Atypical femoral fracture with early PET/CT changes from denosumab for metastatic breast cancer and transition from denosumab to zoledronic acid.

Atypical femoral fractures (AFFs) are potential complications arising from long-term use of bone modifying agents such as denosumab. We describe a case of bilateral AFFs that was treated surgically in a middle-aged woman receiving oncologic doses of denosumab for treatment of metastatic breast cancer for seven years. In retrospect, early cortical change was present on scout computer tomography (CT) and positron emission tomography-computer tomography (PET-CT) prior to her left AFF. This case highlights the potential for earlier opportunistic AFF radiologic screening during cancer surveillance. It also describes our experience with preserving spinal bone density following the cessation of oncologic doses of denosumab through sequential zoledronic acid therapy.