[Adamantinoma and osteofibrous dysplasia of the tibia]

Fibrous dysplasia and adamantinoma of the long bones are two different entities encountered on the same part of the tibial shaft. The relationship between these two diseases seems to be established. We describe a case with some common, features arguing for a single pathology.

A seven year old boy presented in 1974 with a destructive lesion involving the cortex of the tibial shaft. The patient subsequently presented several fractures, treated surgically 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 but no epithelial component could be found.

These pathologic aspects led to the diagnosis of adamantinoma associated with osteofibrous dysplasia of the tibia. Twenty five such cases were found in the literature. Two theories are proposed: 1) these two diseases are independent and coexist on the same bone; 2) there is only one disease with different features that are either those of fibrous dysplasia or those of adamantinoma. Immunohistochemical technics are needed for diagnosis.

Two sorts of adamantinoma can be observed on 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.