The present study presents a case of fibrous dysplasia of the lumbar spine. The patient was a 17-year-old boy. Beginning in March 2001, he began to experience lumbar pain and numbness in the right leg with no apparent cause. On initial examination, plain X-ray, CT, and MRI confirmed a Schmorl's node in the upper margin of the second lumbar vertebra. The patient was closely followed, but seven months later, a kyphotic deformation of the lumbar spine was detected, and plain X-ray and MRI showed more advanced destruction of the second lumbar vertebra. As a result, the patient was admitted to undergo thorough testing. Bone scintigraphy and Ga sintigraphy revealed an abnormal lesion in the second lumbar vertebra and right rib. Chest X-ray showed a swollen lesion exhibiting a ground-glass appearance in the right rib. Bone biopsy of the body of the second lumbar vertebra confirmed fibrous dysplasia. Due to the rib lesion, the patient was diagnosed as having polyostotic fibrous dysplasia. Because the fibrous dysplasia of the second lumbar vertebra increased the risk of fracture and neuropathy, after subtotal extirpation of the body of the second lumbar vertebra, L1/2 and L2/3 anterior lumbar spinal fusion was performed. The patient's postoperative course was uneventful, and on discharge, the patient was able to walk unaided. In this patient, fibrous dysplasia, which is an extremely rare condition, was initially difficult to diagnose.
