Low-grade gliomas are noncancerous tumors arising from primary brain cells. They represent the numerous different types of tumors in the grade I and II category in the Brain Tumor Classification System (grades I through IV). These tumors are low-grade as opposed to the grade III and IV tumors, which are malignant. They generally arise from the supporting cells of the brain (glial cells). There are many types of tumors depending on which cells they arise from: astrocytoma (astrocytes), oligodendroglioma (oligodendrocytes) and ependymoma (empendymal cells). Low-grade gliomas are more rare than malignant brain tumors.
These tumors grow very slowly, therefore causing more subtle symptoms. These tumors are more likely to cause seizures, which are not an unusual presentation for a low-grade glioma.
MRI is the foremost radiological examination used in detecting low-grade gliomas. These tumors often do not enhance with IV contrast.
If the patient presents with seizures, treatment with antiseizure medicines is a first priority. Chemotherapy is usually not useful in low-grade gliomas. Craniotomy for attempted removal of these lesions is generally indicated. Many studies show that patients who have gross total resection have the longest survival durations. On rare occasions, radiation therapy is performed on low-grade gliomas. This is especially true for tumors, which could only be incompletely removed.
Prognosis for low-grade gliomas depends on the individual pathology of the tumors. Grade I tumors can be cured with complete surgical resection. Grade II tumors need to be followed closely for recurrence, which may occur after many years.