Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Gangliocytoma ?
    ### Response:
    Gangliocytoma is a rare type of central nervous system (CNS) tumor made up of mature neurons. Gangliocytomas may occur in all age groups but most often occur in people between the ages of 10 and 30. The most common site is the temporal lobe of the brain, but they can arise anywhere in the CNS including the cerebellum, brainstem, floor of the third ventricle, and spinal cord.
    