MGH Department of Radiology - Osteoid Osteoma

Osteoid osteoma is a benign bone-forming tumor that was first described in 1935.Although most doctors rarely see patients with this condition, compared to other types of bone tumors it is relatively common.

Osteoid osteoma may occur in any part of any bone, but is most frequent in the legs, especially the femur.

Osteoid osteoma is usually found in children and young adults. It is rare in very young children (less than 3 years) and in adults over the age of 40.

Almost all patients have pain from the tumor.

Pain due to osteoid osteoma most often begins as a dull aching sensation, becoming sharper and more severe with time. Pain is typically (but not invariably) worse at night. Although pain may be worsened by activity, it is not due to activity and also occurs at rest.

The tumor may cause a marked inflammatory reaction in surrounding tissues, resulting in the feeling of swelling or a lump.

This is usually prompt pain relief with nonsteroidal antiinflammatory agents (such as aspirin and ibuprofen), but relief may be of variable duration.