Astrocytoma / Glioma
Astrocytoma tumors come in
a variety of forms, and they are named after their
star-shaped cells called astrocytes. They are the
most common type of primary brain tumor.
Astrocytomas are known by many different names,
depending on their characteristics. The terms
"astrocytoma" and "glioma" are used interchangeably.
Astrocytomas are categorized as either low-grade or
high-grade. While low-grade astrocytomas account
for the majority of astrocytomas in children, high-grade
astrocytomas account for the majority of astrocytomas in
adults. About 80% of diagnosed astrocytomas in
children are low-grade.
There are several different types of low-grade
- juvenile pilocytic astrocytoma (JPA)
- fibrillary (diffuse) astrocytoma
- pleomorphic xanthosastroctyoma (PXA)
- diffuse astrocytoma
- desembryoplastic neuroepithelial tumor (DNET)
JPA's typically grow in the cerebellum (the
part of the brain that controls balance) and are more
common in children than adults. Their boundaries
are sharply defined and so surgery is most often the
"cure" for this type of tumor. JPA's are
Grade I tumors.
Fibrillary (or diffuse) astrocytomas must be
distinguished between JPA's and are found in the brain
stem. Fibrillary astrocytomas are the most
common form of low-grade astrocytoma. They are
slow growing but have tentacles that spread into normal
brain tissue. Therefore total surgical removal is
uncommon. This type of tumor typically grows in
the cerebral hemispheres where thought process is
controlled. Fibrillary astrocytomas are
Grade II tumors.
PXA's tend to grow superficially in the brain,
and so like pilocytic astrocytomas they are generally
"cured" with surgery. PXA tumors are Grade
DNET tumors tend to grow in the temporal
regions of the brain. DNET tumors are Grade
The most common types of high-grade astrocytoma are:
- anaplastic astrocytoma (AA)
- glioblastoma multiforme (GBM)
Anaplastic means malignant. AA and
GBM tumors account for about 10% of all pediatric
brain and spinal cord tumors. AA tumors
occur sporadically without identifiable cause.
This is a Grade III tumor and has an increased number of
cells, abnormal cells and nuclei, increased
proliferation of cells and increased growth of blood
vessels. AA tumors have a tendency to
infiltrate adjacent brain tissue and spread outside the
central nervous system.
GBM tumors are Grade IV astrocytomas and are
fatal. There are very rare cases documented where
children with GBM survive beyond five years.
Most children with GBM die within 18 months of
diagnosis. Those that can make it beyond 18 months
generally succumb around three years after diagnosis.
Symptoms for astrocytomas generally include
headaches, nausea and vomiting, as well as other
symptoms depending which part of the brain the tumor is
growing. Like all brain tumors, symptoms will
begin gradually and intensify as the tumor grows.
Survival rates for children with low-grade
astrocytomas are as high as 90% five years after
diagnosis. Prognosis for children with high-grade
astrocytomas is dismal, and in the rare instances where
the child does survive they tend to have severely
impacted quality of life issues.