Paget's Disease of the Spine as a Catalyst for Osteosarcoma: A Narrative Review

Paget's disease of bone (PDB) is one of the most common metabolic bone diseases worldwide. The spine is one of the most common locations for Paget's disease; however, data regarding the incidence, demographic patterns, clinical presentation, and management outcomes of malignant transformation in this region remain limited. We conducted a narrative review to synthesize the existing data and identify knowledge gaps. We found that osteosarcoma arising from PDB of the spine is extremely rare, but when transformation does occur, it most commonly involves the lumbar spine. Pagetic osteosarcoma typically presents in older men. The most prevalent symptom in these cases is back pain, but neurologic issues are also common and can range from radiculopathy to myelopathy and autonomic dysfunction. In cases of PDB in which malignant transformation is suspected, magnetic resonance imaging or computed tomography should be performed in addition to a bone biopsy. Management should be multidisciplinary and individualized, with systemic therapy and surgery considered according to disease extent, surgical feasibility, and patient factors. Outcomes for spinal osteosarcoma secondary to PDB are unfavorable, with past studies reporting a five-year survival rate as low as 10%. En bloc surgical resection may offer a greater chance of survival, but this is not always technically achievable given the surrounding anatomic constraints. Palliative care, physical medicine, and rehabilitation also play important roles in supporting patients through complex spine surgical treatment. Malignant transformation into osteosarcoma is a rare complication of PDB, of which spine surgeons should be aware. Like other forms of spinal osteosarcoma, this condition is challenging to treat and carries a poor prognosis. Patients should be referred to centers with multidisciplinary experience in the management of spinal sarcomas. Significant gaps remain in risk stratification, surveillance, and treatment algorithms for pagetic osteosarcoma of the spine, where data are limited. Standardized, multicenter studies are needed to improve prognostication and management.