OSTEOGENIC-SARCOMA ARISING FROM BONY REGENERATE FOLLOWING ILIZAROV FEMORAL LENGTHENING THROUGH FIBROUS DYSPLASIA

Sarcomatous degeneration of fibrous dysplasia has been previously docu mented in rare cases, often in association with prior radiation therap y. This case report describes the occurrence of osteosarcoma arising i n the distal femur of a 15-year-old male with previous biopsy-proven f ibrous dysplasia, who had undergone limb lengthening through a distal femoral corticotomy using the technique described by Ilizarov. In addi tion, distraction osteogenesis through an area of fibrous dysplasia in the proximal tibia produced a new area of fibrous dysplasia in the re generate tissue as shown by histopathologic examination. This case rai ses two questions: (a) whether the biologic stimulus of distraction os teogenesis through abnormal metaplastic bone increases the risk of mal ignant neoplasia, and (b) whether distraction osteogenesis through dys plastic bone is contraindicated, since the regenerate tissue does not form normal bone.