Understanding chordoma
Chordoma can be difficult to diagnose because it can look like other types of tumors. Getting the right diagnosis helps you and your healthcare team choose the most appropriate treatment.
This information is based on the updated consensus guidelines for diagnosing and treating primary, localized chordoma, developed by the Global Chordoma Consensus Group and published in JAMA Oncology in 2026.
Chordoma symptoms depend on where the tumor is located and which nearby nerves and tissues it affects. Tumors often grow slowly and may not cause symptoms at first.
These symptoms can have many causes and do not necessarily mean you have chordoma. Talk with your doctor about symptoms that persist or worsen.
If chordoma is suspected or has been diagnosed, the most important next step is to be evaluated at a medical center with expertise in treating chordoma. Your care should be coordinated by a multidisciplinary team — specialists from different fields who work together and have substantial experience with chordoma. It is also recommended that your team discuss your case at a multidisciplinary tumor board, where specialists review your diagnosis and develop a treatment plan together.
A biopsy removes a small sample of tumor tissue for testing. If it is not carefully planned and performed by an experienced team, it can make the tumor more difficult to treat and may increase the risk of tumor cells spreading.
Whenever possible, avoid having a biopsy outside of a center with chordoma expertise.
If your diagnosis was made somewhere other than a center with chordoma expertise, it is strongly recommended that your tumor sample be reviewed and tested again at an experienced center.
Chordoma tumors are typically detected through imaging tests, which show organs and other structures inside the body, including tumors. The way the tumor looks on imaging tests can tell a radiologist whether it might be chordoma.
Magnetic resonance imaging, also called MRI, is the best way to see a chordoma and how it affects nearby muscles, nerves, and blood vessels. Chordoma is best seen using an MRI setting called T2-weighted imaging.
Another imaging test called computed tomography, also known as CT or a CAT scan, is recommended in addition to MRI if it is not certain whether the tumor is chordoma. CT scans of the chest, abdomen, and pelvis are also recommended to check for spread to other parts of the body. Your imaging should be reviewed by a radiologist with experience diagnosing bone tumors.
Further imaging helps your team understand the size and exact location of the tumor, check whether it has spread, and plan your treatment. This process is called staging. You should have an MRI of the main tumor site, an MRI of your whole spine, and a whole-body CT scan.
Whole-body MRI should also be considered for children and for people with a genetic syndrome associated with an increased risk of chordoma, such as tuberous sclerosis complex (TSC).
A positron emission tomography (PET) scan looks for areas of increased activity in the body, which can help identify cancer. PET is not very useful for staging conventional chordoma because this subtype does not consistently show up well on the scan.
However, PET is recommended when poorly differentiated or dedifferentiated chordoma is first diagnosed, because these subtypes tend to show up more clearly. PET can also help guide a biopsy or detect whether cancer has returned after complete surgical removal.
Imaging can suggest that a tumor is chordoma, but a definite diagnosis requires a pathologist to examine a sample of tumor tissue. A pathologist is a doctor who diagnoses disease by studying cells and tissue. Your sample should be evaluated by a pathologist with experience diagnosing chordoma.
Pathologists use tests called immunohistochemistry (IHC) to help confirm a diagnosis. These tests use special stains to look for certain proteins in tumor cells.
One of the most important proteins is brachyury, also known as TBXT. Brachyury testing should be done in all suspected cases of chordoma and is essential for confirming the diagnosis. It helps distinguish chordoma from other tumors that can look similar. However, benign notochordal cell tumors — noncancerous tumors related to chordoma — also contain brachyury. Your pathologist will interpret the test together with the appearance of the tissue and other findings.
If your tumor might be poorly differentiated chordoma, it should also be tested for a protein called INI1. This subtype loses expression of INI1, meaning the protein is missing from the tumor cells. The pattern of staining matters: some conventional chordomas can lack INI1 in only part of the tumor. An experienced pathologist should interpret the results.
Broader genomic testing looks for changes in the tumor’s genes. It may be performed for research, but it is not necessary to guide initial decisions about surgery and radiation.
The safest and most useful way to obtain a tissue sample depends on where your tumor is located. Your biopsy should be planned with the team that will treat your chordoma.
Skull base tumors can be difficult to reach safely for a biopsy. If imaging strongly suggests chordoma, your doctors may recommend proceeding without a separate biopsy before surgery. At experienced centers, a pathologist can examine a frozen tissue sample during surgery to help rule out other conditions that would need different treatment.
A biopsy before surgery is recommended if the tumor does not have the usual appearance of chordoma on scans or if poorly differentiated chordoma is suspected. When a biopsy is done, the surgeon should protect the tissues inside the nose that may be needed to rebuild the area during later surgery.
For tumors in the mobile spine — the neck and back above the sacrum — a biopsy is essential because scans alone cannot reliably confirm the diagnosis. A CT-guided biopsy from the back through the pedicle, a part of the vertebra, is recommended. CT images help the doctor guide the needle into the tumor. The needle should not pass through internal organs.
The biopsy path should be marked so it can be removed during surgery and/or included in the area treated with radiation. This helps address any tumor cells that may have spread along the needle’s path.
For tumors in the sacrum, an image-guided core-needle biopsy should be done before surgery. This uses CT or ultrasound images to guide a needle that removes a small sample of tissue. The biopsy should be done from the back along the midline, and its path should be included in the later surgery when possible.
The WHO Classification of Soft Tissue and Bone Tumours (5th edition, April 2020) defines three types of chordoma. They differ in how their cells look and behave, and the subtype can affect your treatment and follow-up plan.
The most common subtype at every tumor location and in every age group.
Usually grows slowly.
Typically contains cells with a bubbly appearance and tests positive for brachyury.
Includes the chondroid variant, which was previously considered a separate type.
Very rare subtype that occurs in 1 percent or less of patients and occurs more often in older adults.
Typically more aggressive, faster-growing, and more likely to metastasize than conventional chordoma.
Contains both conventional chordoma cells and a more aggressive component that resembles high-grade sarcoma and does not stain positive for brachyury.
May have different treatment options, including chemotherapy.
A rare subtype that usually occurs in children and young adults, most often at the skull base or in the neck portion of the spine.
Behaves more aggressively than conventional chordoma and is more likely to spread to other parts of the body.
Tests positive for brachyury and is characterized by loss of INI1 protein expression. INI1 is also known as SMARCB1.
Has different treatment considerations. Chemotherapy should be considered and may be given before surgery.
In addition to testing when poorly differentiated chordoma is suspected, the Chordoma Foundation Medical Advisory Board suggests INI1 testing for patients under age 35 or whose tumors are growing unusually fast. Testing can be done through immunohistochemistry (IHC) or genomic testing, and the results should be interpreted by a pathologist with chordoma expertise. If tissue is not available, talk with a doctor experienced in treating chordoma about whether a biopsy for testing would be helpful. The possible benefits and risks should be weighed carefully.
Read more about chordoma in children and young adults »
Once your diagnosis is confirmed, your team will discuss treatment options based on the tumor’s location, subtype, and relationship to nearby structures, as well as your overall health and priorities. Our patient-facing treatment guidelines can help you understand these recommendations and discuss them with your healthcare team.
Learn more about diagnosing chordoma in these videos from our Expert Answers Series.
Chordoma Foundation Patient Navigators provide personalized information and support to anyone affected by chordoma, anywhere in the world, at any stage of their journey. Your Patient Navigator will use their extensive knowledge of chordoma to help answer your questions, provide information about treatment guidelines, help you find qualified doctors, talk with you about side effects, and connect you with others in the chordoma community who have been through a similar journey.
Read the latest recommendations from the Global Chordoma Consensus Group, written in clear language to help you understand your diagnosis and treatment options and discuss your care with your healthcare team.
