How is a chordoma diagnosed?
A biopsy will be done to diagnose a chordoma and to differentiate it from other types of tumors. The tissue is examined under a microscope, the chordoma can have one of three subtypes: conventional (or classic), chondroid, and dedifferentiated (also called sarcomatous).
Conventional chordomas are most common. They grow slowly but are malignant. Chondroid chordoma grows even more slowly than a conventional chordoma. They are mostly found at the base of the skull. Dedifferentiated chordomas grow quickly.
Because radiological testing can be confusing, chordomas are identified by two types of markers: cytokeratins and brachyury. The brachyury protein is also found in masses that have developed from the notochord, which is the support structure in embryos.
CT and MRI scans are also used to develop strategies for treatment.