chordomas

Chordomas are rare malignant tumors that arise from remnants of the notochord along the axial skeleton, most often at the skull base (clivus) and the sacrum; less commonly in the cervical spine. They are slow growing but locally invasive and tend to recur after treatment.

Histologically, chordomas show physaliphorous cells in a myxoid to chondroid matrix. They typically express brachyury, a transcription factor that is a relatively specific marker for chordoma, and are often positive for cytokeratins, epithelial membrane antigen (EMA), and S-100 protein. The chondroid variant resembles chondrosarcoma, while dedifferentiated chordomas are more aggressive.

Clinical presentation depends on location. Skull base tumors can cause headaches, cranial nerve deficits, or brainstem symptoms; sacral tumors cause back pain, radiculopathy, and bowel or bladder dysfunction. Diagnosis relies on MRI to define extent and CT to assess bone destruction, with biopsy confirming histology and immunohistochemistry.

Treatment is multimodal. The mainstay is maximal surgical resection when feasible, aiming for clear margins. Because chordomas are relatively radioresistant, high-dose radiotherapy—typically with protons or other particle therapy—is used as adjuvant treatment. Conventional radiotherapy may be employed but generally requires higher doses. Chemotherapy has limited benefit; targeted therapies and clinical trials are under investigation.

Prognosis varies with location, size, and extent of resection. Local recurrence is common, necessitating long-term follow-up. Outcomes have improved with advances in surgery and particle radiotherapy, but chordomas remain challenging tumors to manage.