Primary brain tumors comprise a diverse group of neoplasm’s that are often malignant and refractory to treatment, malignant brain tumors. More common in males than in females, malignant brain tumors (gliomas, meningiomas, and schwannomas) they cause central nervous system (CNS) changes by invading and destroying tissues and by secondary effects mainly compression of the brain, cranial nerves, and cerebral vessels; cerebral edema; and increased intracranial pressure ICP. Tumors can occur at any age. In adults, incidence is highest between ages 40 and 60, and the most common tumor types are gliomas and meningiomas. They usually occur above the covering of the cerebellum (supratentorial tumors). Most tumors in children occur before age one or between ages 2 and 12. The most common are astrocytomas, medulloblastomas, ependymomas, and brain stem gliomas. Brain tumors are one of the most common causes of cancer death in children.
Primary brain tumors classified by their siteof origin
- CNS tumors that originate in glial tissue Gliomas, occurring in the glial, or supportive tissues around the brain: Astrocytomas Brain-stem gliomas Ependymomas Oligodendrogliomas
- CNS tumors that do not originate in glial tissue: Medulloblastoma Craniopharyngiomas Germinomas Pineal-region tumors
Causes of Brain Tumor
Brain tumors may be attributed to a familial link or to exposure to ionized radiation (a known environmental risk). Brain tumors may result from metastasis in 20% to 40% of patients with other cancers. In some cases, the cause remains unknown.
Risk Factors of Primary Brain Tumors
Hereditary syndromes (proven): tuberous sclerosis, neurofibromatosis types 1 and 2, nevoid basal cell carcinoma syndrome, Turcot’s syndrome, and Li-Fraumeni syndrome Family History of brain tumors History of prior cancer Exposure to infectious agents Allergies (possible reduced risk) Head trauma Drugs and medications Dietary history: N-nitroso compounds, oxidants, antioxidants Tobacco usage Alcohol consumption Ionizing radiation exposure Cellular telephones, Power frequency electromagnetic field exposure
In malignant brain tumors, life-threatening complications from increasing ICP include coma, respiratory or cardiac arrest, and brain herniation