KRAS, and NF1 mutations among others. However, while the KIAA1549-BRAF fusion occurs in all areas, the incide...
Source: Acta Neuropathologica - Category: Neurology Source Type: research

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AbstractObjective5-Aminolevulinic acid (5-ALA) –guided resection of gliomas in adults enables better delineation between tumor and normal brain, allowing improved resection and improved patients’ outcome. Recently, several reports were published regarding 5-ALA for resection of pediatric brain tumors. The aim of the study was to determine th e intracellular fluorescence of protoporphyrin IX (PPIX) in pediatric brain tumors by hyperspectral imaging and to compare it with visually observed intraoperative fluorescence.Methods5-ALA was administered orally 4  h prior to surgery. During tumor resection, the surg...
Source: Acta Neurochirurgica - Category: Neurosurgery Source Type: research
We present three cases of NF1 patients referred for 18F-fluorocholine PET/CT because of suspected glioma in the setting of ongoing FUMEGA (Functional and Metabolic Glioma Analysis) trial. One case turned out to be a WHO grade I ganglioglioma; the second was a high grade glioma; and the last one (negative in PET) a probable low-grade glioma.
Source: Clinical Nuclear Medicine - Category: Nuclear Medicine Tags: Interesting Images Source Type: research
CONCLUSIONS: The authors' results show that surgical smoke from various brain tumors has distinct DMS profiles and the DMS analyzer connected to a special sampling system can differentiate between tumorous and nontumorous tissue and also between different tumor types ex vivo. PMID: 31200382 [PubMed - as supplied by publisher]
Source: Journal of Neurosurgery - Category: Neurosurgery Authors: Tags: J Neurosurg Source Type: research
Conclusion: This preliminary study suggests that 64CuCl2 is accumulating in some but not all high-grade brain tumors. There appears to variability in the grade of Copper uptake in all grades of tumors. More data is being accumulated to define the cutoff of copper uptake as potential differentiating features for identifying possible theragnostic targets.
Source: Journal of Nuclear Medicine - Category: Nuclear Medicine Authors: Tags: Neurology & amp; Psychiatry Imaging Posters Source Type: research
Authors: Niranjan A, Faramand A, Lunsford LD Abstract Low-grade gliomas represent a heterogeneous group of tumors. The goals of treatment include prolonged survival and reduced morbidity. Treatment strategies vary depending upon tumor histology, anatomic location, age, and the general medical condition of the patient. Safe surgical resection remains the first choice for the treatment of resectable tumors. In cases of unresectable lesions, adjuvant radiotherapy and chemotherapy are considered. Several reports in recent years have documented the safety and effectiveness of stereotactic radiosurgery (SRS) in controlli...
Source: Progress in Neurological Surgery - Category: Neurosurgery Tags: Prog Neurol Surg Source Type: research
Michal Yalon1†, Amos Toren1,2†, Dina Jabarin2, Edna Fadida3, Shlomi Constantini3 and Ruty Mehrian-Shai1* 1Pediatric Hemato-Oncology, Edmond and Lilly Safra Children's Hospital and Cancer Research Center, Sheba Medical Center, Ramat Gan, Israel 2The Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel 3Department of Pediatric Neurosurgery, Dana Children's Hospital, Tel-Aviv-Sourasky Medical Center, Tel Aviv, Israel Pediatric brain tumors are the most common solid tumor type and the leading cause of cancer-related death in children. The immune system plays an important r...
Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research
Publication date: Available online 24 April 2019Source: Journal of Clinical NeuroscienceAuthor(s): Mehmet Osman Akçakaya, Assel Saryyeva, Hans E. Heissler, Elvis J. Hermann, Joachim K. KraussAbstractOccurrence of gliomas in patients with chronic deep brain stimulation (DBS) has been reported few. It has been speculated whether there could be a causal relationship. Here, we report the development of a pilocytic astrocytoma in close vicinity of a DBS electrode during the course of chronic DBS. A 38-year-old man with refractory dystonic head tremor underwent bilateral implantation of quadripolar DBS electrodes in the t...
Source: Journal of Clinical Neuroscience - Category: Neuroscience Source Type: research
Conclusion5-ALA could play a role in resection of pediatric brain tumors. However, further prospective clinical trials are needed.
Source: Acta Neurochirurgica - Category: Neurosurgery Source Type: research
Conclusion: The efficacy of brainstem gliomas—treated with CyberKnife is efficacious with mild toxicity. Introduction Brainstem gliomas (BSGs) account for 5–15% of brain tumors and more likely happen in children (1). BSGs constitute at least 20% of childhood brain neoplasms (2), and the peak age is 7–9 years. In contrast, BSGs is rare in the adult population and account for only 1.5–2.5% of brain glioma, with a peak age of 40–70 years (1). Diffuse intrinsic pontine glioma(DIPG) was the most common type of BSG is that could invade the whole brainstem including midbrain, pons as well as me...
Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research
In conclusion, we have shown the safety and efficacy of Vemurafenib in a pediatric patient with DS affected by PXA. Ethics Statement This study was carried out in accordance with the recommendations of the Internal Review Board of the Bambino Gesù Children's Hospital with written informed consent from all subjects. All subjects gave written informed consent in accordance with the Declaration of Helsinki. The protocol was approved by the Internal Review Board of the Bambino Gesù Children's Hospital. Informed Consent The authors declare that written informed consent was obtained from the pat...
Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research
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