Sarcoma in the bone consists several diagnostic entities. The most common are:
- Osteosarcoma - malignant tumor with bone differentiation
- Ewing's sarcoma/PNET - originate from neuroectodermal-derived cells
- Chondrosarcoma - malignant tumor with cartilage differentiation
Other rare bone sarcomas are chordoma, malignant fibrous histocytomas (MFH) in the bone, fibrosarcoma, angiosarcoma, leiomyosarcoma, malignant giant cell tumor, and adamantinoma.
In approximately 70% of cases, osteosarcoma occurs eccentric to the metaphyseal region in long bones, most often, at the knee joints and at the proximal end of the humerus. Ewing's sarcoma occurs everywhere in the body but is more common in the diaphyseal or metaphyseal regions of long bones, especially the lower extremities as well as the pelvis. In 90% of the cases, chondrosarcoma is localized to the marrow (central) or on the surface (peripheral).
Compared to other cancers, bone cancer is rare and represents 0.2% of all new cancer cases in the United States. Bone sarcoma is most frequently diagnosed among people aged < 20. Osteosarcoma is most common in teenagers. Ewing Sarcoma is most common in teenagers and young adults.
In 2017, it is estimated to be 3,260 new cases of bone sarcoma in the United States (6).