Osteosarcoma in a patient with McCune-Albright syndrome and Mazabraud's syndrome.

Sarcomas infrequently develop in osseous sites of fibrous dysplasia. We report a patient with Mazabraud's syndrome (polyostotic fibrous dysplasia and soft tissue myxomas) complicated by the development of osteogenic sarcoma in a bone affected by fibrous dysplasia. This is the third case of osteosarcoma within the small population of reported patients with Mazabraud's syndrome. There may be an increased incidence of malignant transformation in these individuals' dysplastic bones above that associated with patients suffering from fibrous dysplasia alone.