Chordoma

Chordomas are uncommon malignant tumours that account for 1% of intracranial tumours and 4% of all primary bone tumours. 

They originate from embryonic remnants of the primitive notochord (earliest fetal axial skeleton, extending from the Rathke's pouch to the coccyx). Since chordomas arise in bone, they are usually extradural and result in local bone destruction. They are locally aggressive, but uncommonly metastasise. 

Chordomas occur at any age but are usually seen in adults (30-70 years). Those located in the spheno-occipital region most commonly occur in patients 20-40 years of age, whereas sacrococcygeal chordomas are typically seen in a slightly older age group (peak around 50 years 10). They are commonly found in Caucasians 3.

They are slow growing tumours and present due to mass effect on adjacent structures (brainstem, cranial nerves, nasopharynx, spinal cord), or as a mass (e.g. sacrococcygeal chordoma) 10.

Fluid and gelatinous mucoid substance (associated with recent and old haemorrhage) and necrotic areas are found within the tumour. In some patients, calcification and sequestered bone fragments are found as well. The variety of these components may explain the signal heterogeneity observed on MRI. Incomplete delineation of the tumour and microscopic distal extension of tumour cells may explain the frequency of recurrences. Physaliphorous cells are classically seen on microscopy

Metastatic spread of chordomas is observed in 7-14% of patients and includes nodal, pulmonary, bone, cerebral or abdominal visceral involvement, predominantly from massive tumours. True malignant forms of chordomas occasionally have areas of typical chordoma and undifferentiated areas, most often suggestive of fibrosarcoma; the prognosis is poor.

Location

Chordomas are found along the axial skeleton and a relatively evenly distributed among three locations:

  • sacrococcygeal: 30-50% 2-3
  • spheno-occipital: 30-35%
  • vertebral body: 15-30%
Sacrococcygeal

This is the most common location, accounting for approximately 30-50% 2-3 of all chordomas and involving particularly the fourth and fifth sacral segments 2. In this location a male predilection has been reported (M:F ratio of 2:1)nd the tumour may be particularly large at presentation 10.

Chordoma is the most common primary malignant sacral tumour 9-10.

Spheno-occipital

The clival region is the next most common, accounting for 30-35% 2-3 of cases. Typically the mass projects in the midline posteriorly indenting the pons. This characteristic appearance has been termed the 'thumb sign". In contrast to sacrococcygeal tumours, there is currently no recognised gender difference.

Vertebral bodies

Chordomas of the vertebral bodies are rare but after lymphoproliferative tumours are nonetheless the most common primary malignancy of the spine in adults 2. They most commonly involve the cervical spine (particularly C2), followed by the lumbar spine then the thoracic spine. They often extend across the intervertebral disc space, involving more than one vertebral segment. They may extend into the epidural space, compressing the spinal cord, or along the nerve roots, enlarging the neural exit foramen.  

MRI and CT scan have complementary roles in tumour evaluation. CT evaluation is needed to assess the degree of bone involvement or destruction and to detect patterns of calcifications within the lesion. MRI provides excellent 3-dimensional analysis of the posterior fossa (especially the brainstem), sella turcica, cavernous sinuses, and middle cranial fossa. MRI depicts calcifications and the precise involvement of skull base osteolysis less well than CT, especially for skull base foramina.

CT
  • centrally located
  • well-circumscribed
  • destructive lytic lesion, sometimes with marginal sclerosis
  • expansile soft-tissue mass (usually hyper-attenuating relative to the adjacent brain; however, inhomogenous areas may be seen due to cystic necrosis or haemorrhage; the soft-tissue mass is often disproportionately large relative to the bony destruction)
  • irregular intratumoral calcifications (thought to represent sequestra of normal bone rather than dystrophic calcifications)
  • moderate to marked enhancement 
MRI
  • T1
    • intermediate to low signal intensity
    • small foci of hyperintensity (intratumoral haemorrhage or a mucus pool)
  • T2: most exhibit very high signal 
  • T1 C+ (Gd): heterogeneous enhancement with a honeycomb appearance corresponding to low T1 signal areas within the tumour
  • GE (gradient echo): confirms haemorrhage if present with blooming
Bone scan
  • normal or decreased uptake

Traditionally surgical resection has been the first line of treatment in feasible scenarios, with radiotherapy offered for recurrent cases. Some advocate the combination of radiation therapy and complete or subtotal surgical resection for selected patients 6. Percutaneous radiofrequency ablation has been trialled as an adjunct 8. Recurrence, including seeding along the operative tract, is common.

Prognosis is typically poor, due to the locally aggressive nature of these tumours, with the 10-year survival approximately 40%.

For clival/spheno-occipitial lesions differentials to consider include: 

For vertebral lesions, consider:

  • chondrosarcoma
    • neural arch > vertebral body
    • thoracic spine is the most commonly involved spinal region
    • chondroid matrix (rings & arcs)
    • similar MRI appearance to chordomas (low to intermediate signal intensity on T1, hyperintense on T2, enhances)
  • giant cell tumour
    • F>M
    • location: sacrum > thoracic spine > cervical spine > lumbar spine
    • no mineralised matrix
    • heterogeneous intermediate to hyperintense T2 signal
  • spinal metastases
    • hypointense on T1; variably hyperintense on T2
    • often multiple, involving vertebral bodies and posterior elements
  • plasmacytoma
    • destructive vertebral body lesion (similar appearance to lytic metastases)
  • spinal lymphoma
    • multifocal disease
    • heterogenous T2 signal

Bone tumours

The differential diagnosis for bone tumours is dependent on the age of the patient, with a very different set of differentials for the paediatric patient.

Share Article

Article Information

rID: 1122
Section: Pathology
Synonyms or Alternate Spellings:
  • Chordomas
  • Chordoma - General
  • Chordomas - general

Support Radiopaedia and see fewer ads

  • Drag
    Figure 1: thumb sign illustrated
    Drag here to reorder.
  • Drag
    Case 1: clival chordoma with thumb sign
    Drag here to reorder.
  • Drag
    Figure 2: hystology
    Drag here to reorder.
  • Drag
    Case 2: sacrococcygeal chordoma
    Drag here to reorder.
  • Drag
    Elevated pituitar...
    Case 3: clival chordoma with elevated pituitary
    Drag here to reorder.
  • Drag
    T1 C+ FS
    Case 3: showing strong contrast enhancement on T1 C+
    Drag here to reorder.
  • Drag
    Case 4: C2 vertebral body chordoma on MRI
    Drag here to reorder.
  • Drag
    Case 4: C2 vertebral body chordoma on nuclear medicine study
    Drag here to reorder.
  • Drag
    Case 5: spheno-occipital chordoma in an 8-year-old
    Drag here to reorder.
  • Drag
    Chordoma

Sagital...
    Case 6: spheno-occipital chordoma on sagittal MRI
    Drag here to reorder.
  • Drag
    Chordoma
    Case 6: irregular intratumoral calcifications on CT
    Drag here to reorder.
  • Drag
    Case 7: sacrococcygeal chordoma on CT
    Drag here to reorder.
  • Drag
    Case 8: sacrococcygeal chordoma
    Drag here to reorder.
  • Drag
    Case 10
    Drag here to reorder.
  • Drag
    Case 9: spheno-occipital chordoma on T2
    Drag here to reorder.
  • Drag
    Case 12: sacral
    Drag here to reorder.
  • Drag
    Case 13: clival chordoma
    Drag here to reorder.
  • Drag
    Case 14: clival chordoma
    Drag here to reorder.
  • Drag
    Case 15: recurrent sacrococcygeal chordoma
    Drag here to reorder.
  • Drag
    Case 16
    Drag here to reorder.
  • Drag
    Case 17
    Drag here to reorder.
  • Drag
    Case 18
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.