Brain tumors are the growth of abnormal cells in the brain and mass formation. There are benign (Non-cancer) and malignant (cancer) types of brain tumors. There are risk factors for some tumors, although the causes of tumors are not clear. General risk factors include intense radiation exposure, intensive smoking. A small proportion of brain tumors can be seen in people with a family history of genetic syndrome or brain tumors in the family that increases the risk of brain tumors.
Tumors can develop from the brain’s own tissue (primary brain tumors), as well as by the splash of tumors that are present in any part of the body (secondary brain tumors-metastasis).
Brain’s own tumors
Primary brain tumors occur either from the brain’s own cells or in glands close to the brain tissue such as meninges, cranial nerves (nerves going out from the brain in the skull), pituitary gland or pineal gland.
- Meningioma: These tumors usually develop from the membranes surrounding the brain and spinal cord. They are usually benign, and rarely malignant. They usually grow slowly over the years and show symptoms. Although many times they are located below the skull bone in the brain surface, sometimes they can be located also in deep places of the brain in the head.
- Vestibular Schwannoma: They are usually benign tumors that develop in the nerves that control the balance and hearing in our inner ear. They grow within years. They can cause balance disorder and hearing loss.
- Glial Tumors (astrocytoma, oligodendroglioma, oligoastrocytoma, astroblastoma, glioblastoma, gliosarcoma): These group of tumors can be both benign and malignant tumors that develop from astrocyte and oligodendrogliocyte cells in the brain. These tumors can be from grade 1 to grade 4. Grade 1 is benign, 4 is the most malignant tumor. Some tumors are considered as always malignant (glioblastoma, gliosarcoma, and others) and some are always benign (pilocytic astrocytoma). Nevertheless, some tumors are usually benign (meningioma, schwannoma), sometimes they can also be a higher grade and more malignant. The growth rates of tumors may vary depending on their pathological diagnosis. Complaints of these tumors in patients may vary depending on their type, location, and size.
- Ependymoma: These tumors can be both in the brain or in the spinal cord. Some of these tumors are benign while some are malignant. It can go to other parts of the central nervous system or cerebrospinal fluid and repeat there.
- Medulloblastoma: They are the most common malignant brain tumors that are seen in children. These tumors begin in the posterior pit of the brain and tend to spread throughout the spinal fluid. These tumors are less common in adults.
- Craniopharyngioma: They are benign tumors which secrete hormones that control many body functions which are near pituitary gland of the brain. As they grow slowly, they may affect the pituitary gland and other structures near the brain.
- Choroid Plexus Tumors: They are tumors that develop in the ventricle which are fluid-filled cavities of the brain, and are usually seen in childhood and are usually benign.
- Pituitary Gland Tumors (Pituitary Adenomas): They are mostly benign tumors that develop in the pituitary gland at the base of the brain. These tumors can affect the pituitary hormones and therefore it can show signs in many parts of the body. As a result of the growth of these tumors, they can exert pressure on the nerves of the eyes and make partial or complete blindness.
Secondary brain tumors (metastatic tumors) are tumors that start in another part of the body and then spreads to the brain which are originating from cancer. Although secondary brain tumors are frequently seen in people with a history of cancer and are encountered in examinations, sometimes they may be the first sign of a tumor that starts elsewhere in the body. Secondary brain tumors are more common than the brain’s own primary tumors in adults. Although all cancers can spread to the brain, the most common are Lung Cancer, Breast Cancer, Colon Cancer, Kidney Cancer, and Melanoma.