Atypical femoral fracture in a multiple myeloma patient undergoing treatment with denosumab: A case report and literature review.

Abstract

Denosumab is a new standard treatment for bone disease caused by multiple myeloma. There are a few reports of atypical femoral fracture in patients with multiple myeloma, all of which were associated with long-term use of bisphosphonate. Here, we report the first case of denosumab-induced atypical femoral fracture in a patient with multiple myeloma. A 71-year-old woman with multiple myeloma developed dull pain in her right thigh 8months after restarting high-dose denosumab following its initial administration for 4months and subsequent withdrawal for 2years. Fourteen months later, complete atypical femoral fracture occurred. Osteosynthesis was achieved using an intramedullary nail and she was switched to oral bisphosphonate 7months after cessation of denosumab. There was no exacerbation of the multiple myeloma. Bone union was achieved and she recovered to her pre-injury level of activities. The oncological outcome was alive with disease at 2years after surgery. Prodromal symptoms such as thigh pain and radiographical finding of thickening of the lateral cortex in the subtrochanteric region of the femur were attributed to denosumab-induced atypical femoral fracture in the case. A unique aspect of this case worth highlighting is that the fracture occurred after short-term denosumab use. This may be associated with multiple myeloma or other medication including dexamethasone and cyclophosphamide. Atypical femoral fracture may occur in patients with multiple myeloma who receive denosumab, even for a short period. Attending physicians should be cognizant of the early symptoms and signs of this fracture.