Brain tumors are the result of uncontrolled growth of abnormal cells in the brain. They can affect children and adults, but are considered to be rare among both populations. Brain tumors can be classified as malignant (cancerous) or benign (non-cancerous). Malignant tumors tend to be more aggressive than benign types, but both are very serious and can be fatal. For educational purposes, this article references subject matter related to malignant brain tumors affecting adults only.

There are over 140 different types of brain tumors that can form in the brain. Brain tumors can be classified as primary or metastatic, depending on where they arise in the body. Primary brain tumors originate in the brain and rarely spread outside of it. Metastatic tumors begin in another part of the body and spread to the brain through blood or lymphatic tissue. Some cancer types are more prone to spreading to the brain. These types include breast cancer, kidney cancer, melanoma, and lung cancer. Brain Tumor CausesWe don't know exactly what causes brain tumors, but studies do suggest that there may be many factors that play a role in their development. Risk factors for brain tumors include:

• exposure to radiation
  
• family history of certain genetic disorders like neurofibromatosis, tuberous sclerosis, Von Hippel-Lindau disease, and Li-Fraumeni syndrome
  
• having a compromised immune system (more so associated with CNS lymphomas and people infected with AIDS)