ABTA primer excerpt Copyright ABTA
“Pilocytic Astrocytoma
also called Juvenile Pilocytic Astrocytoma
These grade I astrocytomas are usually non-infiltrating tumors, meaning they tend to stay in the area in which they started and do not spread into surrounding tissue. They generally form cysts, or may be enclosed within a cyst. Invasion (growth into surrounding areas of the brain or spinal cord) is rare. Although these are usually slow growing tumors, they can become very large.
Pilocytic astrocytomas are the most common glioma in children. They are generally diagnosed in children and young adults under the age of 20, and are rarely seen in older adults. They are the most benign tumor of the astrocytomas. Many optic gliomas and cerebellar astrocytomas are pilocytic astrocytomas.
Pilocytic astrocytomas are generally considered “benign” tumors and are often cured by surgery alone. In adults and older children, radiation therapy might follow surgery if the tumor cannot be completely removed, or the residual tumor may be carefully watched. In a “watchful waiting” situation follow-up MRI scans are done at regular intervals to monitor for possible re-growth. If the tumor recurs, re-operation and some form of radiation are options. Some pilocytic tumors, such as most optic gliomas, cannot be safely removed because of their location and initial treatment may involve observation only.
The term “anaplastic” or “malignant” pilocytic astrocytoma is used only when the tumor has developed an extensive blood supply around the tumor, or the tumor contains dead cells called necrosis. These rare tumors require more aggressive treatment than a benign pilocytic astrocytoma”