MDM2 and osteosarcoma: The fluorescence-in-situ-hybridization revealed MDM2-amplification in the intra- and extramedullary as well as the lipomatous component, though, thus confirming a liposarcomatous transdifferentiation of the parosteal osteosarcoma (Fig. 3b). The diagnosis of a low grade parosteal osteosarcoma was confirmed from the extraosseous and the intramedullary matrix-forming component (Fig. 4a and b).