Primary Vertebral Tumors

What are primary tumors of the spine?

Neoplasms that originate from the vertebral bone itself (not metastases from other organs). Their behavior may range from benign to biologically malignant.

Primary tumors of the spine are less common than metastatic disease, but are clinically significant because:

• they may occur in children, adolescents, or young adults,
• they can cause instability, deformity, or pathologic fracture,
• they may compress nerve roots or the spinal cord,
• some require oncologic en bloc resection (complete removal in one piece with tumor-free margins) when feasible.

How common are they and who is affected?

Overall, they account for approximately 10% of spinal tumors. Age and sex distribution vary by tumor type.

Representative patterns by lesion:

• Aneurysmal Bone Cyst (ABC): rare bone lesion, more common in patients < 30 years, with a slight female predominance.
• Giant Cell Tumor (GCT): peak incidence in the 3rd–5th decades, slightly more common in women, with a particular predilection for the sacrum.
• Chordoma: primarily sacral and clival, biologically aggressive with a tendency to recur.
• Vertebral hemangioma: common incidental finding, present in >10% of the general population, usually asymptomatic.
• Osteoid osteoma / Osteoblastoma: more frequent in children/adolescents, with male predominance.

What symptoms do they cause and which are considered “red flags”?

The most common reason patients seek evaluation is localized spinal pain. Certain symptoms, however, warrant urgent assessment.

Common symptoms:

• Persistent focal back, neck, or thoracic pain not otherwise explained.
• Nocturnal pain (particularly characteristic of osteoid osteoma).
• Radicular pain (sciatica, numbness) when nerve roots are involved.
• Instability/deformity or scoliosis, especially in children.

Red-flag symptoms (seek prompt evaluation):

• New weakness in the upper or lower extremities, gait disturbance.
• Signs of myelopathy (imbalance, spasticity).
• Bowel or bladder dysfunction (urgent, particularly in lumbar lesions).
• Rapidly worsening pain or pain associated with fever/systemic symptoms (to differentiate from infection or other etiologies).

What are the most common types and what does “benign but aggressive” mean?

Some tumors are histologically benign yet locally aggressive and prone to recurrence. For this reason, their treatment is often oncologic in nature.

Lesions commonly encountered in clinical practice:

• Aneurysmal Bone Cyst (ABC) – lytic/cystic lesion, often involving the posterior elements.
• Giant Cell Tumor (GCT) – locally aggressive, high recurrence risk if not completely excised.
• Chordoma – histologically “benign,” but biologically malignant with a tendency to recur.
• Vertebral hemangioma – usually innocuous; rarely becomes “aggressive” with neurologic compression.
• Osteoid osteoma / Osteoblastoma – pain pattern and posterior element location are key diagnostic clues.

How is the diagnosis established (MRI/CT, bone scan, biopsy)?

Diagnosis requires correlation of clinical findings with advanced imaging. Whenever feasible, preoperative biopsy helps avoid errors in surgical planning and treatment strategy.

• Plain radiographs: lytic/sclerotic changes, fractures, deformity.
• CT: excellent for osseous detail—demonstrates lytic cavities, sclerosis, cortical integrity, and bony architecture.
• MRI: evaluates marrow, soft tissues, epidural space, and neural compression; may show features such as fluid–fluid levels in aneurysmal bone cysts.
• Bone scintigraphy: highly sensitive for osteoid osteoma/osteoblastoma (intense uptake at the “nidus”).
• CT-guided percutaneous biopsy: when management depends on histology (often essential).

Central objective: to determine whether the lesion is benign, locally aggressive, or malignant, thereby guiding the appropriate extent of resection (intralesional vs en bloc) and the need for spinal stabilization.

What is an Aneurysmal Bone Cyst (ABC)?

A rare, lytic bone lesion most often seen in younger patients, which may cause pain, instability, or neurologic compression.

Typical features:

• Most often in patients < 30 years, with a slight female predominance.
• Distribution: commonly lumbar spine, but may occur in the thoracic or cervical spine.
• Frequently involves the posterior elements (laminae), though it may arise from the vertebral body.
• Clinical presentation: pain, neurologic deficit, or deformity/instability.

Imaging:

• CT: “ballooning,” multiloculated lytic lesion with “soap-bubble” appearance.
• MRI: characteristic fluid–fluid levels.

Treatment (individualized):

• Selective arterial embolization (particularly for hypervascular lesions) and
• en bloc surgical excision when feasible or intralesional curettage.
• If instability is present: instrumentation/fusion.
• In selected cases: vertebroplasty to reinforce the anterior column.

What is a Giant Cell Tumor (GCT) and the role of denosumab?

A locally aggressive osteolytic tumor with risk of recurrence and, rarely, metastasis. When feasible, the goal is complete surgical resection.

Key points:

• Most common in the 3rd–5th decades, with a slight female predominance.
• Common spinal location: sacrum (one of the most frequent sites).
• Typically arises from the vertebral body rather than posterior elements.

Imaging:

• Bone scan: often increased uptake.
• CT: cortical thinning, pathologic fracture, degree of osseous destruction.
• MRI: relatively well-demarcated lesion with a low-signal “rim” (sclerosis/pseudocapsule).
• May exhibit “aneurysmal cystic components,” imparting a more aggressive appearance.

Treatment:

• Complete surgical resection (ideally en bloc) when feasible, given the high recurrence risk after incomplete excision.
• Residual disease: in selected cases, radiotherapy may be considered, with counseling regarding the potential for late recurrence.
• Denosumab: a targeted therapy inhibiting RANKL, a key pathway in GCT biology. In selected patients (e.g., surgically challenging disease), it can be a valuable adjunct in collaboration with a specialized oncology team.

What is chordoma and why does it require specialized oncologic management?

A tumor arising from embryonic remnants of the notochord, most commonly in the sacrum or clivus. Although histologically “benign,” it behaves as a biologically malignant tumor with a high rate of recurrence.

Key points:

• Nearly 50% of primary sacral tumors are chordomas.
• Predominantly involves the sacrum and clivus, but may occur anywhere along the mobile spine.
• Marked tendency for local recurrence and, less commonly, metastasis.

Treatment principles:

• En bloc resection when feasible, with oncologic margins.
• Particular attention to biopsy technique: the biopsy tract must be considered part of the tumor and excised with the specimen to minimize the risk of tumor seeding.
• These tumors are often less responsive to conventional radiotherapy; in specialized centers, advanced modalities (e.g., proton beam therapy) may be used as adjuvant treatment.

Because en bloc resections in the spine are technically demanding, they require meticulous preoperative planning and detailed discussion with the patient regarding potential risks.

What is a vertebral hemangioma and when does it require treatment?

A very common incidental finding on MRI. The majority of patients require no intervention.

Characteristics:

• Prevalence > 10% as an incidental finding, increases with age, slightly more common in women.
• Typically involves the vertebral bodies; rarely extends into pedicles or spinous processes.

Imaging:

• CT: characteristic “polka-dot” pattern (thickened vertical trabeculae).
• MRI: typically high signal on T1/T2 with characteristic appearance and homogeneous contrast enhancement.

When is treatment indicated?

• If asymptomatic: observation only.
• If causing pain without neural compression: embolization, radiotherapy, or vertebroplasty may be considered (especially with pathologic fracture).
• If there is compression of the spinal cord/nerve roots: decompression/resection—often with preoperative embolization to reduce intraoperative bleeding.

Osteoid Osteoma & Osteoblastoma – what is the typical clinical presentation?

Two histologically related lesions that produce osteoid. Key factors in management are patient age, the presence of nocturnal pain, and whether symptoms respond to anti-inflammatory medications.

Key distinctions:

• Osteoid osteoma: small, self-limited, well-circumscribed.
• Osteoblastoma: larger (> 2 cm), may be locally aggressive and rarely undergo malignant transformation.

Typical features:

• More common in children/adolescents, with male predominance.
• Spinal involvement in 10–20% of cases, most frequently in the lumbar region.
• Predilection for the posterior elements (e.g., arches/facet joints).
• Clinically: localized nocturnal pain that improves dramatically with NSAIDs (classically aspirin).

Imaging:

• Bone scan: highly sensitive, intense uptake at the “nidus.”
• CT: low-density nidus with variable surrounding sclerosis (less pronounced in osteoblastoma).
• MRI: nidus with marrow/soft-tissue edema and post-contrast enhancement.

What are the treatment options (embolization, resection, fusion)?

Management is guided by four key questions: diagnosis, neural compression, spinal instability, and risk of recurrence. The goal is oncologic control while minimizing morbidity.

Principal options:

• Observation: for asymptomatic, non-aggressive lesions (e.g., most hemangiomas).
• Embolization: for hypervascular lesions (aneurysmal bone cysts, hemangiomas), often preoperatively.
• Intralesional excision / curettage: appropriate for selected benign lesions when en bloc resection is not feasible, with counseling regarding recurrence risk.
• En bloc resection: preferred for locally aggressive/biologically malignant lesions (e.g., chordoma, selected GCTs, osteoblastoma), when technically feasible.
• Vertebroplasty: in selected cases to reinforce the vertebral body/anterior column.
• Instrumentation/fusion: when spinal instability is present or anticipated (due to the tumor or following resection).

Important: en bloc resections often carry a higher risk of neurologic complications compared with intralesional techniques. This must be discussed in detail so that the treatment decision is shared.