We present a case of polyostotic fibrous dysplasia with limited involvement in thoracic spine and adjacent ribs. The patient underwent posterior instrumentation performed between Th3 and Th11 with pedicle screw system, followed by costotransversectomy of 7th and 8th costovertebral junctions and posterior spinal fusion for costal lesions. In the same operation, curettage was done for the lesion in Th6 vertebra and bone grafting and anterior total corpectomy were performed for Th7 and Th8 vertebrae. 360° spinal fusion was done using titanium mesh as strut graft and autogenous rib grafts. Fibrous dysplasia occurs rarely in axial bones than peripheral bones. The cystic lesions in segments of the whole spine should be evaluated for the possibility of fibrous dysplasia with detailed radiographical examination and biopsy.