Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Cholesteatoma ?
    ### Response:
    What causes cholesteatoma? A cholesteatoma usually occurs because of poor eustachian tube function in conjunction with infection in the middle ear. Negative pressure within the middle ear pulls a part of the eardrum the wrong way, creating a sac or cyst that fills with old skin cells and other waste material.
    