Brain tumors are abnormal cell growth in the brain and may be classified as primary or secondary. Primary tumors are those that start in a part of the brain—its cells, membranes, glands (pineal or pituitary) or cranial nerves. These may be either benign (non-cancerous) or malignant (cancerous). Any abnormal growth—whether benign or malignant—can put pressure on these vital and sensitive tissues, which can impair function.

While primary tumors may result from certain genetic diseases (such as neurofibromatosis or tuberous sclerosis) or from exposure to radiation or cancer-causing chemicals, the number of cases attributed to those is small. The cause of most primary tumors is unknown, and therefore not preventable.

Meningiomas are primary brain tumors in the lining of the brain, called the meninges. They usually don’t spread to the rest of the body, nor into the brain itself. They can, however, push into the brain causing problems. About 90% of meningiomas are benign and very slow-growing.

Secondary brain tumors are always cancerous because they originated in another part of the body (most often a breast or lung), and spread to the brain via the blood stream or lymphatic system. Options for treatment vary greatly, depending on the type and location of the tumor, its site of origin, and the age and general condition of the patient.

Possible symptoms of brain tumors may include headaches, seizures, nausea and vomiting, and problems with any or all of the following: vision, hearing, behavior, cognition, balance and motor skills. Diagnostic tools include neurological examination, lab tests like EEG and spinal tap, and special imaging scans, such as computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET). Physicians may also do a biopsy, a surgical procedure in which a sample of tissue is taken from a suspected tumor, to diagnose the type of tumor.