Pathologic Fracture Due to Osteosarcoma in an Asymptomatic Patient with Paget's Disease of Bone: A Case Report

Paget’s disease of bone (PDB) is a focal, benign disorder of bone metabolism first described by Sir James Paget in 1876. It affects approximately 1% of the general population. 1 Uncomplicated Paget’s disease is generally diagnosed in individuals aged 55 years or older and shows a slight male predominance. The associated morbidity varies depending on the site and number of lesions. The main clinical manifestations are bone pain, deformities in affected areas, and a heightened risk of fracture, although many patients remain asymptomatic. 2,3 There has long been an association between Paget’s disease and an increased risk of osteosarcoma, usually occurring in individuals with long-standing, polyostotic disease and typically affecting patients in their seventh decade of life. 4 While PDB lesions predominate in the axial skeleton, skull, femurs, and tibias, Pagetic osteosarcomas are more commonly found in the pelvis, femur, humerus, and skull. This is somewhat different from osteosarcoma in adolescents, which shows a predilection for the femur. The reason for this discrepancy remains unknown. Osteosarcomas are rare cancers, predominantly occurring in adolescents and young adults during their second and third decades of life, and account for approximately 5% of childhood cancers. 5 The incidence of malignancies, including sarcomas related to Paget’s disease, has been documented across numerous studies, emphasising its complex nature in certain geographic populations and suggesting varied outcomes. 6