Specific musculoskeletal tumors

bone forming tumors
*osteoma
This small, sessile benign body tumor occurs most often in the skull and neither causes symptoms nor requires treatmen. It consists of an abnormal excrescence of surface bone. Similar lesions occur posttraumatically on the femur in the area of the adductor magnus insersion (rider's bone), or in relation to the medial collateral ligament of the knee(pellegrini-stieda lesion).
*osteoid osteoma
Patients prevent with local pain, which can be quite severse and is often relieved by aspirin. Radiographically, a small (less than 1 cm) lucent lesion (nidus) is seen, typically surrounded by marked reactive sclerosis. Sometimes areas of radiodensity are seen within the lucent lesion, corresponding histologically to disorganized woven bone formation.