Gliomas are primary brain tumors which means they arise from within the brain itself. They differ from metastatic brain tumors which begin elsewhere in the body and travel to the brain. Gliomas actually develop in the glial cells in the brain which make up the soft, spongy, tissue that supports the nerve cells in the brain. Gliomas may be considered benign or malignant, depending on the specific type. There are many different types of gliomas. To differentiate these tumors, they are graded from benign to aggressive. The grading scale ranks them from Grades I through IV, with Grade I being a benign tumor and Grade IV being the most aggressive type of tumor, called a glioblastoma multiforme (GBM).

Gliomas are further classified into the type of cell that gave rise to the tumor.   For instance, ependymomas arise from ependymal cells, astrocytomas from astrocytes and oligodendrogliomas from oligodendrocytes.


There are several different types of astrocytomas treated by Dr. Bovis. Grade I astrocytomas are called pitocytic astrocytomas. These are considered benign tumors and most commonly found in children. A complete surgical removal or resection often leads to a cure for this kind of tumor. Astrocytomas classified as Grade II generally occur in adulthood. These tumors are slower growing tumors. These tumors typically develop in the frontal and temporal lobes of the brain, or the front half of the brain. Because of their location, and the growing pressure inside of the skull, symptoms for astrocytomas include headache, vomiting and changes in thinking and cognitive abilities.

Anaplastic astrocytomas are Grade III and tend to arise in the same location as diffuse astrocytomas, described above. These tumors have a more aggressive tendency to infiltrate through neighboring tissues. These tumors tend to occur later in adulthood.

Glioblastoma multiformes

Glioblastoma multiformes (GBMs) are Grade IV and usually affect adults later in life. These tumors grow more rapidly than the other astrocytomas.

Oligodendrogliomas represent approximately 30% of all adult gliomas and they infiltrate brain tissue in a diffuse manner. These tumors can be either high-grade or low-grade, depending upon their rate of growth and the manner in which they diffusely infiltrate surrounding tissue. They typically are associated with seizures.


Ependymomas come in two varieties, classic ependymoma and anaplastic ependymoma. Classic ependymomas are considered Grade II with the anaplastic form being Grade III.

Patients coming to see Dr. Bovis with a confirmed or suspected brain tumor will undergo further diagnostic work-up. A thorough history and physical examination is used to gain appreciation for the onset and changes in a patient’s symptoms. This provides Dr. Bovis valuable information about the location and nature of the tumor. Imaging studies, including an MRI scan, will be used to confirm the presence of the tumor.

Depending on the location of the tumor and its proximity to surrounding eloquent (controlling important functions) brain areas, Dr. Bovis may recommend surgery and biopsy as a combined procedure, or, a biopsy alone may be performed to provide an accurate diagnosis of the type of tumor.

Dr. Bovis performs surgery for a glioma, referred to as craniotomy, using advanced operating room technologies, including intraoperative MRI, and surgical navigation and guidance software. These tools provide the most accurate and current information available, so that Dr. Bovis can determine the best approach to the tumor, and verify, in real-time, how much of the tumor he was able to resect (remove). Dr. Bovis will discuss with each patient his approach and goals for surgery, given their individual facts and circumstances.

Depending upon the diagnosis, Dr. Bovis may recommend additional therapies in follow-up to the surgical removal of the tumor. Radiation therapy and/or stereotactic radiosurgery may be recommended. In addition, chemotherapy regimens are often used to treat patients with higher grade gliomas.

It is important to keep in mind that the treatment of gliomas continues to evolve and improve. Neurosurgeons like Dr. Bovis are on the forefront of introducing new technologies and medicines that improve the treatment of patients with brain tumors. Patients should carefully select a neurosurgeon who will be their partner along each step of the journey. Compassion and clinical excellence is the winning combination.

Dr. Bovis performs surgery to treat gliomas at Advocate Lutheran General Hospital and Alexian Brothers Medical Center. He also welcomes questions about gliomas. Prospective patients are welcome to call (847) 698-1088 to schedule an appointment.