Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Ewing Sarcoma ?
    ### Response:
    Key Points
                    - Ewing sarcoma is a type of tumor that forms in bone or soft tissue.    - Signs and symptoms of Ewing sarcoma include swelling and pain near the tumor.     - Tests that examine the bone and soft tissue are used to diagnose and stage Ewing sarcoma.
    