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Child's Nervous System : ChNS :... Jan 2017Pilocytic astrocytoma (PA) is the most common pediatric brain glioma and is considered the prototype of benign circumscribed astrocytoma. Despite its low malignancy, the... (Review)
Review
BACKGROUND
Pilocytic astrocytoma (PA) is the most common pediatric brain glioma and is considered the prototype of benign circumscribed astrocytoma. Despite its low malignancy, the CT and MRI features of brain PA may resemble those of much more aggressive brain tumors. Misdiagnosis of PA is particularly easy when it demonstrates MR morphological and non-morphological findings that are inconsistent with its non-aggressive nature and that overlap with the features of more aggressive brain tumors.
METHOD
Basing on the evidence that the variation in the histological, genetic, and metabolic "fingerprint" for brain PA is dependent on tumor location, and the hypothesis that tumor location is related to the broad spectrum of morphological and non-morphological MR imaging findings, the authors discuss the MR imaging appearance of brain PA using a location-based approach to underline the typical and less typical imaging features and the main differential diagnosis of brain PA. A brief summary of the main pathological and clinical features, the natural history, and the treatment of brain PA is also provided.
RESULT
A combination of morphological and non-morphological MR imaging features and a site-based approach to differential diagnosis are required for a pre-operative diagnosis. The new "cutting-edge" MR imaging sequences have the potential to impact the ease and confidence of pediatric brain tumor interpretation and offer a more efficient diagnostic work-up.
CONCLUSIONS
Although the typical imaging features of brain pilocytic astrocytoma make radiological diagnosis relatively easy, an atypical and more aggressive appearance can lead to misdiagnosis. Knowing the broad spectrum of imaging characteristics on conventional and advanced MR imaging is important for accurate pre-operative radiological diagnosis and correctly interpreting changes during follow-up.
Topics: Astrocytoma; Brain Neoplasms; Humans; Magnetic Resonance Imaging; Neuroimaging
PubMed: 27757570
DOI: 10.1007/s00381-016-3262-4 -
BMJ Case Reports Mar 2016
Topics: Adult; Astrocytoma; Brain Neoplasms; Confusion; Female; Humans; Neoplasm Recurrence, Local; Paresis; Temporal Lobe
PubMed: 27033282
DOI: 10.1136/bcr-2015-213013 -
The Canadian Journal of Neurological... Sep 2023
Topics: Humans; Astrocytoma; Brain Neoplasms
PubMed: 35860980
DOI: 10.1017/cjn.2022.274 -
Pilocytic astrocytoma: a review of genetic and molecular factors, diagnostic and prognostic markers.Histology and Histopathology Oct 2014In spite of numerous studies concerning the pathogenesis of pilocytic astrocytoma (PA), the exact mechanism of the process still remains undetermined. It is difficult to... (Review)
Review
In spite of numerous studies concerning the pathogenesis of pilocytic astrocytoma (PA), the exact mechanism of the process still remains undetermined. It is difficult to obtain concordance between particular studies, which makes review of existing data especially troublesome. Nevertheless, the most important causative factors seem to be NF1 gene inactivation, in cases related to neurofibromatosis type 1, and BRAF gene overexpression in sporadic PAs, both resulting in MAPK/Erk pathway upregulation. Other molecular alterations, like mTOR or PI3K pathway deregulation, or Matrilin 2 overexpression, may influence the course of the disease, leading to the development of more aggressive and recurrent tumors. In the current paper we review genetic alterations in PA and describe currently studied molecular markers that may contribute to the development of the tumor and can be used in pathological staging of the malformation.
Topics: Astrocytoma; Biomarkers, Tumor; Central Nervous System Neoplasms; Cytogenetics; Humans; Prognosis
PubMed: 24554201
DOI: 10.14670/HH-29.1235 -
Pathology, Research and Practice Dec 2023Pilocytic astrocytoma is the most common primary CNS neoplasm in children and adolescents, rare after the first two decades of life. While some authors report a...
Pilocytic astrocytoma is the most common primary CNS neoplasm in children and adolescents, rare after the first two decades of life. While some authors report a favorable prognosis in the adult age group with the tumor, others have associated it with higher mortality. The molecular alteration most observed in cases of pilocytic astrocytoma in the pediatric group is the BRAF-KIAA1549 gene fusion, and there are still few studies confirming the presence of this fusion in the adult population. This work investigated genetic alterations involving the 7q34 region in BRAF gene in 21 adult individuals with pilocytic astrocytoma, by FISH. In addition, was identified the immunohistochemical expression of BRAFV600E, correlating these findings with histopathological and clinical ones. BRAF-KIAA1549 fusion appeared in only one case, while in two other cases were found deletions related to the FAM131B-BRAF fusion, suggesting that maybe the latter is more frequently in this population. Through the evaluation of immunoreactivity, 71% of the cases were considered positive and 29% negative. Cases considered positive for BRAFV600E immunoreactivity can potentially be treated through drug therapy with BRAF inhibitors; however, it is always recommended to carry out a molecular study for diagnostic confirmation. This is the first Brazilian study that aimed to investigate possible genetic alterations in the BRAF gene in pilocytic astrocytomas, specifically in adults. Only 1 patient died, but due to operative complications and not the disease itself, suggesting a good evolution of these individuals.
Topics: Adolescent; Child; Humans; Adult; Brain Neoplasms; Proto-Oncogene Proteins B-raf; Oncogene Proteins, Fusion; Astrocytoma; Mutation
PubMed: 37984046
DOI: 10.1016/j.prp.2023.154942 -
Neurosurgical Review Apr 2020Primary pilocytic astrocytoma (PA) of the spine is extremely rare and most published case series only include only a few patients. We attempted to explore the clinical... (Review)
Review
Primary pilocytic astrocytoma (PA) of the spine is extremely rare and most published case series only include only a few patients. We attempted to explore the clinical features, radiological findings, and treatment outcomes of patients with spinal PA. Sixteen spinal PA patients who were surgically treated in our hospital between April 2008 and June 2018 were included in this retrospective study. An integrative analysis was performed regarding spinal PA patients by extracting from published studies on PubMed. The 16 patients with spinal PA included eight male and eight female patients with a mean age of 29.1 years. Ten cases (62.5%) had masses located in the cervical segments, five (31.3%) had masses in the thoracic segments, and one (6.2%) had masses in the sacral canal. All the patients were treated surgically with 13 gross total resections (GTRs, 81.3%) and three subtotal resections (STRs). The mean follow-up period was 40.4 months. These tumors accounted for a recurrence rate of 37.5% (6 of 16 patients) and no death during the follow-up periods. The influencing factors of recurrence were mainly STR, gene mutation (NF-1 and H2-K27M), and the number of segments involved. The mean recurrence-free survival duration was 19 months. The imaging features of spinal PA are heterogeneous, and the definitive diagnosis requires pathological support. GTR is the standard therapy for spinal PAs, although patients with GTR are still likely to relapse. The regular spinal magnetic resonance imaging follow-ups are required regardless of the resection status. Reoperation is feasible for patients with recurrence.
Topics: Adolescent; Adult; Astrocytoma; Child; Child, Preschool; Female; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Neoplasm Recurrence, Local; Reoperation; Retrospective Studies; Spinal Cord Neoplasms; Treatment Outcome; Young Adult
PubMed: 31098788
DOI: 10.1007/s10143-019-01109-0 -
Handbook of Clinical Neurology 2016Pilocytic astrocytoma (PA) is the most common pediatric brain tumor in children. PAs are a distinct histologic and biologic subset of glioma that have a slow growth rate... (Review)
Review
Pilocytic astrocytoma (PA) is the most common pediatric brain tumor in children. PAs are a distinct histologic and biologic subset of glioma that have a slow growth rate and may even spontaneously regress. These tumors tend to arise in the cerebellum and chiasmatic/hypothalamic region, but can also occur in other regions of the central nervous system. Dissemination is uncommon, but may occur in newly diagnosed PAs. Alterations in the Ras/RAF/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway (Ras/ERK) have been discovered in a majority of PAs, with KIAA1549-BRAF fusions being the most commonly identified alteration. Children with neurofibromatosis 1 are predisposed to developing PAs, primarily within the optic pathway. When required, treatment consists of surgery, chemotherapy, and/or radiation, although new molecular agents targeting the Ras/ERK and related signaling pathways are promising new approaches. The 10-year survival rates are greater than 90% in pediatric patients; however, they are poorer in adults. Tumors that are amenable to complete resection (i.e., cerebellum and cortex) have the best overall survival.
Topics: Astrocytoma; Brain Neoplasms; Child; Humans
PubMed: 26948364
DOI: 10.1016/B978-0-12-802997-8.00020-7 -
Child's Nervous System : ChNS :... Mar 2013Pilocytic astrocytoma (PA) is a common pediatric glioma that is generally characterized by indolent growth. However, there are reports of PA disseminating throughout the... (Review)
Review
PURPOSE
Pilocytic astrocytoma (PA) is a common pediatric glioma that is generally characterized by indolent growth. However, there are reports of PA disseminating throughout the central nervous system. Given the rarity of dissemination, the appropriate treatment for these patients is poorly defined. In this case series, we describe the clinical characteristics and treatment outcomes of six children treated for disseminated PA at our institution and review the current published literature.
METHODS
Six cases of disseminated PA treated at the University of Texas MD Anderson Cancer Center were identified. Demographics, disease characteristics, and follow-up data were compiled. Fifty-three reported cases were identified in the published literature.
RESULTS
Our cohort's mean age at presentation was 7 years, and the mean time to identification of disseminated disease was 12 months after initial diagnosis. Two patients underwent chemotherapy, and all underwent proton beam radiation therapy to all or part of the craniospinal axis. With a median follow-up of 24 months after radiation therapy, five of six patients were alive, four with stable disease and one with progressive disease.
CONCLUSIONS
Treatment of disseminated PA is frequently multi-modal, including surgical resection, chemotherapy, and radiation therapy. On the basis of early clinical data, extended-field radiation therapy is a viable option for treating disseminated PA.
Topics: Adolescent; Astrocytoma; Brain Neoplasms; Child; Child, Preschool; Cohort Studies; Combined Modality Therapy; Craniospinal Irradiation; Female; Humans; Male; Meningeal Neoplasms; Neoplasm Invasiveness; Proton Therapy; Survival Analysis; Treatment Outcome
PubMed: 23207974
DOI: 10.1007/s00381-012-1970-y -
Neuropathology : Official Journal of... Oct 2023Pilocytic astrocytoma (PA), a central nervous system (CNS) World Health Organization grade 1 tumor, is mainly seen in children or young adults aged 5-19. Surgical...
Pilocytic astrocytoma (PA), a central nervous system (CNS) World Health Organization grade 1 tumor, is mainly seen in children or young adults aged 5-19. Surgical resection often provides excellent outcomes, but residual tumors may still remain. This low-grade tumor is well recognized for its classic radiological and morphological features; however, some unique molecular findings have been unveiled by the application of next-generation sequencing (NGS). Among the genetic abnormalities identified in this low-grade tumor, increasing evidence indicates that BRAF alterations, especially BRAF fusions, play an essential role in PA tumorigenesis. Among the several fusion partner genes identified in PAs, KIAA1549-BRAF fusion is notably the most common detectable genetic alteration, especially in the cerebellar PAs. Here, we report a case of a young adult patient with a large, right-sided posterior fossa cerebellar and cerebellopontine angle region mass consistent with a PA. Of note, NGS detected a novel GNAI3-BRAF fusion, which results in an in-frame fusion protein containing the kinase domain of BRAF. This finding expands the knowledge of BRAF fusions in the tumorigenesis of PAs, provides an additional molecular signature for diagnosis, and a target for future therapy.
Topics: Child; Young Adult; Humans; Proto-Oncogene Proteins B-raf; Astrocytoma; Central Nervous System Neoplasms; Mutation; Carcinogenesis; Brain Neoplasms; GTP-Binding Protein alpha Subunits, Gi-Go
PubMed: 36786200
DOI: 10.1111/neup.12896 -
World Neurosurgery Jan 2018Colloid cyst is a gelatin-containing cyst in the brain almost always found in the third ventricle. The specific shape and location of these cysts, a round... (Review)
Review
BACKGROUND
Colloid cyst is a gelatin-containing cyst in the brain almost always found in the third ventricle. The specific shape and location of these cysts, a round well-delineated mass in the rostral part of the third ventricle adjacent to the foramen of Monro, on imaging are the main findings for diagnosis. Several masses of the third ventricle masquerading colloid cysts on images have been reported. Based on different surgical approaches, preoperative misdiagnosis of colloid cyst may have great impact on prognosis.
METHODS
We report 2 cases that presented with severe headache and hydrocephalus, and their preoperative images were highly indicative of colloid cyst.
RESULTS
Histopathologic investigations after tumor resection showed pilocytic astrocytoma of fornix in both cases.
CONCLUSIONS
Fifteen cases of colloid cyst misdiagnosis with other masses have been reported thus far; among them, 2 cases were pilocytic astrocytoma. In this study we report 2 other cases. Furthermore, we discuss additional clues helping to differentiate pilocytic astrocytoma from colloid cyst on images.
Topics: Astrocytoma; Brain Neoplasms; Child; Colloid Cysts; Diagnosis, Differential; Female; Fornix, Brain; Headache; Humans; Hydrocephalus; Magnetic Resonance Imaging; Male; Tomography, X-Ray Computed; Young Adult
PubMed: 28024978
DOI: 10.1016/j.wneu.2016.12.067