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| __NOTOC__ | | __NOTOC__ |
| {{Astrocytoma}} | | {{Astrocytoma}} |
| {{CMG}}; {{AE}} {{Ammu}} | | {{CMG}}; {{AE}} {{Fs}} |
| ==Overview== | | ==Overview== |
| On cranial [[CT]], astrocytoma is characterized by isodense or hypodense regions of positive [[mass]] effect, often without any enhancement. [[Calcification]] and either cystic or [[fluid]] attenuation components are also encountered in [[CT]] depending on the type and grade of the [[tumor]].
| | [[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 [[ventricle]]s with displacement of anterior and [[middle cerebral arteries]].
| | * In [[low grade astrocytoma]]: |
| * During a [[CT]] scan, [[x ray]]s 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]].
| | ** Poorly demarcated mass |
| {|
| | ** Low density |
| | valign=top |
| | ** No inhancement inside the tumor |
| [[File:Pilocystic 03.jpg|thumb|center|200 px|Axial non contrast CT in a nine-year-old girl showing a slightly hypodense mass in the tectum of the brainstem, compressing the aqueduct of Sylvius and causing obstructive hydrocephalus<SMALL><SMALL>''[https://en.wikipedia.org/wiki/Pilocytic_astrocytoma#/media/File:Pilocytic.jpg]''<ref name="Wikipedia">{{Cite web | title = Wikipedia| url = https://en.wikipedia.org/wiki/Pilocytic_astrocytoma#/media/File:Pilocytic.jpg}}</ref></SMALL></SMALL>]]
| | ** In few cases we might see some [[calcification]] and [[Cyst|cystic]] changes inside the mass |
| |} | | * In [[high grade astrocytoma]]: |
| | ** Poorly demarcated mass |
| | ** Low density |
| | ** There are partial enhancement inside the [[tumor]] mass |
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| ===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>===
| | [[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>]] |
| * 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 [[tumor]]s), although particularly gemistocytic astrocytomas can demonstrates wispy enhancement.
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| * [[Calcification]] is not seldom (10-20% of cases)1 and may be related to [[oligodendroglial]] components (i.e oligoastrocytoma).
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| * Cystic or [[fluid]] attenuation components are also encountered, particularly in gemistocytic and protoplasmic varieties.
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| ====Fibrillary Astrocytoma<ref name=Radiopaedia2-2015>{{cite web | title = Fibrillary Astrocytoma [Dr Frank Gaillard]| url = http://radiopaedia.org/articles/fibrillary-astrocytoma }}</ref>====
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| * 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 [[tumor]]s 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 [[tumor]]s). Areas of the [[tumor]] appear of [[fluid]] attenuation, due to the aforementioned prominent mucinous microcystic component.
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| ===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.
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| ===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 [[tumor]] arises when a [[subependymal nodule]] transforms into subependymal [[giant cell]] astrocytoma over a period of time..
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| * Typically appears as an intraventricular [[mass]] near the [[foramen of Monro]].
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| * They are usually larger than 1 cm.
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| * Lesions are iso- or slightly hypoattenuating to [[grey matter]].
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| * [[Calcification]] is common and [[hemorrhage]] is possible
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| * Accompanying [[hydrocephalus]] may be present
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| * Often shows marked contrast enhancement (subependymal [[nodule]]s also enhance)
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| ===Pleomorphic xanthoastrocytomas (PXA)<ref name=Radiopaedia072015>{{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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| * Pleomorphic xanthoastrocytomas are typically hypo or isodense and may be well or poorly demarcated, usually with little surrounding [[edema]]. [[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 [[tumor]]s that may exhibit a [[dural]] [[tail]], which is reactive rather than due to direct [[dural]] invasion, which is rare .
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| ==References== | | ==References== |
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| {{Nervous tissue tumors}} | | {{Nervous tissue tumors}} |
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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]] |
