A chordoma is a rare type of bone tumor that develops along the spine or at the base of the skull. Chordomas account for less than one percent of all central nervous system tumors and between two percent and four percent of all primary bone tumors. In many cases, chordoma tumors can be treated effectively with surgery, but they have a high rate of recurrence and a high risk of metastases.
Chordomas develop in a region of the body called the neuraxis, so called because of its importance to the central nervous system. During fetal development, the neuraxis contains structures that help regulate development of this system. In particular, a structure called the notochord is instrumental during fetal central nervous system development. The notochord develops into the vertebral column during fetal growth, but some remnants of notochord cells remain in the body. These remnant notochord cells are the location where a chordoma tumor can develop.
Notochord cells typically remain in two locations along the spinal chord. These are the clivus, at the base of the skull, and the sacrococcygeal region, located at the tail end of the spine. For this reason, the clivus and the sacrococcygeal region are the two locations where chordomas are most likely to grow. Notochord cells sometimes can remain in other parts of the spine and potentially give rise to chordomas in a location other than the clivus or the sacrococcygeal region.
Chordoma symptoms depend on the location of primary tumor growth. When the tumor grows in the clivus, symptoms typically include headaches and vision disturbances. When the tumor grows in the sacrococcygeal region or elsewhere in the spine, symptoms might include lower back pain and incontinence. Weakness, pain or numbness of the legs or arms can occur if the tumor presses on a nerve.
Treatment of chordoma tumors most commonly involves surgery to remove as much of the tumor as possible. This surgery often is followed up with radiation therapy to kill any remaining cancer cells. Complete surgical removal of the tumor reduces the risk of recurrence but cannot entirely eliminate the risk. Possible complications of cranial surgery include intracranial hemorrhage, meningitis, increased intracranial pressure and facial palsy. In the case of spinal tumor removal, complications include difficulty walking and bladder or bowel dysfunction.
While chordomas are very slow-growing tumors, they are also very likely to invade surrounding tissues, likely to metastasize, and likely to recur even after surgical removal of a primary tumor. For all of these reasons, the prognosis for this tumor type is often poor. A person who has been diagnosed with this type of tumor has an approximately fifty percent chance of surviving five years or longer, and a ten percent chance of surviving more than ten years.