chordoma

Chordoma is a rare malignant bone tumor that arises from remnants of the notochord. It is typically slow-growing but locally aggressive and tends to recur after treatment. The condition most often affects adults, though it can occur at other ages.

Most chordomas arise in the axial skeleton, especially at the skull base (clivus) and the sacrum, with the mobile spine involved less frequently. The tumor can extend into adjacent structures, creating a challenge for management and contributing to symptoms.

Clinical presentation depends on location. Skull base tumors may cause headaches, diplopia, facial numbness, or cranial nerve deficits. Sacral tumors often cause lower back or tailbone pain, leg weakness or numbness, and bowel or bladder dysfunction. Spinal involvement can lead to myelopathy or radiculopathy.

Diagnosis relies on imaging and histology. Magnetic resonance imaging (MRI) is the preferred modality to delineate extent, with computed tomography (CT) useful for assessing bone destruction. Definitive diagnosis requires a biopsy. Histologically, chordoma shows physaliphorous cells in a myxoid matrix. Immunohistochemistry is typically positive for cytokeratins and epithelial membrane antigen (EMA), with variable S-100 protein expression.

Treatment centers on local control. The mainstay is surgical resection with the goal of negative margins, though achieving this can be difficult near critical structures. Postoperative radiotherapy is commonly employed; high-dose conformal radiotherapy, including proton or carbon ion therapy, often improves local control compared to conventional photons. Unresectable tumors may be treated with radiotherapy alone or palliative approaches. Systemic therapies have limited proven benefit, but targeted therapies and immunotherapies are being explored in clinical trials.

Prognosis is influenced by tumor size, location, and the extent of surgical resection, with recurrence being common and long-term follow-up required.