How Chondrosarcoma Is Diagnosed

Chondrosarcoma is a type of bone cancer that starts in cartilage cells. Cartilage is the smooth connective tissue that protects the ends of bones and lines most joints.

Chondrosarcoma is usually diagnosed with a physical examination, scans, and inspection of a small sample of tissue in a procedure called a biopsy. This article will discuss the diagnostic process for chondrosarcoma.

Doctor checking patient's knee pain

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Can Self-Checks/At-Home Testing Help?

There are no self-checks for chondrosarcoma other than noting any symptoms and speaking to your healthcare provider about them. Chondrosarcoma mainly affects the cartilage cells of the thighbone (femur), shoulder, or pelvis but can affect any area of the body.

Most cases of chondrosarcoma come to medical attention because of pain that becomes more constant over time. Pain from chondrosarcoma is often worse at night and is often accompanied by swelling of the affected area.

The early signs and symptoms of chondrosarcoma can be easily confused for other much more common conditions such as sports injuries, or they may at first be blamed on muscular aches and pains.

What Happens During a Physical Examination?

Your doctor will ask about your signs and symptoms and your health history. They will then examine your body to gather more clues about your diagnosis. They will check the affected area, and may perform tests to check your range of movement.

Your doctor may order blood work, which can be helpful. The levels of two biomarkers in particular—alkaline phosphatase and lactate dehydrogenase—are elevated in some patients with chondrosarcoma.

Imaging Tests Used During Diagnosis

Imaging tests use X-rays, magnetic fields, or radioactive substances to create pictures of the inside of the body. People who have or might have chondrosarcoma will have one or more of these tests.

  • X-ray: An X-ray of the area is often the first test done if some type of bone tumor is suspected. The typical appearance of a cartilage lesion is discrete calcification, although the look varies from lesion to lesion.
  • Magnetic resonance imaging (MRI): MRI scans create detailed images of the inside of the body using radio waves and strong magnets instead of X-rays, so no radiation is involved. An MRI is often done to get a more detailed look at an abnormal area seen on an X-ray. MRIs can usually show if it’s likely to be a tumor, an infection, or some type of bone damage from another cause.
  • Computed tomography (CT) scan: A CT scan combines many X-ray pictures to make detailed cross-sectional images of parts of the body. CT scans are often done to look for possible cancer spread in other parts of the body, such as the lungs, liver, or other organs.
  • Bone scan: For this test, a small amount of low-level radioactive material is injected into the blood and travels to the bones. Areas of active bone changes attract radioactivity and appear as “hot spots” on the skeleton. Hot spots may suggest areas of cancer, but other bone diseases can also cause the same pattern.
  • Positron emission tomography (PET) scan: During this imaging test, radioactive-tagged sugar (glucose) is injected into the blood before the patient goes into the scanning machine. Tissues that use glucose more than normal tissues (such as tumors) will be highlighted in the images. PET scans can help show the spread of bone cancer to the lungs, other bones, or other parts of the body. 

The Labs and Tests Used to Confirm Diagnosis

The results of imaging tests might strongly suggest that a person has chondrosarcoma, but a biopsy (removing a sample of the abnormal area and checking it under a microscope) is usually the only way to be certain.

Tissue samples are removed (with a needle or during surgery) from the body to determine if cancer or other abnormal cells are present. The biopsy will also tell your healthcare team the grade of the cancer, which indicates how fast-growing the tumor is.

How Are Tumors Graded and Staged?

Grading of chondrosarcomas is essential and is useful in predicting how fast a tumor will grow and/or spread. Chondrosarcomas are divided into low-grade, intermediate-grade, or high-grade, based on their biopsy results:

  • Low-grade means the cancer cells are slow-growing and look quite similar to normal cells. They are less aggressive and less likely to spread. 
  • Intermediate-grade means the cancer cells are fast-growing and look very abnormal. They are more aggressive and more likely to spread. 
  • High-grade chondrosarcomas are more likely to come back (recur) and may spread to other parts of the body.

Cancer Staging

The stage of chondrosarcoma describes its size and whether it has spread outside the bone. Knowing the stage of the cancer helps the doctors plan the right treatment.

Stage 1: The cancer is low-grade. If confined to the bone, the tumor is considered stage 1A; if it has grown outside the bone, it is stage 1B.

Stage 2: The cancer is high-grade. When the tumor is confined to the bone, it is stage 2A; if it has spread beyond the bone, it is stage 2B.

Stage 3: The cancer may be any grade and has metastasized (spread) to another part of the body, such as the lungs.

The prognosis for chondrosarcoma varies depending on the grade and stage of the cancer. The five-year survival rate is 91% for localized tumors (tumors confined to the bone), 75% for regional (cancer has spread only to nearby areas), and 22% for distant disease (when cancer has spread to other parts of the body).

Differential Diagnoses

During the diagnostic process, your healthcare provider will rule out other causes of your symptoms. The differential diagnoses of chondrosarcomas include the following:

  • Osteomyelitis: A painful bone infection
  • Aneurysmal bone cyst: A benign bone tumor
  • Ewing sarcoma: A rare type of cancer that affects bones or the tissue around bones. It mainly affects children and young people.
  • Osteosarcoma: The most common type of cancer that starts in the bones

There are many other non-life-threatening issues that can cause symptoms of chondrosarcoma. For instance, the differential diagnosis of a small jaw lesion includes a tooth abscess. Leg pain and swelling can be the result of injury. Limited range of movement in a joint could be the result of arthritis.

Summary

Diagnosis of chondrosarcoma normally involves a series of scans and a biopsy to test for cancer. If cancer is found, a process called staging will look at how fast-growing the tumor cells are and whether they have spread to another part of the body. Staging helps determine the kind of treatment you will have.

A Word From Verywell

Many of the tests for chondrosarcoma are noninvasive and can be performed as an outpatient. If you find yourself suffering from joint pain and stiffness that is persistent and gets worse at night, speak to your healthcare provider. They will be able to order tests to rule out or diagnose chondrosarcoma.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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