Primary bone is the first bone tissue that appears in embryonic development and in fracture repair. It is characterized by its random position of collagen fibers. In most places in adults this tissue is replaced by secondary bone tissue except, for example, near the sutures of calvara or tooth sockets. The secondary bones have lower amounts of osteocytes so primary bone is much more easily penetrated by x-ray.
Primary bone cancer is a type of sarcoma, a cancer that originates in bone, muscle, fibrous tissue, blood vessels, fattissue, as well as some other tissues. Primary bone cancer can arise in any of the 206 bones in the body but is mostly seen to originate the arms and the legs. The most common cases are observed in children and young adults. The following list includes types of primary bone cancer: