The growth is considered a primary tumor if it originates in or near the brain; it is considered secondary (or metastatic) if it has spread from other areas of the body, like the breast, prostate and lung. In rare cases, primary tumors can result from genetic disease or chemical or radiation exposure, but overall their cause remains unknown. Primary tumors tend to grow slowly, while secondary tumors usually progress quickly. Symptoms depend on tumor location and type as well as an individual’s general health status.
EEG, spinal tap and special imaging techniques that include MRI, computed tomography and positron emission tomography are used to help diagnose a brain tumor. When a tumor is suspected, a biopsy is performed to determine the type of tumor and its stage (how advanced it is).