• Occurs in < 1% of all Paget's patients
• Paget’s: 30 X increase in incidence of bone sarcoma
• Sarcomatous change usually occurs in diffuse, long standing, polyostotic Paget's disease
• Sarcomatous change most common in pelvis, humerus, femur
• 50% are osteosarcoma
  • Usually osteolytic
  • Also - fibrosarcoma, chondrosarcoma, giant cell tumor

Frontal radiograph of pelvis demonstrates Paget's Disease of right hemipelvis
as evidenced by thickened cortex and prominent trabeculae with large,
lytic, geographic lesion in iliac crest representing an osteolytic osteosarcoma

• Treatment
  • Palliative resection
  • Chemotherapy
• Prognosis
  • Grave, with survival > 2 years rare