Chordoma

Definition

  • Rare malignant neoplasm arising from notochordal remnants

Epidemiology

  • 1-4% of primary malignant bone tumours
  • M:F – 3:1 in sacral tumours
  • Average age at diagnosis 55 years
  • Midline in axial skeleton
    • Sacrum 50%
    • Base of skull 35%
    • Vertebrae
    • Especially cervical 15%

Embryology

  • Rests of embryonic notochord
  • Incomplete degeneration of notochord in centre of vertebral body at junction of adjacent sclerotomes
  • This undergoes neoplastic change to Chordoma

Clinical features

  • Slow growing with clinical features dependent on location
  • Cranial lesions smaller than sacral lesions at presentation
  • Middle-aged adults
  • Sacral lesions
    • Low back pain
    • Pelvic pain
    • Usually poorly localised
    • Night pain common
    • 40% have rectal dysfunction
    • Will often palpate presacral chordoma PR
    • Neurological compression
  • Often late presentation with mass effect
    • Slow-growing
    • Large potential space to expand into
    • Often very large on presentation
  • Regional lymph node, lung, liver & bone mets in 50% cases

Investigations

Xrays

  • Bone destruction hallmark of chordoma
  • Sacrum
    • Irregular areas of bone destruction
    • Sacral expansion
    • Often multiple levels
    • Soft tissue mass
  • Cervical
    • May see extension anteriorly into soft tissues (dysphagia)
  • Lytic with central location
  • Slowly expansile
  • 50% have focal calcification in lesion
  • Two or more vertebrae may be involved with intervening disc space

Bone Scan

  • Usually reduced uptake or normal

CT Scan

  • Spinal lesions evaluated
  • Lytic or mixed lytic/ sclerotic
  • Epidural tumour extension seen

MRI

  • Delineates full extent of tumour

Pathology

Gross

  • Soft & well encapsulated
  • Lobulations on cut cross-section
  • Tumour has bluish-grey colour with gelatinous translucent areas with interspersed focally cystic & haemorrhagic areas
    • May resemble Chondrosarcoma or Mucinous carcinoma
  • May track along nerve roots in sacral plexus & extend into sciatic notch

Microscopic

  • Tumour cells separated into lobules by fibrous septa of different thickness
    • Various shapes & sizes in chords & sheets with eosinophilic cytoplasm
    • Physaliphorous cell characteristic
      • Vacuoles prominent & displace nucleus to edge
    • Both intracellular & extracellular mucin
    • Vascular fibrous septa
  • 30% of spheno-occipital chordomas contain chondroid component
    • Similar to chondrosarcoma
  • MFH or another poorly differentiated sarcoma can be associated with chordoma
    • Some have history of radiation therapy

Treatment

  • Wide resection is procedure of choice
  • Often impossible & marginal resection is best that can be achieved
    • Recurrence common
    • Palliative Marginal Resection is often only option
  • Radiotherapy added if
  • Resection not possible
  • Palliative resection performed
  • Can resect both S2 roots & preserve one S3 root & get continence in most cases (sphincter control)
  • Metastases 30-50%
  • Pulmonary metastases may occur
  • Death usually secondary to local infiltration