Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Simple Kidney Cysts ?
    ### Response:
    The cause of simple kidney cysts is not fully understood. Obstruction of tubulestiny structures within the kidneys that collect urineor deficiency of blood supply to the kidneys may play a role. Diverticulasacs that form on the tubulesmay detach and become simple kidney cysts.
    