Role of Denosumab in the Treatment of Osteoblastoma - A Case Report

Introduction: Osteoblastoma is an uncommon osteoid tissue forming the primary neoplasm of the bone. Osteoblastoma arises from osteoblasts. Vertebral column or long bones are usual sites of presentation, approx. 40% of all osteoblastoma is located in the spine, and 17% of spinal osteoblastoma is found in the sacrum. Osteoblastoma of long bones are often diaphyseal; fewer are located in the metaphysis. Denosumab inhibits the maturation of osteoclasts by binding to and inhibiting rank ligand. This protects the bone from degradation and helps to counter the progression of osteoblastoma. Methodology: Two patients with osteoblastoma presented to a tertiary Hospital in the year 2018. Both were treated with 120 mg of denosumab subcutaneously on day 0,8,15 and 28, after that monthly. Results: Denosumab therapy caused regression of the tumor and converted the diffuse infiltrative mass into a well-defined solid (osteoma like) structure. Conclusion: A short course of denosumab caused tumor regression, ossification, and conversion of an aggressive osteoblastoma into a sclerotic, well-defined lesion and thus aiding surgical resection and preservation of neural structures. Neoadjuvant therapy reduced osteoclast numbers, and this helps to counter the progression of the disease.