Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Porencephaly ?
    ### Response:
    Porencephaly is an extremely rare disorder of the central nervous system in which a cyst or cavity filled with cerebrospinal fluid develops in the brain. It is usually the result of damage from stroke or infection after birth (the more common type), but it can also be caused by abnormal development before birth (which is inherited and less common).
    