When many people refer to brain tumors, they do not distinguish between tumors that originate in the brain, which are pretty uncommon, and tumors which originated elsewhere and spread, or metastasized to the brain, which are fairly common. Such brain metastases are seen frequently in people with lung cancer and breast cancer. Brain metastases from these cancers are usually diagnosed readily, as doctors are accustomed to this complication and will look for it as soon as any symptoms develop. Therefore, I will focus in this posting on the symptoms that should cause one to think of a tumor originating in the brain.
It is estimated that about 17,500 new cases of primary brain tumors occur each year in the United States. They are the second most common malignancy in childhood, after leukemia, but fall way behind other tumors in incidence in adults. There are quite a few different types of brain tumors, based on the cell types that have become malignant to cause the tumor. Common types are meningiomas — which develop from the cells of the meninges covering the brain and are more common in women than in men — and gliomas, which develop from the supportive glial cells in the brain and which are more common in men than in women. Tumors can also develop in other organs which are within the skull but not considered part of the brain, such as the pituitary gland and the pineal gland.
Almost everyone, if asked to name the most common first symptom of a brain tumor, would say headache; however, headache is the first symptom in only about 30-40 percent of brain tumors and when one considers that probably 40 percent of our country’s 225 million people have at least one severe headache each year, only a tiny fraction of those turn out to be due to a brain tumor. Other common first symptoms are seizures, vision loss, personality changes such as irritability or apathy, or muscular weakness in an arm or leg.
The brain itself does not contain pain receptors, and therefore a tumor may grow to a considerable size without producing any headache or other symptoms, depending on its location. In areas of the brain that are considered silent, such as the frontal lobes, no symptoms or only vague personality changes may develop even with quite large tumors. In the part of the brain controlling our muscular movements, relatively small tumors will often produce seizures or limb weakness. I have a close friend who had been experiencing trembling of one arm for many months and had brushed it off until she had to go to an emergency room with an unrelated injury. The doctor caring for her happened to witness an attack of trembling, and recognized it as a form of seizure. She turned out to have a meningioma very close to the strip of brain that controls muscular movements; it was succesfully removed.
Since the brain itself does not feel pain, headache in brain tumors develops from either an increase in the pressure in the skull — called increased intracranial pressure — or because of pulling or compression of other structures in the skull which can feel pain, such as blood vessels and the fibrous structures that separate different parts of the brain. The headache of brain tumors is often dull, not easily described, and not very severe. People who are having “the worst headache of my life” seldom have a brain tumor.
Headaches developing in an adult who has never had headaches should be investigated further, as should headaches that are often present on awakening in the morning, are made worse by exertion or change of position, or are associated with nausea and vomiting. Sufferers of migraines will recognize that this description can often be applied to their headaches, but the difference is that migraine usually begins in adolescence or young adulthood, and is chronic and recurring, with normal periods of no headache in between periods of headache. The headache of brain tumors, by contrast, usually gets slowly worse over time, and periods with no headache are unusual once they have started.
People with brain tumors who have headaches will often, on careful examination, have other signs indicating that something is seriously wrong. Changes in reflexes, muscular strength or sensation, or weakness of the eye or facial muscles will sometimes be present. The headache of increased intracranial pressure will often be accompagnied by swelling of the head of the optic nerve, called papilledema, which can be seen in the back of the eye by a doctor on careful examination. Any other neurological changes such as these require that a scan be done.
I should mention another condition, about as common as brain tumors, that causes headache and papilledema. This is pseudotumor cerebri, meaning false tumor of the brain, and is a condition of increased intracranial pressure not due to tumor or any other identifiable cause. It is most common in women and may be associated with obesity, various endocrine disturbances, and some drugs, including the antibiotic tetracycline, vitamin A and birth control pills. Weight loss and/or stopping the offending drug will often control the condition.