[Sarcomas occurring on fibrous dysplasia of bone. Apropos of a complex hemimelic form, with a review of the literature].

Bone formation by the sarcoma is exclusive, without any cartilaginous component; the pattern of the tumour being sometimes quite similar to dysplasia lesional tissue. It seems to be a tissular transformation rather than an unicellular sarcomatous change. Among the etiological factors, except the part of the radiotherapy, periostal changes enhanced by a surgical procedure with acrylic cement in the femoral shaft are perhaps contributing to the development of a sarcoma whose pattern is quite particular.