Osteosarcoma occurring in osteogenesis imperfecta tarda.

The combination of osteogenesis imperfecta (OI) and osteosarcoma is rare, as reflected by the fact that there are only eight proven cases in the published English literature. We present here another case, one that was treated by modern oncological techniques and major limb salvage surgery in the form of distal femur endoprosthesis initially and later a total femur replacement. The patient is the only one of the series to have had major limb salvage and is the only--and longest--surviving patient (more than 6 years), thus disproving the probability that this combination of disorders is particularly lethal. We present the case history, review the literature, and look at the cases presented in the past. We contend that adequate awareness, early diagnosis, and prompt oncological management results in better prognosis for osteosarcoma occurring in OI.