Chondrosarcoma Chondrosarcoma, which constitutes ~20–25% of all bone sarcomas, is a tumor of adulthood and old age with a peak incidence in the fourth to sixth decades of life. It has a predilection for the flat bones, especially the shoulder and pelvic girdles, but can also affect the diaphyseal portions of long bones. Chondrosarcomas can arise de novo or as a malignant transformation of an enchondroma or, rarely, of the cartilaginous cap of an osteochondroma. Chondrosarcomas have an indolent natural history and typically present as pain and swelling. Radiographically, the lesion may have a lobular appearance with mottled or. | Chapter 094. Soft Tissue and Bone Sarcomas and Bone Metastases Part 6 Chondrosarcoma Chondrosarcoma which constitutes 20-25 of all bone sarcomas is a tumor of adulthood and old age with a peak incidence in the fourth to sixth decades of life. It has a predilection for the flat bones especially the shoulder and pelvic girdles but can also affect the diaphyseal portions of long bones. Chondrosarcomas can arise de novo or as a malignant transformation of an enchondroma or rarely of the cartilaginous cap of an osteochondroma. Chondrosarcomas have an indolent natural history and typically present as pain and swelling. Radiographically the lesion may have a lobular appearance with mottled or punctate or annular calcification of the cartilaginous matrix. It is difficult to distinguish low-grade chondrosarcoma from benign lesions by x-ray or histologic examination. The diagnosis is therefore influenced by clinical history and physical examination. A new onset of pain signs of inflammation and progressive increase in the size of the mass suggest malignancy. The histologic classification is complex but most tumors fall within the classic category. Like other bone sarcomas high-grade chondrosarcomas spread to the lungs. Most chondrosarcomas are resistant to chemotherapy and surgical resection of primary or recurrent tumors including pulmonary metastases is the mainstay of therapy. This rule does not hold for two histologic variants. Dedifferentiated chondrosarcoma has a high-grade osteosarcoma or a malignant fibrous histiocytoma component that responds to chemotherapy. Mesenchymal chondrosarcoma a rare variant composed of a small cell element also is responsive to systemic chemotherapy and is treated like Ewing s sarcoma. Ewing s Sarcoma Ewing s sarcoma which constitutes 10-15 of all bone sarcomas is common in adolescence and has a peak incidence in the second decade of life. It typically involves the diaphyseal region of long bones and also has an affinity for flat bones. .
