A brain tumor is a mass or growth of abnormal cells in your brain or close to your brain.

Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your brain (primary brain tumors), or cancer can begin in other parts of your body and spread to your brain (secondary, or metastatic, brain tumors).

How quickly a brain tumor grows can vary greatly. The growth rate as well as location of a brain tumor determines how it will affect the function of your nervous system.

Brain tumor treatment options depend on the type of brain tumor you have, as well as its size and location.

Causes--Primary brain tumors originate in the brain itself or in tissues close to it, such as in the brain-covering membranes (meninges), cranial nerves, pituitary gland or pineal gland.

Primary brain tumors begin when normal cells acquire errors (mutations) in their DNA. These mutations allow cells to grow and divide at increased rates and to continue living when healthy cells would die. The result is a mass of abnormal cells, which forms a tumor.

Primary brain tumors are much less common than are secondary brain tumors, in which cancer begins elsewhere and spreads to the brain.

Many different types of primary brain tumors exist. Each gets its name from the type of cells involved. Examples include:

Gliomas. These tumors begin in the brain or spinal cord and include astrocytomas, ependymoma, glioblastomas, oligoastrocytomas and oligodendrogliomas

Meningiomas. A meningioma is a tumor that arises from the membranes that surround your brain and spinal cord (meninges). Most meningiomas are noncancerous.

Acoustic neuromas (schwannomas). These are benign tumors that develop on the nerves that control balance and hearing leading from your inner ear to your brain.

Pituitary adenomas. These are mostly benign tumors that develop in the pituitary gland at the base of the brain. These tumors can affect the pituitary hormones with effects throughout the body.

.Medulloblastomas-- These are the most common cancerous brain tumors in children. A medulloblastoma starts in the lower back part of the brain and tends to spread through the spinal fluid. These tumors are less common in adults, but they do occur.

PNETs. Primitive neuroectodermal tumors (PNETs) are rare, cancerous tumors that start in embryonic (fetal) cells in the brain. They can occur anywhere in the brain.

Germ cell tumors. Germ cell tumors may develop during childhood where the testicles or ovaries will form. But sometimes germ cell tumors move to other parts of the body, such as the brain.

Craniopharyngiomas. These rare, noncancerous tumors start near the brain's pituitary gland, which secretes hormones that control many body functions. As the craniopharyngioma slowly grows, it can affect the pituitary gland and other structures near the brain.

Cancer that begins elsewhere and spreads to the brain

Secondary (metastatic) brain tumors are tumors that result from cancer that starts elsewhere in your body and then spreads (metastasizes) to your brain.

Secondary brain tumors most often occur in people who have a history of cancer. But in rare cases, a metastatic brain tumor may be the first sign of cancer that began elsewhere in your body.

Secondary brain tumors are far more common than are primary brain tumors.

Any cancer can spread to the brain, but the most common types include:

·        Breast cancer

·        Colon cancer

·        Kidney cancer

·        Lung cancer

·        Melanoma

Symptoms--The signs and symptoms of a brain tumor vary greatly and depend on the brain tumor's size, location and rate of growth.

General signs and symptoms caused by brain tumors may include:

·        New onset or change in pattern of headaches

·        Headaches that gradually become more frequent and more severe

·        Unexplained nausea or vomiting

·        Vision problems, such as blurred vision, double vision or loss of peripheral vision

·        Gradual loss of sensation or movement in an arm or a leg

·        Difficulty with balance

·        Speech difficulties

·        Confusion in everyday matters

·        Personality or behavior changes

·        Seizures, especially in someone who doesn't have a history of seizures

·        Hearing problems

Risk factors-In most people with primary brain tumors, the cause of the tumor is not clear. But doctors have identified some factors that may increase your risk of a brain tumor. Risk factors include:

Your age. Your risk of a brain tumor increases as you age. Brain tumors are most common in older adults. However, a brain tumor can occur at any age. And certain types of brain tumors occur almost exclusively in children.

Exposure to radiation. People who have been exposed to a type of radiation called ionizing radiation have an increased risk of brain tumor. Examples of ionizing radiation include radiation therapy used to treat cancer and radiation exposure caused by atomic bombs.

More common forms of radiation, such as electromagnetic fields from power lines and radiofrequency radiation from cellphones and microwave ovens, have not been proved to be linked to brain tumors.

Family history of brain tumors. A small portion of brain tumors occur in people with a family history of brain tumors or a family history of genetic syndromes that increase the risk of brain tumors.

Diagnosis-If it's suspected that you have a brain tumor, your doctor may recommend a number of tests and procedures, including:

A neurological exam. A neurological exam may include, among other things, checking your vision, hearing, balance, coordination, strength and reflexes. Difficulty in one or more areas may provide clues about the part of your brain that could be affected by a brain tumor.

Imaging tests. Magnetic resonance imaging (MRI) is commonly used to help diagnose brain tumors. In some cases a dye may be injected through a vein in your arm during your MRI study.

A number of specialized MRI scan components — including functional MRI, perfusion MRI and magnetic resonance spectroscopy — may help your doctor evaluate the tumor and plan treatment.

Other imaging tests may include computerized tomography (CT) scan and positron emission tomography (PET).

Tests to find cancer in other parts of your body. If it's suspected that your brain tumor may be a result of cancer that has spread from another area of your body, your doctor may recommend tests and procedures to determine where the cancer originated. One example might be a CT scan of the chest to look for signs of lung cancer.

Collecting and testing a sample of abnormal tissue (biopsy). A biopsy can be performed as part of an operation to remove the brain tumor, or a biopsy can be performed using a needle.

A stereotactic needle biopsy may be done for brain tumors in hard to reach areas or very sensitive areas within your brain that might be damaged by a more extensive operation. Your neurosurgeon drills a small hole into your skull. A thin needle is then inserted through the hole. Tissue is removed using the needle, which is frequently guided by CT or MRI scanning.

The biopsy sample is then viewed under a microscope to determine if it is cancerous or benign. This information is critical to establish a diagnosis and prognosis and, most importantly, in guiding treatment.