Paget Disease

2021-02-21 12:00 AM

Paget disease (osteitis deformans) is a localized disorder of bone remodelling, resulting in excessive bone resorption followed by disorganized bone replacement, producing thickened but weak bone that is susceptible to deformity and fracture.

PAGET DISEASE

Paget disease (osteitis deformans) is a localized disorder of bone remodelling, resulting in excessive bone resorption followed by disorganized bone replacement, producing thickened but weak bone that is susceptible to deformity and fracture. There is an association with paramyxovirus and mutations of SQSTM1.

  •  Seen in those age >40
  •  Common in those of European ancestry
  •  Common sites of involvement include the skull, pelvis, femur, and vertebrae
  •  The majority of cases are polyostotic and mild

Paget disease develops in 3 stages:

  •  Osteolytic stage (osteoclastic activity predominates)
  •  Mixed osteolytic-osteoblastic stage
  •  Osteosclerotic stage(osteoblastic activity predominates in this “burnout stage”)

Paget disease can cause bone pain and deformity, fractures, and warmth of the overlying skin due to bone hypervascularity. X-rays show bone enlargement with lytic and sclerotic areas. Lab studies show highly elevated serum alkaline phosphatase and increased levels of urinary hydroxyproline. Complications include arteriovenous shunts within the marrow, which may result in high-output cardiac failure and an increased incidence of osteosarcoma and other sarcomas.

Microscopically, there is a haphazard arrangement of cement lines, creating a “mosaic pattern” of lamellar bone. Involved bones are thick but weak and fracture easily. Skull involvement leads to increased head size and foraminal narrowing that can impinge on cranial nerves, often leading to deafness. The involvement of facial bones may produce lion-like facies.