Paget's disease of bone

Background

• Characterized by areas of bone with excessive osteolytic activity and subsequent increased ostoblastic activity, resulting in disorganized bone formation
• Results in osteolytic lesions and weakened bone
• Eventually, affected bones may be abnormally enlarged
• Exact etiology unknown, likely genetic component
• Prevalence increases with age, more common in people of European descent

Clinical Features

• Initially asymptomatic or mild pain
• Bone pain at affected sites, often worse at night
• Pathologic fractures
• If skull involved, may report increased hat size, headache, decreased hearing

Differential Diagnosis

• Bone tumor (e.g. osteosarcoma or metastesis)
• Multiple myeloma, myelofibrosis
• Fibrous dysplasia
• Intramedullary osteosclerosis
• Sickle cell disease

Bone tumors and their mimics

Malignant

• Multiple myeloma
• Chondrosarcoma
• Paget disease
• Osteosarcoma
• Adamantinoma
• Chordoma
• Primary bone lymphoma
• Fibrosarcoma
• Myosarcoma

Benign

• Giant cell tumor
• Chrondroblastoma
• Enchondroma
• Langerhans cell histiocytosis of bone
• Osteoblastoma
• Osteochondroma
• Osteoid osteoma

Other

• Septic joint
• Fracture
• Abscess

Evaluation

Paget's disease of right innominate bone.

Skull CT showing “cotton wool spots” typical of later stages of Paget’s disease.

• Imaging to evaluate for fractures
  • Initial lesion may be destructive, radiolucent (especially in skull)
  • Involved bones may be expanded, abnormally dense
  • May have multiple fissure fractures in long bones
• Alk phos typically very high
• Serum calcium may be high

Management

• Treat fractures
• Pain control
• Bisphosphonates (e.g. Zoledronate) are treatment of choice for patients with severe symptoms or advanced disease

Disposition

• Discharge uncomplicated patients