What is the differential diagnosis of Pagets Disease of Bone?
The differential for radiographic PDB may include chronic osteomyelitis, vertebral hemangioma, fibrous dysplasia, metastatic disease, metaphyseal dysplasia (Engelmann disease), hyperostosis frontalis interna, familial expansile osteolysis, sternocostal clavicular hyperostosis, osteosarcoma, SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, osteitis), lymphoma, and metastatic cancer (e.g., prostate and breast cancer). Notably PDB affecting the vertebrae and other bony sites tend to cause bony enlargement, which helps separate it from metastatic cancers. Elevated ALP can be seen in liver or biliary disease or any condition with increased bone turnover (e.g., osteomalacia, hyperparathyroidism, skeletal metastases).