Chondrosarcoma

Chondrosarcoma is a type of tumor that forms cartilage tissue and usually arises either in or on a bone’s surface. Rarely, it occurs in soft tissues. Most chondrosarcomas grow very slowly. These are often managed as benign cartilage tumors and usually do not spread beyond their original location.

On rare occasions, chondrosarcomas present as high-grade tumors with a much higher likelihood of spreading to other areas (metastasizing). High-grade chondrosarcoma can arise in any bone. The pelvis, hip, knee and shoulder are the most common locations. This condition is more common in adults over age 50 and extremely rare in the pediatric and young adult population.

Chondrosarcoma subtypes include:

• Conventional chondrosarcoma
• Clear cell chondrosarcoma
• Extraskeletal myxoid chondrosarcoma
• Mesenchymal chondrosarcoma
• Dedifferentiated chondrosarcoma

Several specific genetic mutations have been linked to chondrosarcoma, including in genes often found in hereditary conditions such as Ollier disease and Maffucci syndrome, both of which have a high risk of malignant change. There is no evidence that environmental, social, dietary or other external factors contribute to its development.

Low-grade lesions may result in pain, though often they are incidentally identified on an X-ray obtained for other reasons, such as mild trauma. Sometimes, the bone is weakened enough to result in pain, a fracture or both. Higher-grade lesions often result in a painful swollen area. When this occurs in an extremity, it may be more visible. If located in the pelvis or spine, it may be harder to visualize, and pain may be the main symptom. Patients may report varying degrees of discomfort even while sitting or at rest. They may experience pain that wakes them from sleep. Pain may prevent normal range of motion, and patients may report stiffness, weakness or other types of discomfort.

Chondrosarcoma is diagnosed using imaging studies, such as an X-ray or MRI. A CT scan of the chest and either a PET scan or bone scan is often obtained as well to detect the extent of the disease. Ultimately, a biopsy is required to sample the tumor and review its microscopic appearance.

Chondrosarcoma requires a comprehensive team approach, including the multidisciplinary expertise of orthopedic oncologists, pediatric oncologists, medical oncologists, radiation oncologists, musculoskeletal radiologists, bone and soft tissue pathologists, nuclear medicine specialists, surgical oncologists and plastic and reconstructive surgeons, among others.

Treatment for low-grade lesions generally involves removing the tumor while sparing or maintaining as much normal anatomy as possible. Bone grafting or an equivalent procedure is often also needed. Treatment is generally limited to surgery alone.

Treatment for high-grade lesions also involves surgery. However, these tumors demand much more complex procedures designed to remove the entire tumor, including all microscopic disease. To do so, a more comprehensive surgery is required, after which reconstruction of the involved bone or joint is usually necessary. Again, surgery is the mainstay of treatment in most cases.

Rarely, cytotoxic chemotherapy can be administered. This may be more relevant in specific settings, such as for mesenchymal chondrosarcoma. Generally, conventional chemotherapy and radiation are not effective against chondrosarcoma. 

Novel therapies are being explored, often within the context of ongoing clinical trials. These include IDH1, mTOR, tyrosine kinase, histone deacetylase (HDAC) and angiogenesis inhibitors along with a variety of targeted agents designed to affect a very specific pathway.

Patients treated for high-grade chondrosarcomas require close surveillance for a period of five years. This includes physical examinations and periodic imaging studies. Many patients continue to follow up even after five years, though at a reduced frequency. Some tumors, such as clear cell chondrosarcoma, have been reported to recur many years later. On occasion, there is rationale for longer, more extended surveillance.