Bone enlargement with coarsened trabeculae and cortical thickening, starting at one end of a long bone and advancing with a blade-of-grass lytic front; in the skull, osteoporosis circumscripta then cotton-wool sclerosis.
Orient first
- Older adults; pelvis, spine, skull, femur and tibia.
- Lytic, mixed and sclerotic phases may coexist.
- Complications: fracture (banana fracture), osteoarthritis, basilar invagination, rarely sarcoma.
Acquire the study
- Radiographs of symptomatic sites; bone scintigraphy shows the extent; CT for complications.
The manoeuvre
- Bone size compared with the contralateral side; cortical thickening; coarse trabeculae.
- Long bone: lytic front (blade-of-grass sign) advancing from the articular end.
- Pelvis on the AP projection: thickened iliopectineal line; vertebra on the lateral view: picture-frame or ivory vertebra.
- Skull on the lateral view: osteoporosis circumscripta, cotton-wool appearance, diploic widening.
What confirms it
- Typical radiographic features in a typical distribution, with raised ALP.
What licenses you to exclude it
- Bone of normal size and trabecular pattern excludes Paget disease at that site.
The classic misread
- Calling a sclerotic Pagetic vertebra metastasis — Paget enlarges the bone.
- Missing sarcomatous change hidden in a known Pagetic bone.