Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Childhood Soft Tissue Sarcoma ?
    ### Response:
    The most common sign of childhood soft tissue sarcoma is a painless lump or swelling in soft tissues of the body. A sarcoma may appear as a painless lump under the skin, often on an arm, a leg, or the trunk. There may be no other signs or symptoms at first.
    