• Occurs in a small percentage of patients with Paget’s disease
  • Age range of patients is 46-91 years
  • M:F = 2:1.
  • High-grade osteosarcoma most common malignancy arising in Pagetoid bone
  • Chondrosarcoma, fibrosarcoma, and MFH may also occur
  • Patients will have elevated serum alkaline phosphatase; sudden jump in usual level observed should raise suspicion of malignant change

Plain films


Sites most commonly involved are pelvis, humerus, and femur

h5 Tumor effect on bone

Frank bone destruction common

Tumor response to bone
  • Often little reaction to tumor
  • Margins ill defined
  • Periosteal new bone formation is rare
Soft tissue mass

May develop


High incidence of pathologic fracture

Clinical outcome

Prognosis worse than in conventional osteosarcoma

  • Generally large size and axial location of tumors
  • Occurrence in older patients usually precludes aggressive chemotherapy