Bone Sarcomas Incidence and Epidemiology Bone sarcomas are rarer than soft tissue sarcomas; they accounted for only of all new malignancies and 2370 new cases in the United States in 2007. Several benign bone lesions have the potential for malignant transformation. Enchondromas and osteochondromas can transform into chondrosarcoma; fibrous dysplasia, bone infarcts, and Paget's disease of bone can transform into either malignant fibrous histiocytoma or osteosarcoma. Classification Benign Tumors The common benign bone tumors include enchondroma, osteochondroma, chondroblastoma, and chondromyxoid fibroma, of cartilage origin; osteoid osteoma and osteoblastoma, of bone origin; fibroma and desmoplastic fibroma, of fibrous tissue origin; hemangioma, of vascular origin;. | Chapter 094. Soft Tissue and Bone Sarcomas and Bone Metastases Part 4 Bone Sarcomas Incidence and Epidemiology Bone sarcomas are rarer than soft tissue sarcomas they accounted for only of all new malignancies and 2370 new cases in the United States in 2007. Several benign bone lesions have the potential for malignant transformation. Enchondromas and osteochondromas can transform into chondrosarcoma fibrous dysplasia bone infarcts and Paget s disease of bone can transform into either malignant fibrous histiocytoma or osteosarcoma. Classification Benign Tumors The common benign bone tumors include enchondroma osteochondroma chondroblastoma and chondromyxoid fibroma of cartilage origin osteoid osteoma and osteoblastoma of bone origin fibroma and desmoplastic fibroma of fibrous tissue origin hemangioma of vascular origin and giant cell tumor of unknown origin. Malignant Tumors The most common malignant tumors of bone are plasma cell tumors Chap. 106 . The four most common malignant nonhematopoietic bone tumors are osteosarcoma chondrosarcoma Ewing s sarcoma and malignant fibrous histiocytoma. Rare malignant tumors include chordoma of notochordal origin malignant giant cell tumor and adamantinoma of unknown origin and hemangioendothelioma of vascular origin . Musculoskeletal Tumor Society Staging System Sarcomas of bone are staged according to the Musculoskeletal Tumor Society staging system based on grade and compartmental localization. A Roman numeral reflects the tumor grade stage I is low-grade stage II is high-grade and stage III includes tumors of any grade that have lymph node or distant metastases. In addition the tumor is given a letter reflecting its compartmental localization. Tumors designated A are intracompartmental . confined to the same soft tissue compartment as the initial tumor and tumors designated B are extracompartmental . extending into the adjacent soft tissue compartment or into bone . The tumor node metastasis TNM staging system is .
