Chordoma, a malignant tumor arising from notochordal remnants, MOST commonly occurs at which anatomical location?

• A Thoracic vertebra
• B Lumbar vertebra
• C Sacrococcygeal region (sacrum) ✓
• D Posterior fossa of the skull

Explanation

Chordoma arises from remnants of the notochord and is found at the axial skeleton. The distribution is: sacrococcygeal (~50%), spheno-occipital/clivus (~35%), and vertebral (~15%). The sacrum is the single most common site. Histologically it shows physaliferous cells (large vacuolated cells) in a myxoid matrix, staining positive for S100, EMA, and cytokeratin. Treatment is wide surgical resection; recurrence is common. Chordomas are radioresistant to conventional radiotherapy but respond to proton beam radiation. The 5-year survival is approximately 50–70% but local recurrence is the rule.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.