Abstract

Ossifying fibroma (osteofibrous dysplasia) is a rare fibro-osseous lesion made up of fibrous tissue with woven bone formation. It is most commonly found in the tibia and fibula of children ten years of age or younger. The most important differential diagnosis is monostotic fibrous dysplasia, which is radiologically similar but without woven bone rimmed by active osteoblasts like ossifying fibroma on histological examination. No epitheloid cells are found as in adamantinoma. We report the case of a 45-year-old woman who had a 12-month history of pain and slight swelling. Radiographs showed a multilocular radiolucent lesion with sclerotic rim in the proximal tibia. The lesion was curetted and the defect was packed with bone graft and acrylic cement. Microscopic examination showed active osteoblasts rimming the irregulary woven bone. One-year follow-up showed good functional recovery without recurrence of the lesion.