Signs and symptoms

The visibility of signs and symptoms of brain tumors mainly depends on two factors: tumor size (volume) and tumor location. The moment that symptoms will become apparent, either to the person or people around him (symptom onset) is an important milestone in the course of the diagnosis and treatment of the tumor. The symptom onset - in the timeline of the development of the neoplasm - depends in many cases on the nature of the tumor but in many cases is also related to the change of the neoplasm from "benign" (i.e. slow-growing/late symptom onset) to more malignant (fast growing/early symptom onset).
Symptoms of solid neoplasms of the brain (primary brain tumors and secondary tumors alike) can be divided in 3 main categories :

• Consequences of intracranial hypertension : The symptoms that often occur first are those that are the consequences of increased intracranial pressure: Large tumors or tumors with extensive perifocal swelling (edema) inevitably lead to elevated intracranial pressure (intracranial hypertension), which translates clinically into headaches, vomiting (sometimes without nausea), altered state of consciousness (somnolence, coma), dilation of the pupil on the side of the lesion (anisocoria), papilledema (prominent optic disc at the funduscopic eye examination). However, even small tumors obstructing the passage of cerebrospinal fluid (CSF) may cause early signs of increased intracranial pressure. Increased intracranial pressure may result in herniation (i.e. displacement) of certain parts of the brain, such as the cerebellar tonsils or the temporal uncus, resulting in lethal brainstem compression. In very young children, elevated intracranial pressure may cause an increase in the diameter of the skull and bulging of the fontanelles.
• Dysfunction : depending on the tumor location and the damage it may have caused to surrounding brain structures, either through compression or infiltration, any type of focal neurologic symptoms may occur, such as cognitive and behavioral impairment (including impaired judgment, memory loss, lack of recognition, spatial orientation disorders), personality or emotional changes, hemiparesis, hypoesthesia, aphasia, ataxia, visual field impairment, impaired sense of smell, impaired hearing, facial paralysis, double vision, dizziness, but more severe symptoms might occur too such as: paralysis on one side of the body hemiplegia or impairment to swallow . These symptoms are not specific for brain tumors — they may be caused by a large variety of neurologic conditions (e.g. stroke, traumatic brain injury). What counts, however, is the location of the lesion and the functional systems (e.g. motor, sensory, visual, etc.) it affects. A bilateral temporal visual field defect (bitemporal hemianopia—due to compression of the optic chiasm), often associated with endocrine disfunction—either hypopituitarism or hyperproduction of pituitary hormones and hyperprolactinemia is suggestive of a pituitary tumor.
• Irritation : abnormal fatigue, weariness, absences and tremors, but also epileptic seizures.

The above symptoms are true for ALL types of neoplasm of the brain (including secondary tumors). It is common that a person carry a primary benign neoplasm for several years and have no visible symptoms at all. Many present some vague and intermittent symptoms like headaches and occasional vomiting or weariness, which can be easily mistaken for gastritis or gastroenteritis. It might seem strange that despite having a mass in his skull exercising pressure on the brain the patient feels no pain, but as anyone who has suffered a concussion can attest, pain is felt on the outside of the skull and not in the brain itself. The brain has no nerve sensors in the meninges (outer surface) with which to feel or transmit pain to the brain's pain center; it cannot signal pain without a sensory input. That is why secondary symptoms like those described above should alert doctors to the possible diagnosis of a neoplasm of the brain.
When a person suffering from a metastasized cancer is diagnosed, a scan of the skull frequently reveals secondary tumors.
In a recent study by the Dutch GP Association,^[1] a list of causes of headaches ^[2] was published, that should alert GP's to take their diagnosis further then to choose for symptomatic treatment of headaches with simple pain medication (note the occurrence of brain tumors as possible cause) :