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BACKGROUND: Optic pathway gliomas are uncommon, accounting for 3-5% of childhood brain tumors, and are mostly classified as pilocytic astrocytomas (PAs). PAs of the optic nerve are particularly rare in adults. OBSERVATIONS: The authors presented the case of PA of the left optic nerve in a 49-year-old woman along with detailed pathological and molecular analyses and sequential magnetic resonance imaging. The tumor had progressed during 5 years of follow-up along with cyst formation and intracystic hemorrhage; it had a thick capsule and contained xanthochromic fluid. The boundary between tumor and optic nerve was unclear. B-type Raf kinase (BRAF) V600E point mutations or translocations, IDH1-R132H mutations, loss of alpha-thalassemia/mental retardation X-linked, and 1p/19q codeletion were negative. LESSONS: BRAF alterations in pediatric PAs of the optic nerve are less frequent than those observed in PAs in other lesions; the same molecular pattern was observed in the adult case, without changes in BRAF. Surgical management should be indicated only in cases with severely impaired vision or disfigurement because there is no clear border between the tumor and optic nerve. Further discussion is needed to optimize the treatment for adult optic pathway gliomas, including radiotherapy, chemotherapy, and molecular-targeted therapies, in addition to surgical intervention.

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OBJECTIVE: Solitary posterior fossa low-grade glial tumors (SPFLGT) in children are rarely associated with leptomeningeal dissemination (LMD). To date, there are no clear guidelines regarding the role of screening and surveillance spinal MRI (sMRI) in children with SPFLGT, at diagnosis or during follow-up periods. The current study reviews a cohort of children with SPFLGT, focusing on sMRI findings. METHODS: In this binational retrospective study, the authors analyzed 229 patients with SPFLGT treated and followed over 13 years. One hundred twelve children had at least 1 total sMRI screening or surveillance examination. One hundred seventeen had no sMRI, but did not present with clinical spinal signs or symptoms. Collected data included demographics, disease characteristics, radiology, pathology, and clinical follow-up data. RESULTS: For the 112 children with at least 1 sMRI, the mean duration from diagnosis to first sMRI was 11.73 ± 28.66 months (range 0-165 months). All sMRI scans were conducted as screening examinations, with no spinal-related symptoms. One patient was found to have a sacral intradural lesion concurrent to the brain tumor diagnosis. Over the course of 180 radiological and 533 clinical follow-up years for the 112 patients with sMRI, and 582 clinical follow-up years for the 117 patients with no sMRI, there were no additional cases with spinal tumor spread. CONCLUSIONS: The yield of screening sMRI in the absence of cranial metastasis, or spinal symptoms, is extremely low. Because preoperative sMRI is recommended for medulloblastomas and ependymomas, it may be logical to acquire. During the follow-up period the authors recommend limiting sMRI in patients without symptoms suggesting a spinal lesion, in patients without known cranial metastases, or recurrence or residual SPFLGT.

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Tumors of the central nervous system represent the largest group of solid tumors found in pediatric patients. Pilocytic astrocytoma is the most common pediatric glioma, mostly located in the posterior fossa. The majority of brainstem tumors, however, are classified as highly aggressive diffuse intrinsic pontine gliomas (DIPGs) and their prognosis is dismal.The authors report on the case of a neonate in whom MRI and neuropathological assessment were used to diagnose DIPG. Before initiation of the planned chemotherapy, the tumor regressed spontaneously, and the newborn exhibited a normal neurological development. Meanwhile, Illumina Human Methylation450 BeadChip analysis reclassified the tumor as pilocytic astrocytoma of the posterior fossa.In conclusion, the authors advocate not initiating immediate intensive therapy in newborns with brain tumors, even with classical appearance of a DIPG; rather, they would like to encourage a biopsy to define the best individual therapeutic approach and avoid ineffective chemotherapy.

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In this report, the authors present the first case of adult brainstem pilocytic astrocytoma (PA) with the H3 K27M mutation. A 53-year-old man was incidentally found to have a 2.5-cm partially enhanced tumor in the tectum on MRI. The enhancement in the lesion increased over 3 years, and gross-total removal was performed via the occipital transtentorial approach. The resected tissue indicated PA, WHO Grade I, and genetic analysis revealed the H3 K27M mutation. However, although the radiological, surgical, and pathological findings all corresponded to PA, this entity can easily be misdiagnosed as diffuse midline glioma with the H3 K27M mutation, which is classified as a WHO Grade IV tumor according to the updated classification. This case highlights the phenotypic spectrum of PA, as well as the biology of the H3 K27M-mutated gliomas, and may prove to be an exception to the rule that diffuse midline gliomas with the H3 K27M mutation behave in an aggressive manner. Based on the findings of this case, the authors conclude that, in addition to detecting the existence of the H3 K27M mutation, an integrated approach in which a combination of clinical, pathological, and genetic information is used should be applied for accurate diagnosis and determination of the appropriate treatment for diffuse midline gliomas.

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OBJECTIVE Pilocytic astrocytomas (PAs) are common brain tumors in children. Optimal management of PA is gross-total resection (GTR), after which event-free survival (EFS) is excellent. The tempo of recurrences, when they do occur, is relatively sparsely reported, and there is no agreed upon surveillance recommendation for patients in this category. It has been suggested that surveillance MRI is performed too frequently and could be safely reduced in both frequency and duration. The authors conducted a retrospective review of pediatric patients with PA who underwent GTR at a single institution over an 18-year period and who had documented recurrences. METHODS All patients under 18 years of age who had undergone GTR of a PA between 1996 and 2013 were included in the study. Clinical, radiological, and tumor characteristics were recorded. RESULTS Sixty-seven patients met the criteria for GTR over the period studied. The 5-year EFS rate was 95% (95% CI 89%-100%) and overall survival was 100%. Recurrences showed a nonsignificant trend of occurring more commonly in patients with persistent nonenhancing FLAIR abnormalities after surgery, but there was no difference with regard to tumor location. All recurrences occurred before 3 years postresection, all were asymptomatic, and all patients were observed for at least one additional scan after the initial detection during routine surveillance MRI before further therapy was undertaken. CONCLUSIONS EFS and overall survival are excellent after GTR in this population with PAs. Progression after recurrence occurs slowly and is asymptomatic. A less intensive schedule of MRI surveillance in this group of patients would result in time and cost savings, without compromising safety. The authors suggest a schedule of 6 MRI scans to be obtained postoperatively, at 3-6 months, then at 1, 2, 3.5, and 5 years.

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Acute hemorrhagic presentation in pilocytic astrocytomas (PAs) has become increasingly recognized. This type of presentation poses a clinically emergent situation in those hemorrhages arising in PAs of the cerebellum, the most frequent site, because of the limited capacity of the posterior fossa to compensate for mass effect, predisposing to rapid neurological deterioration. As examples, we describe two cases of fatal hemorrhagic cerebellar PAs: one of a child with a slowly growing stereotypical WHO Grade I PA with a 1-year period of symptomatology that preceded a rapid clinical deterioration, and another of an asymptomatic child having a PA variant, presenting with progressive obtundation following a presumed Valsalva event. These two scenarios parallel previous reports in the literature of either a setting of progressive expression of cerebellar dysfunction and transient episodes of raised intracranial pressure (ICP), or abrupt onset of features of increased ICP in a previously well child. The literature is further reviewed for a current understanding of the factors that predispose, initiate and propagate bleeding, with specific reference to the role of vascular endothelial growth factor and other angiogenic agents in the genesis and stability of the vasculature in PAs. In this context, we propose that obliterative vascular mural hyalinization with associated altered flow dynamics and microaneurysm formation was the pathogenesis of the hemorrhage in our first case. In the second case, large tumor size, increased growth rate, looseness of the background myxoid matrix, and thinness of the tumor blood vessels with calcospherite deposition predisposed to vascular leakage and bleeding concurrent with sudden increases in intravascular hydrostatic pressure. In that cerebellar PAs are common, this report underscores the importance of considering in the differential diagnosis the possibility of a spontaneous hemorrhage in a posterior fossa PA in a child presenting with a sudden neurological ictus and raised ICP.

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Object In the last decade the indications for the endoscopic endonasal approach have been progressively expanded to include lesions that have not been traditionally considered amenable to resection through the transsphenoidal route. In this study, the authors analyze their experience with hypothalamic gliomas treated via the endoscopic endonasal approach. Methods Consecutive cases of hypothalamic gliomas treated since 2007 via an endoscopic endonasal approach were reviewed. Preoperative and postoperative neuroimaging as well as endocrinological, neurological, and visual symptoms were analyzed to assess the surgical outcome. Signs and symptoms of hypothalamic dysfunction including body mass index (BMI), memory, sleep-wake rhythm, and polyphagia were prospectively collected pre- and postoperatively to assess hypothalamic function. Quality of life was evaluated using the Katz scale. Results In the initial phase the endoscopic endonasal approach was adopted in 3 cases with a palliative intent, to obtain a biopsy sample or for debulking of the mass followed by radio- or chemotherapy. In 2 later cases it was successfully adopted to achieve gross-total tumor resection. Complications consisted of 2 postoperative CSF leaks, which required an endoscopic endonasal reintervention. Visual deficit improved in 3 cases and normalized in the other 2. Four patients developed diabetes insipidus, and 3 an anterior panhypopituitarism. All patients had a moderate increase in BMI. No patients presented with any other signs of hypothalamic damage, and their quality of life at follow-up is normal. Conclusions Despite the limitations of a short follow-up and small sample, the authors' early experience with the endoscopic endonasal approach has revealed it to be a direct, straightforward, and safe approach to third ventricle astrocytomas. It allowed the authors to perform tumor resection with the same microsurgical technique: dissecting the tumor with 2 hands, performing a central debulking, and controlling the bleeding with bipolar coagulation. The main limitations were represented by some anatomical conditions, such as the position of the chiasm and the anterior communicating artery complex and, finally, by the challenge of watertight plastic repair. To definitively evaluate the role of this approach in hypothalamic gliomas, a comparison with transcranial series would be necessary, but due to the rarity of these cases such a study is still lacking. The authors observed that more aggressive surgery is associated with a worse endocrinological outcome; thus they consider it to be an open question (in particular in prepubertal patients) whether radical removal is an advisable goal for hypothalamic gliomas.

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