Mitoxantrone as a contributing factor in medication-related osteonecrosis of the jaws

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is usually initiated by dental surgery, but is occasionally exacerbated by other antiresorptive (denosumab) and anti-angiogenic therapies, and in such cases is currently termed medication-related osteonecrosis of the jaws (MRONJ). The case of a 58-year-old female with breast cancer who developed multiple and ultimately fatal metastases despite 3 years of treatment with chemotherapeutic drugs and intravenous bisphosphonates, is presented herein. Her malignant disease worsened and she was started on mitoxantrone. She developed a severe adverse reaction to this drug soon after starting treatment. As well as diarrhoea and vomiting, she had a very aggressive gingival inflammation with multiple ulcerations in both jaws and wide areas of necrotic bone, affecting the attached gingiva, and seemingly unrelated to dental plaque. These ulcerations and the exposed necrotic bone persisted for more that 6 months, until her death. This report describes a case in which severe gingival ulcerations that occurred after mitoxantrone treatment for metastatic breast cancer were a local factor that initiated MRONJ.