Bone tumors may be benign or malignant. Benign tumors enlarge slowly, and do not cause danger to life or limb. Malignant tumors are cancerous, and may spread by the blood stream to other parts of the body.
Examples of Benign Tumors are as follows.
Nonossifying Fibroma or Fibrous Cortical defect is a common tumor, which is usually incidentally found on X-rays taken to rule out fractures in children. Unless they are large and weaken the bone sufficiently to cause a fracture, they can be left alone. If it involves more than 50% of the diameter of a long bone, excision and curettage is advised to prevent fractures from happening.
Unicameral Bone Cyst or Solitary Bone Cyst occurs anywhere in the skeleton, but commonly in the upper part of the humerus (upper arm) and upper part of the femur (thigh bone). It has a characteristic appearance on X-ray, and does not require any treatment if small.
It causes symptoms only if it gets large enough to cause weakness in the bone, resulting in a fracture. When that occurs, treatment is usually directed towards the fracture. Frequently, with the bleeding from the fracture occuring in the cyst, the fracture heals and obliterates the cyst. If the cyst persists even after the fracture heals, it is advisable to excise the cyst and bone graft it to prevent future fractures.
Aneurysmal Bone Cyst (ABC) can occur anywhere in the body, but commonly in the posterior part of the spine, and the long bones. It has a typical expansile appearance on X-rays. It can cause pain, and requires curettage (scraping it out with a spoon-like instrument) or excision and bone grafting. Sometimes the tumor recurs after curettage.
Osteochondroma or Exostosis occurs commonly in the long bones around the major joints like the knee. Typically, the patient can feel a bony lump arising from the bone near a joint. It is typically painless unless it abuts on a nerve. X-rays have a typical appearance, and does not need excision unless it is getting larger, or causes symptoms.
In some children, this tumor occurs at multiple sites in the body (a condition called hereditary multiple exostosis). In these cases, there is a 1% chance of malignant change, and so needs careful observation.
