When it comes to brain tumors, the medical profession does not have a standard system to describe the spread of cancer. Primary brain tumors are usually formed in the central nervous system and invariably they do not spread to other parts of the body. In order to treat these tumors, doctors classify they based on the type of cell in which the tumor began, the location of the tumor in the brain and what grade the tumor is.

Here is a list of some of the different types of primary brain tumors that occur in adults:

o Brain Stem Gliomas: This is a type of tumor that forms in the brain stem, which the part that connects the brain to the spinal cord. The tumor is usually high grade, meaning it spreads very quickly and is difficult to cure.
o Pineal Astrocytic Tumor: This type of tumor occurs in or near the pineal gland. This gland is responsible for producing melatonin hormone which governs our sleeping and waking patterns. This tumor can be of any grade.
o Pilocytic Astrocytoma: This tumor is a grade I tumor and develops in brain cells called astrocytes. The tumor grows slowly and very rarely does it spread to neighboring tissues of the brain. The tumor can be cured and is seen more often in children and young adults.
o Diffuse Astrocytoma: This is another tumor that develops in astrocytes. It grows slowly and has the tendency to spread to the neighboring brain cells. This is a grade II tumor seen mostly in young adults.
o Anaplastic Astrocytoma: This tumor is also called malignant astrocytomas and grows very fast and spreads to the adjacent brain cells. The cancer cells look different from normal cells and is develops mostly by the time a person reaches 40 years of age. This is a grade III brain tumor.
o Glioblastoma: This is one of the most aggressive brain tumors and is categorized as grade IV brain tumor. It is more commonly referred to as glioblastoma multiforme and is usually fatal. It is very difficult to treat and occurs mostly in adults ranging from 45 years to 70 years.