Sarcomatous change in a previously benign osteofibroma in the maxillary sinus.

Ossifying fibromas of the jaws are generally well-defined benign tumors, so that adequate surgical treatment is usually associated with good therapeutic results. However, there are cases--especially in younger individuals with maxillary tumors--in which recurrences are seen, often with aggressive growth and subsequent local destruction. There is no characteristic histological appearance that identifies these "recurring types." A case is presented in which a benign ossifying fibroma was extirpated from a 17-year-old man. Twenty years later a recurrent tumor was found, in which histological examination showed development of a osteosarcoma. The clinical implications of this case are discussed.