Giant cell tumors (GCTs) of the spine are a type of bone tumor affecting the vertebral column. Though uncommon, these tumors involve an abnormal growth of cells within the spinal bone structure.
Understanding Giant Cell Tumors of the Spine
A giant cell tumor of the bone is considered benign. However, GCTs are locally aggressive, capable of rapid growth that can destroy surrounding bone tissue.
These are primary bone tumors, accounting for a small percentage of all primary bone tumors. They are most frequently observed in young adults, with a slightly higher incidence in women. While GCTs commonly develop near the joints of long bones like the knee, wrist, or shoulder, they can also affect any level of the spine: cervical, thoracic, lumbar, or sacrum.
Recognizing Signs and Diagnosis
A common symptom of a giant cell tumor of the spine is localized pain at the tumor site. This pain often intensifies gradually, disrupting sleep or worsening with activity, sneezing, or coughing. It is typically described as aching and deep.
As the tumor grows, it can compress the spinal cord or nerves, leading to neurological deficits. These may include weakness, numbness, or tingling in the arms, legs, or chest, depending on the tumor’s location. Compression in the sacrum might also cause bowel or bladder incontinence or sexual dysfunction.
Diagnosing a spinal GCT involves imaging techniques and a tissue biopsy. X-rays provide an initial assessment of bone changes, revealing expansile, lytic lesions or vertebral compression. Computed tomography (CT) scans offer detailed views of bone destruction and expansion, while magnetic resonance imaging (MRI) assesses soft tissue involvement, tumor extent, and its relationship to the spinal cord and nerves.
While imaging studies suggest a GCT diagnosis, definitive confirmation requires a biopsy, often a CT-guided needle biopsy. This procedure obtains a tissue sample for evaluation, confirming the presence of multinucleated giant cells characteristic of the tumor.
Treatment Approaches
The primary treatment for giant cell tumors of the spine is surgical removal, aiming to remove the tumor, decompress neural elements, and stabilize the spine. Two main surgical approaches are considered: intralesional curettage and en bloc spondylectomy. Curettage involves scraping the tumor from the bone, often followed by extended curettage.
Adjuvant therapies are frequently used during surgery to reduce recurrence risk. These include local application of substances like phenol, liquid nitrogen (cryotherapy), or hydrogen peroxide to eradicate remaining tumor cells. Filling the surgical void with polymethyl methacrylate (PMMA) bone cement is also common; this cement provides structural stability and helps destroy residual tumor cells.
En bloc spondylectomy is considered the most definitive surgical treatment for spinal GCTs, associated with lower recurrence rates compared to intralesional curettage. This procedure can be performed through various approaches, depending on the tumor’s location and extent. Despite its effectiveness, en bloc excision is associated with a higher rate of complications.
Radiation therapy is another treatment option, particularly for cases where complete surgical removal is not feasible, for recurrent tumors, or for palliation. GCTs are responsive to radiation and can provide local control with acceptable side effects.
Targeted medical therapies, specifically denosumab, a RANKL inhibitor, have significantly impacted GCT treatment. Denosumab is a monoclonal antibody that works by binding to RANKL, inhibiting the formation and survival of osteoclasts, which are cells responsible for bone destruction. This drug can be used before surgery to shrink the tumor and clarify its boundaries, for unresectable tumors, or in recurrent cases to control tumor progression and reduce pain. However, preoperative denosumab with curettage may increase the risk of local recurrence.
Recovery and Long-Term Care
Following treatment for a giant cell tumor of the spine, recovery often involves rehabilitation. Physical therapy helps patients regain strength, mobility, and overall function, especially after extensive surgical procedures. The duration of recovery varies based on the surgery’s extent and the patient’s individual response.
Despite successful initial treatment, giant cell tumors of the spine have a notable potential for recurrence. Recurrence rates vary widely depending on the treatment method, with intralesional curettage generally having higher rates compared to en bloc resection.
Due to this risk, long-term follow-up appointments and regular imaging studies, such as X-rays, CT scans, or MRIs, are important for monitoring any signs of tumor return. These follow-up visits are typically frequent in the first two years, becoming less frequent thereafter. Early detection of recurrence allows for timely intervention, which can lead to better outcomes.