1 Type of tissue from which the cancer evolved, including carcinomas and sarcomas. 2  Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. 3  Sarcoma is a cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Type of tissue from which the cancer evolved, including carcinomas and sarcomas. 2  Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. 3  Sarcoma is a cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.