Which type of brain tumor is classified as Grade 3?

Anaplastic astrocytoma is classified as a Grade 3 brain tumor according to the World Health Organization (WHO) grading system for central nervous system tumors. This classification is based on histological features that indicate an increased level of malignancy compared to lower-grade tumors.

Anaplastic astrocytomas are characterized by a higher degree of cellularity, increased nuclear pleomorphism, and mitotic activity. These tumors tend to have a more aggressive behavior and are associated with a poorer prognosis than lower-grade tumors (Grade 1 and 2).

In contrast, glioblastoma multiforme is classified as Grade 4, indicating it is the most aggressive and malignant form of brain tumor. Pilocytic astrocytoma is typically classified as Grade 1, making it benign and usually seen in younger patients. Oligodendroglioma can be classified as either Grade 2 or Grade 3 depending on specific characteristics, but in this context where we are identifying a definitive Grade 3 tumor, the anaplastic astrocytoma stands out.

Understanding tumor grades helps in determining the prognosis and appropriate treatment strategies for different types of brain tumors, which is critical for patient care.