A brain mass consists of abnormal cells that have accumulated over a period of time, according to WebMD. Abnormal cells do not die; they are no longer needed by the body but continue to grow.
A brain mass is commonly known as a tumor. There are two different types: benign and malignant, explains Healthline and WebMD. A benign tumor is made of cells that are not cancerous, which makes it significantly less dangerous. Benign tumors are more clearly defined in their shape and size. Depending on their location, these tumors are easily removable.
A malignant tumor consists of cancerous cells that grow faster, are much more aggressive and invade surrounding areas of the brain. A malignant tumor affects the central nervous system in various ways if it continues to grow without being treated properly, notes WebMD. A malignant tumor sometimes has roots deep inside the brain, which makes it incredibly difficult to remove at times.
One of the most dangerous aspects of brain masses, both benign and malignant, is that because they consist of rapidly growing cells that do not die, they can grow again and come back even after they are removed and the affected area has been treated, states WebMD.