Introduction
Chordomas are a type of tumor in the sarcoma family. Chordomas are low-grade, slow-growing tumors that are locally invasive and aggressive. They develop from notochord remnants and are located anterior to the spinal cord in the midline of the spinal axis. Fifty percent of chordomas are found in the sacrum, 35 percent are at the base of the skull, and 15 percent are in the vertebral bodies of the spine. Chordomas typically grow slowly, but due to their extensive invasion of the nearby nervous system, they can be challenging to treat. Nearly all the subtypes of chordoma are considered malignant (cancerous). Chordomas frequently recur, even after years of treatment.
What Are Chordomas?
Chordoma is a slow-growing malignancy of spine tissue. Chordoma can develop at any point along the spine. It is most commonly discovered at the tailbone (sacral tumor) or where the spine joins the skull (craniosacral tumor). It accounts for nearly 20 percent of all primary spinal tumors, three percent of all bone tumors, and one percent of intracranial tumors. Notochordal sarcoma is the other name for chordoma. The majority of people are diagnosed with chordoma between the age of 50 to 60. Males are more likely affected than females by chordomas in a roughly 2:1 ratio, with an incidence of 1 in 100,000 new diagnoses.
What Are the Different Types of Cranial Chordomas?
Based on the appearance of the cells under a microscope, the World Health Organization (WHO) recognizes three different types of chordoma.
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Conventional or Classic Chordoma - This type accounts for 80 to 90 percent of cases. It consists of a special kind of "bubbly" cell. It accounts for 5 percent to 15 percent of all cases of chordoma. This type has a variant known as chondroid chordoma, which frequently develops in the base of the skull.
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Dedifferentiated Chordoma - A mixture of abnormal cells characterizes this uncommon type of chordoma, which occurs in less than five percent of cases. It is more aggressive, grows more quickly, and is more likely to metastasize than a typical chordoma.
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Poorly Differentiated Chordoma - Children and young adults are most frequently affected by these chordomas. Less than 60 cases have been reported in the medical literature. This kind of chordoma is very uncommon.
What Are the Causes of Cranial Chordomas?
Chordomas are formed from the notochord. The notochord is a mesodermal structure that aids in organizing and differentiating tissues in the embryo. The notochord typically disappears when the fetus is eight weeks old. As it regresses, the notochord eventually becomes the nucleus pulposus in humans. A few notochord cells, however, can sometimes stay in the base of the skull or the spine in a small percentage of people. Few studies suggest a relationship between the incidence of chordoma and mutations in the TBXT gene. Mutations in the TBXT gene can trigger the growth of notochord cells leading to chordoma. No definite genetic marker has been identified for chordoma. However, the brachyury gene, mTOR (mechanistic target of rapamycin) signing pathway, PTEN (phosphatase and tensin homolog) gene, deficiency, INI-1, PDGFR-beta (platelet-derived growth factor receptor beta) are some of the genes implicated in the formation of chordoma.
What Are the Symptoms Associated With Cranial Chordomas?
Chordoma symptoms are caused by pressure, and they differ depending on where the tumor is located along the spine. General symptoms associated with chordomas include weakness, pain, and numbness in the arms, back, and legs. Chordomas may cause pressure on nearby areas of the spinal cord or brain as they grow.
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Double vision.
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Facial numbness.
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Blurred vision.
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Swallowing problems.
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Facial muscle paralysis.
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Neck pain.
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Speech changes.
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Issues with bowel function.
What Are the Diagnostic Tests Used for Chordomas?
A skull base chordoma will be identified using methods commonly used to diagnose cancer. It includes CT (computed tomography) scans, X-rays, and MRI (magnetic resonance imaging) scans. A chordoma typically appears on imaging as a significant sacral destructive mass with secondary soft tissue extension. Radiographs may reveal sacral osteolysis, a soft tissue mass nearby, and calcifications.
A lytic lesion that is locally destructive will be visible on a plain X-ray. Imaging with computed tomography (CT) displays the destructive lytic chordoma more effectively. On rare occasions, the chordoma's margins will show signs of sclerosis. On a CT scan, chordomas are less dense than bones and may show irregular dystrophic calcification. In contrast CT imaging, chordomas exhibit a moderate to significant enhancement. The best way to determine the size of a chordoma is with magnetic resonance imaging (MRI).
To confirm a chordoma diagnosis, a needle or open biopsy is frequently carried out. This includes taking a small sample of the tumor to examine it under a microscope. As the chordoma can spread along the biopsy tract, care must be taken when planning and carrying out the biopsy.
How Is Chordoma Treated?
The treatment for chordoma depends on the location and size of cancer, as well as the invasion of other tissues and nerves. Surgery, radiation therapy, radiosurgery, and targeted therapies are the common treatment options for chordoma.
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Surgery - A skull base chordoma is treated primarily with surgery to remove as much of the tumor as possible. This is frequently an aggressive procedure with potential side effects. The goal of surgery for chordoma is to remove the cancerous tissues as well as some of the healthy surrounding tissues. As the cancer is close to vital structures like nerves and blood vessels, surgery may be complicated.
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Radiation Therapy - Due to the high local recurrence rate, most doctors recommend radiation therapy after any chordoma resection. Chordomas are radioresistant and require high-dose radiation therapy. Due to the proximity of chordomas to neuronal structures, highly conformal radiotherapy, such as proton beam radiation or radiosurgery, is used.
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Radiosurgery - Multiple radiation beams are used in stereotactic radiosurgery to kill cancer cells in a very small area. Radiosurgery can be used prior to or after chordoma surgery. Radiosurgery may be recommended instead of surgery if surgery is not an option.
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Targeted Therapy - It uses drugs that target specific abnormalities found in cancer cells. Cancer cells can be killed by targeted drug treatments that attack these abnormalities.
Conclusion
Chordomas are low-grade, slow-growing tumors that are locally invasive and aggressive. Chordomas develop from the notochord's remains and appear in the middle of the spinal axis. Treatment for chordomas includes surgery, radiation therapy, radiosurgery, and targeted therapy. Imaging and biopsy are the main components of chordoma evaluation. Most doctors advise lifelong surveillance using magnetic resonance imaging (MRI) due to the high local recurrence of chordomas.
