Endocrine Abstracts

Bisphosphonates (BPs) are prescribed to prevent vertebral and hip fractures in osteoporosis and malignancy-related bone loss. However, prolonged therapy has been linked to atypical femoral fractures (AFF). We present the case of a 68-year-old woman with osteoporosis diagnosed in 2022 (T-scores: left femoral neck –2.7, left total hip –2.4). Her medical history included moderately differentiated invasive endometrioid adenocarcinoma, treated in 2021 with total hysterectomy, bilateral salpingo-oophorectomy, paclitaxel–carboplatin chemotherapy, and brachytherapy. One month later, she was diagnosed with right breast invasive ductal carcinoma (node-negative, ER-positive, HER2-negative) subsequent to a wide local excision with sentinel lymph node biopsy, and received radiotherapy, and two years of anastrozole. She had been on monthly ibandronate for approximately three years. In July 2025, she presented to our Emergency Department with bilateral thigh pain, more severe on the left. During admission, she developed sudden onset, severe left thigh pain without trauma. Radiographs revealed a displaced transverse midshaft femoral fracture, necessitating urgent internal fixation. The following day, she experienced worsening right thigh pain, and imaging demonstrated an incomplete transverse fracture of the right proximal femur, which was managed with prophylactic intramedullary nailing. This case fulfils the American Society for Bone and Mineral Research criteria for AFF, characterised by minimal trauma, transverse fracture pattern, and bilateral occurrence. In cancer survivors undergoing hormonal therapy, oestrogen deprivation further amplifies bone fragility. Therefore, in this cohort, periodic monitoring, carefully tailored BP therapy duration, consideration of drug holidays, heightened vigilance for AFF, and early contralateral femur imaging should be implemented.