Exostosis

The most common type of benign bone tumour, in which there is an outgrowth of bone. Exostosis occurs most frequently at the end of the femur or tibia. It may be due to hereditary factors or prolonged pressure on a bone. In most cases, exostosis produces no symptoms. Often, it is recognized only after an injury, when it appears as a hard swelling. Occasionally, the tumour presses on a nerve, causing pain or weakness in the affected area. Diagnosis can be confirmed by X-rays. Treatment, by surgical removal, may be carried out if the tumour is causing symptoms or for cosmetic reasons.