by Brad Norman

Created on: April 14, 2009

A brain tumor, as the name suggests, is a cancerous growth that is localized in the brain. Tumors, which are sometimes called neoplasms, literally mean "new growth". This name is fitting, as a tumor is essentially a part of the body that is growing out of control and out of sync with the rest of the body. It is this "out of control" nature of cancer that makes it so dangerous. Since your body cannot control the growth of these tumors, they monopolize bodily resources (such as nutrients, oxygen and other necessities) and cause normal healthy tissue to become deprived and die off. Normally, cells divide by a strict set of rules and in an orderly fashion, a process called mitosis. These independent growths, termed cancers, are often the result of a mutation, which stop the cells from obeying the normal rules of mitosis. These mutations can occur just by random accident, but more commonly they are induced by toxins are radioactive waves that disrupt that DNA within the cell.

Under the subject of brain tumor, there are several sub-types. A relatively common type of tumor (occurring in about 20% of brain tumor cases) is a meningioma. Meninges are three layers of protective membrane that cover the brain, and a meningioma is a tumor that grows in between these layers. To be completely accurate, these tumors are not brain tumors at all, as they are not composed of brain tissue nor do they directly impact the brain. Meningiomas are still dangerous, however. As they grow, they press against the skull and the brain's surface. This pressure can impact the brain's function and, if left untreated, can cause substantial physical damage to the brain tissue. Luckily, these types of tumors are relatively safe and simple to remove. They are benign, encapsulated tumors, which means they are surrounded by their own membrane and have little risk of spreading to other parts of the body. This makes them simple to locate in the CT scan and remove by surgery without causing any serious damage to surrounding tissue.

A far more serious type of brain tumor, however, is the more common type. These tumors, called infiltrating tumors, are substantially tougher to treat than meningiomas. As you can gather from the name, an infiltrating tumor infiltrates the tissue, growing profusely through the area. In contrast to meningiomas, which are typically benign, infiltrating tumors are almost always malignant. Because of their diffuse location and rapid growth, it is very difficult to successfully remove the cancer by surgery. Although surgery may be one weapon within a battery of treatment options, if even the smallest portion of tumor is missed and left behind, it can continue to grow and spread again.

Though both meningiomas and infiltrating brain tumors can both originate within the brain region, in about one tenth of cases the cancer is the result of an arriving metastatic tumor from another part of the body. A metastatic tumor is one that begins to grow in one part of the body and then detaches and ends up in the blood stream. The blood then carries these detached cancerous cells to the brain where they get lodged and begin to grow again. When metastatic tumors are found, it is very serious. These types of tumors can spread very quickly and very broadly through the body, making surgical excision nearly impossible.

The brain is an incredible organ that can do many things, but it is not immune to cancer. Knowing about the nature and origins of these various types of brain cancers can offer insight into new and better treatments for these potentially fatal diseases. Someday, science may even find a cure for these types of illnesses.

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