Chordoma is a rare tumor that usually occurs in the spine and base of the skull. It is a malignant tumor that grows fairly slowly. It can spread to other organs, usually the lungs. It represents only about 1 percent of all malignant bone tumors.

Chordomas develop in a structure called the notochord. The notochord forms the early spine in the beginning stages of fetal development. Most of the notochord is replaced by the spine during the first six months of development. Small areas can remain, and chordomas can form in these areas.

Most chordomas occur at the base of the spine (sacrum), in the tailbone (coccyx) or at the base of the skull (40 percent), but they can occur other places in the spine.

Most patients with chordomas are between 40 and 70 years of age. Occasionally this tumor can occur in younger patients, even children. The average age of people affected is about 55 years.

Chordomas are life-threatening. They can cause death by direct growth or by spreading to other organs. They spread to the lungs about 20 to 30 percent of the time.

Chordomas occur spontaneously. They are not known to be caused by trauma, environmental factors, or diet. Chordomas are not inherited. Chordomas are not associated with any medical conditions or use of any medications or supplements.

Symptoms depend on the location of the tumor.

Tumors in the skull can cause headache or problems with vision.

Tumors in the spine can cause pain in the area of tumor (neck, back, or tailbone). A tumor pressing on nearby nerves can cause symptoms similar to a "slipped" (herniated) disk. These symptoms include arm or leg pain, weakness, or numbness.

Tumors in the tailbone area can cause a noticeable mass, numbness in the crotch area, and problems with the bowel and bladder.

Chordomas grow slowly. Patients often have symptoms for a long time (more than a year) before they seek medical attention.

X-rays of the sacrum are often difficult for doctors to interpret. Chordomas themselves do not show up well, but the bone damage may be seen on the X-rays.

Typical sacral chordomas.

Computed tomography (CT) scans of the same sacral chordomas.

Corresponding magnetic resonance (MRI) scans.

Treatment of chordomas is very difficult. This is mainly because these tumors are near the brain and spinal cord. Traditional chemotherapy has not been very effective.

Surgery is preferred, where possible. Radiation in combination with surgery is often used to treat these tumors. Radiation alone rarely cures the tumor. When tumors cannot be surgically removed, sometimes radiation therapy can stop the growth of the tumor.

Surgery is the best treatment for chordomas, but in many cases it can be difficult to perform because of important structures near the tumor. The surgeon must remove the tumor and a margin of normal tissue around it.

This often results in a loss of neurologic function. For example, surgical removal of tumors in the sacrum can result in loss of control of bowel and bladder function (incontinence).

Fifty to seventy-five percent of patients treated with surgery will be alive after five years.

Advances in radiation therapy are allowing higher doses of radiation to be applied with less damage to surrounding normal tissues, such as the brain and spinal cord. Different types of radiation therapy (including proton beam therapy, intraoperative radiation, and brachytherapy) may offer better treatment of these tumors. These therapies may be combined with more limited surgery in the future.

New drug treatments, including use of a drug called imatinib mseylate (Gleevac®) are being investigated which may help slow the growth of tumors that can't be removed.