Brain tumors are the growth of abnormal cells and mass formation in the brain. There are benign (non-cancerous) and malignant (cancerous) types of brain tumors. Although the underlying cause of tumor formation is not clear, there are risk factors for some tumors. General risk factors include intense radiation exposure, intensive smoking. A small portion 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 spreading 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), the pituitary gland or the pineal gland.
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 most of the time they are located below the skull bone on the surface of the brain, sometimes they can grow in deeper locations of the brain in the skull base.
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 graded from 1 to 4. Grade 1 is benign, while grade 4 is the most malignant tumor. Some tumors are always considered as malignant (glioblastoma, gliosarcoma, and others) and some are always considered benign (pilocytic astrocytoma). However, while some tumors are usually benign (meningioma, schwannoma), sometimes they can also have a higher grade and be more malignant. The growth rates of tumors may vary depending on their pathological diagnosis. Patient complaints arising from brain tumors may vary depending on their type, location, and size.
These tumors can be both in the brain or in the spinal cord. Some of these tumors are benign while some are malignant. This tumor can travel to other parts of the central nervous system via the cerebrospinal fluid and recur.
They are the most common malignant brain tumors that are seen in children. These tumors begin in the posterior cavity of the brain and tend to spread throughout the spinal fluid. These tumors are less common in adults.
They are benign tumors which are located near the pituitary gland of the brain that secretes hormones that control various bodily functions. As they grow slowly, they may affect the pituitary gland and other structures near the brain.
Choroid Plexus Tumors
They are usually benign tumors that develop in the ventricles, which are fluid-filled cavities of the brain, and are usually seen during childhood.
Pituitary Gland Tumors (Pituitary adenomas)
They are mostly benign tumors that develop in the pituitary gland at the base of the brain. These tumors may affect the pituitary hormones and therefore they can show symptoms in many parts of the body. As a result of the growth of these tumors, they can exert pressure on the eye nerves and cause partial or complete blindness.
Secondary brain tumors (metastatic tumors) are tumors that develop, as a result of cancer, in other parts of the body and are then spread to the brain. Although secondary brain tumors are frequently seen in people with a history of cancer and are encountered in during follow-ups, sometimes they may be the first sign of a tumor that starts elsewhere in the body. Secondary brain tumors are more common in adults than the brain’s own primary tumors. Although all cancers can spread to the brain, the most common metastatic cancers are as follows: Lung cancer, Breast cancer, Colon cancer, Kidney cancer and Melanoma.