musculoskeletal and connective tissue disorders
Primary Malignant Bone Tumors
Chondrosarcoma
Chondrosarcomas are malignant tumors of cartilage. They differ from Osteosarcoma (osteogenic sarcoma) clinically, therapeutically, and prognostically. Of chondrosarcomas, 90% are primary tumors. Chondrosarcomas can also arise in other preexisting conditions, particularly multiple osteochondromas and multiple enchondromatosis (eg, in Ollier disease and Maffucci syndrome). Chondrosarcomas tend to occur in older adults. They often develop in flat bones (eg, pelvis, scapula) but can develop in any portion of any bone (most often femur and humerus among the long bones) and can have a soft tissue tumor component involving surrounding soft tissues. X-rays often reveal punctate calcifications. Chondrosarcomas often also exhibit cortical bone destruction and loss of normal bone trabeculae. MRI may show a soft tissue mass. Bone scan may also be done. Tissue diagnosis is required for chondrosarcoma and can also determine the tumor’s grade (probability of metastasizing). Needle biopsy may provide an inadequate tissue sample. It is often difficult to differentiate low-grade chondrosarcomas from Enchondroma by imaging and sometimes even histology. Low-grade chondrosarcomas (grade 1) are often treated intralesionally with wide curettage with addition of an adjuvant (often freezing with liquid nitrogen, argon beam, heat of methyl methacrylate, radiofrequency, orphenol). Some surgeons prefer surgical en bloc resection for low-grade tumors to reduce risk of recurrence. Higher grade tumors are treated with surgical en bloc resection. When surgical resection with maintenance of function is impossible, amputation may be necessary. Because of the potential to implant the tumor, meticulous care must be taken to avoid spillage of tumor cells into the soft tissues during a biopsy or surgery. Recurrence is inevitable if tumor cells spill. If no spillage occurs, the cure rate depends on the tumor grade. Low-grade tumors are nearly all cured with adequate treatment. Because these tumors have limited vascularity, chemotherapy and radiation therapy have little efficacy. 