Young patients, usually between 10 and 25 years of age

Long bone lesions present with pain at rest and at night, relieved with aspirin or nonsteroidal anti-inflammatory drugs

Spinal lesions can present with painful scoliosis

Intraarticular lesions present with chronic joint pain

Most commonly diaphyseal, intracortical (70% to 75%)

Intramedullary (cancellous) and subperiosteal locations less common

Small, central lytic portion (nidus) demonstrates geographic borders

Surrounding reactive bone demonstrates thick, solid periosteal reaction

Nidus can show central calcification, particularly on CT

Reactive bone demonstrates dense osteoid matrix

Diaphyseal intracortical osteoid osteoma ( left ) with solid periosteal reaction and small central lucency representing the nidus ( arrow ).

Lesions can result in abundant marrow edema on fluid-sensitive MRI images ( right ). This can sometimes obscure the nidus.

The nidus ( arrow ) is usually central within the periosteal reaction and rarely exceeds 1.5 to 2 cm ( left ).

Bone scan shows “double density sign” caused by diffuse uptake in the surrounding reactive region and higher uptake by the central nidus ( right ).

Intraarticular osteoid osteoma with widened left hip joint ( arrow ) and juxtaarticular osteopenia ( left ).

Intraarticular osteoid osteomas can be difficult to detect due to the absence of thick reactive bone. In this case ( right ), the nidus with central calcification is visible on tomogram ( arrow ).