Paget disease

(Redirected from Paget's disease)

[edit] Discussion

AKA osteitis deformans
Important not to confuse its imaging appearance with those of other diseases.
Complications of Paget disease include:
- Deformity and
- Arthritis
- Neurologic symptoms
- Neoplastic transformation

Paget disease is extraordinarily common, affecting 3%–4% of the population over 40 years of age and up to 10%–11% after 80 years of age.
Although Paget disease is unusual in people younger than 40 years of age.

Paget disease is characterized by excessive and abnormal remodeling of bone, with both active and quiescent phases.
Three phases
- Lytic phase (incipient-active), in which osteoclasts predominate
- Mixed phase (active), in which osteoblasts begin to appear
- Blastic phase (late-inactive), in which osteoblastic activity gradually declines

Paget disease is predominantly located in the axial skeleton, with the most commonly affected sites being the pelvis (30%–75% of cases), spine (30%–75%), and skull (25%–65%)
Proximal long bones are also frequently involved, with the femur affected in 25%–35% of cases (2–5). Less commonly affected sites include the shoulder girdle and forearm (humerus, 31% of cases; scapula, 24%; and clavicle, 11%).
Involvement of other sites, including the ribs, fibula, bones of the hands and feet, calcaneus, patella, and tibial tubercle, is infrequent.

Monostotic disease (10%–35% of cases) is more often seen in the axial skeleton, although any site can be the sole region of involvement.
Polyostotic disease (65%–90%) is more frequent than monostotic disease, tends to have right-sided predominance, and usually involves lower extremities

Lytic Phase

The early phase of Paget disease is characterized by osteolysis
In the skull, osteolysis is frequently seen as well-defined, often large areas of radiolucency most commonly affecting the frontal and occipital bones; these areas are referred to as osteoporosis circumscripta or osteolysis circumscripta.
- Both inner and outer calvarial tables are involved, with the former usually more extensively affected.
- This pattern is in contradistinction to that of fibrous dysplasia, which usually affects the outer table more prominently.

In the long bones, osteolysis begins as a subchondral area of lucency.
The advancing wedge of osteolysis often demonstrates a characteristic sharp radiolucent margin without sclerosis likened to a blade of grass or flame.
In rare cases, the disease is isolated to the diaphysis, most commonly in the tibia, rather than subchondral bone, which can cause diagnostic confusion

Mixed Phase

Vast majority of cases of Paget disease seen by radiologists are in the mixed phase.
Characteristic manifestations seen radiographically are coarsening and thickening of the trabecular pattern and cortex.
Trabecular thickening occurs primarily along the lines of stress, although disorganized areas are also seen.

Paget disease of the pelvis usually manifests with cortical thickening and sclerosis of the iliopectineal and ischiopubic lines.
These findings are often asymmetric and more commonly seen on the right side.
These manifestations are also often associated with enlargement of the pubic rami and ischium.

Paget disease of the spine frequently manifests with cortical thickening encasing the vertebral margins, which gives rise to the "picture frame" appearance on radiographs in mixed phase disease.
The osteoblastic activity is seen along all four margins of the vertebral body cortices, unlike the rugger jersey vertebrae in renal osteodystrophy, which only involves the superior and inferior endplates.
The vertical trabecular thickening pattern in Paget disease is coarser than the more delicate pattern seen in hemangiomas with which it can be confused.
Flattening or squaring of the normal concavity of the anterior margin of the vertebral body can be seen on the lateral spinal radiographs.