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| __NOTOC__ | | __NOTOC__ |
| {{Astrocytoma}} | | {{Astrocytoma}} |
| {{CMG}} | | {{CMG}}; {{AE}} {{Fs}} |
| ==Overview== | | ==Overview== |
| | [[CT scan]] may be helpful in the diagnosis of astrocytoma. Findings on [[CT scan]] suggestive of astrocytoma include: Poorly demarcated mass, low density and no inhancement inside the tumor In [[low grade astrocytoma]], poorly demarcated mass, low density and there are partial enhancement inside the [[tumor]] mas In [[high grade astrocytoma]]. |
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| ==CT findings== | | ==CT findings== |
| *A [[Computed Tomography]] (CT) or [[Magnetic Resonance Imaging]] (MRI) scan is necessary to characterize the anatomy of this tumor (size, location, consistency).
| | [[CT scan]] may be helpful in the diagnosis of astrocytoma. Findings on [[CT scan]] suggestive of astrocytoma include:<ref name="pmid22819718">{{cite journal |vauthors=Pedersen CL, Romner B |title=Current treatment of low grade astrocytoma: a review |journal=Clin Neurol Neurosurg |volume=115 |issue=1 |pages=1–8 |date=January 2013 |pmid=22819718 |doi=10.1016/j.clineuro.2012.07.002 |url=}}</ref> |
| *CT will usually show distortion of third and lateral ventricles with displacement of anterior and middle cerebral arteries.
| | * In [[low grade astrocytoma]]: |
| * A [[X-ray computed tomography]] (CT) or [[Magnetic resonance imaging]] (MRI) scan is necessary to characterize the extent of these tumors (size, location, consistency). CT will usually show distortion of third and lateral ventricles with displacement of anterior and middle cerebral arteries. Histologic analysis is necessary for grading diagnosis.
| | ** Poorly demarcated mass |
| * In the first stage of diagnosis the doctor will take a history of symptoms and perform a basic neurological exam, including an eye exam and tests of vision, balance, coordination and mental status. The doctor will then require a computerized tomography (CT) scan and magnetic resonance imaging (MRI) of the patient's brain.
| | ** Low density |
| * During a CT scan, x rays of the patient's brain are taken from many different directions. These are then combined by a computer, producing a cross-sectional image of the brain.
| | ** No inhancement inside the tumor |
| * For an MRI, the patient relaxes in a tunnel-like instrument while the brain is subjected to changes of magnetic field. An image is produced based on the behavior of the brain's water molecules in response to the magnetic fields. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to identify.
| | ** In few cases we might see some [[calcification]] and [[Cyst|cystic]] changes inside the mass |
| ===Low grade infiltrative astrocytoma<ref name=Radiopaedia2015>{{cite web | title = Low grade infiltrative astrocytoma [Dr Bruno Di Muzio and Dr Frank Gaillard]| url = http://radiopaedia.org/articles/low-grade-infiltrative-astrocytoma }}</ref>===
| | * In [[high grade astrocytoma]]: |
| * Typically low grade infiltrating astrocytomas appear as isodense or hypodense regions of positive mass effect, often without any enhancement (in fact presence of enhancement would suggest high tumours), although particularly gemistocytic astrocytomas can demonstrates wispy enhancement.
| | ** Poorly demarcated mass |
| * Calcification is not seldom (10-20% of cases)1 and may be related to oligodendroglial components (i.e oligoastrocytoma).
| | ** Low density |
| * Cystic or fluid attenuation components are also encountered, particularly in gemistocytic and protoplasmic varieties.
| | ** There are partial enhancement inside the [[tumor]] mass |
| ====Fibrillary Astrocytoma<ref name=Radiopaedia2-2015>{{cite web | title = Fibrillary Astrocytoma [Dr Frank Gaillard]| url = http://radiopaedia.org/articles/fibrillary-astrocytoma }}</ref>==== | |
| * Typically fibrillary low grade infiltrating astrocytomas appear as isodense or hypodense regions of positive mass effect, usually without any enhancement (in fact presence of enhancement would suggest high grade, e.g. WHO III or IV tumours.
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| * Calcification is not infrequently seen (10-20% of cases)1 but is more common in mixed tumours relating to an oligodendroglial components (i.e. oligoastrocytoma).
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| * Cystic or fluid attenuation components are also encountered although this is far more common in gemistocytic and protoplasmic variants.
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| ====Protoplasmic Astrocytoma<ref name=Radiopaedia3-2015>{{cite web | title = Protoplasmic astrocytoma [Dr Yuranga Weerakkody and Dr Frank Gaillard]| url = http://radiopaedia.org/articles/protoplasmic-astrocytoma }}</ref>====
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| * Typically protoplasmic low grade infiltrating astrocytomas appear as hypodense regions of positive mass effect, usually without any enhancement (in fact presence of enhancement would suggest high grade tumours). Areas of the tumour appear of fluid attenuation, due to the aforementioned prominent mucinous microcystic component. | |
| ===Anaplastic astrocytomas<ref name=Radiopaedia 2015 Anaplastic astrocytoma>{{cite web | title = Anaplastic astrocytoma [Dr Bruno Di Muzio and Dr Frank Gaillard]| url = http://radiopaedia.org/articles/anaplastic-astrocytoma }}</ref>===
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| * CT appearances are intermediate, appearing as regions of low attenuation with positive mass effect. Enhancement is variable. | |
| ===Subependymal Giant Cell Astrocytoma<ref name=Radiopaedia052015>{{cite web | title = Subependymal giant cell astrocytoma [Dr Bruno Di Muzio and Dr Jeremy Jones]| url = http://radiopaedia.org/articles/subependymal-giant-cell-astrocytoma }}</ref>===
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| * The foramen of Monro is the classic location, and the tumour arises when a subependymal nodule transforms into SGCA over a period of time. | |
| * Typically appears as an intraventricular mass near the foramen of Monro | |
| * They are usually larger than 1 cm
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| * Lesions are iso- or slightly hypoattenuating to grey matter | |
| * Calcification is common and haemorrhage is possible | |
| * Accompanying hydrocephalus may be present | |
| * Often shows marked contrast enhancement (subependymal nodules also enhance)
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| ===Pleomorphic xanthoastrocytomas (PXA)<ref name=Radiopaedia2015>{{cite web | title = Pleomorphic xanthoastrocytomas [Dr Bruno Di Muzio and Dr Frank Gaillard]| url = http://radiopaedia.org/articles/pleomorphic-xanthoastrocytoma }}</ref> ===
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| * PXAs are typically hypo or isodense and may be well or poorly demarcated, usually with little surrounding oedema. Calcification is rare. Due to its superfical location it may cause scalloping of the overlying bone .<ref name="pmid15537977">{{cite journal| author=Koeller KK, Rushing EJ| title=From the archives of the AFIP: pilocytic astrocytoma: radiologic-pathologic correlation. | journal=Radiographics | year= 2004 | volume= 24 | issue= 6 | pages= 1693-708 | pmid=15537977 | doi=10.1148/rg.246045146 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15537977 }} </ref> | |
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| * Often there is a cystic component (50-60%) with an enhancing mural nodule. Additionally they are one of the tumours that may exhibit a dural tail, which is reactive rather than due to direct dural invasion, which is rare . | |
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| | [[File:2169e7e3234fa8afb3a89e0a0bab37 big gallery.jpg|500px|none|thumb|Case courtesy of A.Prof Frank Gaillard, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/8474">rID: 8474</a>]] |
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| ==References== | | ==References== |
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| {{reflist|2}} | | {{reflist|2}} |
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| {{Nervous tissue tumors}} | | {{Nervous tissue tumors}} |
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| [[de:Astrozytom]]
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| [[nl:Astrocytoom]]
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| [[pt:Astrocitoma]]
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| {{WikiDoc Help Menu}} | | {{WikiDoc Help Menu}} |
| {{WikiDoc Sources}} | | {{WikiDoc Sources}} |
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| [[Category:Pathology]] | | [[Category:Pathology]] |
| [[Category:Neurosurgery]] | | [[Category:Neurosurgery]] |
| [[Category:Needs overview]] | | [[Category:Up-To-Date]] |
| | [[Category:Oncology]] |
| | [[Category:Medicine]] |