Core Terms & Classification
Astrocytoma (overview)
An astrocytoma is a glioma arising from astrocyte-like cells, ranging from low-grade tumors to grade 4, and defined in adults largely by IDH status.
In short: Astrocytoma (overview)
- It is a glioma arising from astrocyte-like cells.
- It ranges from low-grade to grade 4.
- In adults, it is largely defined by IDH mutation status.
- The IDH-mutant type generally has a better outlook than glioblastoma.
What it is
An astrocytoma is a glioma arising from cells resembling astrocytes (a type of glial cell). Astrocytomas range from lower-grade, slower-growing tumors to grade 4, and in adults they are largely defined by whether they carry an IDH mutation.
Understanding Astrocytoma (overview)
Astrocytomas are among the most common gliomas. In the modern adult classification, a diffuse astrocytic tumor with an IDH mutation (and without 1p/19q codeletion) is called "astrocytoma, IDH-mutant," and is graded 2, 3, or 4. These IDH-mutant astrocytomas generally have a more favorable outlook than IDH-wildtype glioblastoma, though grade 4 IDH-mutant astrocytomas are still aggressive. (A diffuse astrocytic tumor that is IDH-wildtype, with certain features, is classified as glioblastoma rather than astrocytoma.) There are also circumscribed astrocytomas (such as pilocytic astrocytoma) and pediatric-type astrocytic tumors, which behave differently. The full diagnosis specifies the type, IDH status, and grade. Understanding astrocytoma clarifies a major glioma category and how IDH status shapes its classification and outlook.
Why it matters
Understanding astrocytoma helps patients and families see a major glioma category — and how its IDH status and grade (rather than the word "astrocytoma" alone) determine the specific diagnosis and outlook.
Common questions
What is an astrocytoma?
A glioma arising from astrocyte-like cells.
How is it defined in adults?
Largely by IDH mutation status.
Is it the same as glioblastoma?
No — an IDH-wildtype diffuse astrocytic tumor with certain features is classified as glioblastoma.
Bottom line
An astrocytoma is a glioma from astrocyte-like cells, ranging from low-grade to grade 4 and defined in adults largely by IDH status, with IDH-mutant types generally more favorable.
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