Osteosarcoma arising in a femur with melorheostosis and osteopathia striata.

Osteopathia striata is an asymptomatic autosomal dominant or sporadically inherited disorder that causes dense striations at sites of endochondral bone formation, with a predilection for the metaphyses of long bones. Melorheostosis is a mixed sclerosing dysplasia with disturbance of both endochondral and intramembranous ossification, in which disordered intramembranous ossification dominates. It presents typical radiological changes of cortical hyperostosis distributed along a sclerotome with variable associated cutaneous and clinical features. Overlap syndromes including one or more of these diseases are described. We report a 44-year-old man with both melorheostosis and osteopathia striata who presented with pain secondary to superimposed osteosarcoma. In reporting this case we discuss the relationship between sclerosing dysplasia and either coexisting or complicating sarcoma.