This document discusses four types of bone cancer: Osteosarcoma, Ewing's sarcoma, Chondrosarcoma, and Multiple Myeloma. Osteosarcoma most commonly affects the long bones of teenagers and can develop in the shoulders and hips. Ewing's sarcoma originates in soft tissue near bones and commonly affects young people's long bones and pelvis. Chondrosarcoma usually develops in the thighs, shoulders, and pelvis of older adults. Multiple myeloma is not technically a bone cancer but involves the bones when cancer cells spread to the bone marrow, commonly affecting older adults with tumors in multiple bones.