anaplastic astrocytoma
A WHO grade III malignant glial tumor characterized by increased cellularity and nuclear atypia compared to lower-grade astrocytomas.
Full Definition
Anaplastic astrocytoma is a WHO grade III malignant brain tumor arising from astrocytes, the star-shaped glial cells that support neurons. These tumors exhibit increased cellularity, nuclear atypia, and mitotic activity compared to grade II astrocytomas but lack the microvascular proliferation and necrosis seen in glioblastoma. They typically occur in adults and have an intermediate prognosis between low-grade gliomas and glioblastoma. Treatment usually involves surgical resection followed by radiation therapy and often chemotherapy.
Usage
Usage note: Always specify WHO grade when first mentioned in clinical documentation.
In Context
- "The pathology report confirmed anaplastic astrocytoma with focal areas of increased mitotic activity." — Pathology report
- "Anaplastic astrocytoma patients typically receive adjuvant radiotherapy following maximal safe resection." — Treatment protocol