A brain tumor is any intracranial tumor created by abnormal and uncontrolled cell division, normally either in the brain itself such neurons, glial cells like astrocytes, oligodendrocytes, ependymal cells, lymphatic tissue, blood vessels, in the cranial nerves. Skull, pituitary and pineal gland, or spread from cancers primarily located in the other organs or metastatic tumors.
Some symptoms of brain tumors may depend on two factors are tumor size and tumor location. The time point of symptom onset in the course of disease correlates in many cases with the nature of the tumor. Large tumors or tumors with extensive perifocal swelling edema inevitably lead to elevated intracranial pressure which translates clinically into headaches, vomiting and sometimes without nausea, altered state of conciousness such somnolence, coma, dilatation of the pupil on the side of the lesion or anisocoria, papilledema. 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 of certain parts of the brain, such as the cerebellar tonsils or the temporal uncus, resulting in lethal brainstem compression.
Primary brain tumors are commonly located in the posterior cranial fossa in children and in the anterior two-thirds of the cerebral hemispheres in adults, although they can affect any part of the brain. 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, personality changes, hemiparesis, hypesthesia, ataxia, aphasia, visual field impairment, facial paralysis, double vision, tremor, etc. 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.
Imaging plays a central role in the diagnosis of brain tumors. Early imaging methods as invasive and sometimes dangerous such as cerebral angiography, have been abandoned in recent times in favor of non-invasive, high-resolution modalities, such as computed tomography (CT) and especially magnetic resonance imaging (MRI). Electrophysiological exams, such as electroencephalography (EEG) play a marginal role in the diagnosis of brain tumors.
The definitive diagnosis of brain tumor can only be confirmed by histological examination of tumor tissue samples obtained either by means of brain biopsy or open surgery.
Although there is no generally accepted therapeutic management for primary brain tumors, a surgical attempt at tumor removal or at least cytoreduction is considered in most cases. However, due to the infiltrative nature of these lesions, tumor recurrence, even following an apparently complete surgical removal, is not uncommon.
The main treatment option for single metastatic tumors is surgical removal, followed by radiotherapy and/or chemotherapy. Multiple metastatic tumors are generally treated with radiotherapy and chemotherapy.
Survival rates in primary brain tumors depend on the type of tumor, age, functional status of the patient, the extent of surgical tumor removal, to mention just a few factors.
