Chondrosarcoma

A chondrosarcoma is a rare, malignant (cancerous) bone tumor made up of cartilage cells, the firm tissue that protects the ends of bones. These bone sarcomas usually start in the pelvis, chest, arms, or legs. They can grow fairly large—often bigger than 4 centimeters across. Lower grade chondrosarcomas can grow very slowly over many years.

While chondrosarcomas are rare, they are the most common cancer starting in the bones of adults, making up 25 percent of primary bone cancers. Each year, roughly 1 U.S. resident per 200,000 receives treatment for a chondrosarcoma. They most commonly occur between the ages of 40 and 70.

Most chondrosarcomas are low grade, grow slowly, and don’t metastasize (spread). However, more rare, higher grade forms can act more aggressively, potentially spreading to the lungs or other parts of the body.

The Sarcoma Program at Penn Medicine’s Abramson Cancer Center provides one of the nation’s most experienced chondrosarcoma care teams.

There are additional subtypes of chondrosarcomas. They differ in who they affect, where they’re most often found, and how they typically behave:

• Conventional chondrosarcoma: The main form of the disease includes about 90 percent of cases. Conventional chondrosarcoma is divided into three grades, based on how cancerous cells appear under a microscope and how they’re expected to act. The more common, lowest-grade form is slow-growing but can still press against or invade nearby tissues. Higher-grade forms may behave more aggressively. Intermediate-grade forms fall in between and are treated like higher-grade chondrosarcomas.
• Dedifferentiated chondrosarcoma: This subtype starts as a lower-grade cartilage tumor but then abruptly changes into a more aggressive high-grade tumor. It’s more likely to metastasize, usually to the lungs.
• Mesenchymal chondrosarcoma: This rare subtype of chondrosarcoma has several unique characteristics. It is found most frequently in younger adults. It is occasionally treated with chemotherapy.
• Clear cell chondrosarcoma: This rare form is typically not as aggressive and mainly affects people in their 30s and 40s. It tends to form in the bones of the upper arm (humerus) near the shoulder and in the upper thigh (femur) near the hip. It requires complete removal and can metastasize to the lungs.

Chondrosarcomas may not cause symptoms until they’ve grown large enough to affect nearby tissues. At that point, you may experience:

• Persistent pain that slowly worsens over time—potentially requiring increasing amounts of pain medication
• Pain that may occur at night
• Limited range of motion for tumors near joints
• Slowly enlarging, firm mass occurring over months or years without evaluation and treatment

Depending on their location, chondrosarcomas can also push on nerves or organs. Tumors in the pelvis or spine can lead to pain, numbness, tingling, bowel or bladder problems, or muscle weakness.

Doctors don’t know what causes most chondrosarcomas. In rare cases, radiation therapy and chemotherapy for other cancers can lead to the later development of chondrosarcoma tumors.

The risk for developing one of these tumors also rises for people with certain rare syndromes:

• Enchondromatosis: Also called Ollier disease, this condition leads to benign cartilage tumors developing in bones. While these tumors are initially benign (noncancerous), there is a 25 percent to 30 percent chance that one can transform into a chondrosarcoma. Although enchondromatosis is driven by certain genetic changes in the body, these occur in the womb and are not inherited.
• Multiple hereditary exostoses (multiple osteochondromas): People with this condition develop multiple benign bone tumors in childhood called osteochondromas. In a small percentage of cases, one of these benign tumors can transform into a chondrosarcoma. Multiple hereditary exostoses comes from changes to certain genes inherited from a parent.

Chondrosarcomas can be challenging to treat, especially when they develop in areas like the spine or pelvis. At Penn Medicine, our sarcoma specialists have extensive experience removing these tumors while preserving as much healthy tissue and function as possible. When needed, they work closely with experts in neurosurgery, gynecologic oncology, urology, colon and rectal surgery, and other specialties to plan and perform procedures.

We also offer access to sarcoma clinical trials evaluating promising new treatment approaches. By combining specialized surgical expertise with ongoing research, we continue to advance care for people with chondrosarcoma.