Osteogenic Sarcoma (osteosarcoma) is a bone forming cancer. It is the most frequent type of bone tumour and is most common between the agesof 15 to 25. Over 90% of tumours are located in the metaphysis (the growing ends of the bone), the most common sites are the long bones of the legs. Most tumours are solitary, around 2% are multifocal (2 or more bones). It is known that osteosarcoma can be radiation induced. Osteosarcomas vary greatly in radiological and pathological features and therefore needs careful diagnosis to differentiate this from other bone tumours. Most are high grade intramedullary osteosarcomas, about 5% are low grade lesions, some are secondary osteosarcomas (for example those caused by radiation therapy). See also: Ewing's-Sarcoma See also: Sarcoma. WWW Resources for Osteogenic-sarcoma