Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Synovial Chondromatosis ?
    ### Response:
    Synovial chondromatosis is a type of non-cancerous tumor that arises in the lining of a joint. The knee is most commonly affected, however it can affect any joint. The tumors begin as small nodules of cartilage. These nodules can separate and become loose within the joint.
    