Brain tumor displaces and compresses normal brain tissue.

• A brain tumor is an abnormal growth that starts in the brain and does not spread to other parts of the body.
• The primary brain tumor grows slowly, has distinct boundaries, and rarely spreads. Although it cells are not malignant.
• A malignant brain tumor grows quickly, has irregular boundaries, and spreads to nearby brain areas. Sometimes it is known as brain cancer but it is not fit in the definition of cancer.
• Metastatic or secondary brain tumors form elsewhere in the body. When cancer cells are carried in the blood stream and spread to the brain. The most common cancers causes Metastatic brain tumors are lung and breasts.
• Brain tumor enclosed within the bony skull, the brain unable to expand to make room for a growing mass. As a result, the tumor displaces and compresses normal brain tissue.
• Some brain tumors cause swelling (edema).
• All brain tumors malignant or metastatic are potentially life-threatening.

There are various types of brain tumors but common brain tumors are.

• Gliomas
• Astrocytoma
• Pilocytic Astrocytoma (grade I)
• Diffuse Astrocytoma (grade II)
• Anaplastic Astrocytoma (grade III)
• Glioblastoma Multiforme (grade IV)
• Oligodendroglioma (grade II)
• Anaplastic Oligodendroglioma (grade III)
• Ependymoma (grade II)
• Anaplastic Ependymoma (grade III)
• Craniopharyngioma
• Epidermoid
• Lymphoma
• Meningioma
• Schwannoma (neuroma)
• Pituitary adenoma 
• Pinealoma (pineocytoma, pineoblastoma)
• Medulloblastoma

Medical science does not know how to prevent primary tumors that start in the brain and what causes of brain tumors. There are some risks for the brain tumors.

• People have cancer elsewhere in the body.
• Long contact with pesticides, industrial solvents, and other chemicals.
• Inherited diseases, such as neurofibromatosis.

Symptoms are depending on the tumor’s type, size, and location in the brain.

• Headaches that tend to worsen in the morning.
• Seizures.
• Dizziness, difficulty walking, stumbling.
• Speech problems.
• Vision problems.
• Weakness on one side of the body.
• Increased intracranial pressure, which causes drowsiness, headaches, nausea and vomiting, sluggish responses.

Some specific symptoms are related to functional areas of the brain.

Frontal lobe- behavioral and emotional changes, impaired judgment, impaired sense of smell, memory loss, paralysis on one side of the body, reduced mental abilities, and vision loss.

Parietal lobe- lack of recognition, inability to write and spatial disorders.

Occipital lobe- vision loss in one or both eyes.

Temporal lobe- impaired speech and memory difficulty.

Brainstem- behavioral and emotional changes, difficulty speaking and swallowing, drowsiness, hearing loss, muscle weakness on one side of the face, muscle weakness on one side of the body, drooping eyelid or double vision.

• The doctor obtains personal and family medical history and performs a complete physical examination.
• The doctor performs a neurological examine to check mental status and memory, vision, hearing, smell, tongue and facial movement, muscle strength, coordination, reflexes, and response to pain.
• A lumbar puncture (spinal tap) might be performed to examine cerebrospinal fluid for tumor cells, protein, infection, and blood.
• Computed Tomography (CT) scan and non-invasive test that uses an X-ray beam that create two dimensional images of the brain.
• An MRI, it shows the brain in slices, layer-by-layer and taking an image of each slice. A dye (contrast agent) can be injected into your bloodstream.

In some cases, if a diagnosis cannot be made clearly from the scans then a biopsy may be performed to observe which type of tumor is present.

• It is a procedure to remove a small amount of tumor to be examined by a pathologist under a microscope.
• It is a separate diagnostic procedure that known as a needle biopsy with a small hole drilled in the skull. 
• A hollow needle is handled into the tumor that removed a tissue sample is removed.
• Biopsy is more complex procedure that used for deep tumors in critical locations.

Different types of treatments are available for brain tumor.

• Surgery
• Radiation
• Chemotherapy

Surgery is the one type of the treatment for brain tumors that can be reached without causing major injury to vital parts of the brain. Brain tumor surgeon known as neurosurgeon performs a craniotomy to open the skull and remove the tumor.

Aim of brain surgery.

• Diagnose the type of brain tumor you have.
• Remove the whole tumor to try to cure it.
• Remove as much of the tumor as possible to slow its growth and improve symptoms.
• Remove as much of the tumor as possible to help other treatments work better.
• Insert chemotherapy wafers into the tumor.
• Put in a tube (shunt) to drain fluid from the brain and relieve pressure.
• Put in a small plastic capsule (an Ommaya reservoir or ventricular access device) under the scalp so that cancer drugs can be injected into it.

• Radiation therapy used high-energy rays for treatment of brain tumors.
• There are two ways to deliver radiation, internal and external beams.
• It works to damaging the DNA inside cells making them unable to divide and reproduce.
• The aim of radiation therapy is to maximize the dose to abnormal cells and minimize exposure to normal cells.
• The benefits of radiation are not immediate but occur over time.
• Aggressive tumors, whose cells divide rapidly, typically respond more quickly to radiation.

Chemotherapy drugs works by disrupting the growth of cells division. It affects not only tumor cells but normal cells, thus causing side effects, especially in fast growing cells (e.g., hair, digestive, blood).

• After surgery for some types of brain tumor, it tries to prevent it from coming back.
• With radiotherapy and for some months afterwards to increase survival.
• To treat a brain tumor that has come back since it was first treated.
• Chemotherapy drugs can take orally as a pill, intravenously (IV), or as a wafer placed surgically into the tumor.

Drugs- carmustine (BCNU), lomustine (CCNU), and temozolomide (Temodar).