Bilateral L3-L4 pedicular insufficiency fractures in a patient with breast cancer and treated spinal metastasis: A diagnostic pitfall.

Spinal lesions in patients with breast cancer are often presumed metastatic; however, benign insufficiency fractures can closely mimic metastatic disease, creating a diagnostic challenge. We report the case of a 52-year-old female with estrogen receptor-positive, progesterone receptor-positive, and HER2-negative (ER/PR+, HER2-) metastatic breast cancer to the liver who presented with severe back pain and peripheral numbness. Imaging revealed bilateral pedicular insufficiency fractures at the level of L3 and L4 vertebral bodies. The pedicular fractures demonstrated imaging features favoring insufficiency etiology, likely therapy- or osteopenia-related, with metastatic involvement considered unlikely. This case emphasizes how important it is to take nonmetastatic etiologies into account when assessing new spinal lesions in patients with cancer. Accurate differentiation between metastatic and nonmetastatic fractures using detailed imaging assessment is crucial to prevent unnecessary changes in cancer management.