Sarcoma is usually caused by lipoma, molluscum contagiosum and filiform warts. 1. Lipoma: Lipoma is a kind of benign tumor originated from fat, which is usually related to the abnormal metabolism of fat, long-term inflammatory stimulation and other factors, and may undergo malignant lesions and transform into liposarcoma. 2. Molluscum contagiosum: molluscum contagiosum is a common benign tumor of the skin, usually caused by dermal connective tissue hyperplasia of the body, insect bites and other reasons, which will cause the symptoms of tibial cumbersome organisms, pain and other symptoms, which will lead to the emergence of sarcoma. 3. Filiform warts: Filiform warts are a special type of warts, usually caused by human papilloma virus infection of the skin mucous membranes, can cause benign redundancies, resulting in the appearance of sarcoma. Sarcoma may also be caused by other factors, such as heredity.