Several types of benign tumors can develop in the brain. They are named for the cells or tissues that give rise to them: schwannomas arise from Schwann cells, which form sheaths around nerves; ependymomas arise from cells lining the ventricles of the brain; meningiomas arise from cells of the meninges (tissues surrounding the brain); adenomas arise from glandular cells; osteomas arise from the bony structures of the skull; and hemangioblastomas arise from blood vessels. Some benign brain tumors (such as craniopharyngiomas, chordomas, germinomas, teratomas, dermoid cysts, and angiomas) are congenital.

Symptoms

Signs and symptoms of a brain tumor vary widely, depending on the size of the tumor, its location, and how quickly it is growing.

Common signs and symptoms caused by a brain tumor include:

  • headache or changes in the usual headache pattern (tumor headaches become more frequent and severe over time, and are worse when lying down or after sleep);
  • unexplained nausea or vomiting;
  • vision problems, blurred vision, double vision, or loss of peripheral vision;
  • gradual loss of touch or sensation in an arm or leg;
  • difficulty maintaining balance;
  • speech problems;
  • difficulty performing daily activities;
  • personality or behavioral changes;
  • seizures, particularly in patients who have not had them before;
  • hearing problems;
  • hormonal (endocrine) disorders;
  • confusion, drowsiness, confusion, stupor, cerebral coma.

Classification

Primary brain tumors 

Primary brain tumors begin in the brain tissue or in areas adjacent to it, such as the meninges, cranial nerves, pituitary gland, or pineal gland. Primary brain tumors begin to develop when normal cells encounter errors (mutations) in their DNA. These mutations cause the cells to divide and grow at an accelerated rate and to continue to exist even when healthy cells would die. This leads to the development of abnormal cells that form a tumor. Primary brain tumors are less common than secondary brain tumors, in which the tumor begins in another organ in the body and spreads to the brain. There are many types of primary brain tumors. Primary tumors are classified based on the type of tissue from which the tumor originates.

For example:

  • Acoustic neuroma (schwannoma);
  • Astrocytoma;
  • Glioma and glioblastoma;
  • ependymoma;
  • ependymoblastoma;
  • medulloblastoma;
  • meningioma;
  • neuroblastoma;
  • oligodendroglioma;
  • pineoblastoma.

Metastatic Brain Tumors

Metastatic brain tumors are tumors that develop as a result of a malignant process that begins anywhere in the body and then spreads (metastasizes) to the brain. Any type of malignancy can spread to the brain, but the most common types include:

  • Breast cancer
  • Colon cancer
  • Kidney cancer
  • Lung cancer
  • Melanoma
  • Neuroblastoma
  • Sarcoma.

Risk factors

While doctors are not sure what causes the genetic mutations that can lead to the development of primary brain tumors, they have identified factors that may increase the risk of developing a brain tumor. Risk factors include:

Age. The risk of developing a brain tumor increases with age. Most brain tumors occur in people 45 years of age and older. However, a brain tumor can develop at any age. And some brain tumors, such as medulloblastomas or benign cerebellar astrocytomas, develop mainly only in children.

Radiation. People exposed to ionizing radiation have an increased risk of developing a brain tumor. Examples of ionizing radiation include radiation therapy used to treat cancer and exposure to atomic bombs, as well as man-made disasters that produce radioactive exposure. More common forms of radiation, such as electromagnetic fields from power lines, radio waves from cell phones, and microwave ovens, have not been shown to induce the growth of brain tumors.

Exposure to chemicals in the workplace. People who work in certain industries have an increased risk of developing brain tumors, possibly due to exposure to chemicals in the workplace. Studies do not always confirm this information, but there is some evidence of an increased risk of developing brain tumors in certain industries, including agriculture, electrical engineering, health care, and oil refining.

Family history of brain tumors. A small proportion of brain tumors occur in people who have a family history of brain tumors or a family history of genetic syndromes that increase the risk of developing brain tumors.