Chondrosarcoma


Chondrosarcoma is a malignant tumor of chondrocytes, the cells that produce cartilage. Chondrocytes are present in all the bones of the skeleton so a chondrosarcoma can arise in any bone but it is most commonly found in the femur (thigh bone), humerus (upper arm bone), tibia (larger bone in the lower leg), the pelvis and the ribs. There are more chondrocytes at the ends of the bones (where the joints are located) so chondrosarcomas are more common at the ends of bones than the middle. As with other bone tumors, it is rare; with approximately 400 new cases diagnosed a year in the U.S. It is more commonly seen in adults aged 40 to 70 years, and slightly more often diagnosed in men. 1

A chondrosarcoma that develops in a healthy bone is called a primary chondrosarcoma. Those that develop in a benign tumor such as an enchondroma or osteochondroma are called secondary chondrosarcomas.  

In addition to a more typical chondrosarcoma, there are sub-types. These include:
 

  Clear-cell chondrosarcoma – a lytic lesion in at the ends (epiphysis) of a long bone; the prognosis is a bit better than a chondrosarcoma
  Extraskeletal chondrosarcoma – this type arises from the soft tissue of the extremities, they are very rare and typically need to be treated more aggressively - so in addition to surgical resection, chemotherapy and radiation are considered.
  Mesenchymal chondrosarcoma – this type arises in the bone or soft tissue and is more commonly seen in the jaw, spine, scapula or pelvis; those in bone are typically treated with just surgery while those in the soft tissue may require surgical resection and chemotherapy.
  Dedifferentiated chondrosarcoma – this type consists of a low grade cartilage lesion with high grade sarcoma cells (usually osteosarcoma); it is treated like the higher grade sarcoma so chemotherapy and surgical resection are the most common course of treatment. The probability of lung metastases with this type of chondrosarcoma is 90%2 which leads to a poor prognosis.

Signs and Symptoms of Chondrosarcoma

  • Pain – persistent pain in the area of the lesion is the most common symptom.
  • Soft tissue mass - with some tumors the may be a soft tissue mass or swelling.
  • Limited function – pain often results in a person avoiding using the affected extremity.

Causes of Chondrosarcoma

There is no known cause of a chondrosarcoma. There are some conditions that do place someone at a higher risk of developing a chondrosarcoma.
These include:

  • Ollier’s Disease
  • Maffucci Syndrome
  • Wilms’ Tumor
  • Paget’s Disease
  • Disease of childhood that required chemotherapy of radiation therapy

Diagnosing Chondrosarcoma

A chondrosarcoma is first suspected when an x-ray is taken and it shows a suspicious lesion in the area of the patient’s complaint. Depending on the aggressiveness (or grade), chondrosarcomas produce different patterns of bony destruction on the image. Radiologists and orthopedic oncologists who are experienced in looking at these x-rays can best evaluate the type of destruction and better determine next tests needed for getting an accurate diagnosis.

Accurately establishing the tumor type (metastatic or benign) and grade is extremely important in determining course of treatment.

      CT scan   A CT scan is helpful in providing more detail of bony destruction.
      Bone scan A Bone scan may be necessary to assess if other areas of the skeleton are affected; may also be helpful in differentiating between malignant and benign tumors.
  MRI A MRI can show the extent of the tumor, including if there is extension into the soft tissue or if nerves or vessels are affected; it is necessary for surgical planning.
  Biopsy A biopsy is important in order to confirm what is suspected from the imaging studies and to establish the grade (aggressiveness) of the tumor. The surgeon determines the best approach depending on the location of the tumor and if multiple samples of the tumor are necessary.
  PET/CT scan this test is necessary for staging of the cancer. It reveals if the cancer has metastasized (spread) to other areas of the body.

Chondrosarcoma Grade and Staging

It is important to know how aggressive a tumor is (the grade of the tumor) as well as the stage of the cancer (has it spread to other area of the body). This information helps the physicians in determining the best approach to treatment, as well as assisting in discussions about prognosis.

Chondrosarcoma Grade - by looking at the tumor tissue obtained by biopsy, a pathologist can determine if the tumor has the tendency to grow quickly and spread. Chondrosarcoma grades are:

  • Low-grade – less aggressive with less chance of metastasis or recurrence; sometimes difficult to distinguish from an aggressive benign tumor;
  • Intermediate grade – moderate chance of metastasis and recurrence;
  • High grade – most aggressive type, growing more rapidly and with higher potential to become metastatic or return.

Chondrosarcoma Stage - stage combines the information from the diagnostic testing to determine the extent or severity of the disease process. The size of the tumor, if it has spread to other area such as the lungs, brain or other bones, as well as the grade are all things considered when determining the stage.
Chondrosarcoma staging is from I (one) to III (three) with stage I meaning the tumor is localized (only in the original site) and stage III indicating that the tumor has metastasized to other areas of the body.

Treatment of Chondrosarcoma

Surgical excision (removal) of a chondrosarcoma is usually the best choice for treatment. Chemotherapy and radiation have not been shown to be effective in treatment of most types of chondrosarcoma1. The type of surgery depends on the location of the tumor and if the surgeon will be able to take a layer of normal tissue around the tumor at the time of the excision. This layer of normal tissue is called the “margin” and it is important that there is enough normal tissue to assure the entire tumor is removed without disrupting other structures such as nerves or blood supply.

If the surgeon is not able to remove the tumor and remove an adequate margin of healthy tissue around the tumor, then amputation might be the best approach. In cases where amputation isn’t possible (such as the pelvis or spine) other excision techniques may be attempted but with the knowledge that the resection may leave some disease. In this type of situation, chemotherapy or radiation may be considered to improve a patient’s prognosis.

Prognosis

Prognosis means the ‘chance of survival’ from a specific disease or situation. Prognosis for a person diagnosed with chondrosarcoma is dependent on the grade of that individual’s tumor – those with lower grade tumors have an excellent prognosis as long as they have undergone appropriate treatment; a person with a high grade chondrosarcoma has a high risk that the tumor will be metastatic or return in the area it was originally found 3.

It is extremely important that individuals diagnosed with chondrosarcoma, regardless of the grade, be followed regularly by a medical professional. If a tumor does recur it can be managed early and potentially lead to a better long term result.


References
1. Chow WA: Update on chondrosarcomas. Curr Opin Oncol 19:371–376, 2007.
2. Dickey ID, Rose PS, Fuchs B, Wold LE, Okuno SH, Sim FH, Scully SP. J Bone Joint Surg Am. 2004 Nov;86-A(11):2412-8>
3. Dorfman HD, Czerniak B. Bone Tumors. St Louis, Mo: Mosby; 1998:353-440