Glioma refers to tumors that arise from the support cells of the brain. These cells are called glial cells. These brain tumors include the astrocytomas, ependymomas and oligodendrogliomas. These tumors are the most common primary brain tumors. In this section we will limit our discussion to two particular types of gliomas: brain stem gliomas and optic gliomas. Astrocytomas, ependymomas and oligodendrogliomas are discussed separately.
BRAIN STEM GLIOMA
The brain stem refers to the portion of the brain that connects the cerebral hemispheres to the spinal cord. Tumors in these locations are more commonly seen in children than in adults. The specific type of cell in the brain tumor can vary.
Symptoms
The symptoms of these brain tumors depend upon their location, size and rate of growth. Blockage of spinal fluid can cause hydrocephalus. Other symptoms can include double vision, swallowing problems, speech problems and paralysis. This is only a partial list.
Diagnosis
While a careful history and physical examination are the first step in diagnosis, imaging studies are the next most important step. The diagnostic test that is best able to find these tumors is the MRI. The test should be done without and with intravenous contrast enhancement. A normal CT scan is not enough to rule out a brain stem glioma.
Treatment
The treatment of a brain stem glioma depends upon the characteristics of the individual tumor. In some cases an attempt at surgical removal might be appropriate. In other cases a biopsy might be all that can be accomplished. Sometimes the treatment might be based on the MRI appearance alone. Further treatment with radiation therapy and/or chemotherapy might be used as additional treatments.
OPTIC GLIOMA
These brain tumors are located in the optic area. Specifically, optic gliomas can be located in the optic nerves (extending from behind the eyeball), the optic chiasm (where the optic nerves join) or the optic tracts (the area behind the optic chiasm). These brain tumors are most commonly found in children under the age of ten. They are usually relatively slow growing tumors. These brain tumors can be associated with neurofibromatosis.
Symptoms
The most common symptoms of optic gliomas are visual loss, double vision or rapid eye movements. They can also cause hormonal problems.
Diagnosis
While a careful history and physical examination are the first step in diagnosis, imaging studies are the next most important step. MRI scanning without and with intravenous contrast enhancement is the best way to diagnose these tumors.
Treatment
Treatment for optic nerve tumors is very individualized. Sometimes surgery might be used if the tumor involves only one optic nerve. Various types of radiation therapy might be used, as might chemotherapy. For some tumors careful observation might be recommended.