Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Retroperitoneal fibrosis ?
    ### Response:
    What causes retroperitoneal fibrosis? The cause of retroperitoneal fibrosis is unknown in many cases (idiopathic). Some cases occur in association with other factors, including: Asbestos exposure Smoking Neoplasms (tumor) Infections Trauma Radiotherapy Surg
    