This report describes a 53-year-old male with polyostotic fibrous dysplasia of the thoracic and lumbar spine. He had back pain in the lumbar spine for 1 month and had no evidence of any endocrine abnormality. Plain radiographs of the spine demonstrated lytic lesions from the first to the fifth lumbar spine. Computed tomogram and Magnetic Resonance Image were very useful to evaluate the expanse of the lesions. Biopsy findings confirmed the diagnosis of fibrous dysplasia.
