DEDIFFERENTIATED CHONDROSARCOMA IN PATIENTS WITH MULTIPLE OSTEOCHONDROMATOSIS - REPORT OF A CASE AND REVIEW OF THE LITERATURE

Multiple osteochondromatosis (MOS) is a familial disorder of autosomal dominant transmission characterized by the development of multiple ex ostoses and often derangements of epiphyseal cartilage, sometimes resu lting in long bone growth retardation. Patients with the disorder appe ar to be at increased risk for developing secondary chondrosarcomas. R arely, dedifferentiated chondrosarcomas may also occur. We report a si ngle case of a 27-year-old man with multiple osteochondromatosis who d eveloped a fatal dedifferentiated chondrosarcoma. Radiographically, th e neoplasm arose from the pelvis completely destroying the left pubic ramus. Subsequently, the patient underwent preoperative chemotherapy f ollowed by a left external hemipelvectomy. On pathologic examination, the tumor was characterized by high-grade pleomorphic sarcoma sharply juxtaposed to a low-grade chondrosarcoma. The patient ultimately died of widespread metastatic sarcoma.