Severe rebound hypercalcemia following denosumab treatment in a paediatric patient with cervical aneurysmal bone cyst: a case report

Aneurysmal bone cysts (ABCs) are aggressive bone tumours often treated with denosumab, notably when surgical options are minimal. This case report describes an 8-year-old boy who developed severe hypercalcemia following denosumab treatment for a cervical ABC. Initially managed with surgery and chemotherapy, the patient experienced a significant rebound in calcium levels three months after denosumab cessation, leading to symptoms requiring intensive care. Management included intravenous fluids, calcitonin, and zoledronate, resulting in normalization of calcium levels and symptom resolution. This case highlights the need for vigilant monitoring of electrolyte levels and consideration of alternative therapies to prevent rebound hypercalcemia in paediatric patients.