Brain tumors may arise primarily from brain cells such as astrocytes or neurons (known as primary brain tumors) or spread to the brain from other parts of the body (known as metastatic brain tumors). Glia are the most common form of brain cells, and astrocytes are a category of glial cells. Tumors that arise from glial cells are known as gliomas; a more precise description would be to categorize the tumor based on the specific type of glial cells. Hence, the term astrocytoma is used for tumors that arise from astrocytes.
Astrocytoma is the most common glial tumor and can occur within the brain and spinal cord.
The symptoms that patients present with are predicated by the location of the tumor; headaches, nausea and vomiting are common, as is the occurrence of a seizure. Seizures may manifest as a twitching in the face, arm, or leg and numbness may occur in these areas. Family members of the patient sometimes describe a staring-like episode, during which the patient seems detached. Other symptoms include mood or personality changes, weakness, speech problems or blurred vision. With a spinal cord astrocytoma, weakness or clumsiness of the arms or legs, gait, bowel or bladder problems may be reported.
Symptoms vary depending on the location of the brain tumor, but can also include any of the following:
- Persistent headaches
- Double or blurred vision
- Loss of appetite
- Changes in mood and personality
- Changes in ability to think and learn
- New seizures
- Speech difficulty of gradual onset
Any of these symptoms should prompt consultation with a physician or neurosurgeon, and an immediate CT or MRI scan will attempt to reveal the problem. Contrast dye is administered through an IV during these scans to increase the sensitivity and specificity of the test. A dye allergy may be overcome by careful pre-medication. Control of symptoms usually involves initiation of an anti-epileptic medication (Keppra) and steroid (Decadron). The next step is consultation with a neurosurgeon who specializes in brain tumors. A further review of the case by a multidisciplinary tumor board is a prudent measure. The imaging findings on the CT and MRI scans give the neurosurgeon an idea of the nature of the tumor; however, an accurate diagnosis requires a neuropathologist to study the tumor tissue, which guides further treatment.
Anaplastic astrocytomas are usually not inherited. These tumors typically occur sporadically, in people with no family history of astrocytomas. In most cases, the exact cause is unknown.
Like many other cancers, it is believed that isolated astrocytomas may occur due to a combination of genetic and environmental factors. This means that a person may carry a gene (or a combination of genes) that predisposes them to developing an astrocytoma, but it may not develop unless it is "triggered" by an environmental factor.