Lesion from the Bony Elements of Spine

Case of the Month:Submitted by Dr Sujit Kumar Tripathy, University of Teeside, UK.

Review Questions?

1. What is the most common primary bone tumour arising from the spine?
2. What is the most common location of Giant cell tumour in spine?
3. Does giant cell tumour in the spine behave with same aggression as in other parts of the body?
4. What is the classification employed for bone tumours of the spine?

GIANT CELL TUMOUR OF SPINE- Special Focus
Tarun Goyal, Clinical fellow, Victoria Infirmary Hospital, NHS Greater Glasgow & Clyde , UK
Sujit Kumar Tripathy, Clinical fellow, Southtees Hospital NHS Trust. UK

• Secondary spinal tumours (malignancies from elsewhere) are more common than primary bone tumours in the spine
• Osteoid osteoma is the most common benign tumour arising from the vertebra.
• Multiple myeloma is the most common primary malignant tumour arising in the spine

Giant cell tumour is a relatively rare neoplasm and comprises about 5% of all primary bone tumours in adults. Most common age of presentation is 20-45 years. Males and females are more or less equally involved.

Giant cell tumor of Spine

• Most commonly arise from the body of the vertebra (anterior elements of vertebra)
• The sacrum is the most common location of giant cell tumor in the axial skeleton and the third most common location after the knee and the radius.
• Giant cell tumour of the sacrum makes up about 2-8 % of all cases and involvement of rest of the spine is seen in 2-4%, with all segments of the spine equally involved.
• Patients with these tumors tend to be slightly younger than those with tumors in the appendicular skeleton.

Radiological features

• Radiological features are less diagnostic for a giant cell tumour in the spine.
• The characteristic epiphyseal-metaphyseal location seen in the long bones is not seen in spinal involvement.
• Sacral giant cell tumors usually develop in an eccentric position in superior-lateral aspect, but commonly extend to involve both sides of the midline.
• There is usually a thin cortical rim, which the soft tissue mass can break through. Tumors in mobile spine generally arise from the junction of anterior two-thirds and posterior one-third and are relatively smaller in size.
• In addition, these tumors have the propensity to cross the sacroiliac joints and intervertebral discs, which is unusual for many other spinal lesions and is a useful distinguishing feature of giant cell tumors.
• Vertebral giant cell tumors may extend into the spinal canal and compress the spinal cord, resulting in neurologic symptoms. The tumor can cause vertebral collapse and spinal cord compression, especially when it invades the posterior elements.

MRI is the most useful investigation modality in diagnosis.

• It shows an intermediate T1-weighted signal with hyperontense haemorrhagic areas and hypointense cystic areas.
• Solid areas are often hypointense on T2 weighted image, reflecting a high clooagen content. This feature can help to distinguish sacral GCTs from other more common sacral lesions such as chordomas, metastasis and myeloma.

Treatment

• Diagnosis is often delayed, and tumours are generally large in size when detected. The standard treatment for a giant cell tumour is aggressive curettage followed by adjuvant therapy.
• En-bloc excision is the best treatment for local control, but because of extend of the tumour may be difficult to achieve. These tumours are highly vascular and surgical excision or curettage is a demanding procedure.

• Preoperative angiography with embolisation may help to reduce the vascularity of the tumors before surgical excision.

• Giant cell tumours in spine have a much worse prognosis compared to lesions in the appendicular skeleton. Recurrence rates in spinal disease are higher compared to long bones because of difficulty in obtaining a clear surgical margin, and can be as high as 80% in grade III tumours.

• Although generally considered a benign tumor, 5% to 10% are reportedly malignant, many of which are believed to be related to previous radiation therapy. Histologically benign tumors may show metastasis.
• Surgical excision is the only treatment for resectable single metastasis as no systemic therapy is available for these tumours.

• Radiotherapy has been used for treatment of lesions where excision is incomplete or when there is a recurrence. The available evidence does not conclusively support or reject the effectiveness of radiotherapy in giant cell tumours of spine.
• It has been frequently used, more so because it is easily available and easy to administer to the patients, but clear benefit is lacking. Further, there is a risk, though small, of sarcomatous transformation of the giant cell tumours following radiotherapy.

Classification of tumours of spine- Enneking’s