What happened, in summary

This 51-year-old woman had a history of breast adenocarcinoma treated with surgery in 2014 and had reportedly been cancer-free afterward. She had taken tamoxifen until June 2022. Several years after her breast cancer treatment, she developed severe upper back pain that lasted for 3 months. The pain was localized to the dorsolumbar area, was worse in the morning, and improved somewhat with medication and walking. She had no trauma history, no major neurologic findings, and no bowel or bladder symptoms. Laboratory testing did not show major abnormalities, including a negative M band, and she was taking only daily thyroxine supplementation at presentation. MRI showed a focal lytic lesion in the T9 vertebral body with heterogeneous enhancement, raising concern for a metastatic deposit. PET-CT showed focal FDG uptake in the same vertebral body, with inflammatory, infectious, and metastatic causes all considered. CT-guided biopsy found necrotic bone with normal marrow elements, no organism growth, and negative tumor-marker staining, but the sample was still considered possibly inadequate. Because the diagnosis remained uncertain, she underwent open debridement of the T9 lesion, screw-rod fixation at D8 and D10, and graft placement. The larger surgical specimen showed necrotic bone with regenerating woven bone and fibroblastic reaction. There was no evidence of tuberculosis or metastatic cancer. The final diagnosis was osteonecrosis, not breast cancer recurrence. As of June 2025, eight months after surgery, X-ray showed no further vertebral collapse, and she had no recurrent pain episodes, supporting continued clinical remission rather than active metastatic breast cancer recurrence.