Astrocytoma classification: Difference between revisions
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==Classification== | ==Classification== | ||
Within the astrocytomas, there are two broad classes recognized in literature, those with: | Within the astrocytomas, there are two broad classes recognized in literature, those with: | ||
* Narrow zones of infiltration (mostly invasive tumors; e.g., pilocytic astrocytoma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma), that often are clearly outlined on diagnostic images | * Narrow zones of infiltration (mostly invasive tumors; e.g., pilocytic astrocytoma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma), that often are clearly outlined on diagnostic images | ||
* Diffuse zones of infiltration (e.g., low-grade astrocytoma, anaplastic astrocytoma, glioblastoma), that share various features, including the ability to arise at any location in the CNS, but with a preference for the cerebral hemispheres; they occur usually in adults; and an intrinsic tendency to progress to more advanced grades.<ref> http://emedicine.medscape.com/article/283453-overview </ref> | * Diffuse zones of infiltration (e.g., low-grade astrocytoma, anaplastic astrocytoma, glioblastoma), that share various features, including the ability to arise at any location in the CNS, but with a preference for the cerebral hemispheres; they occur usually in adults; and an intrinsic tendency to progress to more advanced grades.<ref> http://emedicine.medscape.com/article/283453-overview </ref> | ||
===Grading=== | |||
Astrocytomas have great variation in their presentation. The [[World Health Organization]] acknowledges the following grading system for astrocytomas: | |||
* '''Grade 1''' — [[pilocytic astrocytoma]] - primarily pediatric tumor, with median age at diagnosis of 12 | |||
* '''Grade 2''' — diffuse astrocytoma | |||
* '''Grade 3''' — anaplastic (malignant) astrocytoma | |||
* '''Grade 4''' — [[glioblastoma multiforme]] (most common) | |||
In addition to these four tumor grades, astrocytomas may combine with oligodendrocytes to produce [[oligoastrocytoma]]. Unique astrocytoma variants have also been known to exist. | |||
==References== | ==References== | ||
Revision as of 20:38, 19 August 2015
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Astrocytoma Microchapters |
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Diagnosis |
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Treatment |
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Case Study |
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Astrocytoma classification On the Web |
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American Roentgen Ray Society Images of Astrocytoma classification |
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Risk calculators and risk factors for Astrocytoma classification |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
There are two broad classes of classification identified within astrocytomas, based on histology, as to whether the zones of infiltration of cancer cells are narrow or diffuse.
Classification
Within the astrocytomas, there are two broad classes recognized in literature, those with:
- Narrow zones of infiltration (mostly invasive tumors; e.g., pilocytic astrocytoma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma), that often are clearly outlined on diagnostic images
- Diffuse zones of infiltration (e.g., low-grade astrocytoma, anaplastic astrocytoma, glioblastoma), that share various features, including the ability to arise at any location in the CNS, but with a preference for the cerebral hemispheres; they occur usually in adults; and an intrinsic tendency to progress to more advanced grades.[1]
Grading
Astrocytomas have great variation in their presentation. The World Health Organization acknowledges the following grading system for astrocytomas:
- Grade 1 — pilocytic astrocytoma - primarily pediatric tumor, with median age at diagnosis of 12
- Grade 2 — diffuse astrocytoma
- Grade 3 — anaplastic (malignant) astrocytoma
- Grade 4 — glioblastoma multiforme (most common)
In addition to these four tumor grades, astrocytomas may combine with oligodendrocytes to produce oligoastrocytoma. Unique astrocytoma variants have also been known to exist.