Most common in young adults, 20 to 30 years of age; 80% occur between 20 and 50 years of age

Rare in children younger than 14 years of age (1% to 3%)

Pain and swelling, often increased by activity

Gradually worsening over 3 to 6 months

Metaphyseal, eccentric

Originates in the metaphysis and extends into the epiphysis, often to subchondral bone

Distribution: about the knee (50% to 65%), distal radius (10% to 12%), proximal humerus (4% to 8%), anterior spine (7% to 15%); in the spine, the prevalence is sacrum > thoracic > cervical > lumbar

Geographic lysis

Narrow zone of transition in 85% of lesions, 20% with thin rim of sclerosis, usually more evident on CT

Infrequently (15%) can have a wide zone of transition

No matrix mineralization

Typical giant cell tumor, presenting as an eccentric metaphyseal lytic lesion, extending to subchondral bone as seen in the distal femur ( left ) and distal radius ( right ).

Geographic lysis with a wide zone of transition and absence of matrix mineralization is seen in both lesions. Internal septations, which are thickened trabeculae, are more prominent in the radius lesion.

In some cases, a thin sclerotic rim is visible, as seen in this proximal tibia lesion ( left ).

The more common appearance on radiographs is geographic lysis without a sclerotic rim, as seen in this proximal femur lesion ( right ).