Endocrine Abstracts

Background: Aneurismal bone cysts (ABCs) are rare benign tumours of the bone that, similar to the giant cell tumours (GCTBs) of the bone, contain osteoclast-like giant cells. Standard therapeutic options include different surgical approaches and/or radiotherapy. However, in selected cases, other therapeutic options are needed. Denosumab, a human monoclonal antibody to receptor activator nuclear factor kappa B ligand (RANKL) has been approved for the treatment of giant cells tumours of the bone. Similar pathophysiology between ABCs and GCTBs suggests its potential beneficial use in complex ABC cases.Case reportWe report a case of sacral aneurismal bone cyst in an 18-year-old female patient. Considering the localization of the lesion and the ensuing risk of surgery and radiotherapy, our patient was treated with denosumab 120 mg subcutaneously monthly for 12 months. After the initiation of the treatment the patient’s pain resolved completely. New bone formation was evident on magnetic resonance imaging scans at 6 months and continued to show evidence of improvement at 11 months after initiation of treatment. Adverse events following denosumab were not reported.

Conclusion: Treatment with denosumab resulted in symptomatic and radiological improvement in our patient and could be beneficial in selected ABC cases.

Key words: aneurismal bone cyst, denosumab, sacral lesion