A novel case of bisphosphonate-related osteonecrosis of the torus palatinus in a patient with metastatic breast cancer

Bisphosphonates administered orally and intravenously are used for a variety of endocrine and oncologic indications. Long-term intravenous use of bisphosphonates has been shown to cause osteonecrosis of the jaw. We report a case in which a 58-year-old woman with metastatic breast cancer received 18 doses of 4 mg intravenous zoledronic acid over a period of 16 months and developed a region of osteonecrosis on the posterior edge of a large, lobular torus palatinus. Torus palatinus, a type of maxillary exostosis, is common among postmenopausal women, and is vulnerable to blunt trauma that could predispose to osteonecrosis. Sequestrum of dead bone was removed and the site healed within 4 weeks. This case demonstrates that patients with a torus palatinus may be at high risk for osteonecrosis, and reinforces the need for good oral hygiene and frequent dental examination while receiving bisphosphonate therapy.