Chondrosarcoma Health Article

Definition

Chondrosarcoma is a malignant tumor that arises from cells that produce cartilage, the rubbery tissue around joints. Therefore, it is a type of sarcoma that is predominantly found in the area around bones.

Description

Sarcomas of the bone are rare and represent about 0.2% of all new cancer cases each year. The two most common forms of bone cancer are osteosarcoma and Ewing's sarcoma. Among the less common are chondrosarcoma, fibrosarcoma, and malignant fibrous histiocytoma, all of which arise from spindle cell neoplasms.

Chondrosarcomas arise from chondroblasts, cells that form cartilage. Cartilage is the matrix found at the tip of the nose and ears. However, cancer that develops from chondroblasts is usually observed on the surface of the pelvis, in the femur of the upper leg, around the shoulder, in the humerus of the upper arm, and in the ribs.

Depending on the type and location of the chondrosarcoma, the tumor can either be high grade and aggressive or low grade and not as invasive. There are two different categories of chondrosarcomas—classic chondrosarcomas and variant chondrosarcomas. Together they have five main types.

Central chondrosarcoma and peripheral chondrosarcoma are both classic chondrosarcomas. Central chondrosarcoma occurs within a bone, and peripheral chondrosarcoma develops on the surface of a bone. Both can develop as a primary tumor or as a secondary tumor to an existing tumor elsewhere in the body. Most, however, are primary tumors. Seventy-six percent of primary chondrosarcomas occur centrally within a bone.

There are three variant chondrosarcomas: clear cell chondrosarcoma, mesenchymal chondrosarcoma, and dedifferentiated chondrosarcoma. Clear cell chondrosarcoma is the most rare form of chondrosarcoma. It is a low grade, slow growing tumor that typically occurs locally in the epiphysis, or end part, of long tubular bones such as the femur and humerus, meaning that it does not normally invade into surrounding soft tissue. As the name implies, cells biopsied from this type of chondrosarcoma appear clear with many large vacuoles.

Mesenchymal chondrosarcoma is another rare variant. However, as opposed to clear cell chondrosarcoma, it is highly malignant and frequently metastasizes, commonly to the lungs, lymph nodes and other bones. This variant has a tendency to develop in flat bones such as vertebra, the pelvis, or the skull, as opposed to long tubular bones. Under a microscope, the cells appear round and contain spindle cell elements and neoplastic cartilage formation.

Dedifferentiated chondrosarcoma is also rare and is the most malignant form of chondrosarcoma. It is characterized by the presence of a mix of low-grade chondrosarcoma and has undergone malignant degeneration, producing a fully malignant soft tissue mass that is no longer identifiable as cartilage. These cancers occur most commonly in the flat bones of individuals over the age of sixty. Despite varied treatments, they are almost always fatal.

Due to the location of chondrosarcoma tumors, the result is often a decrease in the range of motion of limbs, especially tumors occurring on the epiphysis of bones such as those seen in clear cell chondrosarcoma.

Demographics

Although there are exceptions, chondrosarcomas occur mainly in older adults forty to sixty years old and typically occur more in men than in women. Chondrosarcomas are rarely seen in infants and children. Dedifferentiated chondrosarcomas predominantly arise in the elderly over the age of sixty, equally between males and females. Mesenchymal chondrosarcoma develops in the young adult population between the ages of twenty and forty years old, and it is slightly more common in females. Classic chondrosarcomas usually develop in people over the age of forty. However, when they occur in younger age groups, they have a propensity to be highly malignant, capable of metastasis.

Causes and symptoms

As of 2001, there is little known about what causes chondrosarcomas. However, researchers have discovered that chondrosarcomas are sometimes associated with underlying benign bone tumors. They can also result as a side effect from previous radiation therapy for unrelated primary cancer treatment. Individuals with other bone diseases such as Maffucci's syndrome and Ollier's disease are at a higher risk for developing chondrosarcomas.

There are many symptoms associated with the onset of chondrosarcomas. They tend to develop slowly in most cases, except when the cancer is aggressive. The following is a list of the main symptoms that may present:

• pain
• swelling
• firm lump
• broken bone
• impeded normal range of motion
• urinary frequency (seen in pelvic chondrosarcomas)
• urinary obstruction (seen in pelvic chondrosarcomas)

The above symptoms are not always indicators of the presence of chondrosarcoma. Any one of these symptoms could be related to another, less serious condition. A doctor should be seen to diagnose the problem properly.