A glioma is a type of tumor that originates in glial cells, which are the supportive cells surrounding nerve cells in the brain and spinal cord. These tumors can vary widely in their behavior—some grow slowly and are not considered cancerous, while others are malignant (cancerous) and grow aggressively. Gliomas form as a mass of cells called a tumor that can press on brain or spinal cord tissue, potentially disrupting function and causing symptoms depending on their location. Gliomas include several types based on the specific glial cell they originate from, such as:

• Astrocytomas (from astrocytes)
• Oligodendrogliomas (from oligodendrocytes)
• Ependymomas (from ependymal cells)
• Glioblastomas (an aggressive type of astrocytoma)

These tumors are classified into grades 1 to 4, based on their growth rate and malignancy:

• Grade 1 and 2 gliomas tend to grow slowly and may have a better prognosis.
• Grade 3 and 4 gliomas (including glioblastomas) grow rapidly, are more aggressive, and can invade healthy brain tissue.

Gliomas are the most common type of malignant brain tumor in adults and are often challenging to treat due to their tendency to infiltrate brain tissue. Treatments may include surgery, radiation therapy, and chemotherapy. Symptoms vary based on tumor location and size but can include headaches, seizures, nausea, vision problems, cognitive changes, and weakness or numbness on one side of the body. In summary, a glioma is a brain or spinal cord tumor arising from glial cells, ranging from slow-growing to highly aggressive forms, with various subtypes and grades that influence prognosis and treatment strategies.