Glioma overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Swathi Venkatesan, M.B.B.S.[2]
Overview
A glioma is a type of primary central nervous system (CNS) tumor that arises from glial cells. The most common site of involvement of gliomas is the brain, but gliomas can also affect the spinal cord or any other part of the CNS, such as the optic nerve.[1] Gliomas were reported as early as the 1850s. Retinal gliomas were most commonly reported because they were easier to detect and sample in the absence of advanced imaging and surgical techniques. Glioma may be classified into several subtypes based on the type of cell, grade, and location.[2] The pathogenesis of cerebral glioma involves invasion of the tumor cells into the adjacent normal brain tissue. The gross and histopathological appearance of glioma varies with the tumor grade and type.[3][4][5][6][7] Glioma must be differentiated from primary CNS lymphoma, cerebral metastases, meningioma, brain abscess, cavernous malformation, stroke, acute disseminated encephalomyelitis, cavernous sinus syndrome, intracranial hemorrhage, gerstmann syndrome, spinal tuberculosis, hamartoma, germinoma, teratoma, piloid gliosis, and progressive multifocal leukoencephalopathy.[3][2] The incidence of glioma is estimated to be 4.9 cases per 100,000 individuals in the US.[8] Patients of all age groups may develop glioma. Males are more commonly affected with glioma than females. It usually affects individuals of the caucasian race. African american, latin american, and asian individuals are less likely to develop glioma. Common risk factors in the development of glioma are occupational factors, environmental factors, genetic factors, and viruses.[2][3][8][5][9] Common complications of glioma include brain herniation, coma, metastasis, and recurrence. The prognosis of glioma varies with the grade of tumor. The 1-year and 2-year survival rate of patients with malignant glioma is approximately 50% and 25%, respectively.[10] Common symptoms of glioma include morning headaches, nausea and vomiting, seizures, drowsiness, changes in speech, difficulty in swallowing, vision changes, abnormal eye movements, changes in personality, memory loss, loss of balance, difficulty in walking, weakness in extremities, numbness in extremities, pain in extremities, and loss of appetite.[2] The CT scan and MRI findings of glioma vary with the tumor grade and type.[2][4][3][5][10][6] The predominant therapy for glioma is surgical resection. Adjunctive chemotherapy and radiation may be required.[2]
Historical Perspective
- Gliomas were reported as early as the 1850s.
- The first recorded reports of gliomas were given in British scientific reports, by Berns in 1800 and in 1804 by Abernety
- With the first comprehensive histomorphological description being given in 1865 by Rudolf Virchow.
- In 1926 Percival Bailey and Harvey Cushing gave the base for the modern classification of gliomas.
- Between 1934 and 1941 the most prolific researcher in glioma research was Hans-Joachim Scherer, who postulated some of the clinico-morphological aspects of Glioblastoma multiforme.
- Retinal gliomas were most commonly reported because they were easier to detect and sample in the absence of advanced imaging and surgical techniques.
Classification
- The classification and grading of gliomas have evolved over time, beginning in 1926 with a system devised by Bailey and Cushing and later revised by Kernohan, Ringertz, and others.
- As of the 2016 edition of the WHO classification, gliomas are classified based not only on histopathologic appearance but also on well-established molecular parameters
- Glioma may be classified into several subtypes based on the type of cell (ependymoma, astrocytoma, oligodendroglioma, and mixed gliomas), grade (low-grade and high-grade gliomas), and location (infratentorial and supratentorial).[2]
Pathophysiology
The pathogenesis of cerebral glioma involves invasion of the tumor cells into the adjacent normal brain tissue. Although in certain areas the margin of the tumor may seem to be macroscopically well defined from the brain, there are always microscopic nests of tumor cells extending well out into the brain.[3] Genes involved in the pathogenesis of glioma include ERCC1, ERCC2, XRCC1, MGMT, IDH1, IDH2, p53, EGFR, TSC1, TSC2, RB1, APC, hMLH1, hMSH2, PMS2, PTEN, NF1, and NF2.[2][8] The gross and histopathological appearance of glioma varies with the tumor grade and type.[11][4][5][6][7]
Causes
There are no established causes for glioma.
Differentiating brain tumors from other diseases
Glioma must be differentiated from primary CNS lymphoma, cerebral metastases, meningioma, brain abscess, cavernous malformation, stroke, acute disseminated encephalomyelitis, cavernous sinus syndrome, intracranial hemorrhage, gerstmann syndrome, spinal tuberculosis, hamartoma, germinoma, teratoma, piloid gliosis, and progressive multifocal leukoencephalopathy.[2][3]
Epidemiology and Demographics
Glioma is the most common primary intracranial tumor. The incidence of glioma is estimated to be 4.9 cases per 100,000 individuals in the US.[8] Patients of all age groups may develop glioma. Males are more commonly affected with glioma than females. It usually affects individuals of the caucasian race. African american, latin american, and asian individuals are less likely to develop glioma.
Risk factors
Common risk factors in the development of glioma are occupational factors, environmental factors, genetic factors, and viruses.[2][3][8][5][9]
Screening
There is insufficient evidence to recommend routine screening for glioma.[12]
Natural History, Complications and Prognosis
Common complications of glioma include brain herniation, coma, metastasis, and recurrence. The prognosis of glioma varies with the grade of tumor. The 1-year and 2-year survival rate of patients with malignant glioma is approximately 50% and 25%, respectively.[10]
Staging
There is no established system for the staging of glioma.[10]
History and Symptoms
Common symptoms of glioma include morning headaches, nausea and vomiting, seizures, drowsiness, changes in speech, difficulty in swallowing, vision changes, abnormal eye movements, changes in personality, memory loss, loss of balance, difficulty in walking, weakness in extremities, numbness in extremities, pain in extremities, and loss of appetite.[2]
Physical examination
Common physical examination findings of glioma include aphasia, vision loss, strabismus, memory loss, sensory loss, paresis, abnormal gait, ataxia, papilledema, and focal neurological deficits.[2]
Laboratory Findings
There are no diagnostic lab findings associated with glioma.
X Ray
There are no x-ray findings associated with glioma.
CT
Head CT scan may be diagnostic of glioma. The CT scan findings of glioma vary with the tumor grade and type.[2][4][3][5][10][6]
MRI
Brain MRI may be diagnostic of glioma. The MRI findings of glioma vary with the tumor grade and type.[2][4][3][5][10][6]
Ultrasound
There are no ultrasound findings associated with glioma.
Other Imaging Findings
Other imaging studies for high-grade gliomas include PET scan, which demonstrates accumulation of [18F]-fluorodeoxyglucose (increased glucose metabolism).[2]
Other Diagnostic Studies
Other diagnostic studies for glioma include biopsy, which demonstrates astrocytes with or without atypia and mitoses, depending on the type of glioma.[2]
Medical Therapy
Treatment for glioma depends on the location and grade. The predominant therapy for glioma is surgical resection. Adjunctive chemotherapy and radiation may be required.[2]
Surgery
Surgery is the mainstay of treatment for glioma.[2]
References
- ↑ Mamelak A.N., and Jacoby, D.B. Targeted delivery of antitumoral therapy to glioma and other malignancies with synthetic chlorotoxin (TM-601) Expert Opin. Drug Drliv. (2007) 4(2):175-186.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 Classification of glioma. Wikipedia. https://en.wikipedia.org/wiki/Glioma
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Pathology of pilocytic astrocytoma. Libre Pathology. http://librepathology.org/wiki/index.php/Pilocytic_astrocytoma
- ↑ 4.0 4.1 4.2 4.3 4.4 Pathology of gliomas. Libre Pathology. http://librepathology.org/wiki/index.php/Oligodendroglioma
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Pathology of anaplastic astrocytoma. Libre Pathology. http://librepathology.org/wiki/index.php?title=Neuropathology_tumours&redirect=no#Infiltrative_astrocytomas
- ↑ 6.0 6.1 6.2 6.3 6.4 Pathology of glioblastoma. Libre Pathology. http://librepathology.org/wiki/index.php/Glioblastoma
- ↑ 7.0 7.1 Pathology of ependymoma. Libre Pathology. http://librepathology.org/wiki/index.php/Ependymoma
- ↑ 8.0 8.1 8.2 8.3 8.4 Schwartzbaum JA, Fisher JL, Aldape KD, Wrensch M (2006). "Epidemiology and molecular pathology of glioma". Nat Clin Pract Neurol. 2 (9): 494–503, quiz 1 p following 516. doi:10.1038/ncpneuro0289. PMID 16932614.
- ↑ 9.0 9.1 Ostrom, Quinn T.; Bauchet, Luc; Davis, Faith G.; Deltour, Isabelle; Fisher, James L.; Langer, Chelsea Eastman; Pekmezci, Melike; Schwartzbaum, Judith A.; Turner, Michelle C. (Jul 2014). "The epidemiology of glioma in adults: a "state of the science" review". Neuro-Oncology. 16 (7): 896–913. doi:10.1093/neuonc/nou087. ISSN 1523-5866. PMC 4057143. PMID 24842956.
- ↑ 10.0 10.1 10.2 10.3 10.4 10.5 Prognostic factors of glioma. National Cancer Institute. http://www.cancer.gov/types/brain/patient/adult-brain-treatment-pdq
- ↑ Pathology of pilocytic astrocytoma. Libre Pathology. http://librepathology.org/wiki/index.php/Pilocytic_astrocytoma
- ↑ Early detection, diagnosis, and staging of glioma. American cancer society. http://www.cancer.org/cancer/braincnstumorsinadults/detailedguide/brain-and-spinal-cord-tumors-in-adults-detection