This item is licensed under a Creative Commons License. Show full item record Recommend this item. Introduction: Gliomas are primary brain tumors are characterized by diffuse and invasive growth. Study biomathematical proliferation and migration of gliomas suggests that the growth of tumors in deep brain gray matter would have a longer time interval compared with lesions in the lobar white matter, where the invasion and migration would be faster.
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GBMs are high-grade astrocytomas; they are therefore generally aggressive, largely resistant to therapy, and have a corresponding poor prognosis. They have a predilection for spreading along the condensed white matter tracts such as corticospinal tracts and corpus callosum to involve the contralateral hemisphere.
Glioblastoma was previously known as glioblastoma multiforme; the multiform refers to the tumor heterogeneity. Somewhat confusingly the abbreviation GBM is still considered appropriate Primary glioblastomas are those that arise de novo, without a pre-existing lower grade diffuse astrocytoma. Primary glioblastomas are almost invariably IDH wild-type. Secondary glioblastomas, in contrast, are those which arise from a pre-existing lower grade diffuse astrocytoma.
These tumors tend to be less aggressive than primary glioblastomas and they tend to occur in younger patients 7, Interestingly, and of uncertain significance, they have a predilection for the frontal lobes Secondary glioblastomas also demonstrate p53 mutations , amplification of PDGF-A, loss of heterozygosity of chromosomes 10q and 17p, loss of 19q and increased telomerase activity and hTERT expression 7.
A glioblastoma may occur at any age, however, they usually occur after the age of 40 years with a peak incidence between 65 and 75 years of age. There is a slight male preponderance with a M:F ratio 5.
Caucasians are affected more frequently than other ethnicities: Europe and North America per , whereas Asia 0. The vast majority of glioblastomas are sporadic. Rarely they are related to prior radiation exposure radiation-induced GBM. Although glioblastomas can arise anywhere within the brain, they have a predilection for the subcortical white matter and deep grey matter of the cerebral hemispheres, particularly the temporal lobe Glioblastomas are typically poorly-marginated, diffusely infiltrating necrotic masses localized to the cerebral hemispheres.
The supratentorial white matter is the most common location. These tumors may be firm or gelatinous. Considerable regional variation in appearance is characteristic. Some areas are firm and white, some are soft and yellow secondary to necrosis , and still others are cystic with local hemorrhage.
GBMs have significant variability in size from only a few centimeters to lesions that replace a hemisphere. Infiltration beyond the visible tumor margin is always present. Pleomorphic astrocytes with marked atypia and numerous mitoses are seen. Necrosis and microvascular proliferation are hallmarks of glioblastomas see WHO grading of astrocytomas. Microvascular proliferation results in an abundance of new vessels with a poorly formed blood-brain barrier BBB permitting the leakage of iodinated CT contrast and gadolinium into the adjacent extracellular interstitium resulting in the observed enhancement on CT and MRI respectively Edema and enhancement are however also seen in lower grade tumors that lack endovascular proliferation anaplastic astrocytoma and other diffuse astrocytomas, for example, gemistocytic astrocytomas and this is thought to be due to disruption of the normal blood-brain barrier by tumor produced factors.
Vascular endothelial growth factor VEGF for example has been shown to both disrupt tight junctions between endothelial cells and increase the formation of fenestrations Glioblastomas are capable of demonstrating varied patterns, sometimes within the one tumor.
In addition to the three recognized variants giant cell glioblastoma , gliosarcoma , and epithelioid glioblastoma additional histological features are sometimes encountered which impact imaging appearance and biological behavior. Most of these are seen predominantly in primary IDH wild-type glioblastomas.
These include 16 :. As discussed above, the vast majority of glioblastomas are primary and are IDH wild-type. TERT promoter mutations are frequently encountered and have a negative impact on prognosis, not as pronounced, however, as on lower grade diffuse astrocytomas Glioblastomas are typically large tumors at diagnosis.
They often have thick, irregular-enhancing margins and a central necrotic core, which may also have a hemorrhagic component. They are surrounded by vasogenic-type edema, which in fact usually contains infiltration by neoplastic cells. Multicentric disease, on the other hand, is where no such connection can be seen.
PET demonstrates the accumulation of FDG representing increased glucose metabolism which typically is greater than or similar to metabolism in grey matter. Biopsy and tumor debulking with postoperative adjuvant radiotherapy and chemotherapy temozolomide are the most commonly carried out treatment. Newer therapies include antiangiogenesis e.
Despite this, it carries a poor prognosis with a median survival of fewer than 2 years Glioblastomas are generally followed up fairly closely with MRI. In individuals who have no residual macroscopic disease and remain stable for a protracted time, the frequency of follow-up imaging can be decreased.
Glioblastomas have been the subject of close trial scrutiny with many new chemotherapeutic agents showing promise. As such a number of criteria have been created over the years to assess response to treatment. Currently, the RANO criteria are most widely used.
Other historical systems are worth knowing to allow interpretation of older data. These systems for response criteria for first-line treatment of glioblastomas include 9 :. Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Updating… Please wait. Unable to process the form. Check for errors and try again. Thank you for updating your details. Log In. Sign Up. Log in Sign up. Articles Cases Courses Quiz. About Blog Go ad-free. As of the latest update, Google Chrome and Microsoft Edge have made a breaking change to how file uploads are handled.
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On this page:. Article: Terminology Primary vs secondary Variants Epidemiology Clinical presentation Pathology Radiographic features Radiology report Treatment and prognosis History and etymology Differential diagnosis Related articles References Images: Cases and figures Imaging differential diagnosis. Quiz questions. Robbins and Cotran pathologic basis of disease.
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Tags: astrocytoma , glioma. Support Radiopaedia and see fewer ads. Cases and figures. Figure 1: gross pathology Figure 1: gross pathology. Case 1 Case 1. Case 2 Case 2. Case 3 Case 3. Case 4 Case 4. Case 6 Case 6. Case 7: "gliosarcoma" Case 7: "gliosarcoma". Case 8: mulifocal glioblastoma multiforme Case 8: mulifocal glioblastoma multiforme.
Case 9: with periventricular extension Case 9: with periventricular extension. Case 10 Case Case with subependymal spread Case with subependymal spread. Case 12 Case Case 13 Case Case 15 Case Case multifocal Case multifocal. Case 17 Case Case 18 Case Case transependymal spread Case transependymal spread.
Case 20 Case Case 21 Case Case 22 Case Case 23 Case Case 24 Case Case with intraventricular extension Case with intraventricular extension.
2014, Número 3
Brain stem gliomas: a classification system based on magnetic resonance imaging. Pediatr Neurosurg. Advances toward an understanding of brainstem gliomas. J Clin Oncol. Radiologic classification of brain stem tumors: correlation of magnetic resonance imaging appearance with clinical outcome. Brainstem gliomas in adults: prognostic factors and classification. Adult brainstem gliomas.
2019, Número 1
GBMs are high-grade astrocytomas; they are therefore generally aggressive, largely resistant to therapy, and have a corresponding poor prognosis. They have a predilection for spreading along the condensed white matter tracts such as corticospinal tracts and corpus callosum to involve the contralateral hemisphere. Glioblastoma was previously known as glioblastoma multiforme; the multiform refers to the tumor heterogeneity. Somewhat confusingly the abbreviation GBM is still considered appropriate Primary glioblastomas are those that arise de novo, without a pre-existing lower grade diffuse astrocytoma. Primary glioblastomas are almost invariably IDH wild-type. Secondary glioblastomas, in contrast, are those which arise from a pre-existing lower grade diffuse astrocytoma.