Orthopaedic Surgery - Chordoma

Basics

Chordoma is a low-grade malignant bone tumor arising from remnants of the embryologic notochord.

It accounts for approximately 1–4% of primary malignant bone tumors and is one of the most important primary malignant tumors involving the axial skeleton, particularly the spine and sacrum.

Anatomic Distribution

Chordomas most commonly arise in the sacrococcygeal region, which accounts for approximately 55% of cases.

Around 30% occur in the skull base, particularly the sphenoid or clival region, while approximately 15% develop within the cervical, thoracic, or lumbar spine.

Delayed Diagnosis

Diagnosis is frequently delayed because symptoms are often nonspecific.

Sacral chordoma may present simply as chronic low back, pelvic, or sacral pain and may therefore be mistaken for much more common degenerative musculoskeletal disorders.

Dedifferentiation

Although conventional chordoma is generally considered a low-grade malignancy, a small proportion of tumors, historically reported at less than 5%, may undergo dedifferentiation into a high-grade spindle-cell sarcoma.

Dedifferentiated chordoma behaves much more aggressively than the conventional form.

General Precautions

One of the most important diagnostic pitfalls is failure to consider sacrococcygeal chordoma in a patient with persistent unexplained low back or sacral pain.

Chronic symptoms that are progressive, atypical, or associated with neurologic, bowel, or bladder dysfunction warrant further investigation.

Epidemiology

Chordoma is extremely rare.

The reported annual incidence is approximately 0.08 cases per 100,000 people.

It most commonly presents in adulthood, with a peak incidence around the fourth to fifth decades of life, although it may occur outside this age range.

Risk Factors

No established environmental or lifestyle risk factors have been identified.

Most cases occur sporadically.

Genetics

No common hereditary predisposition is recognized in the majority of patients.

The disease is generally not associated with a typical familial pattern.

Etiology

Chordoma develops from persistent notochordal remnants within the axial skeleton.

The notochord normally contributes to embryologic development of the spine and largely disappears before birth, but residual cells may persist and later undergo malignant transformation.

Tumor Growth

Chordomas often extend beyond the confines of bone.

Sacral tumors, in particular, may produce a large anterior soft-tissue mass extending into the pelvis.

Because the tumor may become very large before producing obvious symptoms, substantial local destruction can be present by the time of diagnosis.

Associated Conditions

No specific associated systemic disorders are typically present.

Diagnosis

Signs and Symptoms

Symptoms depend on tumor location but are usually slowly progressive and nonspecific.

Sacral lesions commonly produce low back pain, pelvic pain, sacral discomfort, or anal pain.

Difficulty Sitting

Patients with sacrococcygeal tumors may find prolonged sitting increasingly uncomfortable.

Pain may arise from direct pressure on the tumor or involvement of adjacent pelvic structures.

Bowel and Bladder Symptoms

Constipation, urinary disturbance, or other pelvic-organ symptoms may develop as the tumor enlarges.

These findings can result from compression or invasion of adjacent pelvic structures or sacral nerve roots.

Radiculopathy

Tumor extension around neural structures may compress or destroy adjacent nerve roots.

This can produce radicular pain, sensory loss, or motor dysfunction corresponding to the level of involvement.

In sacral chordoma, the S1, S2, and S3 roots are commonly at risk.

Physical Examination

Physical findings are often limited despite substantial tumor size.

There may be little to suggest an underlying bone malignancy on routine examination.

Rectal Examination

Large sacral chordomas frequently extend anteriorly into the pelvis.

A mass may be palpable during rectal examination in approximately half of patients with sufficiently advanced sacral disease.

Imaging

Plain Radiographs

Plain radiographs may appear normal or show only subtle abnormalities.

Findings can include bone destruction, cortical expansion, or a lytic sacral lesion.

Limitations of Radiography

Sacral tumors are particularly easy to miss on plain radiographs because bowel gas and fecal material may obscure the lesion.

A normal radiograph therefore does not exclude chordoma when clinical suspicion remains high.

CT

CT is highly sensitive for demonstrating the bony component of chordoma.

Typical findings include midline osseous destruction and an anterior soft-tissue mass.

Calcification

Scattered internal calcifications may be visible on CT.

These mineralized areas can help characterize the lesion but are not specific to chordoma.

MRI

MRI is the preferred modality for defining the full extent of the tumor and its relationship to surrounding structures.

Chordomas are typically low signal intensity on T1-weighted images and high signal intensity on T2-weighted images.

Contrast-Enhanced MRI

Contrast-enhanced MRI helps delineate the dimensions of the mass and its relationship to the spinal canal, nerve roots, pelvic organs, vessels, and surrounding soft tissues.

This information is essential for operative planning.

Imaging the Entire Sacrum

Sacrococcygeal lesions may lie at the extreme inferior edge of lumbar or pelvic MRI studies.

The tumor can therefore be overlooked if the imaging field does not extend far enough inferiorly.

When sacral chordoma is suspected, imaging should include the entire sacrum and coccyx down to the coccygeal tip.

Nuclear Medicine

Conventional technetium bone scans and PET have historically been less useful than CT and MRI for primary characterization of chordoma.

Cross-sectional imaging remains central to diagnosis, staging, and surveillance.

Differential Diagnosis

Destructive Spinal Lesions

Important alternative diagnoses include metastatic bone disease, multiple myeloma, and lymphoma, all of which can produce destructive lesions of the spine or sacrum.

Sacral Tumors

Chondrosarcoma and giant cell tumor may also arise in the sacrum.

Both can produce bone destruction, soft-tissue extension, and in some cases mineralization, making differentiation from chordoma necessary.

Chondrosarcoma

Chondrosarcoma may resemble chordoma radiographically, particularly when it occurs in the pelvis or sacrum.

Tumor location, pattern of calcification, MRI appearance, and histology help distinguish the two lesions.

Treatment

General Principles

The primary treatment for chordoma is complete surgical removal whenever technically feasible.

Because local recurrence strongly influences survival, achieving adequate margins is critical.

Wide En Bloc Resection

The preferred operative strategy is wide en bloc resection with negative surgical margins.

The tumor is removed as a single specimen together with a surrounding margin of uninvolved tissue when anatomy permits.

Importance of Surgical Margins

Incomplete excision or tumor contamination during surgery substantially increases the risk of local recurrence.

Unfortunately, chordomas often lie immediately adjacent to major nerves, blood vessels, bowel, bladder, or spinal structures, making wide margins difficult to achieve.

Chemotherapy

Conventional chemotherapy has little established role in the routine treatment of classic chordoma.

The relatively indolent biology of the tumor and limited chemosensitivity make surgery and local control the major therapeutic priorities.

Radiotherapy

High-dose radiation, particularly proton-beam or other conformal particle-based radiotherapy, may be considered in selected patients.

It can be used when surgical margins are limited, the tumor is unresectable, or as part of a combined treatment strategy.

Follow-Up

Prognosis

Chordoma has a prolonged but potentially aggressive natural history.

Historical series report a median survival of approximately 6.3 years.

Five-year survival has been reported in the range of approximately 50–67%, while 10-year survival has ranged from roughly 28–46%.

Metastatic Risk

The risk of distant metastasis has historically been estimated at approximately 10–40%.

Common metastatic sites include the lungs, bone, liver, and lymph nodes.

Importance of Local Recurrence

Chordoma is unusual among low-grade tumors because local recurrence can itself be a major cause of mortality.

Repeated local growth can progressively involve vital neural, vascular, gastrointestinal, and genitourinary structures.

Relationship Between Recurrence and Survival

Local recurrence is associated with poorer survival.

The best chance for durable control therefore comes from achieving adequate surgical margins during the initial operation whenever possible.

Complications

Wound-Healing Problems

Wound complications are common after major sacral resections.

Historical series have reported wound-healing problems in as many as 45% of patients.

Large incisions, dead space, radiation, extensive soft-tissue dissection, and contamination risk may all contribute.

Injury to Pelvic Structures

Sacral chordoma surgery may place important anterior pelvic structures at risk.

Potential injuries include damage to the iliac vessels, rectum, bladder, ureters, and other pelvic organs.

Sacral Nerve-Root Sacrifice

The functional consequences of surgery depend heavily on which sacral nerve roots must be sacrificed to achieve tumor clearance.

Higher-level bilateral sacrifice produces more severe neurologic deficits.

Bilateral S1 Sacrifice

Sacrifice of both S1 nerve roots, as may occur with total sacrectomy, can result in major lower-extremity motor and sensory deficits together with loss of bowel and bladder function.

Bilateral S2 Sacrifice

Historical data indicate that bilateral S2 root sacrifice is associated with an extremely high likelihood of bowel and bladder dysfunction.

Some patients may require permanent diversion procedures.

Bilateral S3 Sacrifice

Bilateral S3 sacrifice carries a substantial risk of bowel and bladder dysfunction.

Historical series have reported bowel dysfunction in approximately 60% and bladder dysfunction in approximately 75% of such patients.

Bilateral S4 Sacrifice

Sacrifice limited to both S4 roots is associated with a lower risk of bowel dysfunction, although bladder disturbance may still occur.

Historical series reported minimal bowel dysfunction but bladder dysfunction in approximately 31% of patients.

Sexual Dysfunction

Loss of sacral nerve function may also produce sexual dysfunction, depending on the level and extent of nerve-root sacrifice.

Spinopelvic Instability

Major sacral resections can disrupt continuity between the spine and pelvis.

This may produce spinopelvic instability or discontinuity and can require complex reconstruction.

Sacral Insufficiency Fracture

Remaining sacral or pelvic bone may be vulnerable to insufficiency fracture following extensive resection.

Mechanical reconstruction may be required when stability is compromised.

Patient Monitoring

Long-Term Surveillance

Patients require lifelong surveillance because chordoma can recur many years after initial treatment.

Follow-up commonly includes CT or MRI of the operative region once or twice each year, with intervals individualized according to recurrence risk and prior treatment.

Surveillance for Metastases

Imaging should also assess for distant metastatic disease, particularly involving the lungs.

Long-term chest surveillance is therefore commonly incorporated into follow-up.

Clinical Monitoring

Follow-up should assess for new pain, neurologic symptoms, bowel or bladder dysfunction, changes in sitting tolerance, and evidence of wound or reconstructive complications.

Any new or progressive symptom should prompt timely imaging because recurrent disease may initially be subtle.