ADAMANTINOMA OF THE TIBIA

Purpose of the study Fibrous dysplasia and adamantinoma of the long bo nes are two different entities encountered on the same part of the tib ial shaft. The relationship between these two diseases seems to be est ablished. We describe a case with some common, features arguing for a single pathology. Material and methods A seven year old boy presented in 1974 with a destructive lesion involving the cortex of the tibial s haf. The patient subsequently presented several fractures, treated sur gically and has been followed for nineteen and a half years. The first biopsy specimen in 1974 led to the diagnosis of ossifying fibroma or fibrous dysplasia. It was reviewed with immunohistochemical technics b ut no epithelial component could be found. Results and discussion Thes e pathologic aspects led to the diagnosis of adamantinoma associated w ith osteofibrous dysplasia of the tibia. Twenty five such cases were f ound in the literature. Two theories are proposed: 1) these two diseas es are independant and coexist on the same bone; 2) there is only one disease with different features that are either those of fibrous dyspl asia or those of adamantinoma. Immunohistochemical technics are needed for diagnosis. Conclusion Two sorts of adamantinoma can be observed o n the long bones: - adamantinoma without features of fibrous dysplasia with poor prognosis - adamantinoma with fibrous dysplasia's features called << differentiated adamantinoma >> with a better prognosis.