Remarkable regression of a giant cell tumor of the cervical spine treated conservatively with denosumab

INTRODUCTION: Wide resection of giant cell tumors at the cervical spine is sometimes extremely challenging, especially in cases where tumors extend into the nearby tissues, such as vertebral arteries, the spinal cord, or spinal nerve roots. Denosumab, a human monoclonal antibody that binds the receptor activator of nuclear factor κ-β ligand, is reported to be effective for decreasing resorption of giant cell tumor of the bone, but the detailed progress of giant cell tumors in the cervical spine extending into the nearby tissues after such treatment has not been reported. PRESENTATION OF CASE: A 41-year-old man presented with neck pain. Computed tomography-guided needle biopsy showed numerous giant cells with a large vesicular nucleus, consistent with a giant cell tumor. Because of the extension of the tumor with involvement of the vertebral artery and surrounding tissues, denosumab (120mg) was administered subcutaneously once per month for 24 months. Six months after denosumab treatment, follow-up computed tomography revealed a dramatic regression and osteosclerosis of the tumor. Two years after starting denosumab treatment, positron emission tomography showed no tumor recurrence. DISCUSSION: Although the tumor was extended with involvement of the surrounding tissues and surgery following denosumab treatment was not performed, at 24 months since initiation of denosumab treatment we confirmed complete regression radiographically. CONCLUSIONS: Denosumab may be used as an adjuvant by which to avoid or reduce the risks and morbidity of surgical treatment in patients with spinal giant cell tumors extending into nearby tissues.